Fusion of SPECT and multidetector CT images for accurate localization of pelvic sentinel lymph nodes in prostate cancer patients.

OBJECTIVE The present study was performed to investigate the feasibility of fusion of images obtained by SPECT and multidetector CT (MDCT) for the accurate localization of sentinel lymph nodes in prostate cancer patients. METHODS To facilitate the fusion of both SPECT and CT images, a pelvic MDCT scan was performed with 3 markers of small plastic bullets attached to the skin over the bilateral iliac crests and the ventral midline at the same height. SPECT was performed after the same locations were marked with needle caps containing (99m)Tc-pertechnetate. The images were superimposed by use of free software (MRIcro). The results of hot lymph node detection with fusion images were compared with those of surgery. RESULTS The images could be successfully superimposed for all 11 patients examined. Surgeons accurately confirmed 27 (87.1%) of 31 regional lymph nodes on fusion images. CONCLUSION Fusion of SPECT and MDCT images is useful for the precise localization of sentinel lymph nodes in prostate cancer patients.