Challenges in Credentialing Institutions and Participants in Advanced Technology Multi-institutional Clinical Trials

Abstract

The Radiological Physics Center (RPC) has functioned continuously for 38 years to assure NCI and the cooperative groups that institutions participating in multi-institutional trials can be expected to deliver radiation treatments that are clinically comparable to those delivered by other institutions in the cooperative groups. To accomplish this, the RPC monitors the machine output, the dosimetry data utilized by the institutions, the calculation algorithms used for treatment planning, and the institutions' quality control procedures. The methods of monitoring include on-site dosimetry review by an RPC physicist, and a variety of remote audit tools. The introduction of advanced technology clinical trials has prompted several study groups to require participating institutions and personnel to become credentialed, to assure their familiarity and capability with techniques such as 3DCRT, IMRT, SBRT and brachytherapy. The RPC conducts a variety of credentialing activities, beginning with questionnaires to evaluate an institution's understanding of the protocol and their capabilities. Treatment planning benchmarks are used to allow the institution to demonstrate their planning ability, and to facilitate a review of the accuracy of treatment planning systems under relevant conditions. The RPC also provides mailable anthropomorphic phantoms to verify tumor dose delivery for special treatment techniques. While conducting these reviews, the RPC has amassed a large amount of data describing the dosimetry at participating institutions. Representative data from the monitoring programs will be discussed and examples will be presented of specific instances in which the RPC contributed to the discovery and resolution of dosimetry errors.

Commissioning and verification of the collapsed cone convolution superposition algorithm for SBRT delivery using flattening filter‐free beams

“…Ratios of the PTV TLD doses for the other irradiations ranged from 0.95 to 0.98, and the percentage of points passing the gamma index ranged from 96% to 97%. Considering the first time pass rate of the RPC lung phantom is only 71%, (18) it represents a rigorous test for the FFF beam modeling and commissioning.…”

Preparation and fabrication of a full‐scale, sagittal‐sliced, 3D‐printed, patient‐specific radiotherapy phantom

“…While implementation of multi‐material 3D printed phantoms would be a further improvement, homogeneous phantoms are at present routinely used for many different types of radiation treatment QA. Examples include patient‐specific IMRT QA and accreditation procedures for clinical trials 15, 16…”

Is pre-trial quality assurance necessary? Experiences of the CONVERT Phase III randomized trial for good performance status patients with limited-stage small-cell lung cancer

“…Such programmes should result in both improved robustness of the study results and improved quality of the radiation technique once implemented in routine practice. [15][16][17][18] RT protocol deviations should be minimized as they can have a major impact on the outcome of a study as demonstrated in the HeadSTART trial evaluating the role of tirapazamine in advanced head and neck cancer. 19 The participating centres were required to submit the diagnostic imaging and treatment plans for patients entered into the trial to a QA review committee by the end of the first week of RT.…”