TY - JOUR
T1 - A novel imaging scheme for optical cameras used in a quality assurance detector for discrete spot scanning proton beam systems
AU - Alsanea, Fahed
AU - Darne, Chinmay
AU - Hojo, Yoshifumi
AU - Beddar, Sam
N1 - Funding Information:
The authors would like to thank Dr. Narayan Sahoo for his help with proton beam measurements, and Dr. Jim Bankson for his help with trigger equipment testing. This work was supported by the National Cancer Institute of the National Institutes of Health (Award Number R01CA182450 ). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2019
PY - 2019/9/21
Y1 - 2019/9/21
N2 - Quality assurance detectors comprising cameras and a scintillator volume are of interest for use in spot scanning proton therapy due to its dynamic delivery. In this work, we aimed to image scanned proton beams with greater flexibility than is provided by previous systems by using an innovative camera triggering solution. The main objective was to synchronize image acquisitions with proton beam deliveries. A 3D detector composed of 3 scientific complementary metal–oxide–semiconductor cameras and a volumetric liquid scintillator (20 ×20× 20 cm)were used. We identified relevant signals from the synchrotron beam delivery system to trigger the cameras. These signals were processed using an open hardware microcontroller and monitored using an oscilloscope. We evaluated the camera triggering scheme by comparing the mean signal intensity and standard deviations for triggered versus non-triggered image acquisitions at 5 energies (161.6, 140.9, 124.0, 100.9, and 85.6 MeV)with 50 spots per energy. The performance of the triggering scheme was further investigated by testing the image intensity variability for 5 energies delivered at 9 different location (2 spots/location). We also measured the background signals for different exposure times (1–1000 ms)using both triggered and non-triggered schemes. The mean signal intensity difference between triggered and non-triggered schemes was 10% ± 0.4% for low SNR (∼20 dB). The image intensity variability was within 2%. The background signal intensity varied by only 0.6% from the shortest exposure time (1 ms)to the longest (1 s). We demonstrated a flexible triggering scheme using an open hardware microcontroller with a camera and scintillator detector system for a spot scanning proton beam, which will enable efficient machine quality assurance and treatment plan verification measurements in the future.
AB - Quality assurance detectors comprising cameras and a scintillator volume are of interest for use in spot scanning proton therapy due to its dynamic delivery. In this work, we aimed to image scanned proton beams with greater flexibility than is provided by previous systems by using an innovative camera triggering solution. The main objective was to synchronize image acquisitions with proton beam deliveries. A 3D detector composed of 3 scientific complementary metal–oxide–semiconductor cameras and a volumetric liquid scintillator (20 ×20× 20 cm)were used. We identified relevant signals from the synchrotron beam delivery system to trigger the cameras. These signals were processed using an open hardware microcontroller and monitored using an oscilloscope. We evaluated the camera triggering scheme by comparing the mean signal intensity and standard deviations for triggered versus non-triggered image acquisitions at 5 energies (161.6, 140.9, 124.0, 100.9, and 85.6 MeV)with 50 spots per energy. The performance of the triggering scheme was further investigated by testing the image intensity variability for 5 energies delivered at 9 different location (2 spots/location). We also measured the background signals for different exposure times (1–1000 ms)using both triggered and non-triggered schemes. The mean signal intensity difference between triggered and non-triggered schemes was 10% ± 0.4% for low SNR (∼20 dB). The image intensity variability was within 2%. The background signal intensity varied by only 0.6% from the shortest exposure time (1 ms)to the longest (1 s). We demonstrated a flexible triggering scheme using an open hardware microcontroller with a camera and scintillator detector system for a spot scanning proton beam, which will enable efficient machine quality assurance and treatment plan verification measurements in the future.
KW - CMOS
KW - Camera
KW - Proton therapy
KW - Scintillator
KW - Trigger
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U2 - 10.1016/j.nima.2019.05.038
DO - 10.1016/j.nima.2019.05.038
M3 - Article
AN - SCOPUS:85066260360
SN - 0168-9002
VL - 939
SP - 16
EP - 21
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
ER -