Proton Imaging System Incorporating Positron Emission Tomography (PET) Modules for Optimization of Proton Therapy

A method for operating a novel proton imaging system with positron emission tomography (PET) modules to enable rapid on-the-fly in vivo range verifications for proton therapy by utilizing information from short-lived positron emitters produced during a proton beam treatment, the method comprising the steps of:

• aligning a patient to an isocenter of a next proton beam treatment field in the novel proton imaging system;
• transforming PET detector coordinates to isocenter coordinates, which are derived from diverging pencil beams and a time-of-flight (TOF) technique, wherein relative TOFs of two photons from a positron annihilation provide a measurement of annihilation positions along a line between the two photons;
• tracking detectors and a target object in the patient aligned to the isocenter through native alignments provided by the novel proton imaging system;
• acquiring positron annihilation coincidence and TOF data from PET detector panels that detect positron emitters produced from a proton beam during treatment, wherein the positron annihilation coincidence and TOF data involves detection of secondary radiation from an interaction of the proton beam with the target object, which provides an opportunity for an in vivo range verification by detecting electron-positron annihilation events with scintillators in the PET detector panels;
• executing gamma coincidence line and TOF-derived position probability density calculations in the isocenter coordinates in a scalable graphical processing unit (GPU) of the novel proton imaging system;
• creating a treatment plan involving positions, timing, and gaps for delivery of pencil beams, a relative stopping power (RSP) map, and tissue composition information;
• uploading the treatment plan to a real-time update of a treatment background model and a current pencil beam signal model executed in the scalable GPU or a central processing unit (CPU) of the novel proton imaging system, wherein the treatment background model and the current pencil beam signal model are configured to incorporate outputs of GPU calculations of the gamma coincidence line and the TOF-derived position probability density calculations dynamically in real time to enable real-time model refinements during the proton beam treatment;
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• performing a fast range check before the next proton beam treatment field after taking account of the real-time model refinements to the treatment background model and the current pencil beam signal model.