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Evaluation of Coordinate Coincidence Among Multiple Image Guidance Systems

K Ouchi1*, N Hayashi2, T Ogawa2, T Saito3, H Anma3, K Yasui2, (1) Graduate School of Health Sciences, Fujita Health University, Toyoake, Aichi, JP, (2) School of Medical Sciences, Fujita Health University, Toyoake, Aichi, JP, (3)Department of Radiology, Seirei Hamamatsu General Hospital, Hamamatsu, Aichi, JP


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: multiple image guidance systems including surface guided radiation therapy (SGRT) systems were implemented worldwide. However, a comprehensive End-to-End test (E2E) among multiple image guidance systems has been hardly reported. The purpose of this study is to make sure the coordinate coincidence between SGRT system and image guided radiotherapy (IGRT) systems using X-rays in E2E.

Methods: system, which is named VOXELAN (ERD Co. Ltd., Japan), creates images of the body surface using a red slit laser and light section method. A pelvic phantom implanted with a metallic ball was scanned by CT to define the isocenter onto the metallic ball. The procedure of the image matching from the plan was carried out by VOXELAN, ExacTrac and CBCT in order to compare the isocenter coordinates. We also evaluated the averaged value to calculate detection error of each process of VOXELAN related to the image matching as follows: (a) Detected error of reference image shift using reference images centered at the CT origin and the metallic ball, (b) Matching of CT and VOXELAN coordinates using the CT image and the portal image, and (c) Detected error of VOXELAN when the slice thickness of CT image used for creating reference images is changed 1.25 mm, 2.5 mm, 5 mm.

Results: isocentric coordinate coincidence between VOXELAN and ExacTrac based on CBCT were within 1 mm and 1°, except for the vertical direction of VOXELAN. The error (a) and the difference (b) were within 0.6 mm, respectively, but the error (a) was 1.9 mm only in the long direction. Errors (c) tended to be in the long direction.

Conclusion: confirmed that the coincidence in coordinates between VOXELAN and IGRT systems using X-rays in E2E. This procedure is one of the simple E2E among multiple image guidance systems.


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Not Applicable / None Entered.

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