PRECISION AND RELIABILITY: CALIBRATION COEFFICIENTS AND LONG-TERM STABILITY ANALYSIS OF RADIOTHERAPY DOSIMETERS CALIBRATED BY SSDL, NUKLEAR MALAYSIA

One of the main objectives Secondary Standard Dosimetry Laboratory (SSDL) in radiotherapy dosimetry is verifying radiation dose provided to patients accurate and meets globally recognised standards. Properly calibrating therapy dosimeters used centres first step SSDL must take ensure this goal attained. This study analyses calibration coefficients long-term stability calibrated by Nuklear Malaysia's SSDL. The were absorbed water using 60Co gamma rays, following procedure described IAEA TRS No. 398 469. Two hundred from 33 evaluated for percentage deviation manufacturer. Furthermore, variation coefficient 2011 2021 examined. between manufacturers found that most (82%) user within IAEA's acceptance limit ± 1.5%. Overall, values ranged 33.25% -27.24%, with an average 0.03%. As predicted, only 15% fulfill criteria 0.5%. In conclusion, proper maintenance annual are very important improve accuracy, minimise measurement uncertainty, thus reduce likelihood errors dosimetry.