Verification of absorbed dose and single-field dosimetry of MLC-shaped IMRT photon beams in Hubei province
10.3760/cma.j.issn.0254-5098.2018.02.010
- VernacularTitle:湖北省调强放疗多叶光栅野光子线束吸收剂量和二维剂量分布验证研究
- Author:
Wenshan ZHOU
1
;
Gangtao SUN
;
Song YE
;
Suming LUO
Author Information
1. 湖北省疾病预防控制中心
- Keywords:
Intensity modulated radiotherapy;
Thermoluminescent dosimeter;
Film;
Absorbed dose;
Two-dimensional dose distribution
- From:
Chinese Journal of Radiological Medicine and Protection
2018;38(2):129-133
- CountryChina
- Language:Chinese
-
Abstract:
Objective To verify the absorbed dose and two-dimensional dosimetry delivered by MLC-shaped IMRT photon beams using thermoluminescent dosimeters (TLDs) and radiochromic films.Methods Different types of medical linear accelerators at 7 third-grade first-class hospitals in Hubei were selected for this audit study.Besides TLDs and films,a small polystyrene phantom measuring 15 cm × 15 cm × 15 cm,supplied by the International Atomic Energy Agency (IAEA),was also used.The TPS dose calculation were performed with 6 MV X-ray beam and by delivering 6 Gy dose to the TLDs or films at 10 cm depth for 5 cm × 5 cm field size at 90 cm SSD.After irradiation,comparations were conducted of dose derivations between TPS-calculated values and TLD-or film-measured values.The two-dimensional dosimetry audit was carried out by using 30 cm × 30 cm homogeneous solid phantoms in which a 25 cm × 25 cm film was located at 5 cm depth.A single-filed profile generated by TPS was delivered to the film,and the film was measured.And then,two-dimensional dose distribution was analyzed using the film analysis system.Results The results suggested that the relative deviations of TLD and film to TPS dose was-8.5％ and-1.9％ for accelerator 1,5.4％ and 0.5％ for accelerator 7,respectively,whereas those for other accelerators were within ± 5％.The passing rates for two-dimensional dose distribution at all accelerators were all higher than 90％.Conclusions TLD and film quality audit for IMRT can be applied for a wide range of application in view of its simplicity,reliability and postal convenience.
