Dual PET-TRUS prostate image registration

Multimodality imaging has an increasingly important role in the diagnosis and treatment of a large number of diseases, particularly if both functional and structural information are acquired and accurately registered. Transrectal ultrasound (TRUS) imaging is currently an integral part of prostate cancer diagnosis and treatment procedures, providing high-resolution anatomical detail of the prostate region. PET imaging with 11 C-choline is a sensitive functional imaging technique that can identify biochemical states associated with prostate cancer. We believe that merging these prostate imaging technologies will help identify the location and aggressiveness of prostate cancer. We envision using dual PET-TRUS prostate imaging to guide biopsy, guide treatment procedures, and detect local recurrence earlier than is currently possible. Hence, we have developed a dual PET-TRUS prostate imaging system and protocol designed to allow accurate 3-D image registration. We have evaluated this PET-TRUS system by performing dual PET-TRUS imaging of custom phantoms. We describe here our dual-modality system, custom phantoms and phantom study results. We also discuss our investigation of the PET-TRUS registration accuracy. We currently have a PET-TRUS registration error of 1 mm axially and 1–5 mm transaxially (depending on the image study, image slice, and line source measured), which is sufficient for clinical applications such as biopsy guidance and early detection of recurrence.