Efficacy of butylscopolamine in obtaining clear MR image for intensity-modulated radiotherapy for prostate cancer.

Abstract

The use of butylscopolamine in magnetic resonance imaging (MRI) of the prostate is controversial in the context of diagnostic imaging where local invasion and the presence of metastases are evaluated. However, in radiation oncology, MRI is performed as part of the simulation process, and the objectives differ to the diagnostic setting. MRI is primarily used for accurate target delineation; hence, the use of an agent to reduce intestinal peristalsis and increase image quality may be beneficial. The impact of butylscopolamine on MRI for radiation oncology purposes has not previously been described. The aim of this study was to evaluate the efficacy of butylscopolamine in MRI acquired for radiation oncology simulation of the prostate. In total, 67 patients were enrolled in this study. Thirty-five patients received intramuscular injection of butylscopolamine (group A) and 32 patients did not (group B). Visualization of the prostate outline and detection of fiducial gold markers (GMs) in the prostate were evaluated on MRI. Two blinded radiation oncologists (ROs) and one radiation technologist (RT) scored the image quality of the detection of prostate outline and recognition of GMs in the prostate on a scale of 1-5 (1=poor; 5=excellent), and the results were evaluated using Mann-Whitney U test and p<0.05 was considered as statistically significant. On MRI, group A was statistically superior to group B in terms of fiducial marker detection by two ROs (p<0.01). However, there was no significant difference in RT scoring. Furthermore, on MRI, group A was statistically superior to group B in terms of the detection of the prostate outline by an RT. Butylscopolamine is effective with respect to detection of the prostate outline and GM recognition (without endorectal coil). The addition of butylscopolamine is simple and cost efficient. We recommend the use of butylscopolamine routinely to obtain good MR images, particularly in the detection of GMs.