Delivering the Dose, Precisely
A mainstay in today’s healthcare fight against cancer are radiotherapy (RT) machines that irradiate tumours with photons or charged particles. Particle therapy (PT) is the type of RT that is particularly useful in treating deep-seated tumours, for example, in the head or abdomen. A PT machine consists of various pieces of equipment of which the closest one to the patient is the scanning or the dose delivery system (DDS). The latter controls how the beam nozzle delivers the prescribed dose to the treated area, directing and measuring the particle beam as accurately as possible. The DDS must both meet high-performance requirements and observe all the relevant standards to ensure patient and user safety.
One of the advantages of particle therapy over photon radiotherapy is that PT inflicts less collateral damage to the patient’s tissue that surrounds the tumour. A DDS plays an essential role in further optimising the efficiency of the therapy process in a PT installation. The better the dose delivery system performs in a PT facility, the faster the machine can deliver the radiation dose, and the greater number of indications it can treat. Additionally, an effective DDS improves patient-therapy throughput, shortens the average treatment time and improves the patient’s experience.
The Need for Speed
The C-DDS will allow MedAustron facility to treat more patients and high-volume tumours. For the technically inclined, the goals of the development program are to let MedAustron safely treat patients at higher beam intensities, up to a nominal/peak 2×1010/2,5×1011 protons per second and 1×109/7,5×109 carbon-ions per second. To do this and to satisfy the requirements of IEC 60601-2-64, C-DDS in MedAustron has to react to a beam-parameter venturing out of bounds quickly – in 50 µs (particle rate) and 120 µs (beam position).
Furthermore, C-DDS does not need to turn the beam off between scanning spots and controls the particle rate control dynamically. The system automatically controls the beam intensity based on the weight of previous, current and next spots.
Integration into a PT Facility
As the C-DDS has to integrate into an existing operational PT facility, we had to design the system carefully, taking into account not only the current constraints but also future functionality and performance. That is why we have designed the system around a high-performance COTS (Commercial-Off-The-Shelf) modular hardware platform, enabling fast replacement in case of hardware failures and easier upgrades with future functionality.
All the external software and hardware interfaces of the C-DDS are customisable, allowing engineers to integrate it into various proton and ion-beam therapy centres and adapt to diverse accelerator types, particle species, room configurations and geometries (single/multiple fixed or gantry nozzles) and to existing interfaces of the PT centres. The modular architecture also allows us to upgrade the C-DDS in the future with features like advanced beam monitors, commissioning and QA automation, advanced dose delivery methods and real-time anatomy/beam monitoring.
But the integration into a PT facility is not only about the nitty-gritty of interfacing equipment. We are working with users to provide well-designed user interfaces to allow for the implementation of efficient user workflows during clinical operation, commissioning, QA and research. The C-DDS supports multiple modes of operation and configuration control – Clinical, Service, QA, Manual – in which it allows various system configurations and functionalities.
Figure 2: C-DDS Service Toolkit
And let’s not forget about the Cosylab radiotherapy software suite – the C-DDS is integrated “out of the box” with other Cosylab products for PT machine control, the C-TCS (Treatment Control System) and C-ACS (Accelerator Control System). C-DDS is, at the same time, also an upgradeable generic solution that Cosylab is bringing to the market as a finished product that can be integrated into any PT installation.
We believe that tight integration of software is crucial for efficient operation today and even more so in the future – it is an enabler for implementation of advanced workflows, such as log-based QA and real-time adaptive radiotherapy.
Conclusions
We designed our new dose delivery system to contains all the features and performance of a modern beam scanning system right out of the box. That is why C-DDS is compatible with future functionalities, such as FLASH, adaptive proton therapy, tracking, proton imaging, range verification and arc therapy. The modular architecture of C-DDS allows for easy integration into a multitude of existing PT systems and customisation with vendor-specific features, regardless of accelerator type or particle species used. This design strategy will allow C-DDS to incorporate future updates straightforwardly. It will also permit the introduction of revolutionary techniques in beam generation with a minimum of medical recertification effort.
Figure 3: Beam scan, delivered with C-DDS at MedAustron
In 2021, we will install, commission and test the C-DDS in the MedAustron research room. We expect to integrate the C-DDS into clinical rooms and thus enable the first patient treatments at MedAustron in 2022. At the same time, we are already working hard on integrations of the C-DDS as a generic scanning system product into other PT facilities around the world.
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