Implantable MOSFET detectors: evaluation of a new design.
The authors have studied the performance of a new version of the implantable MOSFET detector designed for clinical use. Detectors were irradiated under 6- and 18-MV beams in water at body temperature to the calibration dose of 200 cGy/fraction for 20 daily fractions to determine their response and reproducibility. Additional measurements were performed in a solid phantom under 6-MV irradiation at room temperature to daily doses of 100, 150, 200, 250, 400 and 600 cGy/ fraction. Finally, the angular dependence with respect to rotation about the detector's longitudinal axis was studied. At body temperature, the detectors were found to have an average response within +/- 3% of the calibration dose with a standard deviation of 2% or less. At room temperature, doses lower than the calibration dose led to a slight overresponse while doses higher than the calibration dose led to a slight underresponse. Angular dependence was not significant, on average within 1.2% of the mean. When used as specified by the manufacturer, these detectors should provide data useful to verify the delivered dose for external beam radiation therapy within a certain tolerance.
Briere
Tina Marie
TM
Department of Radiation Physics, Division of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Gillin
Michael T
MT
Beddar
A Sam
AS
D001831:Body Temperature; D002138:Calibration; D004867:Equipment Design; D020007:Implants, Experimental; D010087:Oxides / Q000737:chemistry*; D017785:Photons / Q000627:therapeutic use; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012399:Rotation; D013696:Temperature; D014173:Transistors, Electronic
D010087:Oxides