| Zhou Wenshan,Sun Gangtao,Ye Song,Luo Suming.Verification of absorbed dose and single-field dosimetry of MLC-shaped IMRT photon beams in Hubei province[J].Chinese Journal of Radiological Medicine and Protection,2018,38(2):129-133 |
| Verification of absorbed dose and single-field dosimetry of MLC-shaped IMRT photon beams in Hubei province |
| Received:August 17, 2017 |
| DOI：10.3760/cma.j.issn.0254-5098.2018.02.010 |
| KeyWords:Intensity modulated radiotherapy Thermoluminescent dosimeter Film Absorbed dose Two-dimensional dose distribution |
| FundProject:IAEA基金资助项目（17821/CRP） |
| Author Name | Affiliation | E-mail | | Zhou Wenshan | Hubei Provincial Center for Disease Control and Prevention, Wuhan 430079, China | | | Sun Gangtao | Hubei Provincial Center for Disease Control and Prevention, Wuhan 430079, China | | | Ye Song | Hubei Provincial Center for Disease Control and Prevention, Wuhan 430079, China | | | Luo Suming | Key Laboratory of Radiological Protection and Nuclear Emergency, China CDC, National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing 100088, China | sumingluo@163.com |
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| 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. |
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