Proton radiography produces images of patients in terms of proton stopping power, by tracking individual protons before and after the patient and measuring the proton residual range after traversing the patient, and would be the most direct method of image guidance for proton radiation therapy. Radiation therapy is needed for more than 50% of the 1.6 million Americans who are annually diagnosed with cancer. A conservative estimate from the Mayo Clinic states that 137,000 new cancer patients each year in the United States could benefit from proton radiation therapy, well above current capacity. Proton radiation therapy can potentially spare large amounts of normal tissue from low to intermediate radiation dose and avoid organs at risk. This reduces late effects and improves quality of life, and is especially important for patients with high cure rates and long survival times. There is a clear need to enable more complex treatments delivering a high dose to the tumor with reduced uncertainty margins [2,3]. There is also a clear need to increase patient throughput and to improve the cost-effectiveness of proton therapy relative to conventional radiation therapy [6]. The use of a proton beam for both imaging and treatment streamlines patient setup and quality assurance procedures, reduces alignment uncertainties, and reduces proton range uncertainties. Our academic partner previously participated in the clinical implementation of an analogous strategy applying megavoltage CT to image guidance for adaptive helical tomotherapy [13]. Our goal is to commercialize a high-performance low-cost proton radiography system based on well- established fast scintillator technology, with optimal proton range resolution, and dose to the patient lower than for equivalent x-ray images. In Phase II we propose to construct a fully functional prototype of a clinical proton radiography system with 40 x 40 cm2 field size, mounted on a c-arm to accommodate a wide variety of patient and beam orientations, with a CPU-GPU workstation for prompt delivery of a reconstructed image, and to perform a series of tests culminating in the production of images of phantoms. Our design is high-performing as well as compact, simple and monolithic with a low electronics channel count. We have chosen an approach that is conservative and low-risk, using off-the-shelf components whenever possible. Our commercialization plan discusses a path to commercialization involving research partners, clinical partners and development partners to achieve the integration of our technology into treatment rooms for clinical use. We have obtained a strong set of letters of support from potential partners, indicating a high probability of commercialization. This includes some of the lead authors of Ref. [14] who state that it would be natural to incorporate actual proton radiographs, as well as proton facility vendors, developers, and investors.
Proton radiation therapy treats cancer while potentially sparing large amounts of normal tissue from low to intermediate radiation dose and avoiding organs at risk. Proton radiography can precisely target tumors, minimizing uncertainty margins while streamlining patient setup and quality assurance procedures by using a proton beam for both imaging and treatment.
