The utility of the Philips SRI-100 Real Time Portal Imaging Device in a case of postoperative irradiation for prevention of heterotopic bone formation following total hip replacement.

Abstract

The new Radiation Oncology Department at the Heidelberg Repatriation Hospital in Melbourne, Australia commenced operation in June 1992. As part of quality control the Philips SL-15 linear accelerator was fitted with the Philips SRI-100 Real Time Portal Imaging Device (RTPID), the first such apparatus in Australia. One of its major advantages over older systems is its ability to provide a permanent hard copy of the image of the field treated. The computer image can be immediately manipulated and enhanced on the screen (with respect to such qualities as brightness and contrast) prior to the printing of the hard copy. This is a significant improvement over the more cumbersome older port films that required developing time, without any pre-assessment of the image quality. The utility of the Philips SRI-100 RTPID is demonstrated in the case of a patient irradiated soon after total hip replacement, as prophylaxis against heterotopic bone formation (HBF). The rapidity and quality of image production is a major advantage in these patients where post-operative pain may result in positional change between film exposure and image production. Extremely accurate shielding block position is essential to shield the prosthesis (and allow bone ingrowth for fixation) whilst avoiding inadvertent shielding of the areas at risk for HBF. A review of the literature is provided.