Dosimetric evaluation of a new OneDose MOSFET for Ir-192 energy
| Autor: | Deepak D. Deshpande, Chandrashekhar M Tambe, Rajesh A Kinhikar, Pramod K. Sharma |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Reproducibility
Materials science Dosimeter Radiological and Ultrasound Technology Phantoms Imaging business.industry medicine.medical_treatment Brachytherapy Reproducibility of Results Linearity Iridium Radioisotopes MOSFET Ionization chamber medicine Humans Dosimetry Radiology Nuclear Medicine and imaging Thermoluminescent dosimeter Radiometry Nuclear medicine business Biomedical engineering |
| Zdroj: | Physics in Medicine and Biology. 51:1261-1268 |
| ISSN: | 1361-6560 0031-9155 |
| Popis: | The purpose of this study was to investigate dosimetry (reproducibility, energy correction, relative response with distance from source, linearity with threshold dose, rate of fading, temperature and angular dependence) of a newly designed OneDosetrade mark MOSFET patient dosimetry system for use in HDR brachytherapy with Ir-192 energy. All measurements were performed with a MicroSelectron HDR unit and OneDose MOSFET detectors. All dosimeters were normalized to 3 min post-irradiation to minimize fading effects. All dosimeters gave reproducible readings with mean deviation of 1.8% (SD 0.4) and 2.4% (SD 0.6) for 0 degrees and 180 degrees incidences, respectively. The mean energy correction factor was found to be 1.1 (range 1.06-1.12). Overall, there was 60% and 40% mean response of the MOSFET at 2 and 3 cm, respectively, from the source. MOSFET results showed good agreement with TLD and parallel plate ion chamber. Linear dose response with threshold voltage shift was observed with applied doses of 0.3 Gy-5 Gy with Ir-192 energy. Linearity (R2 = 1) was observed in the MOSFET signal with the applied dose range of 0.3 Gy-5 Gy with Ir-192 energy. Fading effects were less than 1% after 10 min and the MOSFET detectors stayed stable (within 5%) over a period of 1 month. The MOSFET response was found to be decreased by approximately 1.5% at 37 degrees C compared to 20 degrees C. The isotropic response of the MOSFET was found to be within +/-6%. A maximum deviation of 5.5% was obtained between 0 degrees and 180 degrees for both the axes and this should be considered in clinical applications. The small size, cable-less, instant readout, permanent storage of dose and ease of use make the MOSFET a novel dosimeter and beneficial to patients for skin dose measurements with HDRBT using an Ir-192 source compared to the labour demanding and time-consuming TLDs. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|