Review on ocular particle therapy (OPT) by international experts
Beamline with nozzzle for ocular treatments at HZB. © HZB
Treatment planning based on fused multimodality imaging with images from optical coherence tomography, ultrasound, fundus photography, computed tomography (CT) and magnetic resonance imaging. © HZB
A team of leading experts in medical physics, physics and radiotherapy, including HZB physicist Prof. Andrea Denker and Charité medical physicist Dr Jens Heufelder, has published a review article on ocular particle therapy. The article appeared in the Red Journal, one of the most prestigious journals in the field. It outlines the special features of this form of eye therapy, explains the state of the art and current research priorities, provides recommendations for the delivery of radiotherapy and gives an outlook on future developments.
Fortunately, ocular tumours are quite rare. While a few decades ago, treatment consisted of removing the eyeball, there are now a few places in the world where an alternative is available that not only successfully treats the tumour, but in many cases also saves the eye: Radiotherapy with protons has a high chance of success. Decades ago, the cyclotron on the Lise Meitner Campus (at the former Hahn-Meitner Institute) was optimised for this purpose and a treatment centre for proton therapy of ocular tumours was set up. Over the past 25 years, more than 4,700 people have been successfully treated at this treatment centre in close collaboration with the Charité – Universitätsmedizin Berlin.
Many of the procedures presented in this review have been part of the clinical standard for the treatment of patients at the HZB for many years. Some of them were even developed at the HZB and transferred to clinical routine at the Charité. These include, for example, treatment planning based on multimodal imaging using photos of the ocular fundus, computed tomography (CT) and magnetic resonance imaging (MRI). The special treatment planning system required for this was developed at the HZB in collaboration with the German Cancer Research Centre (DKFZ).
A major problem with this particular form of particle therapy is that many treatment centres are so-called in-house solutions with long running times. Due to the low demand and complexity of the field, the industry does not currently offer dedicated treatment centres for ocular irradiation, but only standard irradiation solutions, e.g. on a gantry, which are sub-optimal for ocular treatments.
The final conclusion of the article is: “With a well-designed approach, high tumour control rates can be achieved with proton and other particle beams, with the potential to preserve the eye and vision, optimise the cost-benefit ratio in the treatment of ocular tumours and thus maximise the quality of life of patients. High patient throughput and close collaboration between ophthalmology, radiotherapy and medical physics are essential for successful particle therapy of eye tumours”.
The Particle Therapy Co-Operative Group (PTCOG) is an international scientific organisation in the field of proton and particle therapy. It brings together researchers from more than 130 particle therapy centres. Prof Andrea Denker is a member of the Steering Committee and Dr Jens Heufelder is co-chair of the Ocular Subcommittee.
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