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Title: TH-C-17A-07: Visualizing and Quantifying Radiation Therapy in Real-Time Using a Novel Beam Imaging Technique

Purpose: Radiation therapy uses invisible high energy X-rays to treat an invisible tumor. Proper positioning of the treatment beam relative to the patient's anatomy during dose delivery is critically important to the success of treatment. We develop and characterize a novel radiation therapy beam visualization technique for real-time monitoring of patient treatment. Methods: Custom made flexible scintillator sheets were fabricated from gadolinium oxysulfide (GOS) particles that had been doped with terbium within a silicone elastomer matrix. Sheets of several thicknesses ranging from 0.3 to 1mm were prepared and tested. Sheets were exposed to megavoltage X-ray and electron beams from a Varian linac and the resulting optical signal was collected by multiple CMOS cameras placed in the treatment room. Real-time images were collected for different beam energies and dose rates. Signal intensity and SNR were calculated by processing the acquired images. Results: All signals were detectable in the presence of full room lighting and at an integration time of 45ms. Average signal intensity and SNR increased with both sheet thickness and dose rate and decreased with beam energy and incident light. For a given sheet thickness and beam energy the correlation between dose rate and signal intensity was highly linear. Increasedmore » sheet thickness or dose rate results in a linear increase in the detected signal. All results are consistent with analytical approximations. Conclusion: The technique offers a means of accurately visualizing a radiation therapy beam shape and fluence in real time. The effects of salient parameters have been characterized and will enable further optimization of the technique as it is implemented into the clinical workflow. The project described was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health through UL1 TR001085.« less
Authors:
; ;  [1]
  1. Stanford University, Stanford, CA (United States)
Publication Date:
OSTI Identifier:
22409857
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ANATOMY; DOSE RATES; ELECTRON BEAMS; LINEAR ACCELERATORS; MONITORING; NEOPLASMS; OPTIMIZATION; POSITIONING; RADIOTHERAPY