This phase II trial evaluates an imaging technique called 18F-rhPSMA-7.3 positron emission tomography (PET)-multiparametric (mp) magnetic resonance imaging (MRI) in identifying tumor tissue in men suspected to have prostate cancer. This clinical trial also seeks to determine if the abnormal tissue identified during imaging represents the tumor tissue removed during transrectal ultrasound-magnetic resonance imaging (TRUS-MR) fusion biopsy of the prostate. PET is an established imaging technique that utilizes small amounts of radioactivity attached to very minimal amounts of tracer, in the case of this research, 18F-rhPSMA-7.3. Because some tumors take up 18F-rhPSMA-7.3 it can be seen with PET. MRI uses radio waves and a powerful magnet linked to a computer to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. Standard of care imaging for prostate cancer includes mpMRI, which is the combination of multiple magnetic resonance techniques, including diffusion weighted imaging, dynamic contrast-enhanced imaging, and spectroscopy, to achieve an image that will allow for better identification of tumor size and location, as well as possibly identifying tumor spread and aggressiveness. However, mpMRI may not be as effective in identifying prostate tumors that are clinically significant. A TRUS-MR biopsy involves using both ultrasound and MRI scans to locate abnormal areas in the prostate. An 18F-rhPSMA-7.3 PET-mpMRI may be more effective than mpMRI alone in identifying tumor tissue and may increase the accuracy of TRUS-MRI fusion biopsies in men suspected of having prostate cancer.