Conversion of the helical tomotherapy plans to the step-and-shoot IMRT plans for patients with hip prosthesis during radiotherapy for prostate cancer.

To evaluate the SharePlan software in conversion of helical tomotherapy (HT) to a step and shoot IMRT (sIMRT) for patients with high-risk prostate cancer and hip prosthesis.

Analysis was performed for 16 consecutive patients treated on HT.

The HT plans were converted to sIMRT plans. 3DCRT, sliding window IMRT (dIMRT) and VMAT plans for a c-arm linear accelerator (CLA) were created manually. The doses in planning target volume (PTV), bladder, rectum, bowels, femoral heads and hip prosthesis were compared using: (i) a qualitative analysis of doses in averaged dose-volume histograms, (ii) a quantitative, ranking procedure performed for each patient separately, and (iii) statistical testing based on the Friedman ANOVA and Nemenyi method.

For the bladder, rectum, and femoral head, the best dose distributions were observed for HT and sIMRT and then for dIMRT, VMAT, and finally for 3DCRT (p-values were, respectively, 0. 002, 0. 004 and p = 0. 024). For the bowels, 3DCRT was significantly different from the rest of the techniques (p = 0. 009). For the hip prosthesis, the differences were only between 3DCRT and HT/sIMRT (p = 0. 038).

The SharePlan is an efficient tool for the conversion of HT plans for patients with prostate cancer and hip prosthesis. Dose distributions in sIMRT and in HT plans are similar and are generally better than in CLA plans.

Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB). 2015 Dec 07 [Epub ahead of print]

Maria Olmińska, Tomasz Piotrowski, Joanna Litoborska, Bartosz Pawałowski, Agata Jodda

Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland. , Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland; Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland. Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland. , Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland; Department of Technical Physics, Poznan University of Technology, Poznan, Poland. , Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland.

PubMed