Visualization of an Intra-Operative X-Ray Source With Liquid Scintillation Imaging

Peter A. Sandwall

Department of Radiation Oncology, OhioHealth - Mansfield , OH, USA

Dr. Peter A. Sandwall,
Department of Radiation Oncology, OhioHealth - Mansfield, Ohio, USA.

Keywords: Luminescence; Scintillation; Dosimetry; Intraoperative Radiotherapy

Abstract

Intraoperative radiotherapy (IORT) is an alternative to full course radiotherapy for select patients. The IntraBeam (Zeiss, Germany) delivery system uses a low energy (50kVp) x-ray source. In this communication, a method for rapidly characterizing emissions from an IORT x-ray source is shared. A leaded glass phantom was filled with liquid scintillation cocktail (LSC) (Ultima Gold; PerkinElmer, USA) and a 13 MP CMOS detector used to collect images and videos. Scintillation images were analyzed with relative intensity plotted as a function of distance from the bare probe tip. RGB channels were separated, blue selected, smoothed, and overlaid with isodose lines. Videos allowed time-resolved visualization of energy deposition. Elemental composition of LSC fluid was compared to water and soft tissue. LSC has a lower effective Z (5.9) than water (7.2) and tissue (7.1). Observed relative intensity compared to Monte Carlo depth dose in water revealed an under-response (max, 9.49% at 5mm). Optimization of LSC composition, parameters for image collection, and derivation of correction factors are areas of future study. This visualization method shows potential for rapid commissioning of an IORT x-ray source with scintillation imaging.

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