Water-Equivalent Plastic Scintillation Detectors for Small-Field Radiotherapy

Standard Imaging, Inc., Middleton WI

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Abstract

DESCRIPTION (provided by applicant): Standard Imaging, Inc. is developing a new generation of radiation dosimeters for small field dosimetry, which are needed in clinical applications such as stereotactic radiosurgery/ stereotactic radiotherapy (SRS/SRT), intensity modulated radiation therapy (IMRT), dynamical arc therapy and tomotherapy treatments. The enabling technology is the point scintillation detector which employs a miniature plastic scintillator coupled to a color PIN diode detector via an optical fiber. The overall aim of this project is to transform the critical performance features of a proven benchtop Plastic Scintillation Detector (PSD) system into a reliable, miniaturized PSD system that eliminates cumbersome optical subsystems and is suitable for daily usage in typical clinical settings. This project will design, build, and test a Plastic Scintillator Detector and will result in a prototype system that can be characterized for use in small fields. To bring the scintillation detector system from the benchtop to the clinic, several strategies will be implemented. First, the CCD-based photodetector will be replaced with a PIN diode. This will permit subtraction of Cerenkov noise without the need to separate the light signal with filters. Second, the optics will be replaced with a simple direct coupling to the PIN diode. This will enable replacing the bulky optical bench with a small black box that can easily be placed on the treatment couch. Finally, modified software designed to run on the Standard Imaging SuperMAX electrometer with specific features for this application will be developed during this Phase I study. Two complete prototype systems will be independently tested-one at a collaborative medical site under realistic clinical conditions by experts in the field and one at Standard Imaging's facilities;instrument behavior will be fully characterized. Standard Imaging has obtained the services of two individuals who are internationally renowned experts in scintillation dosimetry and have been pioneering the development of scintillation dosimetry for radiotherapy applications for more than a decade. In Phase II, this new miniature radiation PSD system will be commercialized for use in the clinic. PUBLIC HEALTH RELEVANCE: Patients undergoing very delicate radiation treatment, such as stereotactic radiosurgery/ stereotactic radiotherapy (SRS/SRT), intensity modulated radiation therapy (IMRT), dynamical arc therapy, or tomotherapy treatments, need extremely precise and accurate doses. Current methods are adequate, but could be much better. Standard Imaging is developing a reliable, miniaturized Plastic Scintillation Detector (PSD) system that will accurately measure the actual radiotherapy dose-and improve patient care and safety.