Patients who are unable to undergo MRI Definitive T3 disease on MRI Unable to undergo brain MRI Unable to undergo brain MRI Subject who cannot undergo MRI. Ability to undergo MRI scanning with contrast Participants who cannot undergo a brain MRI Inability to undergo MRI and/or contraindication for MRI examinations following the MRI protocol; prosthesis or orthopedic or dental braces that would interfere with volumetric analysis of target PN on MRI Unable tolerate an MRI, or have a contraindication to MRI Unable to undergo MRI scan (e.g., pacemaker) Patients unable to undergo MRI are not eligible. Unable to undergo MRI of the brain (i.e. pacemaker or any other contraindication for MRIs) Able to undergo brain MRI with and without contrast Patients who are unable to obtain MRI Patient unable to have an MRI of the brain Ability to undergo MRI evaluation. Patients unable to undergo MRI of the brain Unable to undergo MRI of the spine Inability to undergo brain MRI due to medical or personal reasons. Patients who are allergic to MRI contrast medium or unable to undergo MRI for any other reason. Inability to undergo MRI due to personal or medical reasons Inability to undergo MRI due to personal or medical reasons (Arm B) Patients must be able to undergo an MRI with contrast Patients unable to undergo an MRI with contrast Subject is able to undergo either an MRI or administration of contrast agent for CT Inability to undergo MRI with and without contrast administration Contraindication to contrast enhanced MRI (i.e. unable to undergo follow-up imaging) History of having MRI non-compatible metal (injury- or treatment-related) in the body will be an exclusion criteria specific to the MRI sub-study The subject is unable to undergo MRI scan (e.g., has pacemaker) Subjects unable to undergo an MRI with contrast Patients will be excluded if they are unable to obtain an MRI scan Any contra-indications to undergo MRI imaging. Unable to undergo MRI Pre-operative and post-operative brain magnetic resonance imaging (MRI) with and without contrast must be obtained. The requirement for a post-operative MRI is waived for patients who undergo biopsy only. A spine MRI is not required, but may be obtained if clinically indicated. If the spine MRI is positive, the patient would be considered to have M+ disease (defined as neuraxis dissemination) and would be ineligible MRI of the brain (or contrast CT scan of the brain if patients are unable to undergo MRI) must be obtained in patients with symptoms suggesting possible central nervous system (CNS) metastatic disease; neuroimaging is recommended but not required in asymptomatic patients Patients who are unable to undergo MRI Patients unable to undergo MRI exams. Inability to undergo MRI evaluation for treatment planning and follow-up Multi-parametric MRI at University of California, Los Angeles (UCLA) within 6 months of study treatment, demonstrating a\r\n* Region of interest (ROI) of MRI suspicion level 3 or higher \r\n* MRI-calculated prostate volume 25 cc to 100 cc Unable to undergo imaging by either CT scan or MRI Contraindication for safe MRI, implants, or other conditions that interfere with imaging required for the study (e.g., pacemaker or non-MRI compatible hip prostheses); Note: subjects with bilateral hip implants are not eligible for the study; subjects with a unilateral hip implant may be eligible assuming the implant is MRI compatible and does not present artifact on MRI in the areas of interest Unable to undergo MRI of the spine Ability to have MRI as part of post-implant assessment Patients unable to undergo an MRI of the brain with contrast. The subject is unable to undergo MRI scan (eg, has pacemaker) Inability to undergo MRI Unwilling or unable to undergo a MRI or CT Scan per study protocol requirements Inability to undergo MRI due to personal and medical reasons Patient must be willing and able to undergo MRI as outlined in protocol Patient must be able to undergo MRI with and without contrast; patients who are unable to undergo MRI are ineligible Must be able to undergo MRI of abdomen (spleen and liver). Patients who are contra indicated for MRI may be enrolled and evaluated by CT scan at the discretion of the Sponsor. Able to safely undergo MRI exam and receive mild sedation for the treatment Patients unable to undergo contrast-enhanced MRI. Patient willing and able to provide written informed consent, including willingness to undergo both endorectal multiparametric MRI and transrectal MRI-guided biopsy at Oregon Health & Science University (OHSU) Unable to undergo brain MRI due to medical or personal reasons Inability to undergo MRI and/or contraindication for MRI examinations following the MRI protocol; prosthesis or orthopedic or dental braces that would interfere with volumetric analysis of target PN on MRI Inability to undergo MRI evaluation for treatment planning and follow-up Inability to undergo MRI with and without contrast (e.g. claustrophobia, non-MRI compatible implant or foreign body, gadolinium allergy or renal dysfunction preventing the patient from receiving gadolinium- institutional guidelines should be used to determine if patients are at risk for renal dysfunction); note that patients with severe claustrophobia are permitted on this study if they are willing and able to undergo MRI with adequate sedation or anesthesia Ever been told not to get an MRI MRI-incompatible metal implant\r\n* If a potential participant reports implanted metal objects, which might be affected by MRI magnets, the study personnel or MRI technologist will screen over the phone or in person to determine whether the potential participant would be safe during the MRI scan; a current list of implants compatible with MRI will be consulted Inability to get brain MRI Patients scheduled to undergo screening breast MRI with contrast Women too claustrophobic to undergo MRI Participant is able to undergo radiographic evaluation with CT or MRI Patients who are unwilling or unable to undergo MRI including patients with contraindications to MRI such as the presence of cardiac pacemakers or non-compatible intracranial vascular clips, claustrophobia, inability to lie flat for the duration of the study etc Patients who are unwilling or unable to undergo MRI including patients with contraindications to MRI such as the presence of cardiac pacemakers or non-compatible intracranial vascular clips, claustrophobia, inability to lie flat for the duration of the study etc Patient must meet standard MRI guidelines and be able and willing to undergo MRI Participants who are unable to undergo MRI because of documented contra-indications for contrast-enhanced MRI, including but not limited to renal failure Patient must meet standard MRI guidelines and be able and willing to undergo MRI Unable to cooperate for MRI Subjects must be able to undergo MRI imaging without anesthesia Patients who are unable to undergo MRI scanning due to exclusion by University Hospitals Case Medical Center (UHCMC) MRI restriction policies as mentioned in the standard UHCMC MRI informed consent form Inability to undergo or cooperate with an MRI or PET scan (e.g., claustrophobia, metal implant) Participants must be able to undergo MRI scan Able to undergo contrast enhanced MRI MRI is contraindicated based on responses to MRI screening questionnaire Patients who are too claustrophobic to undergo MRI or PET imaging Patients must agree to undergo serial multiparametric MRI and MRI-guided biopsy Patients who are unwilling or unable to undergo MRI including patients with contra-indications to MRI such as the presence of cardiac pacemakers or non-compatible intracranial vascular clips Patients who are too claustrophobic to undergo MRI or PET imaging Patients who cannot undergo MRI imaging due to MRI exclusion criteria Unable to cooperate for MRI and/or radiation therapy planning Age and mental status wherein he/she is unable to cooperate for MRI study Patients who are unable to undergo MRI Patient is unable to have a MRI or transrectal ultrasound If a breast MRI is advised and there is no contraindication to MRI, a breast MRI and ABUS will performed at KUCC (study Arm 1) If a breast MRI is not performed, an ABUS exam without MRI will be performed (study Arm 2) Patients with contraindications to MRI (e.g., pacemaker, claustrophobia, etc.) (MR/TRUS only) ---Patients with renal dysfunction are excluded due to their inability to undergo contrast enhanced MRI Participant must successfully complete the MRI screening form if receiving an MRI Patients who are unwilling or unable to undergo MRI including patients with contraindication to MRI such as the presence of cardiac pacemakers or non-compatible intracranial vascular clips, claustrophobia, inability to lie flat for the duration of the study etc Patients unwilling or unable to undergo the ecoil placement or multiparametric MRI exam Patients who are unable to undergo MRI imaging Patients need not undergo a baseline MRI prior to enrollment Patients who have undergone a sedated MRI 5-7 days prior, can be re-sedated for post-ferumoxytol MRI For patients who choose to undergo MRI imaging, hypersensitivity to MRI IV contrast media not suitable for pre-medication For patients who choose to undergo MRI imaging, patients who are ineligible for an MRI with contrast based on radiology department screening