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SU‐E‐J‐215: Onboard Split PET Including the Effects of Attenuation, Scatter, and Random Events
Author(s) -
Darwish N,
Kao C,
Thomadsen B,
Mackie T
Publication year - 2014
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4888268
Subject(s) - monte carlo method , tomotherapy , attenuation , image quality , positron emission tomography , correction for attenuation , iterative reconstruction , computer science , physics , optics , computer vision , nuclear medicine , mathematics , image (mathematics) , radiation therapy , statistics , medicine
Purpose: Positron emission tomography (PET) using split PET geometry was investigated as an on‐board system for functional imaging and PET marker tracking, specifically with tomotherapy. The open dual ring PET would allow measurement of both inter and intra‐fractional variation, improving the delineation of tumor volume at any stage in the radiation treatment delivery process. We present results from data obtained using Monte Carlo simulations including the effects of attenuation, random events, and scatter. Methods: PET design was accomplished via Monte Carlo simulations with GATE, the Geant4 Application for Emission Tomography. Images were reconstructed using Software for Image Reconstruction (STIR) with a fully 3D ordered subset expectation maximization (OSEM) image reconstruction technique. Results: Monte Carlo simulations of the split PET geometry indicate that including physical factors that degrade image quality such as attenuation, random events, and scatter still prove the feasibility of near real‐time PET for both inter and intra‐fractional radiation delivery. The image quality of scan times under 1 minute reveals that it is possible to utilize PET scanning and reconstruction during the treatment session intrafractionally. GATE also simulates the depth information but does not correct obliqueness of the path of line of response so the data is much more realistic than the data obtained with ray tracing. Conclusion: Onboard split PET with TomoTherapy can generate quality images under 1 minute scan times without the need to correct for attenuation, scatter, random events, or depth information of the interaction.