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Program Information

Clinical Implementation of An Online Replanning Process

O Ates

O Ates*, E Ahunbay , G Chen , C Lawton , X Li , Medical College of Wisconsin, Milwaukee, WI


TU-H-CAMPUS-JeP3-3 (Tuesday, August 2, 2016) 5:30 PM - 6:00 PM Room: ePoster Theater

Purpose: The purpose of this study is to report the clinical implementation of an online replanning process with CT-on-Rails to address daily interfractional variations.

Methods: A treatment planning package (MONACO/ADMIRE/MOSAIQ, Elekta) is used to perform online adaptive replanning, using segment aperture morphing (SAM) algorithm implemented in MONACO, based on daily CTs acquired from a CT-on-Rails (ARTISTE, Siemens). The online replanning is implemented in prostate RT in the following workflow:

(1) Generating a target contour based on the image of the day, using ADMIRE deformable image registration software with manual editing if necessary;

(2) Automatically modifying segment apertures from the original plan using the SAM algorithm to account for the changes in the target from planning to daily CTs including deformation;

(3) Calculating the dose distribution for the new apertures with the same MUs as in the original plan;

(4) Transferring the new plan into MOSAIQ Record & Verify system;

(5) Performing a pre-delivery QA using both our home-grown and RADCALC software (LifeLine);

(6) Delivering the adaptive plan for the fraction.

The entire workflow takes <10 min. using a 16-CPU hardware.

Results: The online adaptive replanning process was successfully applied during RT for prostate cancers. The adaptive plan significantly improved the plan quality in both target coverage and organs-at-risk (OAR) sparing when compared to the current standard of practice; IGRT repositioning plan. For the average of 10 prostate cases, PTV-V100, Rectum-V70, and Bladder-V45 (%) coverages were (92.84 ± 1.61/97.61 ± 1.45/98.85 ± 1.13), (6.76 ± 2.37/5.40 ± 2.61/3.52 ± 0.94) and (8.20 ± 3.55/5.72 ± 2.61/6.68 ± 3.21) for the IGRT, online SAM, and reoptimization plans, respectively.

Conclusion: The online adaptive replanning workflow is clinically practical for prostate RT and can quickly generate adaptive plans with superior plan qualities when compared to the repositioning plans, improving the management of interfractional variations.

Funding Support, Disclosures, and Conflict of Interest: This study was partially supported by Elekta Inc.

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