Re: Magnetic Resonance Imaging-Ultrasound Fusion Biopsy during Prostate Cancer Active Surveillance

Magnetic Resonance Neuroimaging Contrast Agents of Nanomaterials

Since the early 1980s when MRI imaging technology was put into clinical use, the number of MRI clinical tests has steadily increased by more than 10% every year. At the same time, exogenous MRI contrast agents have also been developed with the development of MRI technology. However, there are still challenges in the preparation of contrast agents for magnetic resonance imaging, such as how to prepare high-efficiency contrast agents with high stability and low biological toxicity. In order to study the contrast agent with simple preparation method, low cost, and good imaging effect, a magnetic resonance contrast agent was prepared by magnetic nanoparticles. By acting on magnetic resonance imaging detection method, and using polymer ligands to synthesize magnetic nanoparticles, experiments and tests of P(MA-alt-VAc) polymer ligand-modified magnetic nanoparticles were carried out. The experimental results showed that when nanoparticles containing different iron ion concentrations were incubated with DC 2.4 normal cells for 48 hours, the cell viability was still higher than 80% at concentrations up to 200 μm. It shows that the nanoparticle has high cell activity and good biological adaptability. The transverse relaxation (r²) value of the nanoparticles in aqueous solution at 37°C and 1.5 T magnetic field is 231.1 m⁻¹ s⁻¹, which is much higher than that of PTMP-PMAA (r² = 35.1 mM⁻¹ s⁻¹), which is also more than five times the relaxation of SHU-555C (r² = 44 mM⁻¹ s⁻¹). It shows that the nanoparticles prepared in this paper have good effect and can be used as a contrast agent in human brain for magnetic resonance imaging.

Robotic Transrectal Ultrasound Guided Prostate Biopsy

We present a robot-assisted approach for transrectal ultrasound (TRUS) guided prostate biopsy. The robot is a hands-free probe manipulator that moves the probe with the same 4 DoF that are used manually. Software was developed for three-dimensional (3-D) imaging, biopsy planning, robot control, and navigation. Methods to minimize the deformation of the prostate caused by the probe at 3-D imaging and needle targeting were developed to reduce biopsy targeting errors. We also present a prostate coordinate system (PCS). The PCS helps defining a systematic biopsy plan without the need for prostate segmentation. Comprehensive tests were performed, including two bench tests, one imaging test, two in vitro targeting tests, and an IRB-approved clinical trial on five patients. Preclinical tests showed that image-based needle targeting can be accomplished with accuracy on the order of 1 mm. Prostate biopsy can be accomplished with minimal TRUS pressure on the gland and submillimetric prostate deformations. All five clinical cases were successful with an average procedure time of 13 min and millimeter targeting accuracy. Hands-free TRUS operation, transrectal TRUS guided prostate biopsy with minimal prostate deformations, and the PCS-based biopsy plan are novel methods. Robot-assisted prostate biopsy is safe and feasible. Accurate needle targeting has the potential to increase the detection of clinically significant prostate cancer.