Motoo Nomura MD, Presenter: Nothing to Disclose

Atsushi Komemushi MD, PhD, Abstract Co-Author: Nothing to Disclose

Minoru Kamata MD, Abstract Co-Author: Nothing to Disclose

Noboru Tanigawa MD, Abstract Co-Author: Nothing to Disclose

Hiroyuki Kojima MD, Abstract Co-Author: Nothing to Disclose

Satoshi Sawada MD, Abstract Co-Author: Nothing to Disclose

To clarify the effects of bone cement injected into vertebral bodies by percutaneous vertebroplasty on spatial dose distribution during intensity-modulated radiotherapy.

Four water-equivalent phantoms (Toughwater Phantom, Kyoto Kagaku CO., Japan) were prepared by tracing the shape of the anthropomorphic phantom (RANDO phantom, Kyoto Kagaku CO., Japan). We prepared two water-equivalent phantoms with bone cement, and the other two water-equivalent phantoms without bone cement. An intensity-modulated radiotherapy plan was generated in a treatment planning system (Eclipse Treatment Planning System, version 8.1; Varian Medical Systems, USA). The planning algorithm was batho method. The plan was prepared after delineation of bone cement and organs at risk such as spinal cord. 2Gy was irradiated. A spatial dose distribution map for the phantoms with bone cement was calculated using the treatment planning system. A dose distribution analysis system (DD-System, R-Tech, Japan) was used to measure spatial dose distribution based on the film density. Effects of bone cement on irradiation as assessed by the film dosimetry were investigated by comparing spatial dose distribution between the phantoms with and without bone cement.

For the phantom with bone cement, dose increases were seen inside cement and around the cement. With 2Gy of radiation, average degree of dose increase within bone cement was 11.1 (± 8.11) cGy. Dose at the area corresponding to spinal cord as measured by the film dosimetry with the equivalent phantom with bone cement was 0.57 (± 4.42) cGy higher than that with the equivalent phantom without bone cement. With the phantom with bone cement, dose at the spinal cord measured by the film dosimetry was 0.48 (± 3.67) cGy higher than dose calculated by treatment planning system.

With vertebral bodies with bone cement placed by percutaneous vertebroplasty, spinal cord dose can appear to a little exceed planned dose.

This study demonstrates the basic data of combination therapy consisting of percutaneous vertebroplasty and intensity-modulated radiotherapy, and can be recommended the combination therapy.

Nomura, M, Komemushi, A, Kamata, M, Tanigawa, N, Kojima, H, Sawada, S, Effect of Percutaneous Vertebroplasty Combined with Intensity-modulated Radiotherapy: A Phantom Study.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6006583.html