View source for Medicine:Brachytherapy

{{Short description|Type of radiation therapy}}
{{EngvarB|date = February 2019}}
{{Infobox medical intervention 
|  Name        = Brachytherapy  
|  Image       = Brachytherapybeads.png 
|  Caption     = Arrow points to brachytherapy beads used to treat prostate cancer.
|  synonyms      = internal radiotherapy, sealed source radiotherapy, curietherapy, endocurietherapy 
|  ICD10       = {{ICD10PCS|D|D}}?1  
|  ICD9        = {{ICD9proc|92.27}}  
|  MeshID      = D001918  
|  OPS301      =  
|  OtherCodes  =  
}}

'''Brachytherapy''' is a form of [[Physics:Radiation therapy|radiation therapy]] where a sealed [[Physics:Radiation|radiation source]] is placed inside or next to the area requiring treatment. ''Brachy'' is [[Social:Greek language|Greek]] for short.  Brachytherapy is commonly used as an effective treatment for [[Medicine:Cervical cancer|cervical]], [[Medicine:Prostate cancer|prostate]], [[Medicine:Breast cancer|breast]], [[Medicine:Esophageal cancer|esophageal]] and [[Medicine:Skin cancer|skin cancer]] and can also be used to treat tumours in many other body sites.<ref name="GEC-ESTRO">{{Cite book | editor1-last = Gerbaulet | editor1-first = Alain | editor2-last = Pötter | editor2-first = Richard | editor3-last = Mazeron | editor3-first = Jean-Jacques | editor4-last = Meertens | editor4-first = Harm | editor5-last = Limbergen | editor5-first = Erik Van | year = 2002 | title = The GEC ESTRO handbook of brachytherapy | publisher = European Society for Therapeutic Radiology and Oncology | location = Leuven, Belgium | oclc=52988578}}</ref> Treatment results have demonstrated that the cancer-cure rates of brachytherapy are either comparable to surgery and [[Medicine:External beam radiotherapy|external beam radiotherapy]] (EBRT) or are improved when used in combination with these techniques.<ref name="Viswanathan 2007">{{Cite book | last = Viswanathan AN | editor = Devlin P | year = 2007 | title = Brachytherapy: Applications and Techniques | chapter = Gynecologic brachytherapy | publisher = LWW | location = Philadelphia | display-authors = etal }}</ref><ref name="Kishan-2018">{{Cite journal | first1 = Amar |last1=Kishan | first2 = Ryan |last2=Cook| first3 = Jay | last3=Ciezki|display-authors=et al|title = Radical Prostatectomy, External Beam Radiotherapy, or External Beam Radiotherapy With Brachytherapy Boost and Disease Progression and Mortality in Patients with Gleason Score 9-10 Prostate Cancer| journal = JAMA| volume = 319 |issue=9 | pages = 896–905| year = 2018 | doi = 10.1001/jama.2018.0587|pmid=29509865 |pmc=5885899 }}</ref><ref name="Pieters -2009">{{Cite journal| first1 = B. R. | first2 = D. Z.| first3 = C. C. E.| last1 = Pieters| first4 = A. H.| title = Comparison of three radiotherapy modalities on biochemical control and overall survival for the treatment of prostate cancer: A systematic review| journal = Radiotherapy and Oncology| volume = 93| pages = 168–173| year = 2009 | doi = 10.1016/j.radonc.2009.08.033| pmid =  19748692| last2 =  De Back| last3 =  Koning| last4 =  Zwinderman| issue =  2}}</ref> Brachytherapy can be used alone or in combination with other therapies such as surgery, EBRT and [[Medicine:Chemotherapy|chemotherapy]].

Brachytherapy contrasts with [[Medicine:Unsealed source radiotherapy|unsealed source radiotherapy]], in which a therapeutic [[Physics:Radionuclide|radionuclide]] (radioisotope) is injected into the body to chemically localize to the tissue requiring destruction. It also contrasts to External Beam Radiation Therapy (EBRT), in which high-energy x-rays (or occasionally gamma-rays from a radioisotope like [[Physics:Cobalt-60|cobalt-60]]) are directed at the tumour from outside the body. Brachytherapy instead involves the precise placement of short-range radiation-sources (radioisotopes, [[Physics:Iodine-125|iodine-125]] or [[Physics:Caesium-131|caesium-131]] for instance) directly at the site of the cancerous tumour. These are enclosed in a protective capsule or wire, which allows the ionizing radiation to escape to treat and kill surrounding tissue but prevents the charge of radioisotope from moving or dissolving in body fluids. The capsule may be removed later, or (with some radioisotopes) it may be allowed to remain in place.<ref name="GEC-ESTRO" />{{rp|Ch. 1}}<ref name="Stewart 2007">{{Cite book | last = Stewart AJ | editor = Devlin P | year = 2007 | title = Brachytherapy. Applications and Techniques | chapter = Radiobiological concepts for brachytherapy | publisher = LWW | location = Philadelphia | display-authors = etal }}</ref>

A feature of brachytherapy is that the irradiation affects only a very localized area around the radiation sources. Exposure to radiation of healthy tissues farther away from the sources is therefore reduced. In addition, if the patient moves or if there is any movement of the tumour within the body during treatment, the radiation sources retain their correct position in relation to the tumour. These characteristics of brachytherapy provide advantages over EBRT – the tumour can be treated with very high doses of localised radiation whilst reducing the probability of unnecessary damage to surrounding healthy tissues.<ref name="GEC-ESTRO" />{{rp|Ch. 1}}<ref name="Stewart 2007" />

A course of brachytherapy can be completed in less time than other radiotherapy techniques. This can help reduce the chance for surviving cancer-cells to divide and grow in the intervals between each radiotherapy dose.<ref name="Stewart 2007" /> Patients typically have to make fewer visits to the radiotherapy clinic compared with EBRT, and may receive the treatment as outpatients. This makes treatment accessible and convenient for many patients.<ref name="BMJGroup-2009" /><ref name="Kelley 2007">{{Cite book | last = Kelley JR | editor = Devlin P | year = 2007 | title = Brachytherapy. Applications and Techniques | chapter = Breast brachytherapy | publisher = LWW | location = Philadelphia | display-authors = etal }}</ref> These features of brachytherapy mean that most patients are able to tolerate the brachytherapy procedure very well.

The global market for brachytherapy reached US$680 million in 2013, of which the high-dose rate (HDR) and LDR segments accounted for 70%. Microspheres and electronic brachytherapy comprised the remaining 30%.<ref>{{cite web| url= http://www.prlog.org/12390829-brachytherapy-market-recovery-to-reach-us-2-4-billion.html| title= Brachytherapy Market Recovery to Reach US$ 2.4 Billion|last= CSIntell | quote = The global market for brachytherapy reached US$ 680 million in 2013, of which the High-Dose Rate (HDR) and LDR segments accounted for 70%. Microspheres and electronic brachytherapy commanded the remaining 30%.}}</ref> One analysis predicts that the brachytherapy market may reach over US$2.4 billion in 2030, growing by 8% annually, mainly driven by the microspheres market as well as electronic brachytherapy, which is gaining significant interest worldwide as a user-friendly technology.<ref>{{cite web| url= http://www.prlog.org/12390829-brachytherapy-market-recovery-to-reach-us-2-4-billion.html| title= Brachytherapy Market Recovery to Reach US$ 2.4 Billion|last= CSIntell | quote = The brachytherapy market is expected to reach over US$ 2.4 billion in 2030, growing by 8% annually, mainly driven by the microspheres market as well as electronic brachytherapy, which is gaining significant interest worldwide as a user-friendly technology.}}</ref>

==Medical uses==
[[File:Clinical applications of brachytherapy.jpg|thumb|upright=1.5|Body sites in which brachytherapy can be used to treat cancer]]
Brachytherapy is commonly used to treat cancers of the [[Medicine:Cervix|cervix]], [[Biology:Prostate|prostate]], breast, and [[Biology:Skin|skin]].<ref name="GEC-ESTRO" />

Brachytherapy can also be used in the treatment of tumours of the [[Biology:Human brain|brain]], [[Biology:Human eye|eye]], head and neck region (lip, floor of mouth, tongue, nasopharynx and oropharynx),<ref name="Mazaron-2009" /> respiratory tract (trachea and bronchi), digestive tract (oesophagus, gall bladder, [[Biology:Bile duct|bile-ducts]], [[Biology:Rectum|rectum]], [[Biology:Anus|anus]]),<ref name="Dvorák-2002">{{Cite journal| pmid = 12143240| year = 2002| author1 = Dvorák | first2 = P. | first3 = B. | first4 = B. | first5 = J. | first6 = Z. | first7 = Z. | first8 = J.| title = Intraluminal high dose rate brachytherapy in the treatment of bile duct and gallbladder carcinomas| volume = 49| issue = 46| pages = 916–917| journal = Hepato-gastroenterology| last2 = Jandík| last3 = Melichar| last4 = Jon| last5 = Mergancová| last6 = Zoul| last7 = Vacek| last8 = Petera}}</ref> urinary tract ([[Biology:Bladder|bladder]], urethra, penis), female reproductive tract ([[Biology:Uterus|uterus]], [[Biology:Vagina|vagina]], [[Medicine:Vulva|vulva]]), and soft tissues.<ref name="GEC-ESTRO" />

As the radiation sources can be precisely positioned at the tumour treatment site, brachytherapy enables a high dose of radiation to be applied to a small area. Furthermore, because the radiation sources are placed in or next to the target tumour, the sources maintain their position in relation to the tumour when the patient moves or if there is any movement of the tumour within the body. Therefore, the radiation sources remain accurately targeted. This enables clinicians to achieve a high level of dose conformity – i.e. ensuring the whole of the tumour receives an optimal level of radiation. It also reduces the risk of damage to healthy tissue, organs or structures around the tumour,<ref name="Nag-2004" /> thus enhancing the chance of cure and preservation of organ function.

The use of HDR brachytherapy enables overall treatment times to be reduced compared with EBRT.<ref name="Joseph-2008">
{{Cite journal| first1 = K. J.| last1 = Joseph | first2 = R.| first3 = D.| first4 = J.| first5 = N.| first6 = C.| last2 = Alvi| last6 = Small| last3 = Skarsgard| last5 = Pervez| last4 = Tonita| last7 = Tai | first7 = P.| title = Analysis of health related quality of life (HRQoL) of patients with clinically localized prostate cancer, one year after treatment with external beam radiotherapy (EBRT) alone versus EBRT and high dose rate brachytherapy (HDRBT)| journal = Radiation Oncology| volume = 3| pages = 20| year = 2008 | doi = 10.1186/1748-717X-3-20| pmid =  18627617| pmc =  2494997 | doi-access = free }}</ref><ref name="Holmboe-2000">
{{Cite journal | pmid = 11089712 | year = 2000 | author1 = Holmboe | first2 = J. | title = Treatment decisions for localized prostate cancer: asking men what's important | volume = 15 | issue = 10 | pages = 694–701 | pmc = 1495597 | journal = Journal of General Internal Medicine | doi = 10.1046/j.1525-1497.2000.90842.x | last2 = Concato}}</ref>
Patients receiving brachytherapy generally have to make fewer visits for radiotherapy compared with EBRT, and overall radiotherapy treatment plans can be completed in less time.<ref name="Hoskin 2005 book">
{{Cite book |veditors=Hoskin P, Coyle C | year = 2005 | title = Radiotherapy in practice: brachytherapy | publisher = Oxford University Press | location = New York | isbn =978-0-19-852940-8}}</ref>
Many brachytherapy procedures are performed on an outpatient basis. This convenience may be particularly relevant for patients who have to work, older patients, or patients who live some distance from treatment centres, to ensure that they have access to radiotherapy treatment and adhere to treatment plans. Shorter treatment times and outpatient procedures can also help improve the efficiency of radiotherapy clinics.<ref name="Guedea-2008">
{{Cite journal| first1 = F.| last1 = Guedea | first2 = M.| first3 = J.| first4 = J.| first5 = P.| first6 = J.| title = Patterns of Care for Brachytherapy in Europe: Facilities and resources in brachytherapy in the European area| journal = Brachytherapy| volume = 7| pages = 223–230| year = 2008 | doi = 10.1016/j.brachy.2008.03.001| pmid =  18579448| last2 =  Ventura| last3 =  Mazeron| last4 =  Torrecilla| last5 =  Bilbao| last6 =  Borràs| issue =  3}}</ref><ref name="Quang-2007">
{{Cite journal | author = Quang TS | year = 2007 | title = Technological evolution in the treatment of prostate cancer | journal = Oncology | volume = 21 | url = http://www.cancernetwork.com/display/article/10165/62318  | display-authors = etal  }}</ref>

Brachytherapy can be used with the aim of curing the cancer in cases of small or locally advanced tumours, provided the cancer has not metastasized (spread to other parts of the body). In appropriately selected cases, brachytherapy for primary tumours often represents a comparable approach to surgery, achieving the same probability of cure and with similar side effects.<ref name="Guedea-2009">
{{Cite journal | doi = 10.1007/s12094-009-0387-x | last1 = Guedea | first1 = F. | last2 = Ferrer | first2 = M. | last3 = Pera | first3 = J. | last4 = Aguiló | first4 = F. | last5 = Boladeras | first5 = A. | last6 = Suárez | first6 = J. F. | last7 = Cunillera | first7 = O. | last8 = Ferrer | first8 = F. | last9 = Pardo | first9 = Y. | last10 = Martínez | first10 = E. | last11 = Ventura | first11 = M. | title = Quality of life two years after radical prostatectomy, prostate brachytherapy or external beam radiotherapy for clinically localised prostate cancer: The Catalan Institute of Oncology/Bellvitge Hospital experience | journal = Clinical & Translational Oncology | volume = 11 | issue = 7 | pages = 470–478 | year = 2009 | pmid = 19574206| s2cid = 22946298 }}</ref><ref name="Litwin-2007">
{{Cite journal| first1 = M. S.| last1 = Litwin | first2 = J. L.| first3 = L.| first4 = J. M.| first5 = S. P.| first6 = H. R.| first7 = R. E.| title = Quality of life after surgery, external beam irradiation, or brachytherapy for early-stage prostate cancer| journal = Cancer| volume = 109| pages = 2239–2247| year = 2007 | doi = 10.1002/cncr.22676| pmid =  17455209| last2 =  Gore| last3 =  Kwan| last4 =  Brandeis| last5 =  Lee| last6 =  Withers| last7 =  Reiter| issue =  11| doi-access = | s2cid = 25926233 }}</ref>
However, in locally advanced tumours, surgery may not routinely provide the best chance of cure and is often not technically feasible to perform. In these cases radiotherapy, including brachytherapy, offers the only chance of cure.<ref name="Pistis -2009">
{{Cite journal| first1 = F.| first2 = F.| first3 = J.| last1 = Pistis| first4 = C.| first5 = M.| first6 = A.| first7 = E.| first8 = A.| first9 = F.| last10 = Gabriele | first10 = P.| last11 = Linares | first11 = L.| title = External beam radiotherapy plus high-dose-rate brachytherapy for treatment of locally advanced prostate cancer: the initial experience of the Catalan Institute of Oncology| journal = Brachytherapy| year = 2009 | doi = 10.1016/j.brachy.2009.05.001| last2 =   Guedea| last3 =   Pera| last4 =   Gutierrez| last5 =   Ventura| last6 =   Polo| last7 =   Martinez| last8 =   Boladeras| last9 =   Ferrer| volume =   9| pages =   15–22| pmid = 19734106| issue = 1}}</ref><ref name="Lertsanguansinchai-2004">
{{Cite journal| first1 = P.| last1 = Lertsanguansinchai | first2 = C.| first3 = K.| first4 = C.| first5 = P.| first6 = T.| first7 = A.| first8 = S.| first9 = C.| last10 = Tresukosol | first10 = D.| last11 = Charoonsantikul | first11 = C.| title = Phase III randomized trial comparing LDR and HDR brachytherapy in treatment of cervical carcinoma| journal = International Journal of Radiation Oncology, Biology, Physics| volume = 59| issue = 5| pages = 1424–1431| year = 2004| pmid = 15275728 | doi = 10.1016/j.ijrobp.2004.01.034| last2 =  Lertbutsayanukul| last3 =  Shotelersuk| last4 =  Khorprasert| last5 =  Rojpornpradit| last6 =  Chottetanaprasith| last7 =  Srisuthep| last8 =  Suriyapee| last9 =  Jumpangern}}</ref>
In more advanced disease stages, brachytherapy can be used as palliative treatment for symptom relief from pain and bleeding.

In cases where the tumour is not easily accessible or is too large to ensure an optimal distribution of irradiation to the treatment area, brachytherapy can be combined with other treatments, such as EBRT and/or surgery.<ref name="GEC-ESTRO" />{{rp|Ch. 1}} Combination therapy of brachytherapy exclusively with chemotherapy is rare.<ref name="Roddiger-2006">
{{Cite journal | author = Roddiger SJ | year = 2006 | title = Neoadjuvant interstitial high-dose-rate (HDR) brachytherapy combined with systemic chemotherapy in patients with breast cancer | journal = Strahlenther Onkol | volume = 182 | issue = 1 | pages = 22–9 | pmid =16404517 | doi = 10.1007/s00066-006-1454-7  | s2cid = 23210347 | url = https://boris.unibe.ch/20639/ | display-authors = etal  }}</ref>

===Cervical cancer===
Brachytherapy is commonly used in the treatment of early or locally confined [[Medicine:Cervical cancer|cervical cancer]] and is a standard of care in many countries.<ref name="GEC-ESTRO" />{{rp|Ch. 14}}<ref name="Gaffney-2007">
{{Cite journal| first1 = D.| last1 = Gaffney | first2 = A.| first3 = K.| first4 = N.| first5 = T.| first6 = S.| first7 = P.| first8 = L.| first9 = A.| last10 = Pötter | first10 = R.| last11 = Colombo | first11 = A.| last12 = Randall | first12 = M.| last13 = Mirza | first13 = M. R.| last14 = Trimble | first14 = E. L.| title = Practice Patterns of Radiotherapy in Cervical Cancer Among Member Groups of the Gynecologic Cancer Intergroup (GCIG)| journal = International Journal of Radiation Oncology, Biology, Physics| volume = 68| issue = 2| pages = 485–490| year = 2007| pmid = 17336465 | doi = 10.1016/j.ijrobp.2006.12.013| last2 =  Du Bois| last3 =  Narayan| last4 =  Reed| last5 =  Toita| last6 =  Pignata| last7 =  Blake| last8 =  Portelance| last9 =  Sadoyze}}</ref><ref name="NICE-IPG160">
{{cite web | url = http://www.nice.org.uk/IPG160 | title = High dose rate brachytherapy for carcinoma of the cervix | access-date = 25 September 2009 | author = National Institute for Health and Clinical Excellence |date= March 2006 |publisher = NICE }}</ref><ref name="Viswanathan-ABS">
{{cite web | url = http://www.americanbrachytherapy.org/guidelines/cervical_cancer_taskgroup.pdf | title = American Brachytherapy Society cervical cancer brachytherapy task group | access-date = 25 September 2009 | author = Viswanathan AN |publisher = American Brachytherapy Society |display-authors=0}}</ref><ref name="Viswanathan-2009">
{{Cite journal| first1 = A. N.| last1 = Viswanathan | first2 = B. A.| title = Three-Dimensional Imaging in Gynecologic Brachytherapy: A Survey of the American Brachytherapy Society| journal = International Journal of Radiation Oncology, Biology, Physics| year = 2009| pmid = 19619956 | doi = 10.1016/j.ijrobp.2009.01.043| last2 =  Erickson| volume = 76| issue = 1| pages = 104–109}}</ref>
Cervical cancer can be treated with either LDR, PDR or HDR brachytherapy.<ref name="Viswanathan-ABS" /><ref name="Haie-Meder-2009">
{{Cite journal| first1 = C.| last1 = Haie-meder | first2 = C.| first3 = A.| first4 = I.| first5 = P.| first6 = N.| title = DVH parameters and outcome for patients with early-stage cervical cancer treated with preoperative MRI-based low dose rate brachytherapy followed by surgery| journal = Radiotherapy and Oncology| volume = 93| pages = 316–321| year = 2009 | doi = 10.1016/j.radonc.2009.05.004| pmid =  19586673| last2 =  Chargari| last3 =  Rey| last4 =  Dumas| last5 =  Morice| last6 =  Magné| issue =  2}}</ref><ref name="Kim-2009">
{{Cite journal| first1 = D. H.| last1 = Kim | first2 = A. .| first3 = V. .| first4 = J. .| first5 = L. M.| first6 = J. .| first7 = R. .| first8 = I. C.| title = High–Dose Rate Brachytherapy Using Inverse Planning Simulated Annealing for Locoregionally Advanced Cervical Cancer: A Clinical Report with 2-Year Follow-Up| journal = International Journal of Radiation Oncology, Biology, Physics| year = 2009| pmid = 19409728 | doi = 10.1016/j.ijrobp.2009.01.002| last2 =  Wang-Chesebro| last3 =  Weinberg| last4 =  Pouliot| last5 =  Chen| last6 =  Speight| last7 =  Littell| last8 =  Hsu| volume =  75| issue = 5| pages =  1329–1334}}</ref>
Used in combination with EBRT, brachytherapy can provide better outcomes than EBRT alone.<ref name="Viswanathan 2007"/>
The precision of brachytherapy enables a high dose of targeted radiation to be delivered to the cervix, while minimising radiation exposure to adjacent tissues and organs.<ref name="NICE-IPG160" /><ref name="Viswanathan-ABS" /><ref name="Pötter-2008">
{{Cite journal| first1 = R.| last1 = Potter | first2 = C.| first3 = E.| first4 = J.| first5 = D.| first6 = K.| first7 = J.| title = Present status and future of high-precision image guided adaptive brachytherapy for cervix carcinoma| journal = Acta Oncologica| volume = 47| pages = 1325–1336| year = 2008 | doi = 10.1080/02841860802282794| pmid =  18661430| last2 =  Kirisits| last3 =  Fidarova| last4 =  Dimopoulos| last5 =  Berger| last6 =  Tanderup| last7 =  Lindegaard| issue =  7| doi-access = free}}</ref><ref name="Pötter-2006">
{{Cite journal| first1 = R.| last1 = Pötter | first2 = C.| first3 = E. V.| first4 = I.| first5 = M. D.| first6 = J.| first7 = I.| first8 = B.| first9 = S.| last10 = Nulens | first10 = A.| last11 = Petrow | first11 = P.| last12 = Rownd | first12 = J.| last13 = Kirisits | first13 = C.| last14 = Gec Estro Working | first14 = G.| title = Recommendations from gynaecological (GYN) GEC ESTRO working group (II): Concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy—3D dose volume parameters and aspects of 3D image-based anatomy, radiation physics, radiobiology| journal = Radiotherapy and Oncology| volume = 78| pages = 67–77| year = 2006 | doi = 10.1016/j.radonc.2005.11.014| pmid =  16403584| last2 =  Haie-Meder| last3 =  Van Limbergen| last4 =  Barillot| last5 =  De Brabandere| last6 =  Dimopoulos| last7 =  Dumas| last8 =  Erickson| last9 =  Lang| issue =  1}}</ref>

The chances of staying free of disease (disease-free survival) and of staying alive (overall survival) are similar for LDR, PDR and HDR treatments.<ref name="Lertsanguansinchai-2004" /><ref name="Hareyama-2002">
{{Cite journal | doi = 10.1002/cncr.10207 | title = High-dose-rate versus low-dose-rate intracavitary therapy for carcinoma of the uterine cervix | pmid = 11815967 | year = 2002 | last1 = Hareyama | first1 = M. | last2 = Sakata | first2 = K. I. | last3 = Oouchi | first3 = A. | last4 = Nagakura | first4 = H. | last5 = Shido | first5 = M. | last6 = Someya | first6 = M. | last7 = Koito | first7 = K. | journal = Cancer | volume = 94 | issue = 1 | pages = 117–124| doi-access = free }}</ref>
However, a key advantage of HDR treatment is that each dose can be delivered on an outpatient basis with a short administration time<ref name="Viswanathan 2007" /> providing greater convenience for many patients.

Research shows locally advanced carcinoma of the cervix must be treated with a combination of external beam radiotherapy (EBRT) and intracavity brachytherapy (ICBT).<ref>{{Cite journal|last1=Liu|first1=Ruifeng|last2=Wang|first2=XiaoHu|last3=Tian|first3=Jin Hui|last4=Yang|first4=KeHu|last5=Wang|first5=Jun|last6=Jiang|first6=Lei|last7=Hao|first7=Xiang Yong|date=2014-10-09|title=High dose rate versus low dose rate intracavity brachytherapy for locally advanced uterine cervix cancer|journal=Cochrane Database of Systematic Reviews|volume=2022|issue=10|pages=CD007563|doi=10.1002/14651858.cd007563.pub3|pmid=25300170|pmc=8734152|issn=1465-1858}}</ref>

===Prostate cancer===
{{cite web | url = http://www.americanbrachytherapy.org/guidelines/prostate_low-doseratetaskgroup.pdf | title = American Brachytherapy Society prostate low-dose rate task group | access-date = 25 September 2009 | author = Merrick GS |publisher = American Brachytherapy Society |display-authors=0}}</ref><ref name="Hsu-ABS">
{{cite web | url = http://www.americanbrachytherapy.org/guidelines/HDRTaskGroup.pdf | title = American Brachytherapy Society prostate high-dose rate task group | access-date = 25 September 2009 | author = Hsu I-C |publisher = American Brachytherapy Society |display-authors=0}}</ref>

Permanent seed implantation is suitable for patients with a localised tumour and good prognosis<ref name="Merrick-ABS" /><ref name="Batterman-2004">
{{Cite journal| first1 = J.| title = Results of permanent prostate brachytherapy, 13 years of experience at a single institution| last1 = Battermann| journal = Radiotherapy and Oncology| volume = 71| pages = 23–28| year = 2004 | doi = 10.1016/j.radonc.2004.01.020| pmid =  15066292| last2 =  Boon | first2 =  T.| last3 =  Moerland | first3 =  M.| issue =  1  }}</ref><ref name="Ash 2005">
{{Cite book | last = Ash D |veditors=Hoskin P, Coyle C | year = 2005 | title = Radiotherpay in practice: brachytherapy | chapter = Prostate Cancer | publisher = Oxford University Press | location = New York | display-authors = etal }}</ref><ref name="Morris-2009">
{{Cite journal| last1 = Morris | first1 = W. J.| first2 = M.| first3 = D.| first4 = M.| first5 = I.| first6 = A.| first7 = T.| first8 = M.| first9 = W.| last10 = Wu | first10 = J.| last11 = Lapointe | first11 = V.| last12 = Berthelet | first12 = E.| last13 = Pai | first13 = H.| last14 = Harrison | first14 = R.| last15 = Kwa | first15 = W.| last16 = Bucci | first16 = J.| last17 = Racz | first17 = V.| last18 = Woods | first18 = R.| title = Evaluation of Dosimetric Parameters and Disease Response After 125Iodine Transperineal Brachytherapy for Low- and Intermediate-Risk Prostate Cancer| journal = International Journal of Radiation Oncology, Biology, Physics| volume = 73| pages = 1432–1438| year = 2009 | doi = 10.1016/j.ijrobp.2008.07.042| last2 =  Keyes| last3 =  Palma| last4 =  McKenzie| last5 =  Spadinger| last6 =  Agranovich| last7 =  Pickles| last8 =  Liu| last9 =  Kwan| pmid =  19036530| issue =  5}}</ref> and has been shown to be a highly effective treatment to prevent the cancer from returning.<ref name="Batterman-2004" /><ref name="Pickles-2009">
{{Cite journal| first1 = T.| last1 = Pickles | first2 = M.| first3 = W. J.| title = Brachytherapy or Conformal External Radiotherapy for Prostate Cancer: A Single-Institution Matched-Pair Analysis| journal = International Journal of Radiation Oncology, Biology, Physics| year = 2009| pmid = 19570619 | doi = 10.1016/j.ijrobp.2009.01.081| last2 =  Keyes| last3 =  Morris| volume = 76| issue = 1| pages = 43–49}}</ref> The survival rate is similar to that found with EBRT or surgery (radical prostatectomy), but with fewer side effects such as impotence and [[Medicine:Urinary incontinence|incontinence]].<ref name="Frank-2007">
{{Cite journal| first1 = S.| last1 = Frank | first2 = L.| first3 = J.| first4 = A.| first5 = R.| first6 = D.| title = An Assessment of Quality of Life Following Radical Prostatectomy, High Dose External Beam Radiation Therapy and Brachytherapy Iodine Implantation as Monotherapies for Localized Prostate Cancer| journal = The Journal of Urology| volume = 177| pages = 2151–2156| year = 2007 | doi = 10.1016/j.juro.2007.01.134| pmid =  17509305| last2 =  Pisters| last3 =  Davis| last4 =  Lee| last5 =  Bassett| last6 =  Kuban| issue =  6}}</ref> The procedure can be completed quickly and patients are usually able to go home on the same day of treatment and return to normal activities after one to two days.<ref name="BMJGroup-2009">
 {{cite web|url=https://www.theguardian.com/lifeandstyle/besttreatments/prostate-cancer-treatments-internal-radiotherapy-brachytherapy |title=Prostate cancer: internal radiotherapy (brachytherapy) |access-date=25 September 2009 |author=BMJ Group |date=June 2009 |publisher=Guardian.co.uk |url-status=dead |archive-url=https://web.archive.org/web/20090404040935/http://www.guardian.co.uk/lifeandstyle/besttreatments/prostate-cancer-treatments-internal-radiotherapy-brachytherapy |archive-date=April 4, 2009 }}</ref>
Permanent seed implantation is often a less invasive treatment option compared to the surgical removal of the prostate.<ref name="BMJGroup-2009" />

Temporary HDR brachytherapy is a newer approach to treating prostate cancer, but is currently less common than seed implantation. It is predominantly used to provide an extra dose in addition to EBRT (known as "boost" therapy) as it offers an alternative method to deliver a high dose of radiation therapy that conforms to the shape of the tumour within the prostate, while sparing radiation exposure to surrounding tissues.<ref name="Pieters -2009" /><ref name="Hsu-ABS" /><ref name="Ash 2005" /><ref name="Galalae-2004">
{{Cite journal| first1 = R.| last1 = Galalae | first2 = A.| first3 = T.| first4 = C.| first5 = G.| first6 = N.| first7 = S.| first8 = G.| first9 = M.| last10 = Kovács | first10 = G.| title = Long-term outcome by risk factors using conformal high-dose-rate brachytherapy (HDR-BT) boost with or without neoadjuvant androgen suppression for localized prostate cancer| journal = International Journal of Radiation Oncology, Biology, Physics| volume = 58| issue = 4| pages = 1048–1055| year = 2004| pmid = 15001244 | doi = 10.1016/j.ijrobp.2003.08.003| last2 =  Martinez| last3 =  Mate| last4 =  Mitchell| last5 =  Edmundson| last6 =  Nuernberg| last7 =  Eulau| last8 =  Gustafson| last9 =  Gribble}}</ref><ref name="Hoskin-2007">
{{Cite journal| first1 = P. J.| last1 = Hoskin | first2 = K.| first3 = P.| first4 = L.| first5 = P.| title = High dose rate brachytherapy in combination with external beam radiotherapy in the radical treatment of prostate cancer: initial results of a randomised phase three trial| journal = Radiotherapy and Oncology| volume = 84| pages = 114–120| year = 2007 | doi = 10.1016/j.radonc.2007.04.011| pmid =  17531335| last2 =  Motohashi| last3 =  Bownes| last4 =  Bryant| last5 =  Ostler| issue =  2}}</ref><ref name="Pisansky-2008">
{{Cite journal | last1 = Pisansky | first1 = T. M. | last2 = Gold | first2 = D. G. | last3 = Furutani | first3 = K. M. | last4 = MacDonald | first4 = O. K. | last5 = McLaren | first5 = R. H. | last6 = Mynderse | first6 = L. A. | last7 = Wilson | first7 = T. M. | last8 = Hebl | first8 = J. R. | last9 = Choo | first9 = R. | title = High-dose-rate brachytherapy in the curative treatment of patients with localized prostate cancer | journal = Mayo Clinic Proceedings | volume = 83 | issue = 12 | pages = 1364–1372 | year = 2008 | doi = 10.4065/83.12.1364| pmid = 19046556 | doi-access = free }}</ref>
HDR brachytherapy as a boost for prostate cancer also means that the EBRT course can be shorter than when EBRT is used alone.<ref name="Pistis -2009" /><ref name="Galalae-2004" /><ref name="Hoskin-2007" /><ref name="Pisansky-2008" />

===Breast cancer===
Radiation therapy is standard of care for women who have undergone [[Medicine:Lumpectomy|lumpectomy]] or [[Medicine:Mastectomy|mastectomy]] surgery, and is an integral component of breast-conserving therapy.<ref name="GEC-ESTRO" />{{rp|Ch. 18}}<ref name="Keisch-ABS">
{{cite web | url = http://www.americanbrachytherapy.org/guidelines/HDRTaskGroup.pdf | title = American Brachytherapy Society breast brachytherapy task group | access-date = 25 September 2009 | author = Keisch |date= February 2007 |publisher = American Brachytherapy Society |display-authors=0}}</ref>
Brachytherapy can be used after surgery, before chemotherapy or palliatively in the case of advanced disease.<ref name="Hoskin 2005">
{{Cite book | last = Hoskin P |veditors=Hoskin P, Coyle C | year = 2005 | title = Radiotherapy in practice: brachytherapy | chapter = Breast Brachytherapy | publisher = Oxford University Press | location = New York | isbn = 978-0-19-852940-8| display-authors = etal }}</ref> Brachytherapy to treat [[Medicine:Breast cancer|breast cancer]] is usually performed with HDR temporary brachytherapy. Post surgery, breast brachytherapy can be used as a "boost" following whole breast irradiation (WBI) using EBRT.<ref name="Keisch-ABS" /><ref name="Polgár-2009">
{{Cite journal| first1 = C.| last1 = Polgár | first2 = T.| title = Current status and perspectives of brachytherapy for breast cancer| journal = International Journal of Clinical Oncology| volume = 14| issue = 1| pages = 7–24| year = 2009| pmid = 19225919 | doi = 10.1007/s10147-008-0867-y| last2 =  Major| s2cid = 20971836 }}</ref>
More recently, brachytherapy alone is used to deliver APBI (accelerated partial breast irradiation), involving delivery of radiation to only the immediate region surrounding the original tumour.<ref name="Keisch-ABS" /><ref name="Polgár-2009" /><ref name="Nelson-2009">
{{Cite journal| first1 = J. C.| last1 = Nelson | first2 = P. D.| first3 = F. A.| first4 = C. A.| first5 = D.| first6 = H. C.| first7 = M. A.| first8 = V. J.| first9 = P. W.| last10 = Fine | first10 = R. E.| last11 = Keleher | first11 = A. J.| last12 = Kuerer | first12 = H. M.| title = Four-year clinical update from the American Society of Breast Surgeons MammoSite brachytherapy trial| journal = The American Journal of Surgery| volume = 198| issue = 1| pages = 83–91| year = 2009| pmid = 19268900 | doi = 10.1016/j.amjsurg.2008.09.016| last2 =  Beitsch| last3 =  Vicini| last4 =  Quiet| last5 =  Garcia| last6 =  Snider| last7 =  Gittleman| last8 =  Zannis| last9 =  Whitworth}}</ref>

The main benefit of breast brachytherapy compared to whole breast irradiation is that a high dose of radiation can be precisely applied to the tumour while sparing radiation to healthy breast tissues and underlying structures such as the ribs and lungs.<ref name="Hoskin 2005" /> APBI can typically be completed over the course of a week.<ref name="Nelson-2009" /> The option of brachytherapy may be particularly important in ensuring that working women, the elderly or women without easy access to a treatment centre, are able to benefit from breast-conserving therapy due to the short treatment course compared with WBI (which often requires more visits over the course of 1–2 months).<ref name="Kelley 2007" />

There are five methods that can be used to deliver breast brachytherapy: Interstitial breast brachytherapy, Intracavitary breast brachytherapy, Intraoperative radiation therapy, Permanent Breast Seed Implantation and non-invasive breast brachytherapy using mammography for target localization and an HDR source.

====Interstitial breast brachytherapy====
Interstitial breast brachytherapy involves the temporary placement of several flexible plastic catheters in the breast tissue. These are carefully positioned to allow optimal targeting of radiation to the treatment area while sparing the surrounding breast tissue.<ref name="Kelley 2007" /> The catheters are connected to an afterloader, which delivers the planned radiation dose to the treatment area. Interstitial breast brachytherapy can be used as "boost" after EBRT, or as APBI.<ref name="Polgár-2009" />

==== Intraoperative radiation therapy ====
Intraoperative radiation therapy (IORT) delivers radiation at the same time as the surgery to remove the tumour (lumpectomy).<ref name=":1">{{Cite book|title=Accelerated Partial Breast Irradiation|last=Vaidya|first=Jayant S.|date=2009|publisher=Springer, Berlin, Heidelberg|isbn=9783540880059|pages=327–344|doi=10.1007/978-3-540-88006-6_19|chapter=APBI with 50 kV Photons: Targeted Intraoperative Radiotherapy (TARGIT)}}</ref> An applicator is placed in the cavity left after tumour removal and a mobile electronic device generates radiation (either x-rays<ref name=":1" /> or electrons<ref>{{Cite book|title=Accelerated Partial Breast Irradiation|last1=Orecchia|first1=Roberto|last2=Ivaldi|first2=Giovanni B.|last3=Leonardi|first3=Maria C.|chapter=APBI Intraoperative Technique with Electrons |date=2009|publisher=Springer, Berlin, Heidelberg|isbn=9783540880059|pages=345–366|doi=10.1007/978-3-540-88006-6_20}}</ref>) and delivers it via the applicator. Radiation is delivered all at once and the applicator removed before closing the incision.

====Intracavitary breast brachytherapy====
Intracavitary breast brachytherapy (also known as "balloon brachytherapy") involves the placement of a single catheter into the breast cavity left after the removal of the tumour (lumpectomy).<ref name="Kelley 2007" /> The catheter can be placed at the time of the lumpectomy or postoperatively.<ref name="Kelley 2007" /> Via the catheter, a balloon is then inflated in the cavity. The catheter is then connected to an afterloader, which delivers the radiation dose through the catheter and into the balloon. Currently, intracavitary breast brachytherapy is only routinely used for APBI.<ref name="Shah-2010">{{Cite journal| last1 = Shah | first1 = A. P.| last2 = Strauss | first2 = J. B.| last3 = Kirk | first3 = M. C.| last4 = Chen | first4 = S. S.| last5 = Dickler | first5 = A.| title = A dosimetric analysis comparing electron beam with the MammoSite brachytherapy applicator for intact breast boost| journal = Physica Medica| volume = 26| issue = 2| pages = 80–87| year = 2010| pmid = 19836283| doi = 10.1016/j.ejmp.2009.08.004}}</ref>

There are also devices that combine the features of interstitial and intracavitary breast brachytherapy (e.g. SAVI). These devices use multiple catheters but are inserted through a single-entry point in the breast. Studies suggest the use of multiple catheters enables physicians to target the radiation more precisely.<ref>{{cite journal |vauthors=Scanderbeg D, Yashar C, White G, Rice R, Pawlicki T | year = 2010 | title = Evaluation of Three APBI Techniques under NSABP B-39 Guidelines | journal = Journal of Applied Clinical Medical Physics | volume = 11 | issue = 1| pages = 274–280 | doi = 10.1120/jacmp.v11i1.3021 | pmid = 20160680 | pmc = 5719777 }}</ref><ref>{{cite journal |vauthors=Yashar C, Blair S, Wallace A, Scanderbeg D | year = 2009 | title = Initial Clinical Experience with the Strut-Adjusted Volume Implant Brachytherapy Applicator for Accelerated Partial Breast Irradiation | journal = Brachytherapy | volume = 8 | issue = 4| pages = 367–372 | doi=10.1016/j.brachy.2009.03.190 | pmid=19744892}}</ref>

==== Permanent breast seed implantation ====
Permanent breast seed implantation (PBSI) implants many radioactive "seeds" (small pellets) into the breast in the area surrounding the site of the tumour, similar to permanent seed prostate brachytherapy.<ref name=":0">{{Cite book|title=Accelerated Partial Breast Irradiation|last1=Pignol|first1=Jean-Philippe|last2=Keller|first2=Brian M.|chapter=Permanent Breast Seed Implants |date=2009|publisher=Springer, Berlin, Heidelberg|isbn=9783540880059|pages=263–276|doi=10.1007/978-3-540-88006-6_15}}</ref> The seeds are implanted in a single 1–2 hour procedure and deliver radiation over the following months as the radioactive material inside them decays. Risk of radiation from the implants to others (e.g. partner/spouse) has been studied and found to be safe.<ref name=":0" />

===Brain tumors===
Surgically Targeted Radiation Therapy (STaRT), branded as GammaTile Therapy, is a type of brachytherapy implant specifically designed for use inside the brain.  GammaTile is FDA-cleared to treat newly diagnosed, operable malignant intracranial neoplasms (i.e., brain tumors) and operable recurrent intracranial neoplasms, including meningiomas, metastases, high-grade gliomas, and [[Medicine:Glioblastoma|glioblastoma]]s.<ref>{{cite web |title=GammaTile - Isoray Medical Inc. - K180515 |url=https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K180515 |website=510(k) Premarket Notification |publisher=FDA |date=23 January 2020}} [https://www.accessdata.fda.gov/cdrh_docs/pdf19/K190839.pdf Summary]</ref>

In a clinical study, GammaTile Therapy improved local tumor control compared to previous same-site treatments without an increased risk of side effects.<ref>{{Cite web|url=https://www.aans.org/Annual-Scientific-Meeting/2019/Online-Program/Eposter?eventid=48888&itemid=SSI&propid=46135|title=2019 AANS Annual Scientific Meeting in San Diego|access-date=2020-04-15|archive-date=2019-12-21|archive-url=https://web.archive.org/web/20191221173334/https://www.aans.org/Annual-Scientific-Meeting/2019/Online-Program/Eposter?eventid=48888&itemid=SSI&propid=46135|url-status=dead}}</ref><ref>{{Cite journal|url=https://www.brachyjournal.com/article/S1538-4721(19)30237-5/abstract|doi = 10.1016/j.brachy.2019.04.076|title = Surgically Targeted Radiation Therapy: Safety Profile of Collagen Tile Brachytherapy in 79 Recurrent, Previously Irradiated Intracranial Neoplasms on a Prospective Clinical Trial|year = 2019|last1 = Brachman|first1 = David|last2 = Youssef|first2 = Emad|last3 = Dardis|first3 = Christopher|last4 = Smith|first4 = Kris|last5 = Pinnaduwage|first5 = Dilini|last6 = Nakaji|first6 = Peter|journal = Brachytherapy|volume = 18|issue = 3|pages = S35–S36|s2cid = 196511749}}</ref>

=== Esophageal cancer ===
For [[Medicine:Esophageal cancer|esophageal cancer]] radiation treatment, brachytherapy is one option for effective treatment, involves definitive radiotherapy (boost)<ref>{{Cite journal|last1=Folkert|first1=Michael R.|last2=Cohen|first2=Gil'ad N.|last3=Wu|first3=Abraham J.|last4=Gerdes|first4=Hans|last5=Schattner|first5=Mark A.|last6=Markowitz|first6=Arnold J.|last7=Ludwig|first7=Emmy|last8=Ilson|first8=David H.|last9=Bains|first9=Manjit S.|date=September 2013|title=Endoluminal high-dose-rate brachytherapy for early stage and recurrent esophageal cancer in medically inoperable patients|journal=Brachytherapy|volume=12|issue=5|pages=463–470|doi=10.1016/j.brachy.2012.12.001|pmid=23434221|issn=1538-4721}}</ref><ref>{{Cite journal|last1=Hishikawa|first1=Yoshio|last2=Kurisu|first2=Kouichi|last3=Taniguchi|first3=Midori|last4=Kamikonya|first4=Norihiko|last5=Miura|first5=Takashi|date=October 1991|title=High-dose-rate intraluminal brachytherapy (HDRIBT) for esophageal cancer|journal=International Journal of Radiation Oncology, Biology, Physics|volume=21|issue=5|pages=1133–1135|doi=10.1016/0360-3016(91)90267-8|pmid=1938510}}</ref> or palliative treatments.<ref name="Fuccio 332–339">{{Cite journal|last1=Fuccio|first1=Lorenzo|last2=Mandolesi|first2=Daniele|last3=Farioli|first3=Andrea|last4=Hassan|first4=Cesare|last5=Frazzoni|first5=Leonardo|last6=Guido|first6=Alessandra|last7=de Bortoli|first7=Nicola|last8=Cilla|first8=Savino|last9=Pierantoni|first9=Chiara|date=March 2017|title=Brachytherapy for the palliation of dysphagia owing to esophageal cancer: A systematic review and meta-analysis of prospective studies|journal=Radiotherapy and Oncology|volume=122|issue=3|pages=332–339|doi=10.1016/j.radonc.2016.12.034|pmid=28104297}}</ref><ref>{{Cite journal|last1=Homs|first1=Marjolein YV|last2=Steyerberg|first2=Ewout W|last3=Eijkenboom|first3=Wilhelmina MH|last4=Tilanus|first4=Hugo W|last5=Stalpers|first5=Lukas JA|last6=Bartelsman|first6=Joep FWM|last7=van Lanschot|first7=Jan JB|last8=Wijrdeman|first8=Harm K|last9=Mulder|first9=Chris JJ|date=October 2004|title=Single-dose brachytherapy versus metal stent placement for the palliation of dysphagia from oesophageal cancer: multicentre randomised trial|journal=The Lancet|volume=364|issue=9444|pages=1497–1504|doi=10.1016/S0140-6736(04)17272-3|pmid=15500894|s2cid=29529166}}</ref> Definitive radiotherapy (boost) can deliver the dose precisely and palliative treatments can be given to relieve dysphagia. The large diameter applicators or balloon type catheter are used with the afterloader to expand the esophagus and facilitate the delivery of radiation dose to tumor with sparing of nearby normal tissue.<ref>{{Cite journal|last1=Nonoshita|first1=Takeshi|last2=Sasaki|first2=Tomonari|last3=Hirata|first3=Hideki|last4=Toh|first4=Yasushi|last5=Shioyama|first5=Yoshiyuki|last6=Nakamura|first6=Katsumasa|last7=Honda|first7=Hiroshi|date=2007-10-26|title=High-dose-rate brachytherapy for previously irradiated patients with recurrent esophageal cancer|journal=Radiation Medicine|volume=25|issue=8|pages=373–377|doi=10.1007/s11604-007-0152-4|pmid=17952540|s2cid=7294379|issn=0288-2043}}</ref><ref>{{Cite journal|last1=Akagi|first1=Yukio|last2=Hirokawa|first2=Yutaka|last3=Kagemoto|first3=Masayuki|last4=Matsuura|first4=Kanji|last5=Ito|first5=Atsushi|last6=Fujita|first6=Kazushi|last7=Kenjo|first7=Masahiro|last8=Kiriu|first8=Hiroshi|last9=Ito|first9=Katsuhide|date=February 1999|title=Optimum fractionation for high-dose-rate endoesophageal brachytherapy following external irradiation of early stage esophageal cancer|journal=International Journal of Radiation Oncology, Biology, Physics|volume=43|issue=3|pages=525–530|doi=10.1016/S0360-3016(98)00433-7|pmid=10078632}}</ref>

Brachytherapy followed EBRT or surgery have been shown to improve the survival rate and local recurrent rate than EBRT or surgery only for esophageal cancer patients.<ref>{{Cite journal|last1=Sai|first1=Heitetsu|last2=Mitsumori|first2=Michihide|last3=Araki|first3=Norio|last4=Mizowaki|first4=Takashi|last5=Nagata|first5=Yasushi|last6=Nishimura|first6=Yasumasa|last7=Hiraoka|first7=Masahiro|date=August 2005|title=Long-term results of definitive radiotherapy for stage I esophageal cancer|journal=International Journal of Radiation Oncology, Biology, Physics|volume=62|issue=5|pages=1339–1344|doi=10.1016/j.ijrobp.2004.12.042|pmid=16029790|issn=0360-3016}}</ref><ref name="Fuccio 332–339"/>

===Skin cancer===
HDR brachytherapy for nonmelanomatous [[Medicine:Skin cancer|skin cancer]], such as basal cell carcinoma and [[Medicine:Squamous cell carcinoma|squamous cell carcinoma]], provides an alternative treatment option to surgery. This is especially relevant for cancers on the nose, ears, eyelids or lips, where surgery may cause disfigurement or require extensive reconstruction.<ref name="GEC-ESTRO" />{{rp|Ch. 28}} Various applicators can be used to ensure close contact between the radiation source(s) and the skin, which conform to the curvature of the skin and help ensure precision delivery of the optimal irradiation dose.<ref name="GEC-ESTRO" />{{rp|Ch. 28}}

Another type of brachytherapy which has similar advantages as the HDR is provided be the Rhenium-SCT ([[Medicine:Skin cancer|Skin Cancer]] Therapy). It makes use of the beta ray emissions of [[Chemistry:Rhenium|Rhenium]]-188 to treat [[Medicine:Basal-cell carcinoma|basal cell]] or [[Medicine:Squamous cell carcinoma|squamous cell carcinoma]]s. the radiation source is enclosed in a compound which is applied to a thin protective foil directly over the lesion. This way the radiation source can be applied to complex locations and minimize radiation to healthy tissue.<ref>{{Cite journal|last1=Cipriani|first1=Cesidio|last2=Desantis|first2=Maria|last3=Dahlhoff|first3=Gerhard|last4=Brown|first4=Shannon D.|last5=Wendler|first5=Thomas|last6=Olmeda|first6=Mar|last7=Pietsch|first7=Gunilla|last8=Eberlein|first8=Bernadette|date=2020-07-22|title=Personalized irradiation therapy for NMSC by rhenium-188 skin cancer therapy: a long-term retrospective study|journal=Journal of Dermatological Treatment|volume=33 |issue=2 |language=en|pages=969–975|doi=10.1080/09546634.2020.1793890|pmid=32648530|issn=0954-6634|doi-access=free}}</ref>

Brachytherapy for skin cancer provides good cosmetic results and clinical efficacy; studies with up to five years follow-up have shown that brachytherapy is highly effective in terms of local control, and is comparable to EBRT.<ref name="Guix-2000">
{{Cite journal | doi = 10.1016/S0360-3016(99)00547-7 | pmid = 10758310 | year = 2000 | author1 = Guix | first2 = F. | first3 = J. | first4 = C. | first5 = A. | first6 = J. | first7 = R. | title = Treatment of skin carcinomas of the face by high-dose-rate brachytherapy and custom-made surface molds | volume = 47 | issue = 1 | pages = 95–102 | journal = International Journal of Radiation Oncology, Biology, Physics | last2 = Finestres | last3 = Tello | last4 = Palma | last5 = Martinez | last6 = Guix | last7 = Guix}}</ref><ref name="Sedda-2008">
{{Cite journal| first1 = A. F.| last1 = Sedda | first2 = G.| first3 = C.| first4 = A. M.| first5 = P.| title = Dermatological high-dose-rate brachytherapy for the treatment of basal and squamous cell carcinoma| journal = Clinical and Experimental Dermatology| volume = 33| pages = 745–749| year = 2008 | doi = 10.1111/j.1365-2230.2008.02852.x| pmid =  18681873| last2 =  Rossi| last3 =  Cipriani| last4 =  Carrozzo| last5 =  Donati| issue =  6| hdl = 2108/59410 | s2cid = 26912830 |url=https://art.torvergata.it/bitstream/2108/59410/1/Dermatological%20high-dose-rate%20brachytherapy.pdf| hdl-access = free}}</ref><ref name="Rio-2005">
{{Cite journal| first1 = E.| last1 = Rio | first2 = E.| first3 = C.| first4 = P.| first5 = S.| first6 = L.| first7 = C.| first8 = M.| first9 = B.| title = Interstitial brachytherapy of periorificial skin carcinomas of the face: A retrospective study of 97 cases| journal = International Journal of Radiation Oncology, Biology, Physics| volume = 63| issue = 3| pages = 753–757| year = 2005| pmid = 15927410 | doi = 10.1016/j.ijrobp.2005.03.027| last2 =  Bardet| last3 =  Ferron| last4 =  Peuvrel| last5 =  Supiot| last6 =  Campion| last7 =  Beauvillain De Montreuil| last8 =  Mahe| last9 =  Dreno}}</ref> Treatment times are typically short, providing convenience for patients.<ref name="Musmacher-2006">
{{Cite journal | author = Musmacher J | year = 2006 | title = High dose rate brachytherapy with surface applicators: Treatment for nonmelanomatous skin cancer | journal = Journal of Clinical Oncology | volume = 24 | issue = 18_suppl| page = 15543 | doi = 10.1200/jco.2006.24.18_suppl.15543 | display-authors = etal  }}</ref>
It has been suggested that brachytherapy may become a standard of treatment for skin cancer in the near future.<ref name="Musmacher-2006" />

===Blood vessels===
Brachytherapy can be used in the treatment of [[Medicine:Coronary stent#Restenosis|coronary in-stent restenosis]], in which a catheter is placed inside blood vessels, through which sources are inserted and removed.<ref name="ESC-2005">
{{Cite journal| first1 = A. /T. F. | first2 = S.| last5 = Colombo| last4 = Camici| last7 = Jørgensen | first3 = P. | first4 = F. F.| last3 = Avilés| last1 = Members | first5 = P. G.| last2 = Albertsson | first6 = A.| last8 = Marco | first7 = C. | first8 = E.| last6 = Hamm| last9 = Nordrehaug | first9 = J.| title = Guidelines for Percutaneous Coronary Interventions: the Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology| author14 = Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology | first13 = W.| last13 = Wijns | first12 = G. W.| last12 = Stone| journal = European Heart Journal | first11 = P.| volume = 26| issue =  8| last10 = Ruzyllo| last11 = Urban| pages = 804–847| year = 2005| pmid =  15769784 | first10 =  W. | doi = 10.1093/eurheartj/ehi138| doi-access = free}}</ref>
In treating In-stent restenosis (ISR) Drug Eluting stents (DES) have been found to be superior to Intracoronary Brachytherapy (ICBT).<!--<ref name="Clinical Cardiology 5/10/11>-->
However, there is continued interest in vascular brachytherapy for persistent restenosis in failed stents and vein grafts.
The therapy has also been investigated for use in the treatment of peripheral vasculature stenosis<ref name="Sidawy-2002">
{{Cite journal | doi = 10.1067/mva.2002.123751 | pmid = 12021726 | year = 2002 | author1 = Sidawy | first2 = J. | first3 = R. | title = Peripheral vascular brachytherapy | volume = 35 | issue = 5 | pages = 1041–1047 | journal = Journal of Vascular Surgery | last2 = Weiswasser | last3 = Waksman| doi-access = free }}</ref> and considered for the treatment of [[Medicine:Atrial fibrillation|atrial fibrillation]].<ref name="Pérez-Castellano-2006">
{{Cite journal| last1 = Perez-castellano | first1 = N.| first2 = J.| first3 = P.| first4 = P.| first5 = M.| first6 = M. J.| first7 = C.| first8 = J. M.| first9 = J.| last10 = Fernández-Ortiz | first10 = A.| last11 = Vano | first11 = E.| last12 = MacAya | first12 = C.| title = Pathological Effects of Pulmonary Vein beta-Radiation in a Swine Model| journal = Journal of Cardiovascular Electrophysiology| volume = 17| issue =  6| pages = 662–669| year = 2006| pmid =  16836719 | doi = 10.1111/j.1540-8167.2006.00462.x| last2 =  Villacastín| last3 =  Aragoncillo| last4 =  Fantidis| last5 =  Sabaté| last6 =  García-Torrent| last7 =  Prieto| last8 =  Corral| last9 =  Moreno| s2cid = 22161263}}</ref>

==Side effects==
The likelihood and nature of potential acute, sub-acute or long-term side-effects associated with brachytherapy depends on the location of the tumour being treated and the type of brachytherapy being used.

===Acute===
Acute side effects associated with brachytherapy include localised bruising, swelling, bleeding, discharge or discomfort within the implanted region. These usually resolve within a few days following completion of treatment.<ref name="Macmillan-brachytherapy">
 {{cite web|url=http://www.macmillan.org.uk/Cancerinformation/Cancertreatment/Treatmenttypes/Radiotherapy/Beingtreated/Brachytherapy.aspx |title=Brachytherapy |access-date=25 September 2009 |author=Macmillan Cancer Support |url-status=dead |archive-url=https://web.archive.org/web/20091003160536/http://www.macmillan.org.uk/Cancerinformation/Cancertreatment/Treatmenttypes/Radiotherapy/Beingtreated/Brachytherapy.aspx |archive-date=October 3, 2009 }}</ref>
Patients may also feel fatigued for a short period following treatment.<ref name="Macmillan-brachytherapy" /><ref name="Fieler-1997">
{{Cite journal | pmid = 9127366 | year = 1997 | author1 = Fieler | title = Side effects and quality of life in patients receiving high-dose rate brachytherapy | volume = 24 | issue = 3 | pages = 545–553 | journal = Oncology Nursing Forum}}</ref>

Brachytherapy treatment for cervical or prostate cancer can cause acute and transient urinary symptoms such as urinary retention, urinary incontinence or painful urination (dysuria).<ref name="Frank-2007" /><ref name="Doust-2004">
{{Cite journal | pmid = 15301172 | year = 2004 | author1 = Doust | first2 = E. | first3 = G. | first4 = M. | first5 = D. | title = A systematic review of brachytherapy. Is it an effective and safe treatment for localised prostate cancer? | volume = 33 | issue = 7 | pages = 525–529 | journal = Australian Family Physician | last2 = Miller | last3 = Duchesne | last4 = Kitchener | last5 = Weller}}</ref><ref name="Magné-2009">
{{Cite journal| last1 = Magné | first1 = N.| first2 = N. C.| first3 = E.| first4 = P.| first5 = P.| first6 = D.| first7 = C.| first8 = P.| first9 = C.| title = Patterns of care and outcome in elderly cervical cancer patients: A special focus on brachytherapy| journal = Radiotherapy and Oncology| volume = 91| issue =  2| pages = 197–201| year = 2009| pmid =  18954913 | doi = 10.1016/j.radonc.2008.08.011| last2 =  Mancy| last3 =  Chajon| last4 =  Duvillard| last5 =  Pautier| last6 =  Castaigne| last7 =  Lhommé| last8 =  Morice| last9 =  Haie-Meder}}</ref>
Transient increased bowel frequency, diarrhoea, constipation or minor rectal bleeding may also occur.<ref name="Frank-2007" /><ref name="Doust-2004" /><ref name="Magné-2009" /> Acute and subacute side effects usually resolve over a matter of days or a few weeks. In the case of permanent (seed) brachytherapy for prostate cancer, there is a small chance that some seeds may migrate out of the treatment region into the bladder or urethra and be passed in the urine.

Brachytherapy for skin cancer may result in a shedding of the outer layers of skin (desquamation) around the area of treatment in the weeks following therapy, which typically heals in 5–8 weeks.<ref name="GEC-ESTRO" />{{rp|Ch. 28}} If the cancer is located on the lip, ulceration may occur as a result of brachytherapy, but usually resolves after 4–6 weeks.<ref name="Casino-2006">
{{Cite journal | author = Casino AR | year = 2006 | title = Brachytherapy in lip cancer | journal = Medicina Oral | volume = 11 | pages = E223–9 | display-authors = etal  }}</ref>

Most of the acute side effects associated with brachytherapy can be treated with medication or through dietary changes, and usually disappear over time (typically a matter of weeks), once the treatment is completed. The acute side effects of HDR brachytherapy are broadly similar to EBRT.<ref name="Fieler-1997" />

===Long-term===
In a small number of people, brachytherapy may cause long-term side effects due to damage or disruption of adjacent tissues or organs. Long-term side effects are usually mild or moderate in nature. For example, urinary and digestive problems may persist as a result of brachytherapy for cervical or prostate cancer, and may require ongoing management.<ref name="Frank-2007" /><ref name="Doust-2004" /><ref name="Magné-2009" />

Brachytherapy for prostate cancer may cause erectile dysfunction in approximately 15–30% of patients.<ref name="GEC-ESTRO" />{{rp|Ch. 20}}<ref name="Moule-2009" /> However, the risk of erectile dysfunction is related to age (older men are at a greater risk than younger men) and also the level of erectile function prior to receiving brachytherapy. In patients who do experience erectile dysfunction, the majority of cases can successfully be treated with drugs such as Viagra.<ref name="GEC-ESTRO" />{{rp|Ch. 20}} Importantly, the risk of erectile dysfunction after brachytherapy is less than after radical prostatectomy.<ref name="Guedea-2009" /><ref name="Doust-2004" />

Brachytherapy for breast or skin cancer may cause scar tissue to form around the treatment area. In the case of breast brachytherapy, fat necrosis may occur as a result of fatty acids entering the breast tissues. This can cause the breast tissue to become swollen and tender. Fat necrosis is a benign condition and typically occurs 4–12 months after treatment and affects about 2% of patients.<ref name="Vicini-2009">
{{Cite journal| last1 = Vicini | first1 = F.| first2 = P. D.| first3 = C. A.| first4 = A. J.| first5 = D.| first6 = H. C.| first7 = M. A.| first8 = V. J.| first9 = H. M.| last10 = Lyden | first10 = M.| title = Three-year analysis of treatment efficacy, cosmesis, and toxicity by the American Society of Breast Surgeons MammoSite Breast Brachytherapy Registry Trial in patients treated with accelerated partial breast irradiation (APBI)| journal = Cancer| volume = 112| issue = 4| pages = 758–766| year = 2008| pmid = 18181095 | doi = 10.1002/cncr.23227| last2 = Beitsch| last3 = Quiet| last4 = Keleher| last5 = Garcia| last6 = Snider Jr| last7 = Gittleman| last8 = Zannis| last9 = Kuerer| doi-access = free}}</ref><ref name="Humonc-breast">{{cite web|url=http://www.humonc.wisc.edu/modules/mediawiki/index.php?title=Breast_brachytherapy |title=Breast brachytherapy |access-date=25 September 2009 |author=Department of Human Oncology, University of Wisconsin School of Medicine and Public Health }} </ref>

==Safety around others==
Patients often ask if they need to have special safety precautions around family and friends after receiving brachytherapy. If temporary brachytherapy is used, no radioactive sources remain in the body after treatment. Therefore, there is no radiation risk to friends or family from being in close proximity with them.<ref name=rtanswers.com>{{Cite web |url=http://www.rtanswers.com/Brachytherapy/ |title=Treatment Types: Brachytherapy |work=RT Answers |publisher=American Society for Radiation Oncology |access-date=24 July 2017 }}{{dead link|date=February 2019|bot=medic}}{{cbignore|bot=medic}}</ref>

If permanent brachytherapy is used, low dose radioactive sources (seeds) are left in the body after treatment – the radiation levels are very low and decrease over time. In addition, the irradiation only affects tissues within a few millimeters of the radioactive sources (i.e. the tumour being treated). As a precaution, some people receiving permanent brachytherapy may be advised to not hold any small children or be too close to pregnant women for a short time after treatment. Radiation oncologists or nurses can provide specific instructions to patients and advise for how long they need to be careful.<ref name=rtanswers.com />

==Types==
Different types of brachytherapy can be defined according to (1) the [[Medicine:Brachytherapy#Source placement|placement of the radiation sources]] in the target treatment area, (2) the [[Medicine:Brachytherapy#Dose rate|rate or 'intensity' of the irradiation dose]] delivered to the tumour, and (3) the [[Medicine:Brachytherapy#Duration of dose delivery|duration of dose delivery]].

===Source placement===
The two main types of brachytherapy treatment in terms of the placement of the radioactive source are interstitial and contact.

In the case of interstitial brachytherapy, the sources are placed directly in the target tissue of the affected site, such as the prostate or breast.<ref name="GEC-ESTRO" />{{rp|Ch. 1}}

Contact brachytherapy involves placement of the radiation source in a space next to the target tissue.<ref name="GEC-ESTRO" />{{rp|Ch. 1}} This space may be a body cavity (intracavitary brachytherapy) such as the [[Medicine:Cervix|cervix]], [[Biology:Uterus|uterus]] or [[Biology:Vagina|vagina]]; a body lumen (intraluminal brachytherapy) such as the trachea or oesophagus; or externally (surface brachytherapy) such as the [[Biology:Skin|skin]].<ref name="GEC-ESTRO" />{{rp|Ch. 1}} A radiation source can also be placed in blood vessels (intravascular brachytherapy) for the treatment of [[Medicine:Coronary stent#Restenosis|coronary in-stent restenosis]].<ref name="Giap 2007">
{{Cite book |vauthors=Giap H, Tripuraneni P| editor = Devlin P | year = 2007 | title = Brachytherapy. Applications and Techniques | chapter = Vascular brachytherapy | publisher = LWW | location = Philadelphia }}</ref>

===Dose rate===
The dose rate of brachytherapy refers to the level or 'intensity' with which the radiation is delivered to the surrounding medium and is expressed in [[Physics:Gray (unit)|Grays]] per hour (Gy/h).

Low-dose rate (LDR) brachytherapy involves implanting radiation sources that emit radiation at a rate of up to 2&nbsp;Gy·h<sup>−1</sup>.<ref name="Thomadsen 2005">
{{Cite book | last = Thomadsen BR | year = 2005 | title = Brachytherapy Physics | publisher = Medical Physics Publishing | display-authors = etal }}</ref> LDR brachytherapy is commonly used for cancers of the oral cavity,<ref name="Mazaron-2009">
{{Cite journal | last1 = Mazeron | first1 = J. J. | last2 = Ardiet | first2 = J. M. | last3 = Haie-Méder | first3 = C. | last4 = Kovács | first4 = G. R. | last5 = Levendag | first5 = P. | last6 = Peiffert | first6 = D. | last7 = Polo | first7 = A. | last8 = Rovirosa | first8 = A. | last9 = Strnad | first9 = V. | doi = 10.1016/j.radonc.2009.01.005 | title = GEC-ESTRO recommendations for brachytherapy for head and neck squamous cell carcinomas | journal = Radiotherapy and Oncology | volume = 91 | issue = 2 | pages = 150–156 | year = 2009 | pmid = 19329209 }}</ref> oropharynx,<ref name="Mazaron-2009" /> sarcomas<ref name="GEC-ESTRO" />{{rp|Ch. 27}} and [[Medicine:Prostate cancer|prostate cancer]]<ref name="GEC-ESTRO" />{{rp|Ch. 20}}<ref name="Koukourakis-2009" >
{{Cite journal | author = Koukourakis G | year = 2009 | title = Brachytherapy for prostate cancer: A systematic review | journal = Adv Urol | volume = 26 | issue = 1 | pages =63–8 | pmid = 2735748 | display-authors = etal  | doi = 10.1177/000456328902600109 | doi-access =  | s2cid = 32151003 }}</ref>

Medium-dose rate (MDR) brachytherapy is characterized by a medium rate of dose delivery, ranging between 2&nbsp;Gy·h<sup>−1</sup> to 12&nbsp;Gy·h<sup>−1</sup>.<ref name="Thomadsen 2005" />

High-dose rate (HDR) brachytherapy is when the rate of dose delivery exceeds 12&nbsp;Gy·h<sup>−1</sup>.<ref name="Thomadsen 2005" /> The most common applications of HDR brachytherapy are in tumours of the [[Medicine:Cervix|cervix]], [[Biology:Esophagus|esophagus]], lungs, breasts and [[Biology:Prostate|prostate]].<ref name="GEC-ESTRO" /> Most HDR treatments are performed on an outpatient basis, but this is dependent on the treatment site.<ref name="Nag-2004">
{{Cite journal | author = Nag S. | year = 2004 | title = High dose rate brachytherapy: its clinical applications and treatment guidelines | journal = Technology in Cancer Research and Treatment | volume = 3 | issue = 3 | pages = 269–87 | pmid = 15161320 | doi = 10.1177/153303460400300305 | doi-access =  | s2cid = 36764232 }}</ref>

Pulsed-dose rate (PDR) brachytherapy involves short pulses of radiation, typically once an hour, to simulate the overall rate and effectiveness of LDR treatment. Typical tumour sites treated by PDR brachytherapy are gynaecological<ref name="GEC-ESTRO" />{{rp|Ch. 14}} and head and neck cancers.<ref name="Mazaron-2009" />

[[File:Radioactive seed dose calculation geometry.png|right|thumb|Dose calculation geometry]]
The calculation of radiation dose from radioactive seeds is crucial in the planning and administration of [[Medicine:Brachytherapy|brachytherapy]] treatments.  Most modern calculation are done using the formalism published by the [[Organization:American Association of Physicists in Medicine|American Association of Physicists in Medicine]].<ref>{{cite journal|last1=Nath|first1=R.|last2=Anderson|first2=L. L.|last3=Luxton|first3=G.|last4=Weaver|first4=K. A.|last5=Williamson|first5=J. F.|last6=Meigooni|first6=A. S.|title=Dosimetry of interstitial brachytherapy sources: Recommendations of the AAPM Radiation Therapy Committee Task Group N. 43.|journal=Medical Physics|date=1995|volume=22|issue=2|pages=209–234|doi=10.1118/1.597458|pmid=7565352}}</ref>  For the geometry in figure 1, this formalism uses five parameters.
*''Strength of the source'': How much radiation is being emitted by the seed, expressed as [[Physics:Kerma|air kerma strength]] and denoted by <math>S_k</math>.
*''Dose rate of the source'': How much dose the seed will deliver to the reference point over a certain period of time, denoted by <math>\Lambda</math>.
*''Geometry factor'': How the shape of the seed will affect the dose at points away from the reference point, denoted by <math>G(r,\theta)</math>.
*''Anisotropy function'': How the much radiation will be stopped before passing out of the seed, denoted by <math>F(r,\theta)</math>.
*''Radial dose function'': How the radiation will interact with the material surrounding the seed, denoted by <math>g(r)</math>.
The equation which links these parameters is, <math>D(r,\theta)=S_k \Lambda \frac{G(r,\theta)}{G(r_0,\theta_0)}g(r)F(r,\theta)t</math>

===Duration of dose delivery===

The placement of radiation sources in the target area can be temporary or permanent.

Temporary brachytherapy involves placement of radiation sources for a set duration (usually a number of minutes or hours) before being withdrawn.<ref name="GEC-ESTRO" />{{rp|Ch. 1}} The specific treatment duration will depend on many different factors, including the required rate of dose delivery and the type, size and location of the cancer. In LDR and PDR brachytherapy, the source typically stays in place up to 24 hours before being removed, while in HDR brachytherapy this time is typically a few minutes.<ref name="Flynn 2005">{{Cite book | last = Flynn A |veditors=Hoskin P, Coyle C | year = 2005 | title = Radiotherapy in practice: brachytherapy | chapter = Isotopes and delivery systems for brachytherapy | publisher = Oxford University Press | location = New York | display-authors = etal }}</ref>

Permanent brachytherapy, also known as seed implantation, involves placing small LDR radioactive seeds or pellets (about the size of a grain of rice) in the tumour or treatment site and leaving them there permanently to gradually decay. Over a period of weeks or months, the level of radiation emitted by the sources will decline to almost zero. The inactive seeds then remain in the treatment site with no lasting effect.<ref name="Moule-2009">
{{Cite journal| first1 = R. N.| last1 = Moule | first2 = P. J.| title = Non-surgical treatment of localised prostate cancer| journal = Surgical Oncology| volume = 18| pages = 255–267| year = 2009 | doi = 10.1016/j.suronc.2009.03.006| pmid =  19442516| last2 =  Hoskin| issue =  3}}</ref> Permanent brachytherapy is most commonly used in the treatment of [[Medicine:Prostate cancer|prostate cancer]].<ref name="Koukourakis-2009" />
{{Clear}}

==Procedure==
[[File:Brachytherapy procedure flow.jpg|thumb|upright=1.75|Typical stages of a brachytherapy procedure]]

===Initial planning===
To accurately plan the brachytherapy procedure, a thorough clinical examination is performed to understand the characteristics of the tumour. In addition, a range of imaging modalities can be used to visualise the shape and size of the tumour and its relation to surrounding tissues and organs. These include x-ray radiography, ultrasound, computed axial tomography (CT or CAT) scans and magnetic resonance imaging (MRI).<ref name="GEC-ESTRO" />{{rp|Ch. 5}} The data from many of these sources can be used to create a 3D visualisation of the tumour and the surrounding tissues.<ref name="GEC-ESTRO" />{{rp|Ch. 5}}

Using this information, a plan of the optimal distribution of the radiation sources can be developed. This includes consideration of how the source carriers (applicators), which are used to deliver the radiation to the treatment site, should be placed and positioned.<ref name="GEC-ESTRO" />{{rp|Ch. 5}} Applicators are non-radioactive and are typically needles or plastic catheters. The specific type of applicator used will depend on the type of cancer being treated and the characteristics of the target tumour.<ref name="GEC-ESTRO" />{{rp|Ch. 5}}

This initial planning helps to ensure that 'cold spots' (too little irradiation) and 'hot spots' (too much irradiation) are avoided during treatment, as these can respectively result in treatment failure and side-effects.<ref name="Pötter-2008" />

===Insertion===
Before radioactive sources can be delivered to the tumour site, the applicators have to be inserted and correctly positioned in line with the initial planning.

Imaging techniques, such as x-ray, fluoroscopy and ultrasound are typically used to help guide the placement of the applicators to their correct positions and to further refine the treatment plan.<ref name="GEC-ESTRO" />{{rp|Ch. 5}} CAT scans and MRI can also be used.<ref name="GEC-ESTRO" />{{rp|Ch. 5}} Once the applicators are inserted, they are held in place against the skin using sutures or adhesive tape to prevent them from moving. Once the applicators are confirmed as being in the correct position, further imaging can be performed to guide detailed treatment planning.<ref name="GEC-ESTRO" />{{rp|Ch. 5}}

===Creation of a virtual patient===
[[File:Brachytherapy virtual patient.jpg|thumb|Creation of a virtual patient to plan the delivery of brachytherapy]]

The images of the patient with the applicators in situ are imported into treatment planning software and the patient is brought into a dedicated shielded room for treatment. The treatment planning software enables multiple 2D images of the treatment site to be translated into a 3D 'virtual patient', within which the position of the applicators can be defined.<ref name="GEC-ESTRO" />{{rp|Ch. 5}} The spatial relationships between the applicators, the treatment site and the surrounding healthy tissues within this 'virtual patient' are a copy of the relationships in the actual patient.
{{Clear}}

===Optimizing the irradiation plan===
[[File:Brachytherapy treatment planning.jpg|thumb|upright|Refinement of the treatment plan during a brachytherapy procedure]]
To identify the optimal spatial and temporal distribution of radiation sources within the applicators of the implanted tissue or cavity, the treatment planning software allows virtual radiation sources to be placed within the virtual patient. The software shows a graphical representation of the distribution of the irradiation. This serves as a guide for the brachytherapy team to refine the distribution of the sources and provide a treatment plan that is optimally tailored to the anatomy of each patient before actual delivery of the irradiation begins.<ref name="GYNOpt-2009">{{Cite journal | author = Trnková P. | author2 = Pötter R. | author3 = Baltas D. | author4 = Karabis A. | author5 = Fidarova E. | author6 = Dimopoulos J. | author7 = Georg D. | author8 = Kirisits C. | year = 2009 | title = New inverse planning technology for image-guided cervical cancer brachytherapy: Description and evaluation within a clinical frame | journal = Radiotherapy and Oncology | volume = 93 | issue = 2 | pages = 331–340 | pmid = 19846230 | url = http://www.pi-medical.gr/sites/default/files/New%20inverse%20planning%20technology%20for%20image-guided%20cervical%20cancer%20brachytherapy_1.pdf | doi = 10.1016/j.radonc.2009.10.004 | access-date = 2010-03-11 | archive-url = https://web.archive.org/web/20151017210629/http://www.pi-medical.gr/sites/default/files/New%20inverse%20planning%20technology%20for%20image-guided%20cervical%20cancer%20brachytherapy_1.pdf | archive-date = 2015-10-17 | url-status = dead }}</ref> This approach is sometimes called 'dose-painting'.

===Treatment delivery===
The radiation sources used for brachytherapy are always enclosed within a non-radioactive capsule. The sources can be delivered manually, but are more commonly delivered through a technique known as 'afterloading'.

Manual delivery of brachytherapy is limited to a few LDR applications, due to risk of radiation exposure to clinical staff.<ref name="Flynn 2005" />

In contrast, afterloading involves the accurate positioning of non-radioactive applicators in the treatment site, which are subsequently loaded with the radiation sources. In manual afterloading, the source is delivered into the applicator by the operator.

Remote afterloading systems provide protection from radiation exposure to healthcare professionals by securing the radiation source in a shielded safe. Once the applicators are correctly positioned in the patient, they are connected to an 'afterloader' machine (containing the radioactive sources) through a series of connecting guide tubes. The treatment plan is sent to the afterloader, which then controls the delivery of the sources along the guide tubes into the pre-specified positions within the applicator. This process is only engaged once staff are removed from the treatment room. The sources remain in place for a pre-specified length of time, again following the treatment plan, following which they are returned along the tubes to the afterloader.

On completion of delivery of the radioactive sources, the applicators are carefully removed from the body. Patients typically recover quickly from the brachytherapy procedure, enabling it to often be performed on an outpatient basis.<ref name="Nag-2004" />
{{Clear}}

Between 2003 and 2012 in United States community hospitals, the rate of hospital stays with brachytherapy (internal radiation therapy) had a 24.4 percent average annual decrease among adults aged 45–64 years and a 27.3 percent average annual decrease among adults aged 65–84 years. Brachytherapy was the OR procedure with the greatest change in occurrence among hospital stays paid by Medicare and private insurance.<ref>{{cite web |vauthors=Fingar KR, Stocks C, Weiss AJ, Steiner CA | title =  Most Frequent Operating Room Procedures Performed in U.S. Hospitals, 2003-2012 | work = HCUP Statistical Brief #186 | publisher = Agency for Healthcare Research and Quality | location = Rockville, MD | date = December 2014 | url =https://www.hcup-us.ahrq.gov/reports/statbriefs/sb186-Operating-Room-Procedures-United-States-2012.jsp}}</ref>

==Radiation sources==
Commonly used radiation sources (radionuclides) for brachytherapy include:<ref>Alex Rijnders. Photon Sources for Bracytherapy.  pp 185-194 in Radiotherapy and Brachytherapy, Eds. Yves Lemoigne, Alessandra Caner.  NATO Science for Peace and Security Series B: Physics and Biophysics. Springer Science & Business Media, 2009 {{ISBN|9789048130955}} [https://books.google.com/books?id=ewDNqCQ52S8C&pg=PA191 Pg 191]</ref>

{| class="wikitable"
|-
! Radionuclide
! Decay mode
! Half-life
! Energy
|-
| [[Physics:Caesium-131|Caesium-131]] (<sup>131</sup>Cs)
| [[Physics:Electron capture|ε]]
| 9.7 days
| 30.4 [[Physics:Kiloelectronvolt|keV]] (mean)
|-
| [[Physics:Caesium-137|Caesium-137]] (<sup>137</sup>Cs)
| [[Physics:Beta decay|β<sup>−</sup>]], [[Physics:Gamma ray|γ]]
| 30.17 years
| 0.512, 0.662 [[Physics:Megaelectronvolt|MeV]] γ-rays
|-
| [[Physics:Cobalt-60|Cobalt-60]] (<sup>60</sup>Co)
| β<sup>−</sup>, γ
| 5.26 years
| 1.17, 1.33 MeV γ-rays
|-
| [[Physics:Iridium-192|Iridium-192]] (<sup>192</sup>Ir)
| β<sup>−</sup>, ε, γ
| 73.8 days
| 0.38 MeV (mean)
|-
| [[Physics:Iodine-125|Iodine-125]] (<sup>125</sup>I)
| ε
| 59.6 days
| 27.4, 31.4 and 35.5 keV
|-
| [[Physics:Palladium-103|Palladium-103]] (<sup>103</sup>Pd)
| ε
| 17.0 days
| 21 keV (mean)
|-
| [[Physics:Ruthenium-106|Ruthenium-106]] (<sup>106</sup>Ru)
| β<sup>−</sup>
| 1.02 years
| 3.54 MeV
|-
| [[Physics:Radium-226|Radium-226]] (<sup>226</sup>Ra)
| [[Physics:Alpha decay|α]]
| 1599 years
|}

==History==
Brachytherapy dates back to 1901 (shortly after the discovery of radioactivity by [[Biography:Henri Becquerel|Henri Becquerel]] in 1896) when [[Biography:Pierre Curie|Pierre Curie]] suggested to Henri-Alexandre Danlos that a radioactive source could be inserted into a tumour.<ref name="Gupta-1995">
{{Cite journal | author = Gupta VK. | year = 1995 | title = Brachytherapy – past, present and future | journal = Journal of Medical Physics | volume = 20 | issue = 2 | pages = 31–38 | doi = 10.4103/0971-6203.50045 | doi-access = free }}</ref><ref name="Nag 2009">{{cite web | url = http://www.americanbrachytherapy.org/aboutBrachytherapy/history.cfm | title = A brief history of brachytherapy | access-date = 25 September 2009 | author = Nag S | archive-date = 22 December 2017 | archive-url = https://web.archive.org/web/20171222050622/https://www.americanbrachytherapy.org/aboutBrachytherapy/history.cfm | url-status = dead }}</ref>
It was found that the radiation caused the tumour to shrink.<ref name="Nag 2009" /> Independently, [[Biography:Alexander Graham Bell|Alexander Graham Bell]] also suggested the use of radiation in this way.<ref name="Nag 2009"/> In the early twentieth century, techniques for the application of brachytherapy were pioneered at the Curie institute in Paris by Danlos and at St Luke's and Memorial Hospital in New York by Robert Abbe.<ref name="GEC-ESTRO" />{{rp|Ch. 1}}<ref name="Nag 2009" />

Working with the Curies in their radium research laboratory at the University of Paris, American physicist [[Biography:William Duane (physicist)|William Duane]] refined a technique for extracting radon-222 gas from [[Chemistry:Radium sulfate|radium sulfate]] solutions. Solutions containing 1 gram of radium were "milked" to create radon "seeds" of about 20 millicuries each.  These "seeds" were distributed throughout Paris for use in an early form of brachytherapy named endocurietherapy. Duane perfected this "milking" technique during his time in Paris and referred to the device as a "radium cow".<ref name=Coursey>{{cite journal |last1=Coursey |first1=Bert M. |title=150th Anniversary of the Birth of Marie Curie |journal=Applied Radiation and Isotopes |year=2017 |volume=130 |pages=280–284 |publisher=National Institute of Standards & Technology |doi=10.1016/j.apradiso.2017.10.028 |pmid=29079418 |doi-access=free }}</ref>

Duane returned to the United States in 1913 and worked in a joint role as assistant professor of physics at Harvard and Research Fellow in Physics of the Harvard Cancer Commission.<ref>{{cite web |last1=Bridgman |first1=P.W. |title=Biographical Memoir of William Duane 1872-1935 |url=http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/duane-william.pdf |website=www.nasonline.org |publisher=National Academy of Sciences |access-date=16 June 2021}}</ref> The Cancer Commission was founded in 1901 and hired Duane to investigate the usage of radium emanations in the treatment of cancer.<ref>{{cite journal |last1=Webster |first1=Edward W. |title=The origins of Medical Physics in the USA: William Duane, Ph.D., 1913-1920 |journal=Medical Physics |date=1993 |volume=20 |issue=6 |pages=1607–1610 |doi=10.1118/1.597159 |pmid=8309432 |bibcode=1993MedPh..20.1607W |url=http://www.uthgsbsmedphys.org/GS02-0093/Webster%201993%20manuscript%20about%20radon.pdf |access-date=16 June 2021 |archive-date=13 June 2021 |archive-url=https://web.archive.org/web/20210613132843/http://www.uthgsbsmedphys.org/GS02-0093/Webster%201993%20manuscript%20about%20radon.pdf |url-status=dead }}</ref> In 1915 he built Boston's first "radium cow" and thousands of patients were treated with the radon-222 generated from it.<ref>{{cite journal |last1=Brucer |first1=Marshall |title=William Duane and the radium cow: An American contribution to the emerging atomic age |journal=Medical Physics |date=November 1993 |volume=20 |issue=6 |pages=1601–1605 |doi=10.1118/1.596947 |pmid=8309431 |bibcode=1993MedPh..20.1601B |url=https://doi.org/10.1118/1.596947 |access-date=15 June 2021}}</ref>

Interstitial radium therapy was common in the 1930s.<ref name="GEC-ESTRO" />{{rp|Ch. 1}} Gold seeds filled with [[Chemistry:Radon|radon]] were used as early as 1942<ref>{{Cite journal | doi = 10.1001/archderm.1975.01630180085013 | last1 = Goldstein | first1 = N. | title = Radon seed implants. Residual radioactivity after 33 years | journal = Archives of Dermatology | volume = 111 | issue = 6 | pages = 757–759 | year = 1975 | pmid = 1137421}}</ref> until at least 1958.<ref>{{cite journal|last=Winston|first=P.|title=Carcinoma of the Trachea Treated by Radon Seed Implantation|journal=The Journal of Laryngology & Otology|date=June 1958|volume=72|issue=6|pages=496–499|doi=10.1017/S0022215100054232|pmid=13564019|s2cid=36790323 }}</ref> [[Chemistry:Gold|Gold]] shells were selected by Gino Failla around 1920 to shield beta rays while passing [[Physics:Gamma ray|gamma ray]]s.<ref>{{cite web|last=Oak Ridge Associated Universities|title=Seeds (ca. 1940s - 1960s)|url=https://www.orau.org/health-physics-museum/collection/brachytherapy/seeds.html|work=ORAU Museum of Radiation and Radioactivity|access-date=12 October 2021}}</ref> [[Chemistry:Cobalt|Cobalt]] needles were also used briefly after World War II.<ref name="GEC-ESTRO" />{{rp|Ch. 1}} Radon and cobalt were replaced by radioactive [[Chemistry:Tantalum|tantalum]] and gold, before [[Chemistry:Iridium|iridium]] rose in prominence.<ref name="GEC-ESTRO" />{{rp|Ch. 1}} First used in 1958, iridium is the most commonly used artificial source for brachytherapy today.<ref name="GEC-ESTRO" />{{rp|Ch. 1}}

Following initial interest in brachytherapy in Europe and the US, its use declined in the middle of the twentieth century due to the problem of radiation exposure to operators from the manual application of the radioactive sources.<ref name="Nag 2009" /><ref name="Aronowitz-2008">
{{Cite journal| first1 = J.| title = The "Golden Age" of prostate brachytherapy: A cautionary tale| last1 = Aronowitz| journal = Brachytherapy| volume = 7| pages = 55–59| year = 2008 | doi = 10.1016/j.brachy.2007.12.004| pmid =  18299114| issue =  1}}</ref> However, the development of [[Medicine:Brachytherapy#Treatment delivery|remote afterloading systems]], which allow the radiation to be delivered from a shielded safe, and the use of new radioactive sources in the 1950s and 1960s, reduced the risk of unnecessary radiation exposure to the operator and patients.<ref name="Gupta-1995" /> This, together with more recent advancements in three-dimensional imaging modalities, computerised treatment planning systems and delivery equipment has made brachytherapy a safe and effective treatment for many types of cancer today.<ref name="GEC-ESTRO" />{{rp|Ch. 1}}

The word "brachytherapy" comes from the [[Social:Ancient Greek|Greek]] word {{Lang-el|βραχύς|translit=brachys|label=none}}, meaning "short-distance" or "short".

==Environmental hazard==
Due to the small size of brachytherapy sources and low control in early decades, there is a risk that some of these have escaped into the environment to become orphaned sources. A radium needle was found in a Prague playground in 2011, radiating 500&nbsp;µSv/h from one metre away.<ref>{{cite news|title="Radioactive" little cylinder found underground in a park in Podolí|url=http://praha.idnes.cz/zdrojem-zvysene-radiace-v-prazskem-podoli-byl-maly-zakopany-valecek-1gw-/praha-zpravy.aspx?c=A110929_083242_praha-zpravy_cen|access-date=12 November 2012|newspaper=iDNES.cz|date=29 September 2011}}</ref><ref>{{cite web|last=Motl|first=Luboš|title=Why a small cylinder buried in Prague radiates 500 μSv/h?|url=http://motls.blogspot.ca/2011/09/do-they-have-500-sv-in-prague-and-why.html|access-date=12 November 2012}}</ref><ref>{{cite news|last=Falvey|first=Christian|title=Passerby stumbles upon radioactive playground thanks to wristwatch|url=http://www.radio.cz/en/section/curraffrs/passerby-stumbles-upon-radioactive-playground-thanks-to-wristwatch|access-date=21 November 2012|newspaper=Radio Prague|date=29 September 2011}}</ref>

==See also==
* [[Medicine:External beam radiotherapy|External beam radiotherapy]]
* [[Medicine:Prostate brachytherapy|Prostate brachytherapy]]
* [[Medicine:Targeted intra-operative radiotherapy|Targeted intra-operative radiotherapy]]
* [[Medicine:Unsealed source radiotherapy|Unsealed source radiotherapy]]
* [[Medicine:Nuclear medicine|Nuclear medicine]]
* [[Medicine:Intraoperative radiation therapy|Intraoperative radiation therapy]]
* [[Physics:Radiation therapy#Contact X-ray brachytherapy|Contact X-ray brachytherapy]] (also called "electronic brachytherapy")

==References==
{{Reflist|32em}}

==External links==
{{wikt}}
* [https://www.americanbrachytherapy.org/ American Brachytherapy Society (ABS)]

{{Nuclear Technology}}
{{Radiation oncology}}

[[Category:Medical physics]]
[[Category:Cancer treatments]]

{{Sourceattribution|Brachytherapy}}