How effective can optical-CT 3D dosimetry be without refractive fluid matching?

7th International Conference on 3D Radiation Dosimetry

Rankine, L.^1 ; Oldham^1

Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States^1

关键词: Cost penalty;    Detector size;    Optical CT;    Parallel beams;    Point sources;    Refractive fluids;    Refractive media;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/444/1/012065/pdf
DOI  :  10.1088/1742-6596/444/1/012065

来源: IOP

【 摘 要 】

Achieving accurate optical CT 3D dosimetry without the use of viscous refractive index (RI) matching fluids would greatly increase convenience. Software has been developed to simulate optical CT 3D dosimetry for a range of scanning configurations including parallel-beam, point and converging light sources. For each configuration the efficacy of 3 refractive media were investigated: air, water, and a fluid closely matched to Presage (RI = 1.00, 1.33 and 1.49 respectively). The results revealed that the useable radius of the dosimeter (i.e. where data was within 2% of truth) reduced to 68% for water-matching, and 31% for dry-scanning in air. Point source incident ray geometry produced slightly more favourable results, although variation between the three geometries was relatively small. The required detector size however, increased by a factor six for dry-scanning, introducing cost penalties. For applications where dose information is not required in the periphery, some dry and low-viscous matching configurations may be feasible.