Goal: merge US with MR to visualize targets for biopsy needles, radioactive seeds and ablation instruments.
Prostate interventions such as biopsy, brachytherapy, and therapeutic tissue ablation are visually guided by trans-rectal ultrasound images (TRUS). TRUS shows the overall shape of the prostate but does not distinguish cancer from normal prostate tissue. The inability to actually see where cancer is located during a TRUS procedure severely limits the ability of the surgeon to accurately aim his/her instrument at suspected cancer growths. Due to this limitation current biopsy procedures lead to a relatively high number of undetected cases (false negatives). Moreover brachytherapy and ablation procedures must target volumes of tissue larger than necessary to assure inclusion of the cancer growths in the target region, an approach that can lead to unwanted side effects. Recent research has shown that the combination of magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) can pinpoint regions likely to harbor cancer cells inside the prostate. M-reps are being investigated to accurately map potential cancer-bearing regions found on pre-intervention MR/MRS images to TRUS images, and display those regions as targets for interventional instruments such as biopsy needles, radioactive seeds, and ablation instruments.