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http://dx.doi.org/10.14316/pmp.2014.25.4.255

Feasibility Study of the microDiamond Detector for Measurement of Small Field Photon Beam  

Lee, Chang Yeol (Department of Radiation Oncology, College of Medicine, Inha University)
Kim, Woo Chul (Department of Radiation Oncology, College of Medicine, Inha University)
Kim, Hun Jeong (Department of Radiation Oncology, College of Medicine, Inha University)
Ji, Young Hoon (Research Institute of Radiological and Medical Sciences, Korea Institute of Radiological and Medical Sciences)
Kim, Kum Bae (Research Institute of Radiological and Medical Sciences, Korea Institute of Radiological and Medical Sciences)
Lee, Sang Hoon (Department of Radiation Oncology, College of Medicine, Kwandong University)
Min, Chul Kee (Department of Radiation Oncology, College of Medicine, Soonchunhyang University)
Jo, Gwang Hwan (Department of Radiation Oncology, College of Medicine, Soonchunhyang University)
Shin, Dong Oh (Department of Radiation Oncology, College of Medicine, Kyunghee University)
Kim, Seong Hoon (Department of Radiation Oncology, College of Medicine, Hanyang University)
Huh, Hyun Do (Department of Radiation Oncology, College of Medicine, Inha University)
Publication Information
Progress in Medical Physics / v.25, no.4, 2014 , pp. 255-263 More about this Journal
Abstract
The dosimetry of very small fields is challenging for several reasons including a lack of lateral electronic equilibrium, large dose gradients, and the size of detector in respect to the field size. The objective of this work was to evaluate the suitability of a new commercial synthetic diamond detector, namely, the PTW 60019 microDiamond, for the small field dosimetry in cyberknife photon beams of 6 different collimator size (from 5 mm to 30 mm). Measurements included dose linearity, dose rate dependence, output factors (OF), percentage depth doses (PDD) and off center ratio (OCR). The results were compared to those of pinpoint ionization chamber, diamond detector, microLion liquid Ionization chamber and diode detector. The dose linearity results for the microDiamond detector showed good linearly proportional to dose. The microDiamond detector showed little dose rate dependency throughout the range of 100~600 MU/min, while microLion liquid Ionization chamber showed a significant discrepancy of approximately 5.8%. The OF measured with microDiamond detector agreed within 3.8% with those measured with diode. PDD curves measured with silicon diode and diamond detector agreed well for all the field sizes. In particular, slightly sharper penumbras are obtained by the microDiamond detector, indicating a good spatial resolution. The results obtained confirm that the new PTW 60019 microDiamond detector is suitable candidate for application in small radiation fields dosimetry.
Keywords
microDiamond detector; Small field; Dosimetry;
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