Speakers:
Taylon Clark (Student Presentation)
Title: Experimental Validation of eDCC-Based Cardiac SPECT Attenuation Correction
Abstract:
In cardiac SPECT (single photon emission computed tomography) projections, accurate attenuation correction requires manual alignment of a separately acquired attenuation map. Exponential data consistency conditions (eDCCs) have been shown in idealized simulations to allow attenuation map alignment without the need for manual registration. The presence of activity outside the heart violates the eDCC assumption and prevents eDCC-based attenuation map alignment. The “sine-amplitude” approach could be used to remove the violating activity and allow attenuation map alignment even if the original activity distribution contained activity outside the heart. This work extended the evaluation to experimental data acquired with a torso phantom on a clinical SPECT/CT system.
For control purposes, the attenuation map was aligned by-eye to give a reference point for attenuation map alignment. At the reference position, the mean eDCC-metric value with heart-only data was measured to provide a baseline level of consistency. With liver activity, the mean eDCC-metric value worsened because the liver activity violated the eDCC assumption. This result improved back to the heart-only baseline when the sine-amplitude method was applied to remove the liver activity. The attenuation map was shifted transversely -9.8 mm to 9.8 mm to assess eDCC-based attenuation map alignment. For heart-only activity, the eDCCs replicated the manual attenuation map registration to within 0.87 mm. With liver activity the alignment error was 5.77 mm, which improved to 0.91 mm with the sine-amplitude method applied.
Marc Chamberland, QA Manager - ClearCalc, Radformation
Title: Clinical implementation of a new low-dose-rate brachytherapy mesh implant program for pancreatic cancer patients
Abstract:
This talk describes the technical implementation of a new program based on implanting a LDR directional brachytherapy mesh implant for pancreatic cancer patients, from a (formerly) U.S.-based physicist’s point of view. Policies and procedures were developed for technical staff involved. The treatment planning system (TPS) was commissioned for the device and dosimetry equipment was calibrated at an accredited dosimetry calibration laboratory (ADCL). A patient was selected to be the first to receive the procedure. The source strength of the device was verified using extra sources from the same batch. Post-dosimetry was performed on a post-operative CT. The selected patient had a successful procedure and post-dosimetry showed adequate placement and dose distribution.