AIM: To study the use of RapidArc techniques in the treatment of prostate cancer patients with hip prosthesis.
BACKGROUND: An important aspect of treatment planning is to achieve dose homogeneity inside the planning target volume (PTV). Especially for those patients presenting with hip prosthesis, it becomes a challenging task to achieve dose uniformity inside the PTV.
MATERIALS AND METHODS: Five prostate patients presenting with hip prosthesis who had undergone radical radiotherapy were selected for this study. Depending on the composition of prosthesis, a predefined set of Hounsfield values were assigned to each study set. RapidArc plans were generated on an Eclipse treatment planning system. Two arcs that include clockwise and counter-clockwise arcs were used in all these cases. To avoid beams passing through the prosthesis, a simple structure was defined around it with 1 cm margin and a strict dose constraint applied to the block during VMAT optimization.
RESULTS: The mean D2/D98 ratio of PTV for all the patients was 1.06 ± 0.01. The mean percentage rectum volume receiving 50 Gy, 60 Gy, 70 Gy and 75 Gy for all the patients were 33.1 ± 5.9, 21.7 ± 5.5, 13.8 ± 4.4 and 9.5 ± 3.0, respectively.
CONCLUSIONS: This study shows that using a double arc RapidArc technique is a simple and effective treatment method of treating prostate cancer in patients presenting with a hip prosthesis. The definition of a beam avoidance structure encompassing the prosthesis and applying strict dose constraints to it reduces the beam contribution to the prosthesis.
Written by:
Prabhakar R, Kumar M, Cheruliyil S, Jayakumar S, Balasubramanian S, Cramb J. Are you the author?
Peter MacCallum Cancer Centre, Victoria, Australia; Malabar Cancer Center, Thalaserry, Kerala, India.
Reference: Rep Pract Oncol Radiother. 2013 Apr 28;18(4):209-13.
doi: 10.1016/j.rpor.2013.03.006
PubMed Abstract
PMID: 24416555
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