title: 3D reconstruction of scintillation light emission from proton pencil beams using limited viewing angles-a simulation study.
abstract: An accurate and high-resolution quality assurance (QA) method for proton radiotherapy beams is necessary to ensure correct dose delivery to the target. Detectors based on a large volume of liquid scintillator have shown great promise in providing fast and high-resolution measurements of proton treatment fields. However, previous work with these detectors has been limited to two-dimensional measurements, and the quantitative measurement of dose distributions was lacking. The purpose of the current study is to assess the feasibility of reconstructing three-dimensional (3D) scintillation light distributions of spot scanning proton beams using a scintillation system. The proposed system consists of a tank of liquid scintillator imaged by charge-coupled device cameras at three orthogonal viewing angles. Because of the limited number of viewing angles, we developed a profile-based technique to obtain an initial estimate that can improve the quality of the 3D reconstruction. We found that our proposed scintillator system and profile-based technique can reconstruct a single energy proton beam in 3D with a gamma passing rate (3%/3 mm local) of 100.0%. For a single energy layer of an intensity modulated proton therapy prostate treatment plan, the proposed method can reconstruct the 3D light distribution with a gamma pass rate (3%/3 mm local) of 99.7%. In addition, we also found that the proposed method is effective in detecting errors in the treatment plan, indicating that it can be a very useful tool for 3D proton beam QA.
authors: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors: CheukKai
authors: C
authors: Hui
authors: Daniel
authors: D
authors: Robertson
authors: Sam
authors: S
authors: Beddar
mesh_terms: D005240:Feasibility Studies; D006801:Humans; D008027:Light; D008297:Male; D009010:Monte Carlo Method; D055585:Physical Phenomena; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D061766:Proton Therapy / Q000295:instrumentation*; D011786:Quality Control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D012588:Scintillation Counting / Q000295:instrumentation*