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Joined-up thinking in proton therapy
With dedicated clinical facilities proliferating, proton therapy is fast becoming a standard treatment option in radiation oncology – the result of a dose distribution that sees the radiation payload deposited over a narrow depth range with reduced collateral damage to adjacent healthy tissue and nearby organs at risk. Martin Janson, RaySearch’s senior product manager for proton therapy, explains why sustained, user-driven software innovation makes RayStation®* the treatment planning system (TPS) of choice for established and new-entrant proton treatment centers.
Janson, who has been part of the RaySearch ® development team for 14 years, interprets his product management role on an expansive canvas. For starters, he’s the company’s internal domain expert for all things proton therapy – responsible for prioritizing new proton requirements from customers and partners and feeding those requests into the RayStation development roadmap. At the same time, he’s active along several other coordinates, whether that’s supporting the development teams; training service team colleagues on new proton therapy features in RayStation; working closely with sales and marketing on customer engagement and education; or talking to proton clinics about ideas for joint R&D projects.
A BIG YEAR FOR PROTONS “RaySearch has been extremely successful with proton therapy innovations for RayStation,” explains Janson, “and 2020 was especially notable in this regard, reinforcing our position as the TPS market-leader for proton planning.” A case in point is the latest iteration of the software’s Monte Carlo dose calculation engine which, thanks to its graphics processing unit (GPU)-based implementation, offers accurate and extremely fast dose computations – typically less than five seconds. “The GPU is fantastic at parallel processing and represents a revolution in performance for our proton Monte Carlo dose engine,” notes Janson. “Those ultrafast computation times enable robust evaluation of multiple treatment plans and, ultimately, a more personalized solution for every patient.”
Another significant milestone in 2020 was the launch of RayOcular to support the complex planning requirements when using proton therapy to treat rare eye cancers. While this is a niche application just now, clinical interest is ticking up. “RayOcular will improve the planning and outcomes for clinics that have worked with proton-based treatments of eye cancers for many years,” says Janson. The breakthrough is adding MR and CT capabilities into the mix so that clinical users can decrease their margins to ensure better sparing and reduced toxicity – capabilities that should in turn encourage new players to adopt proton therapy for the treatment of ocular cancers.
The release of RayStation 10B* at the end of last year also saw the software’s machine learning capabilities extended to support the automated planning of pencilbeam-scanned proton treatments. In other words: oneclick automated planning to generate treatment plans with
a quality to match manual plans generated by a clinic’s best treatment planners. “We now have proton auto planning with real robustness, offering significantly enhanced standardization of plans across specific disease indications and patient cohorts,” notes Janson. By extension, there are also opportunities to automatically provide treatment alternatives to a physician by creating a series of auto plans with different emphasis. “One planning strategy, for example, might favor greater coverage of the target, while another might prioritize the sparing of healthy tissue,” Janson adds.
THE PROTON ROADMAP If 2020 was a banner year for the introduction of proton-related functionality in RayStation, it seems there are plenty more innovations in the works for 2021 and 2022. Near term, one key focus for Janson and his colleagues is a parameter called linear energy transfer (LET) – i.e. the rate at which protons lose their energy when traversing through the patient – and its integration within the treatment planning process.
Besides the physical dose, LET is an important factor for the biological response of a proton beam, with higher LET corresponding to enhanced cell death – an effect, to date, that is not accurately accounted for in proton planning. “If you can access LET in the optimization, you can create treatment plans in such a way that the high LET is kept away from any organs at risk and localized within the tumor,” explains Janson. “Proton clinics are eager to get hold of this capability, so we will market it heavily upon release.”
On a parallel development track is proton arc therapy, a next-generation treatment modality in which radiation is delivered continuously (rather than from just three or four angles) as the gantry rotates around the patient. Right now, proton arc therapy remains a work-in-progress and is not part of routine clinical practice. That’s why RaySearch is working closely with IBA, the Belgian proton therapy OEM, to ensure joined-up development of treatment planning functionality to align with the anticipated release of the first proton arc delivery systems for clinical use – likely towards the end of 2021.
“Watch this space,” Janson concludes. “We’re having monthly meetings with our colleagues at IBA, as well as the cancer centers engaged in evaluation and optimization of the proton arc treatment planning and hardware, to ensure that everything comes to market at the same time.”
