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Completion of Multi-Institutional Evaluation of MVCT Guided Patient Registration and Dosimetric Precision in Total Marrow Irradiation: A Global Health Initiative by the International Consortium of Total Marrow Irradiation

D Zuro1*, S Vagge2 , S Broggi3 , S Agostinelli4 , Y Takahashi5 , J Brooks6 , P Leszcynska7 , A Liu8 , M Mahe9 , C Zucchetti10 , S Simonetta11 , C Han12 , C Mauro13 , S Giebel14 , J Sanchez15 , P Alaei16 , C Anna17 , K Dusenbery18 , G Storme19 , C Aristei20 , J Wong21 , S Hui22 , (1) ,Azusa, CA, (2) ,Genova, ,(3) ,Milan, ,(4) ,Genoa, ,(5) Osaka University Graduate School of Medicine, Osaka, ,(6) ,Bloomington, MN, (7) ,Gliwice Branch, ,(8) City of Hope Medical Center, Duarte, CA, (9) ,Nantes, ,(10) ,Perugia, ,(11) ,Perugia, ,(12) City of Hope Medical Center, Duarte, CA, (13) ,Milan, ,(14) ,Gliwice Branch, ,(15) ,Durate, CA, (16) University of Minnesota, Minneapolis, MN, (17) ,Milan, ,(18) University of Minnesota, Minneapolis, MN, (19) ,Brussel, ,(20) ,Gliwice Branch, ,(21) ,Duarte, CA, (22) Beckman Research Institute, Duarte, CA

Presentations

(Sunday, 7/14/2019) 4:00 PM - 5:00 PM

Room: 302

Purpose: Total Marrow Irradiation (TMI) is a highly focused radiation treatment of the human skeleton structure requiring a high degree of precision and accuracy for treatment delivery. Although many centers worldwide initiated clinical studies using TMI, currently there is no standard for pretreatment patient setup. The goal of this work was to measure the accuracy of different patient pretreatment setup techniques, and their impact on dose delivery among multiple institutions.

Methods: Whole body imaging (WBI) or partial body imaging (PBI) was performed using pre-treatment megavoltage computed tomography (MVCTs) in a helical Tomotherapy machine. Pre-treatment rigid registration between MVCT and planning kilovoltage computed tomography (kVCTs) were performed to measure setup error and its effect on dose distribution. The entire skeleton was considered as the planning target volume (PTV) with five sub regions: head/neck (HN), spine (regions from L-spine and T-spine), shoulder and clavicle (SC), and one avoidance structure, the lungs.68 total patients (>300 images) across 6 institutions were analyzed.

Results: Pretreatment patient setup techniques differed between centers, creating variations in dose delivery. Rigid registration accuracy varied by anatomical region and by technique in body imaging, with the lowest to the highest degree of pretreatment rigid shifts in the following order: spine, pelvis, HN, SC, and lungs. Mean fractional dose delivery was affected by variations of up to 5% in the mean target dose in regions of high registration mismatch, in particular the lungs.

Conclusion: WBI and PBI MVCT were essential for assessing patient setup. WBI allows for the analysis of the 3D dose distribution which is useful for dosimetric validation of treatment coverage in the PTV and or dosimetric sparing of avoidance structures i.e. lungs. This study recommends the standardization of image guidance and dosimetric evaluation for comparing institutional performance.

Funding Support, Disclosures, and Conflict of Interest: This work was supported by the National Institute of Health grants 1R01CA154491-01 and partially supported by the National Cancer Institute of the National Institutes of Health under award number P30CA033572.

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