A robust quality assurance prostate brachytherapy QA program is essential to ensure accurate image guidance and dosimetry calculations. The CIRS Model 045 used in conjunction with the CIRS Model 053G Ultrasound Prostate Phantom offers a complete solution for implementing a QA program specific to transrectal ultrasound used for guidance of prostate brachytherapy as recommended by AAPM Task Group 1281. The Model 045 is designed to enable users to check key imaging parameters such as depth of penetration, axial and lateral resolution, distance measurements, area measurements, volume measurements and geometric consistency with the treatment planning computer. When scanning towards the top of the phantom, a partial grid of wires appears. This N-shaped pattern should line up with the electronic grid that appears on your screen thus ensuring correct vertical and horizontal distance measurements. This target group can also be used to assess axial and lateral resolution of the system. Five cross wires are embedded within the phantom to determine if the probe is being retracted by the stepper system by the specified distance.