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Among the new emerging cancer therapies, Microbeam Radiation Therapy (MRT) is currently showing very promising results in terms of limiting or decreasing tumor growth while keeping the damage to healthy tissue to a minimum. The MRT is able to deliver unprecedented dose rates of up to 20 kGy/s, posing important questions in terms of treatment planning and patient safety during treatment. For this reason, a beam monitoring system must be built, in which a detector acquires the microbeam array profile in real-time. In case of anomalies detection, the detector signals the beam-line to close the shutter as an emergency safety measure. Many sensors technologies for beam monitoring are currently being considered and silicon strip detectors seem to be very promising candidates. In this study the characterisation in full MRT conditions of a novel silicon strip detector is reported explaining strengths and weaknesses of the devices. Modifications to the sensor layout are also suggested in this study.

The Micro-Beam Radiation Therapy (MRT) is a promising newly emerged cancer treatment currently under development at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Several safety requirements must be complied with, prior to the human clinical trials of the MRT such as the ability to send a signal to the emergency beam shutter in case of any beam anomalies, in order to avoid exposing the patient to excess radiation. This will require a beam monitor that can work under the demanding operating conditions of the MRT. A good candidate for this application is a silicon strip detector. A novel device layout has been proposed and numerical simulations were performed to carry out the optimisation of design and fabrication at SINTEF MiNaLab, Oslo, Norway. Simulation results and preliminary electrical measurements on wafer level are reported and discussed.

On the biomedical beamline ID17 at the ESRF a gas attenuator system has been installed to complement and protect the standard solid state attenuators (graphite, Al and Cu) against fatigue and damage due to the very high heat load from the beamline's wiggler source. This series of attenuators defines the flux (dose rate) and the X-ray beam spectrum for the Microbeam Radiation Therapy (MRT) research at ID17 which is currently under development towards clinical application. For this, the attenuators at MRT will be crucial elements to guarantee beam- and dose rate characteristics and the new gas attenuator will become a radiation therapy safety device. The installed gas attenuator and its test results will be presented.

Synchrotron-generated X-ray microplanar beams (microbeams) are characterized by the ability to avoid widespread tissue damage following delivery of doses ranging from hundreds to over a thousand Gray. The preservation of tissue architecture following high-dose microbeam irradiation is known as “tissue-sparing effect” and is strictly related to the ability of microbeams to restrict spatially these exceedingly high doses to the beam path with minimal doses spreading outside to the adjacent tissue. Image-guided microbeam radiosurgery has been recently used to generate cortical transections or to induce deep-seated lesions in the rat brain. The ability to generate focal lesions or microscopic transections over the eloquent and non-eloquent cortex in experimental animals is of great interest for the development of experimental models in neurobiology, opening new treatment avenues for a variety of neuropsychiatric disorders originating from focal brain dysfunction. This paper reviews the current state of research on the radiobiological properties of synchrotron-generated microscopic X-ray beams and their emerging microradiosurgical application, with special reference to the treatment of a variety of brain disorders.

Synchrotron radiation (SR) therapy is a promising alternative to treat brain tumors, whose management is limited due to the high morbidity of the surrounding healthy tissues. Several approaches are being explored by using SR at the European Synchrotron Radiation Facility (ESRF), where three techniques are under development Synchrotron Stereotactic Radiation Therapy (SSRT), Microbeam Radiation Therapy (MRT) and Minibeam Radiation Therapy (MBRT). The sucess of the preclinical studies on SSRT and MRT has paved the way to clinical trials currently in preparation at the ESRF. With this aim, different dosimetric aspects from both theoretical and experimental points of view have been assessed. In particular, the definition of safe irradiation protocols, the beam energy providing the best balance between tumor treatment and healthy tissue sparing in MRT and MBRT, the special dosimetric considerations for small field dosimetry, etc will be described. In addition, for the clinical trials, the definition of appropiate dosimetry protocols for patients according to the well established European Medical Physics recommendations will be discussed. Finally, the state of the art of the MBRT technical developments at the ESRF will be presented. In 2006 A. Dilmanian and collaborators proposed the use of thicker microbeams (0.36-0.68 mm). This new type of radiotherapy is the most recently implemented technique at the ESRF and it has been called MBRT. The main advantage of MBRT with respect to MRT is that it does not require high dose rates. Therefore it can be more easily applied and extended outside synchrotron sources in the future.

Microbeam Radiation Therapy (MRT) is a preclinical synchrotron radiation based therapy technique in its preclinical stage with the potential to treat brain tumours in children when other kinds of radiotherapy would be excessively toxic to the developing normal brain. The most promising feature of MRT lies in its unusual resistance of MRT irradiated tissues to radioneurotoxicity even for peak doses of several hundreds of Gray. Results obtained with the spatially fractionated beams indicate a superior therapeutic effect compared to conventional radiotherapy. MRT, solely possible at SR sources with negligible beam divergence, is profiting from the dose volume effect and most probably from some differences in the tumour and the normal tissue responses, yet to be fully understood. This paper demonstrates that dosimetric measurements requiring a spatial resolution of a few microns is feasible with the use of GafChromic® films together with a high resolution scanner system. The data so obtained can be used to benchmark Monte Carlo calculations. © 2009 Springer-Verlag.

We present here the latest results from tests performed at the ESRF ID17 and ID21 beamlines for the characterization of novel beam monitors for Microbeam Radiation Therapy (MRT), which is currently being implemented at ID17. MRT aims at treating solid tumors by exploiting an array of evenly spaced microbeams, having an energy spectrum distributed between 27 and 600. keV and peaking at 100. keV. Given the high instantaneous dose delivered (up to 20. kGy/s), the position and the intensity of the microbeams has to be precisely and instantly monitored. For this purpose, we developed dedicated silicon microstrip beam monitors. We have successfully characterized them, both with a microbeam array at ID17, and a submicron scanning beam at ID21. We present here the latest results obtained in recent tests along with an outlook on future developments.

Among the new emerging cancer therapies, Microbeam Radiation Therapy (MRT) is currently showing very promising results in terms of limiting or decreasing tumor growth while keeping the damage to healthy tissue to a minimum. The MRT is able to deliver unprecedented dose rates of up to 20 kGy/s, posing important questions in terms of treatment planning and patient safety during treatment. For this reason, a beam monitoring system must be built, in which a detector acquires the microbeam array profile in real-time. In case of anomalies detection, the detector signals the beam-line to close the shutter as an emergency safety measure. Many sensors technologies for beam monitoring are currently being considered and silicon strip detectors seem to be very promising candidates. In this study the characterisation in full MRT conditions of a novel silicon strip detector is reported explaining strengths and weaknesses of the devices. Modifications to the sensor layout are also suggested in this study.

Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper.

Microbeam radiation therapy (MRT), a novel form of spatially fractionated radiotherapy (RT), uses arrays of synchrotron-generated X-ray microbeams (MB). MRT has been identified as a promising treatment concept that might be applied to patients with malignant central nervous system (CNS) tumours for whom, at the current stage of development, no satisfactory therapy is available yet. Preclinical experimental studies have shown that the CNS of healthy rodents and piglets can tolerate much higher radiation doses delivered by spatially separated MBs than those delivered by a single, uninterrupted, macroscopically wide beam. High-dose, high-precision radiotherapies such as MRT with reduced probabilities of normal tissue complications offer prospects of improved therapeutic ratios, as extensively demonstrated by results of experiments published by many international groups in the last two decades. The significance of developing MRT as a new RT approach cannot be understated. Up to 50% of cancer patients receive conventional RT, and any new treatment that provides better tumour control whilst preserving healthy tissue is likely to significantly improve patient outcomes.

The Micro-Beam Radiation Therapy (MRT) is a promising newly emerged cancer treatment currently under development at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Several safety requirements must be complied with, prior to the human clinical trials of the MRT such as the ability to send a signal to the emergency beam shutter in case of any beam anomalies, in order to avoid exposing the patient to excess radiation. This will require a beam monitor that can work under the demanding operating conditions of the MRT. A good candidate for this application is a silicon strip detector. A novel device layout has been proposed and numerical simulations were performed to carry out the optimisation of design and fabrication at SINTEF MiNaLab, Oslo, Norway. Simulation results and preliminary electrical measurements on wafer level are reported and discussed.

Introduction: Multiple subpial transections are an alternative to resection of the epileptic focus for select patients. Microradiosurgery is a developing technique, which uses submillimetric beams of radiation to treat disease. This preliminary study was designed to evaluate electroencephalography and behavioral findings following microradiosurgical transcortical transection (MTT) of a rat seizure focus. Materials and Methods: Kainic acid was used to induce a seizure focus within the left sensorimotor cortex of two rats. Before and up to 10 hours following synchrotron-generated MTT, video-EEG was recorded. Results: Convulsive seizures were eliminated less than five hours after the MTT. Although more subtle electrographic ictal events remained detectable by EEG recording, the propagation of seizures was effectively disrupted. Conclusions: These results demonstrate the feasibility of recording VEEG before and after precise microbeam irradiation from a synchrotron source. VEEG allowed evaluation of electrographic ictal events, in addition to clinical seizures. The results show some promise that MTT can limit the spread of seizures without causing clinically evident neurological damage.