Determination of the surface dose of a water phantom using a semiconductor detector for diagnostic kilovoltage x-ray beams
| Autor: | Ryuki Tanabe, Fujio Araki |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Monte Carlo method Biophysics General Physics and Astronomy Fluence Imaging phantom 030218 nuclear medicine & medical imaging 03 medical and health sciences Kerma 0302 clinical medicine Optics Calibration Radiology Nuclear Medicine and imaging Radiometry Phantoms Imaging business.industry X-Rays Detector Water General Medicine Semiconductor detector Semiconductors 030220 oncology & carcinogenesis Ionization chamber business Monte Carlo Method |
| Zdroj: | Physica Medica. 84:198-204 |
| ISSN: | 1120-1797 |
| DOI: | 10.1016/j.ejmp.2021.04.009 |
| Popis: | Purpose To determine the surface dose of a water phantom using a semiconductor detector for diagnostic kilovoltage x-ray beams. Methods An AGMS-DM+ semiconductor detector was calibrated in terms of air kerma measured with an ionization chamber. Air kerma was measured for 20 x-ray beams with tube voltages of 50–140 kVp and a half-value layer (HVL) of 2.2–9.7 mm Al for given quality index (QI) values of 0.4, 0.5, and 0.6, and converted to the surface dose. Finally, the air kerma and HVL measured by the AGMS-DM+ detector were expressed as a ratio of the surface dose for 10 × 10 and 20 × 20 cm2 fields. The ratio of both was represented as a function of HVL for the given QI values and verified by comparing it with that calculated using the Monte Carlo method. Results The air kerma calibration factor, CF, for the AGMS-DM+ detector ranged from 0.986 to 1.016 (0.9% in k = 1). The CF values were almost independent of the x-ray fluence spectra for the given QI values. The ratio of the surface dose to the air kerma determined by the PTW 30,013 chamber and the AGMS-DM+ detector was less than 1.8% for the values calculated using the Monte Carlo method, and showed a good correlation with the HVL for the given QI values. Conclusion It is possible to determine the surface dose of a water phantom from the air kerma and HVL measured by a semiconductor detector for given QI values. |
| Databáze: | OpenAIRE |
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