Room: Exhibit Hall | Forum 8
Purpose: To evaluate the contrast resolution of Trans-Rectal Ultrasound (TRUS) systems used to guide prostate brachytherapy procedures, a novel contrast-detail (C-D) phantom with application specific and clinically relevant contrasts and targets was developed.
Methods: The contrasts used in the C-D phantom were determined to be relevant from clinical prostate data. Formulations of IEC agar  tissue mimicking material were manufactured to produce relative contrast differences of -3dB, -6dB and -9dB and anechoic to background material. Small spherical cyst like targets ranging from 2mm in diameter to 10mm were produced from custom moulds. Arrays of the spherical targets were produced in each of the contrasts, for each target size, and were encased in a background IEC agar-based material. The C-D phantom was designed with scanning windows to allow for bi-plane TRUS transducers to be optimally positioned.
Results: The novel C-D phantom was designed and constructed to be clinically relevant to the TRUS prostate brachytherapy procedure. Preliminary data from TRUS systems demonstrated the efficacy of the device as an image quality evaluation tool and informed refinement of the C-D phantom. The final design of the phantom also allowed for a more reproducible and optimised evaluation of the end-fire curvilinear array that can prove tedious to evaluate with commercially available phantoms due to poor contact with the phantom.
Conclusion: The contrast resolution of a TRUS system impacts the ability to adequately contour the prostate gland for treatment planning and this has the potential to impact dose. This novel phantom provides a clinically relevant means to determine these systemâ€™s contrast resolution. The targets were designed to be application specific, and the phantom was developed to accommodate the bi-plane TRUS transducer. Future work will involve the validation of this quality assurance phantom for objective assessment of a range of TRUS systems.Teirlinck et al.,1998. Ultrasonics
Ultrasonics, Quality Assurance, Brachytherapy