Program Information
Clinical Translation of Prompt Gamma-Ray Spectroscopy for In Vivo Proton Range Verification
J Verburg1*, T Ruggieri1, P Botas1,2, E Cascio1, F Hueso-Gonzalez1, M Rabe1,2, T Bortfeld1, (1) Massachusetts General Hospital and Harvard Medical School, Boston, MA (2) Heidelberg University, Heidelberg, Germany
Presentations
SU-F-601-2 (Sunday, July 30, 2017) 2:05 PM - 3:00 PM Room: 601
Purpose: We will present our completed clinical prototype system to measure the range of proton beams using prompt gamma-ray spectroscopy.
Methods: The clinical prompt gamma-ray spectroscopy system consists of an array of lanthanum(III) bromide scintillation detectors, a tungsten collimator, integrated readout electronics, and a data acquisition system. It will be positioned superior of the patient’s head for the first clinical study, in which we will measure the range of proton pencil-beam delivered during meningioma treatments. Accurate positioning of the device relative the patient is achieved using a 7-axis robotic system. By synchronizing the in vivo measurements to both the beam delivery systems and the phase of the cyclotron radiofrequency, proton-induced prompt gamma-ray emissions from many different nuclear reactions are resolved and quantified. Before the treatment, models of these gamma-ray emissions are created using a GPU-accelerated simulation. The range deviations of the delivered pencil-beams are determined from the measurements using a maximum likelihood estimation method.
Results: Tests of the system showed good performance of all detectors and electronics. Compatibility of the system with beam currents in excess of 2 nA was demonstrated, which facilitates clinical studies without any changes to the current treatment practice. The GPU acceleration of the pre-treatment nuclear reaction calculations reduced the computation time to a few minutes, which is promising in view of future use for real-time treatment adaptation.
Conclusion: We successfully developed a clinical prototype prompt gamma-ray spectroscopy system. IRB approval has been obtained for the first-in-human proton range measurements using this technology, which will be performed during meningioma treatments.
Funding Support, Disclosures, and Conflict of Interest: This work was supported by the Federal Share of program income earned by Massachusetts; General Hospital on C06-CA059267, Proton Therapy Research and Treatment Center.
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