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Session: Imaging BLUE RIBBON [Return to Session]

Prompt Gamma 2D Imaging With a Slit-Slat Gamma Camera For Real-TimeTreatment Monitoring in Protontherapy: Monte Carlo Simulation Study

E Malekzadeh1, H Rajabi, P Sabouri2*, E Fiorina3, F Kalantari2, (1) Tarbiat Modares University, Faculty of medical sciences ,Tehran, 07, IR, (2) University of Arkansas for Medical Sciences, Little Rock, Ar, AR, (3) Infn, Sezione Di Torino, Torino, Italy And Cnao, Pavia, Italy,


SU-I400-BReP-F1-5 (Sunday, 7/10/2022) 4:00 PM - 5:00 PM [Eastern Time (GMT-4)]

Exhibit Hall | Forum 1

Purpose: In proton therapy, the uncertainties associated with the proton range can severely reduce the agreement between planned and delivered doses, with potentially negative impacts on the treatment outcome. A range monitoring system can help mitigate some of these uncertainties, thereby improving dose conformity to the clinical target volume and potentially reducing toxicities.

Methods: The Monte Carlo simulations were performed with the GATE package (version 8.2), which is based on GEANT4 version 10.5.1. To reduce the simulation time, the interactions inside the phantom were simulated once and the outgoing particles were stored in phase space using phase space actors in GATE. The slit-slat camera was evaluated using the trade-off between the signal-to-noise ratio and spatial resolution to determine the best configuration of the camera.

Results: According to the simulation data, the system’s detection efficiency for 4.4 MeV single prompt gammas is 0.01% at the middle of the defined FOV, and the axial and transaxial resolutions are 23 mm and 18 mm, respectively. There is less than 2 mm of beam positioning precision along with both the beam incidence and the transverse direction. Our proposed slit-slat camera with 2D imaging capability can be installed under the patient’s couch in the treatment room with minimum interference to the treatment process and without limiting the beam nozzle performance.

Conclusion: Prompt gamma-based imaging systems can potentially provide a real-time, in-vivo treatment monitoring method for proton therapy. The acquired data from the suggested slit-slat system was determined to be suitable for real-time range uncertainty monitoring. As a result, by integrating this information with a specified dose during the treatment process, the range and dose uncertainties in proton therapy can be revealed. Furthermore, using analytical or machine learning methods, the retrieved data may be beneficial for dose reconstruction.


Not Applicable / None Entered.


Not Applicable / None Entered.

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