Quantitative Validation of an Integrated Prostate-Specific Positron Emission Tomography and 3D Transrectal Ultrasound Image Fusion–Guided Trans-Perineal Prostate Biopsy Platform
Abstract
Purpose
Transrectal ultrasound (TRUS)–guided biopsy remains the most widely used method for diagnosing prostate cancer despite its poor lesion conspicuity. Prostate-specific PET (P-PET) provides improved spatial resolution compared to whole-body PET. However, P-PET lacks real-time anatomical context, which limits its use for needle targeting. This work presents a benchtop evaluation of an integrated P-PET and 3D TRUS–guided trans-perineal prostate biopsy system, designed to enable accurate lesion targeting through registration, multimodal image fusion, and mechatronic needle guidance.
Methods
Our developed system includes a 3D TRUS system, a tracking arm, and a needle guidance device integrated with the P-PET system. Registration between the P-PET and 3D TRUS systems was established, enabling transfer of P-PET-defined targets into 3D TRUS image. Registration accuracy was quantified using Fiducial Registration Error (FRE). Target Localization Error (TLE) was quantified by comparing target coordinates with their known positions. Following image registration and fusion, mock biopsy experiments were performed under 3D TRUS guidance using P-PET-defined target coordinates. Biopsy performance was evaluated using Needle Targeting Error (NTE), Needle Targeting Bias (NTB), and Needle Angular Error (NAE).
Results
Registration between the P-PET and 3D TRUS systems achieved a mean FRE of 0.70 ± 0.42 mm (N=6), demonstrating high registration accuracy. TLE resulted in a mean error of 1.44 ± 0.78 mm. Following image registration, mock biopsy trials (N=4) yielded a mean NTE of 1.78 ± 1.32 mm, NTB of 0.66 ± 1.69 mm, and NAE of 1.13° ± 0.70° across all trials.
Conclusion
This work demonstrates that accurate registration and image fusion of P-PET with 3D TRUS can be achieved within a mechatronic guided biopsy platform and that registration accuracy directly translates into accurate targeting. The presented results establish a quantitative experimental baseline for a clinically relevant P-PET/3D-TRUS–guided prostate biopsy workflow and support continued development toward clinical translation.