The growing complexity of radiotherapy treatment plans is demanding more rigorous and accurate methods for calculating, measuring and verifying the radiation dose that is delivered to the patient. For stereotactic treatments in particular, where high levels of radiation are concentrated into small target volumes, it becomes critically important for clinical physicists to have access to precise information about the dose profile and how it relates to the anatomy of the patient.
That need for accuracy in the treatment planning process has been the guiding principle behind IBA Dosimetry’s system for patient-specific quality assurance (QA), called myQA iON. First released in 2019 for use in proton therapy and launched in 2022 for the photon radiotherapy sector, myQA iON provides an end-to-end solution that allows clinicians to access comprehensive and reliable verification information to guide and manage the treatment process. By combining independent three-dimensional (3D) dose calculations for treatment plans with real-world measurement data and irradiation log files, the software has been designed to help radiotherapy clinics boost their workflow efficiency while also enhancing patient safety and treatment outcomes.
At the Duke University Medical Center, for example, medical physicist Guoquiang Cui has been evaluating the potential of myQA iON for improving the stereotactic radiosurgery (SRS) treatments that target multiple sites at the same time. “These SRS plans might have anywhere between five and fifteen different targets,” Cui explains. “For delivery efficiency we plan them using a single isocentre so that we only need to deliver one dose of radiation to treat them all at the same time.”
In the clinic, Cui and his team currently exploit a 2D detector array to measure and verify the dose distribution for these single-isocentre multiple-target (SIMT) treatments. However, this measurement-based approach does not allow them to easily access 3D information about the radiation profile, or to evaluate the dose delivered to all of the targets at the same time. “We can only look at the overall plan,” says Cui. “We typically check one or two targets using the 2D measurements, but we don’t verify them one-by-one because it would take too much time.”
In contrast, myQA iON makes it possible to examine the total 3D dose distribution across the whole plan, as well as the dose delivered to each of the individual targets. The independent dose calculation provided by the system exploits the gold-standard Monte Carlo method, which provides a full 3D analysis of the dose distribution in relation to the patient’s anatomy. “The Monte Carlo algorithm provides more accurate dose calculations than the algorithm we usually use in our planning system,” says Cui. “It is slightly slower but it gives accurate dose information across the full 3D volume.”
As an additional verification tool, the software also provides access to the log files generated automatically by the radiotherapy system during treatment, providing accurate measurement data of the delivered dose to check against the treatment plan. According to Mehgan Boone, product manager at IBA Dosimetry for software and integration, access to the log-file data could be particularly useful for fractional treatments, since it allows clinicians to check the dose delivered in each fraction and make any subsequent adjustments to their treatment plan. “By bringing the log files into myQA iON we can calculate the dose delivered to the patient based on the information generated by the treatment machine,” she explains. “These raw delivery data are already available to the user, we’re just providing clinical context, helping users to determine actionable outcomes, and making the data accessible from a single place.”
Completing the picture As part of their evaluation of myQA iON, Guoqiang Cui and colleagues at the Duke University Medical Center used the software to verify and evaluate an SIMT-SRS treatment of six separate brain tumours (left). The Monte Carlo algorithm provided in myQA iON yielded accurate dose calculations (right), and allowed the dose to be evaluated for each individual target at the same time. A 3D gamma analysis based on the log-file data from the radiotherapy machine showed an almost identical match between the calculated and delivered doses. (Courtesy: G Cui)
For the evaluation work at Duke University, these log-file data were used to compare the Monte Carlo dose calculations produced by myQA iON against the results from the treatment planning system. In one example, Cui and his team used the software to plan an SIMT-SRS treatment of the brain with six separate targets of varying sizes. They found that the Monte Carlo method provided extremely accurate dose calculations for each of the targets, with a 3D gamma analysis showing close agreement between the planned and delivered doses. “The results so far have been very promising,” says Cui. “By combining the 3D dose information from myQA iON with the measurement data from the log files, we can obtain a more complete picture of these complex SRS plans.”
Boone agrees that the ability to integrate independent dose calculations with irradiation log files and real-world detector measurements can offer additional insights to guide the planning and delivery of complex treatments. “The independent Monte Carlo method provides the additional accuracy, including a full volumetric analysis of the dose distribution,” she says. “Bringing all the information together into a unified and automated software solution provides greater flexibility and efficiency, avoiding the need to pull data from different systems or computers.”
The software solution is easy to install and intuitive to use, with the web-based portal designed to allow clinical teams to access all their QA data from any device that connects to the hospital network. In practice, says Cui, that means that IT expertise is likely to be needed for the system to be implemented in the clinic. “The software needs to operate alongside the firewalls and security systems deployed on hospital networks, which will need careful configuration by the IT specialists in our department,” he says. “For our specific clinical environment and practices the biggest benefit of myQA iON is the additional 3D dose information that we can obtain for our complex SRS treatments.”
For its part, IBA is continuing to use the feedback from early adopters like Cui to refine and improve the myQA iON system. “We will be adding new features to enable our users to make the best possible use of our software,” says Boone. “We want to make the system as seamless as possible, while also delivering further improvements in automation and integration.”
To learn more about myQA iON and its role in revolutionizing radiation therapy, visit: https://www.iba-dosimetry.com/product/myqa-ion-radiation-therapy
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