Micrometer-resolved film dosimetry using a microscope in microbeam radiation therapy.

摘要: Purpose: Microbeam radiation therapy (MRT) is a still preclinical tumor approach that uses arrays of few tens micrometer wide parallel beams separated by 100 μm. The production, measurement, and planning such fields are challenge up to now. Here, the authors investigate feasibility radiochromic film dosimetry in combination with microscopic readout as tool validate peak valley doses MRT, which an important requirement for future clinical application therapy. Methods: Gafchromic® HD-810 HD-V2 films exposed MRT at biomedical beamline ID17 European Synchrotron Radiation Facility (ESRF) afterward scanned microscope. measured dose compared Monte Carlo calculations. Image analysis tools handling protocols developed allow accurate reproducible dosimetry. performance detailed resolution, noise, energy dependence carried out. Measurement uncertainties identified analyzed. Results: was resolution 5 × 1000 μm2 accuracy 5% between 10% 15% region. As main causes uncertainties, statistical inhomogeneities, calibration errors were identified. Calibration strongly increase low exceeded 3% below 50 70 Gy films, respectively. While grain size both types approximately 2 μm, noise much higher than films. However, show photon energies. Conclusions: Both appropriate microscope superior microdensitometer used before ESRF respect reproducibility. very careful image data required. Dosimetry energies should be performed great caution due sensitivity In this respect, showed have advantage over lower level. When required, e.g., pencil beam irradiations, may render inapplicable.