Inclusion Criteria:

- Histologically confirmed prostate adenocarcinoma

- diagnosis of low risk or intermediate risk prostate cancer

- approved for proton therapy treatment at CDH ProCure Proton Therapy Center

- prescribed and consented for the placement of fiducial markers into the prostate as
part of the standard treatment procedure

- capable of receiving an MRI of the pelvis region for prostate localization

- the prostate gland of eligible patients must be capable of imaging from an anterior
trans-abdominal ultrasound as determined by the treating investigator

- must be fluent in the English language; must be able to provide written study consent

Exclusion Criteria:

- Evidence of a large TURP defect per investigator discretion

- previous prostate cancer surgery including prostatectomy, hyperthermia and
cryosurgery

- previous pelvic radiation for prostate cancer

- current grade 2 or above incontinence

- history of orthopedic procedures in the area of the treatment, specifically no prior
hip replacement or procedure in which metallic or high density material remains which
would be within stereoscopic kilovoltage imaging area

- prior permanent placement of any metallic or high density material within the
prostate

- known allergy to ultrasonic gel