In-bore MRI-compatible transrectal ultrasound and photoacoustic imaging.

Prostate cancer (PCa) remains one of the leading causes of cancer-related mortality in males. While MRI is widely used for PCa diagnosis due to its high sensitivity, it is limited by its poor specificity in detecting aggressive PCa. Molecular targeted photoacoustic (PA) imaging is a non-ionizing technique known for its potential to achieve both high sensitivity and specificity. It also provides real-time imaging capability, which complements MRI's limitation of slow imaging speed during intraoperative image-guided procedures. This research presents a tri-modal imaging system that integrates MRI, PA, and ultrasound (US) to enhance PCa diagnosis and image-guided procedures. We introduce an MRI-compatible PA/US imaging platform featuring a reflector-based transrectal probe with an integrated optical fiber delivery channel. The probe's MRI-compatible actuation system enables 3D PA/US imaging in parallel with MRI scanning. Comprehensive performance evaluation included phantom studies to assess imaging quality, MRI compatibility, and in vivo validation. Results demonstrated successful tri-modal imaging capabilities with acceptable MRI artifacts and confirmed the system's effectiveness for spectroscopic PA imaging with an exogenous contrast agent. The platform functions during active MRI scan sequences, enabling rapid target visualization without requiring patient repositioning between MRI and PA/US suites. These findings support the feasibility of in-bore MRI-compatible PA/US imaging and demonstrate its potential for clinical translation in the diagnosis and management of PCa.