Measurement of half-life of iridium-192 (HDR brachytherapy)by clinical dosimeters

Abstract

<span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">Iridium-192 is a very common radioisotope, used in the treatment of the cancer patients worldwide. Usually the treatment is performed by brachytherapy, with remote afterloader machine of high dose rate (HDR). Half-life of iridium -192 varies from 73.83 to 74.2 days. In clinical practice, the calibration of iridium-192 is performed by clinical dosimeters.

<span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">The authors used clinical dosimeters of 0.6 cc graphite thimble chamber with calibration jig and a re-entrant/well-type chamber to perform comprehensive measurements of half-life of iridium-192. There were six different iridium-192 radioisotopes taken one by one up to their clinical lifetime for measurement on routine basis. <span style="font-size:15.5pt;mso-bidi-font-size:8.5pt; font-family:" arial","sans-serif""="">It <span style="font-size:15.0pt; mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">was found that each individual iridium-192 source has a single decay constant and half-life ranging from 73.81 to 73.84 days with a mean value of 73.825 days. The standard deviation was found to be± 0.0084.

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