Development of a PET-Transrectal Ultrasound Prostate Imaging System

Multimodality imaging has an increasing role in the management 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. Positron Emission Tomography (PET) imaging with
$^{11}{\rm C}$
-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 imaging system, custom phantoms and phantom study results. We also discuss our investigation of the PET-TRUS registration accuracy. We measure an average PET-TRUS registration error for our phantom studies of
$2.1 \pm 1.7~{\rm mm}$
in the x direction,
$1.9 \pm 1.6~{\rm mm}$
in the y direction, and
$0.6 \pm 0.2~{\rm mm}$
in the z direction. This registration accuracy is sufficient for some clinical applications such as biopsy guidance and early detection of recurrence.