SBIR Phase I: Medical Devices for Real-time Radiation Dosimetry at Sub-millimeter Spatial Resolution

This Small Business Innovation Research Phase I project seeks development of a novel dosimeter for 2-D mapping of radiation dose in real-time at sub-millimeter spatial resolution. The high spatial resolution of the dosimeter is essential in supporting stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) treatments. These rapidly emerging modalities deliver precise doses of radiation to small, well defined treatment sites while minimizing exposure of critical neighboring anatomy. With the annual number of SRS/SBRT treatments approaching 1,000,000 and growing 5-10% annually there is a market need for a dosimeter with sub-millimeter resolution and the capability of measuring in real-time. The routine pre-treatment verification of each patient therapy plan becomes a target application. The value of the market for the dosimeter alone exceeds $10 million annually. The value is amplified through enablement of the safe and efficacious delivery of SRS and SBRT treatments. Use of these modalities greatly impacts the efficiency of radiotherapy by substantially reducing the number of individual sessions in a course of treatment. The net result is lower cost for the treatment course, an increase in the number of patients/year for each linear accelerator equipment unit and a large reported improvement in patient outcomes. The intellectual merit of this project lies in combining and adapting key elements of two well-established commercial technologies, piezoelectric polymers and radiochromic film, to produce a hybrid dosimeter. This dosimeter preserves the high spatial resolution of radiochromic film while improving its usability by making the changes caused by radiation exposure to become detectable by electronic means in real-time. During use, the flexible, single-use piezoelectric array dosimeter (PARD) fits into a re-usable data acquisition electronics module that transmits a map of measured doses to a Medical Physicist outside the radiation cell. Radiochromic film, the only current dosimeter with sub-millimeter spatial resolution, is inconvenient owing to the long delay between exposure and measurement as well as the extra time and effort in facilitating the measurements. This drawback adversely impacts its usefulness in the day-to-day verification of patient treatment plans. The hybrid PARD product provides a dense, flexible array (0.1 mm spacing) of detectors with the unique ability for dose measurement at sub-millimeter resolution in real time. This overcomes key drawbacks of existing electronic array devices which are incapable of spatial resolution below 5 mm and unsuitable for the small radiation fields associated with SRs and SBRT treatments.