AAPM Task Group 128: Quality assurance tests for prostate brachytherapy ultrasound systems

Abstract

While ultrasound guided prostate brachytherapy has gained wide acceptance as a primary treatment tool for prostate cancer, quality assurance of the ultrasound guidance system has received very little attention. Task Group 128 of the American Association of Physicists in Medicine was created to address quality assurance requirements specific to transrectal ultrasound used for guidance of prostate brachytherapy. Accurate imaging guidance and dosimetry calculation depend upon the quality and accuracy of the ultrasound image. Therefore, a robust quality assurance program for the ultrasound system is essential. A brief review of prostate brachytherapy and ultrasound physics is provided, followed by a recommendation for elements to be included in a comprehensive test phantom. Specific test recommendations are presented, covering grayscale visibility, depth of penetration, axial and lateral resolution, distance measurement, area measurement, volume measurement, needle template/electronic grid alignment, and geometric consistency with the treatment planning computer.

Reduction of seed motion using a bio‐absorbable polymer coating during permanent prostate brachytherapy using a mick applicator technique

“…In accordance with the periodic quality control tests described in the AAPM task group report TG‐128, annual measurements of axial and lateral resolution had been obtained by imaging small high‐contrast targets within a quality assurance phantom. No discernable change in resolution over that reported by the manufacturer had been observed, a result more than satisfying the <1 mm control limit in measured change in spatial resolution recommended by TG‐128 20. To further assure the accuracy of images acquired during the implant procedure, preprocedural daily quality assurance was conducted of the functionality of the stepper encoder, agreement of the digital templates in the ultrasound display and planning software, and of the clinical acceptability of the US images once the transducer was inserted.…”

“…Finally, a postprocedural plan was generated based on seed positions visualized in the same‐day CT images taken after patient recovery. In order to assure the integrity of images used in the clinic, periodic quality assurance was performed on the US unit and CT scanner according to the protocols promulgated in the AAPM task group reports TG‐128 and TG‐66, respectively 20, 21…”

COMP report: CPQR technical quality control guidelines for low‐dose‐rate permanent seed brachytherapy

“…Some have detailed descriptions indicating how to conduct the various quality control tests. The guidelines promoted in this document are based on the experience of the authors and expert practitioners and are broadly consistent with recommendations from other jurisdictions 6, 7, 8, 9, 10, 11…”

“…There are several other publications dealing with the performance, specifications, and quality control of low‐dose‐rate (LDR) permanent seed brachytherapy 4, 5, 6, 7, 8, 9, 10, 11. Most of these publications have extensive reference lists.…”

NCS Report 20: Dosimetry and quality control of brachytherapy with low-energy photon sources (I-125)

“…AAPM TG-128 [53] recommends setup and defining the monitor in terms of greyscale visibility. Image quality also depends on depth of penetration and axial and lateral resolution, which can be measured in a phantom with a distribution of single targets.…”