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Evaluation of the Lens-absorbed Dose of the Scattered Radiation Generated During Tomotherapy IMRT to the H&N Cancer Patient

Journal of Magnetics, Volume 22, Number 1, 31 Mar 2017, Pages 141-145
Jae-Won Choi (Department of Radiation Oncology, Samsung Medical Center), Hae-Kag Lee (Department of Computer Science and Engineering, Soonchunhyang University), Jae-Hwan Cho (Department of Radiological Technology, Ansan University), Cheon Woong Choi (Department of Respiratory and Critical Care Medicine, Kyung Hee University Hospital at Gangdong), Myung Sik Ju (Department of Radiology, Soonchunhyang University Bucheon Hospital), Bok Soon Chang (Department of Pulmonary and Critical Care Medicine, Kyung Hee Univeristy Hospital at Gangdong), Cheol-Soo Park * (Department of Radiological Science, Hallym Polytechnic University)
Abstract
This paper uses a glass dosimeter to evaluate the lens-absorbed dose of scattered radiation generated in tomotherapy intensity modulated radiation therapy (IMRT). The head and neck portion of the rando phantom was subjected to a CT scan. The tomotherapy plan was designed to ensure delivery of the prescribed total 70 Gy day 2.2 Gy. With the lens portion of the glass dosimeter, a 5mm bolus was subjected to the scattered radiation treatment, and the dose was measured in each of the three megavoltage CT (MVCT) modes. The result is multiplied by 30 times and was determined once as the mean value. The measurement at the MVCT Coarse mode is RT mode 10.797 mGy, that for the Normal mode is 13.360 mGy, for the Fine mode is a maximum of 22.872 mGy, and for the treatment mode is 895.830 mGy. A small amount of scattered radiation in the MVCT is measured in the lens scattered radiation, but scattered radiation during treatment was measured to be near 1 Gy on the lens. Compared to a one-time radiation treatment of 2.2 Gy, the survey showed something unexpected in that it was half the value of that research to the patient. Therefore, will be aware of how much of an influence there will be on sensitive organs, such as the lens by scattered radiation generated during intensity modulated radiation therapy.
Keywords: scattered radiation; IMRT (intensity modulated radiation therapy); absorbed dose; tomotherapy; MVCT (megavoltage CT)
DOI: https://doi.org/10.4283/JMAG.2017.22.1.141
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