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Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
Published on: May 9, 2014
Evaluation of chamber response function influence on IMRT verification using 2D commercial detector arrays
A Gago-Arias1, L Brualla-González, D M González-Castaño
1Departamento de Física de Partículas, Facultad de Física, Universidad de Santiago de Compostela, Spain. araceli.gago@usc.es
Physics in Medicine and Biology
|March 21, 2012
Summary
The response functions of air-ionization chambers and diode detectors have minimal impact on standard IMRT verification using the gamma function. Detector arrays perform similarly, with slight differences emerging at tighter tolerances.
Area of Science:
- Medical Physics
- Radiotherapy Physics
- Radiation Detection
Background:
- Intensity-modulated radiation therapy (IMRT) verification is crucial for patient safety.
- Detector technology, including air-ionization chambers and diodes, influences IMRT verification accuracy.
- Understanding chamber response functions is key to reliable dosimetry.
Purpose of the Study:
- To investigate the influence of detector response functions on IMRT verification.
- To compare the performance of air-ionization chamber and diode detector arrays.
- To assess the impact of response functions across different detector technologies.
Main Methods:
- Simulated detector response functions using Monte Carlo methods.
- Measured response functions using slit and pinhole collimators.
- Evaluated IMRT verification using the gamma function with varying tolerances.
Main Results:
- The impact of response function differences on gamma analysis (3 mm/3%) was limited.
- Air-ionization chamber arrays showed similar performance down to 1.5 mm/1.5% tolerances.
- Air-ionization chambers were more sensitive to fluence perturbations than silicon diodes.
Conclusions:
- Detector technology has a limited impact on standard IMRT verification with typical gamma tolerances.
- Silicon diode arrays offer higher accuracy for point-by-point dose distribution assessment.
- Careful consideration of detector response is necessary for precise radiotherapy dosimetry.
