TY  - GEN
ID  - heidok13323
Y1  - 2012///
KW  - Heavy ion therapy 
KW  -  Dosimetry 
KW  -  Scintillating screens
AV  - public
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/13323/
N2  - Scanned heavy ion radiotherapy produces complex dose distributions, which have to be measured with high resolution in quality assurance. This work investigates a scintillating screen detector, originally developed for beam diagnosis, for fluence measurements at the Heidelberg Ion-Beam Therapy Center (HIT). Measurement control and evaluation software was developed, implemented and used to investigate background, camera settings, influence of the lens and the 45 tilt of the screen relative to the beam on the image signal. Correction methods for background, vignetting and perspective were developed and applied for detector response measurements. The signal of the detector is independent on beam intensity and shows a strictly linear dependence on fluence with an energy-dependent slope. As the fluence calibration showed large day-by-day variations, a recalibration is required for each measurement session. Comparisons of measured and calculated 2d fluence maps of treatment plans showed broader distributions in the measurement. This was attributed to an optical blurring e ect, which has not been corrected for and has to be further investigated before the system can be used clinically. In conclusion, a method for vignetting and perspective correction was developed and the system was characterized for di erent beam parameters. Finally, requirements for an optimized system were derived.
TI  - Investigation of a scintillating screen detector for ion beam therapy
A1  - Lahrmann, Sonja
ER  -