Program Information
A Prototype for Couch Based Real-Time Dosimetry in External Beam Radiotherapy
P Ramachandran1*, (1) Peter MacCallum Cancer Centre, Bendigo,
Presentations
SU-E-T-66 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: The main purpose of this study is to design a prototype for couch-based based real time dosimetry system in external beam radiotherapy
Methods: A prototype of 100 ionization chambers was designed on a printed circuit board by etching the copper layer and each ionization chamber was wired to a 50 pin connector. The signals from the two 50 pin connectors collected from the ionization chambers were then transferred to a PXI module from National Instruments. The PXI module houses a current amplifier that amplifies the charge collected from the ionization chamber. The amplified signal is then sent to a digital multimeter module for converting the analog signal to digital signal. A software was designed in labview to read and display the signals obtained from the PXI module. A couch attachment frame was designed to house the 100 ionization chamber module. The frame was fixed underneath the treatment couch for measuring the dose during treatment.
Resutls: The ionization chamber based prototype dosimetry was tested for simple radiotherapy treatment fields and found to be a useful device for measuring real time dosimetry at the treatment couch plane. This information could be used to assess the delivered dose to a patient during radiotherapy. It could be used as an invivo dosimeter during radiotherapy.
Conclusion: In this study, a prototype for couch based real time dosimetry system was designed and tested. The prototype forms a basis for the development of large scale couch based real time dosimetry system that could be used to perform morning QA prior to treatment, assess real time doses delivered to patient and as a device to monitor the output of the treatment beam.
Funding Support, Disclosures, and Conflict of Interest: Peter MacCallum Cancer Foundation
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