(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose:
An early indicator of radiation induced skin reactions would be a valuable tool for mitigating skin toxicity in radiation therapy patients. Based on previous mouse studies, a tomographic reconstruction of skin effusivity using a flash pulsed thermal imaging system could be used for early detection, but translation of the technique to human subjects requires additional development.
Methods:
Due to the finite speed of heat propagation, one can calculate the thermal properties of materials at depth based on the decay of surface temperature after impulse heating. A pulsed thermal imaging system has been employed using two flash lamps and an infrared camera. Vinyl tape with measured thermal properties was used as a fiducial and effusivity values of a custom 3D printed imaging phantom to assess image quality were performed. The phantom was water filled to provide contrast for the imaging test.
Results:
The thermal effusivity of vinyl tape was first calibrated using the known value of water (1588 W s¹/² /(m² °K)). Calculated values of tape effusivity were found to be 590±7.5 W s¹/² /(m² °K). Effusivity profiles were taken of a 3D printed phantom with a measured effusivity of 450±20 W s¹/² /(m² °K). After effusivity reconstruction of the water filled phantom, bar patterns were analyzed and a modulation transfer function calculated. The best limiting spatial resolution of 5.9 lines / cm producing 10% modulation is achieved at a depth of 0.67mm beneath the vinyl tape.
Conclusion:
We have validated the precision and repeatability of the measurement apparatus in a previous study and the imaging quality in this study, allowing detection of effusivity changes which may manifest as a precursor to skin toxicities grade 2 or higher.
Keywords
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Not Applicable / None Entered.
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