CONTRAST-SPECIFIC SPHERICAL LESION PHANTOMS AND ANCILLARY ANALYSIS SOFTWARE FOR THE OBJECTIVE EVALUATION OF TRANSRECTAL ULTRASOUND SYSTEM CONTRAST DETECTABILITY

is an efficacious treatment option because of its benefits for patient recovery, dose localization and conformity, but these favorable outcomes can be ensured only if the transrectal ultrasound (TRUS) system is optimized for the specific application of ultrasound-guided prostate brachytherapy. The ability to delineate the prostate from surrounding tissue during TRUS-guided prostate brachytherapy is vital for treat-ment planning, and consequently, so is the contrast resolution. This study describes the development of task -spe-cific contrast-detail phantoms with clinically relevant contrast and spherical target sizes for contrast-detail performance evaluation of TRUS systems used in the brachytherapy procedure. The procedure for objective assessment of the contrast detectability of the TRUS systems is also described; a program was developed in MAT-LAB (R2017a, The MathWorks, Natick, MA, USA) to quantitatively analyze image quality in terms of the lesion signal-to-noise ratio (LSNR) and validated with representative control test images. The LSNR of the Hitachi EUB-7500A (2013, Hitachi, Ltd, Tokyo, Japan) TRUS system was measured on sagittal and transverse TRUS images of the contrast-detail phantoms described in this work. Results revealed the efficacy of the device as an image quality evaluation tool and the impact of the size, depth and relative contrast of the targets to the sur-rounding tissue on the contrast detectability of a TRUS system for both transducer arrays. The MATLAB pro-gram objectively measured the contrast detectability of the TRUS system and has the potential to determine optimized imaging parameters that could be designed as part of standardization of the imaging protocol used in TRUS-guided prostate brachytherapy for prostate cancer. (C) 2022 World Federation for Ultrasound in Medicine & Biology. All rights reserved.

Automated summary

Ultrasound-guided prostate brachytherapy is an effective treatment option, but it requires an optimized transrectal ultrasound (TRUS) system. This study developed task-specific contrast-detail phantoms and an objective assessment procedure to evaluate the contrast detectability of TRUS systems used in brachytherapy. The results showed the efficacy of the device as an image quality evaluation tool and the impact of target characteristics on TRUS system's contrast detectability.