Tomographic-based 3D scintillation dosimetry using a three-view plenoptic imaging system.

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Optical Imaging

Background:

• Accurate three-dimensional (3D) dose distribution measurement is critical for radiation therapy.
• Current dosimetry methods face challenges in volumetric dose reconstruction.

Purpose of the Study:

• To demonstrate the feasibility of a three-plenoptic camera, scintillation-based dosimetry system.
• To measure 3D dose distributions of static photon radiation fields.

Main Methods:

• Utilized a cubic plastic scintillator and a multifocus plenoptic camera to record orthogonal projections.
• Employed an iterative maximum likelihood-expectation maximization (ML-EM) algorithm for 3D reconstruction.
• Validated reconstructions against treatment planning system data using cross beam profiles and percentage depth dose curves.

Main Results:

• Successfully reconstructed light distributions with 2 mm resolution over a 60 mm³ volume.
• Achieved high accuracy in relative 3D dose measurements, with root-mean-square errors as low as 1.1% for square fields.
• Demonstrated improved 3D gamma passing rates (up to 94.9%) and correlation coefficients (up to 0.976) with increased plenoptic projections.

Conclusions:

• A tomographic model for a plenoptic camera-based scintillation dosimetry system was established using optical design software.
• The system is adaptable for dynamic dose delivery measurements, with temporal resolution limited by camera exposure time.
• This feasibility study simplifies the development of volumetric scintillation dosimetry prototypes for clinical 3D dose measurements.