Accuracy of radiation dose for cancer treatment

Abstract

Objective: The accuracy of radiation dose will reduce the risk of radiation complication to the patients. The accuracy of radiation dose at Songklanagarind hospital was audited by the postal TI.D intercomparision which is the IAEA standard method.

Materials and method: The radiation output of Cobalt-60 machine measured and calculated the irradiation time for 200 cGy in water to TLD by the LAEA setup conditions. Expose 200 cGy to each TLDs by the calculated irradiation time. These exposed TLDs were proceed at the SSDL of Medical Science Department and reported to the hospital. Evaluation data were collected from 1984-2002.

Discussion of results: The radiation dose of exposed TLDs will be interpreted by Medical Science Department using IAEA standard scoring. The percentage difference from the quoted radiation of more than 5% would be requested more data, repeat the measurement or need to visit the site by the expert physicists.

Conclusion: The TLD evaluation were 11 satisfied, 2 were acceptable and 2 were request more data. The maximum degree of different was (-5.45%) and minimum was (-0.05%). The treatment time calculation software was developed to reduce the degree of calculation error. Result of TLD evaluation was used to check the dose accuracy agreement of the ionization chamber measurement and treatment planning system calculation. The results could support the physicist accurately control the radiation dose in patient treatment and the understanding of radiation dosage. The site could know self accuracy and have a qualified reference of radiation dose. The radiation risk reduction for patient treatment is extremely required for the evaluation purpose.