ABSTRACT
Brachytherapy is a method of treatment where sealed radioactive sources are used to deliver radiation at a short distance [1]. It allows a high radiation dose to be given to the target volume while giving a lower dose to surrounding normal tissue. Brachytherapy can be broken up into two categories: low and high dose rate (LDR and HDR). In LDR brachytherapy, low activity sources or seeds are implanted into the area being treated. These may be removed after a few days once the required dose is reached, or implanted with a set activity and left in the patient permanently so that the desired dose is delivered in the time taken to decay completely. Three common isotopes used in LDR brachytherapy are https://www.w3.org/1998/Math/MathML"> Â 137 C s , Â 125 I https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq1173.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> , and https://www.w3.org/1998/Math/MathML"> Â 103 P d https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq1174.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> , which have half-lives of 30.17 years, 60 days, and 17 days, respectively, and emit photons of average energy 662,28 , and https://www.w3.org/1998/Math/MathML"> 21 k e V https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq1175.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> , respectively. The relatively low energy photons of https://www.w3.org/1998/Math/MathML"> Â 125 I https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq1176.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> and https://www.w3.org/1998/Math/MathML"> Â 103 P d https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq1177.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> have a short range in tissue and are mostly attenuated by the patient’s body, requiring less shielding to protect staff and the general public.
