AbstractID: 9432 Title: Acceptance and Commissioning of AcQSim Using AAPM TG-66 Guidelines.
The Quality Assurance (QA) guidelines for Computed Tomography (CT) scanners have
been well established through AAPM Diagnostic X- ray imaging committee Task Group
Report 2. However, for CT- Simulator or AcQsim there are no established guidelines for
acceptance & periodic QA. Task Group Report 66 (in press) from AAPM is first such
document in literature to address this important topic.
Based on the recommendation of TG-66, recently we commissioned AcQsin in our
department.
Following commissioning process was performed for Quality assurance of AcQsim.
A. Evaluation of Digitally Reconstructed Radiograph (DRRs) for
1.Spatial & contrast resolution, 2.Geometric accuracy 3. Hardcopy quality & accuracy.
B. Spatial & Geometric accuracy tests for
1.Image input tests to planning systems. 2.Structure delineation & accuracy.
3.Linear Accelerator definition, 4.Accuracy of isocenter calculation & movement.
C. The AcQsim lasers QA
1.Gantry laser accuracy, 2.Vertical wall laser calibration and accuracy
3.Overhead or Sagittal laser calibration & movement accuracy
D.Couch & Table top movement accuracy
1.Tabletop level & orthogonal with respect to imaging plane.
2.Table indexing & position accuracy.
E.Generation of RED curve for planning system using RMI phantom.
These acceptance tests indicated results within protocol tolerance limits, including the
laser alignment accuracy within ±0.5mm, DRR divergence and spatial accuracy within
±1mm, table top indexing accuracy was better than 0.5mm, and the RED curves on our
planning systems indicated linear pattern.
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