SBIR-STTR Award

Proton beam radiotherapy holds the promise for improving local control of cancer as it permits improved dose localization compared to perhaps any other radiation technique. The improved dose localization, possible through the dose deposition properties of charged particles, permits higher tumor doses with increased sparing of normal tissue doses. Thus, both an increase in tumor control and a reduction in radiation morbidity are expected. Current and future proton beam facilities require instrumentation to monitor the proton beam in real time for control and safety. Current developments in dynamically controlled scanned proton beams are expected to further improve the therapeutic advantage of protons. These developments, and the comparable developments in conventional X-ray radiotherapy, further increase the need for accurate and fast detector instrumentations. We will develop a new scintillator-based detector for the real-time monitoring of a scanned, narrow-focused, proton beam during the irradiation of a patient. This detector will track the position of the proton beam with millimeter and microsecond resolution in real-time in order to verify the relevant spatial and dosimetric beam parameters. The detector can provide feedback into the control system of the scanning beam to dynamically correct for any deviations in the beam parameters. The use of a scintillator minimally affects the proton beam and ensures that delicate instrument components are not unduly exposed to primary or scattered radiation. The only component in the beam, the scintillator, is inherently radiation robust and should show little aging due to radiation exposure, and is inexpensive to replace if needed. In Phase I, we will validate the main detector components and performance, including position response, time response, and accuracy using the proton beam facilities at the Northeast Proton Therapy Center, NPTC, at the Massachusetts General Hospital. In Phase II, we will construct a working detector that can be integrated into the treatment facility at the NTPC, and which can be easily replicated for other proton facilities. A scanning proton beam facility requires a detector system that performs like the one proposed. While many other elements go into a useful proton beam facility, this detector is one essential element of the technology that will promote improved control of cancerous tumors.

Thesaurus Terms:
biomedical equipment development, proton beam, radiation detector, radiation dosage biomedical equipment safety, light intensity, radiation therapy, time resolved data bioengineering /biomedical engineering, scintillation counter

Particle (proton and ion) beam radiotherapy holds the promise for improving cancer radiation treatment since it delivers energy in a better localized volume than X-ray (photon) therapy, owing to the Bragg peak of energy deposition near the end of an ion track. This increases the proportion of tumor cells to healthy cells that are damaged in radiation therapy. Current and future facilities require detectors to monitor the beam in real time for safety and to verify the dosimetry. This is especially true for facilities performing scanning beam therapy, since they can yield the best treatment results, using intensity modulated particle therapy, and highest patient throughputs but conversely need the best monitoring to ensure safety and proper dosage. We are developing a new scintillator-based detector for monitoring a scanning particle beam as it is used to irradiate the patient. This detector will track the position of the beam with millimeter and microsecond resolution in real-time in order to verify the beam position. In addition the detector will monitor the accumulated dose over a scan in order to validate the treatment. Using a scintillator means that the proton beam is minimally affected and no delicate components are exposed to the beam. The only component in the beam, the scintillator, is inherently robust and should show little aging due to the beam, and is inexpensive to replace, in any event. In Phase I, we tested several scintillators at the Francis H. Burr Proton Therapy Center at Mass. General Hospital (formerly called Northeast Proton Therapy Center or NPTC) and found two with the properties needed for a detector with the required position response, time response, and linearity. In Phase II, we will design and fabricate a working detector that is integrated into that treatment facility with the final scintillator chosen after additional measurements and design considerations. The design will provide the baseline detector that can easily be adapted to other proton and particle centers with some customization. A scanning particle beam facility requires a detector that performs like the one proposed. While many other elements go into a useful facility, this detector is a necessary item that helps produce improved radiation treatments for a wide variety of cancers. In addition to particle radiotherapy, the high resolution offered by robust, scintillator-based detectors also has application to photon radiotherapy. In particular, QA of IMRT treatment plans, which is currently time- consuming and difficult to perform with existing detectors, could be significantly improved using our technology. Part of our Phase II development will be devoted to this application, which can have significant impact on a radiotherapy modality that has a very large market. The proposed research will develop novel medical devices for radiotherapy, both for newer cancer radiation treatment facilities that use scanning particle beams and for more conventional facilities that use high-energy X-rays for IMRT. Intensity modulated radiation therapy requires better diagnostics in order to safely concentrate the radiation dose in the diseased tissue while sparing healthy tissue. The outcome of this research will enable therapists to deliver intensity modulated radiotherapy with greater confidence and patient safety and will also increase patient throughput and hence lower treatment costs. The net result will be improved cancer treatment for more patients