Abstract:
Protocols, considered as guidelines in Medical Physics, admit the safety measures and effective practices in diagnostic and therapeutic radiology. The changes of the beam calibration due to adaption of the TRS-398 protocol based on standards of absorbed dose to the water and TRS-277 protocol based on air kerma standards were compared at Tellipalai Cancer Unit.
This research was carried out to compare the TRS-398 and TRS-277 protocols used to calculate the dose measurements in high energy X-ray. Using reading of FC65-G ion chamber and influencing factors of the TRS-398 and TRS-277 protocols, estimated doses for depths 5 cm and 10 cm were 0.9917 and 1.0045, and 1.0046 and 0.9926, respectively. Similarly, for CC13 ion chamber and influencing factors of the TRS-398 and TRS-277 protocols estimated doses for depths 5 cm and 10 cm were 0.9946, 1.0060 and 1.0077 and 0.9820, respectively. Calculations revealed that for the FC65-G chamber, deviation percentage of the doses for the depths 5 cm and 10 cm were 0.2% and 1.2% for the TRS-398 and TRS-277 protocols, respectively, and for the CC13 chamber, the deviation percentages for the depths were 1.19% and 2.4%, respectively. Even the deviations of the readings obtained by the protocols were too small, but the reading estimated using the TRS-398 is the best as it is based on absorbed dose to water and 90% of the human body weight consist of water
