Feasibility and initial dosimetric findings for a randomized trial using dose painted Multi-parametric-MRI Defined targets in Prostate Cancer

Publication date: Available online 4 February 2016
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Elizabeth L. Bossart, Radka Stoyanova, Kiri Sandler, Matthew Studenski, Amber Orman, Matthew Abramowitz, Alan Pollack
Purpose/ObjectiveTo compare dosimetric characteristics to multi-parametric MRI identified imaging tumor volume (GTV), prostate CTV and PTV, and organs at risk (OARs) for two treatment techniques representing two arms of an institutional phase III randomized trial of Hypofractionated External Beam Image-Guided Highly Targeted (HEIGHT) radiotherapy (RT).Methods and MaterialsGroup I (n=20) patients were treated prior to the trial inception with the standard dose prescription. Each patient had an additional treatment plan generated per the experimental arm. A total of 40 treatment plans were compared (20 plans for each technique). Group II (n=15) consists of patients currently accrued to the HEIGHT trial. Plans were created as per treatment arm with additional plans for 5 of the Group II experimental arm with a 3mm expansion in the imaging GTV (GTV).ResultsFor all plans in both patient groups, PTV coverage ranged from 95% to 100%; GTV coverage of 89.3Gy for the experimental treatment plans ranged from 95.2% to 99.8%. For both group I and II, the percent volumes of rectum/anus and bladder receiving 40Gy, 65Gy and 80Gy were smaller in the experimental plans than the standard plans. The percent volume at 1Gy per fraction and 1.625Gy per fraction were compared between the standard and the experimental arm, and these were found to be equivalent.ConclusionsThe dose per fraction to the OARs can be made equal even when giving a large simultaneous integrated boost to the GTV. The data suggests that a GTV margin may be added without significant dose effects on the OARs.

Teaser

Dosimetric characteristics for multi-parametric (MP-) MRI identified imaging tumor volume (ImTV), prostate CTV and PTV, and organs at risk (OARs) for two treatment techniques representing two arms of an institutional phase III randomized trial of Hypofractionated External Beam Image-Guided Highly Targeted (HEIGHT) radiotherapy (RT) are given. The MP-MRI protocols are detailed.


from Cancer via ola Kala on Inoreader http://ift.tt/1nJ07zZ
via IFTTT