Search

As a prerequisite for clinical treatments it was necessary to characterize the Elekta 1.5 T MRI-linac 7 MV FFF radiation beam. Following acceptance testing, beam characterization data were acquired with Semiflex 3D (PTW 31021), microDiamond (PTW 60019), and Farmer-type (PTW 30013 and IBA FC65-G) detectors in an Elekta 3D scanning water phantom and a PTW 1D water phantom. EBT3 Gafchromic film and ion chamber measurements in a buildup cap were also used. Special consideration was given to scan offsets, detector effective points of measurement and avoiding air gaps. Machine performance has been verified and the system satisfied the relevant beam requirements of IEC60976. Beam data were acquired for field sizes between 1 × 1 and 57 × 22 cm2. New techniques were developed to measure percentage depth dose (PDD) curves including the electron return effect at beam exit, which exhibits an electron-type practical range of cm. The Lorentz force acting on the secondary charged particles creates an asymmetry in the crossline profiles with an average shift of +0.24 cm. For a 10 × 10 cm2 beam, scatter from the cryostat contributes 1% of the dose at isocentre. This affects the relative output factors, scatter factors and beam profiles, both in-field and out-of-field. The average 20%–80% penumbral width measured for small fields with a microDiamond detector at 10 cm depth is 0.50 cm. MRI-linac penumbral widths are very similar to that of the Elekta Agility linac MLC, as is the near-surface dose PDD(0.2 cm) = 57%. The entrance surface dose is ~36% of . Cryostat transmission is quantified for inclusion within the treatment planning system. As a result, the 1.5 T MRI-linac 7 MV FFF beam has been characterised for the first time and is suitable for clinical use. This was a key step towards the first clinical treatments with the MRI-linac, which were delivered at University Medical Center Utrecht in May 2017 (Raaymakers et al 2017 Phys. Med. Biol. 62 L41–50).

The Forschungszentrum Juelich (FZJ) has taken the leadership of a consortium to design and construct the HESR as part of the Facility for Antiproton an Ion Research (FAIR) project at the Gesellschaft fuer Schwerionenforschung (GSI) in Germany. The HESR is a 50 Tm synchrotron/storage ring for antiprotons using superconducting magnet technology, where the development of a bent dipole magnet (cosine theta) with a radius of curvature of 13.9 m and a length of 3.3 m is the major task. On basis of the HERA cooling system the cryogenic design for the HESR has started. One key issue will be the design of several cold-warm transitions e.g. at PANDA, the E-Cooler and in the region of the stochastic beam cooling system. Another important development is the cryostat layout housing the superconducting curved magnets and in particular the alignment system and measurement equipment for the bent magnets. This paper will present an overview both of the cryogenic layout and the cryostat design. It will give a status report on the achievements so far and discuss the future plans.

The design of superconducting quadrupoles for a proton and antiproton low beta section and the test of a prototype coil are presented. Previous studies [1,2] show that high gradient and short quadrupole magnets are required for a compact low beta section in order to allow the insertion of such a magnetic system with minor changes of the lattice [3]; each quadrupole is 400 mm long and has to provide a magnetic induction gradient of 60 T/m. A beam pipe of at least 120 mm diameter is required to avoid beam loss during injection and before the beam cooling. The magnetic design of the superconducting magnets for the low beta section is presented, together with a detailed discussion of the quench protection design. Two prototype coils were produced and one of them was tested. A detailed description of the test setup and a full discussion of the results will be presented.

This work is part of the EC funded PISA project which aims at the development of tools for design and manufacturing of Personalized Implants and Surgical Aids. Sub-optimal implant positioning is a major reason for implant failure and (too) early revision. Although planning is possible to various extends on currently available systems, there is in general no means to transfer the planning to the patient. The PISA project covers the transfer to the patient as well as the planning. Within this project, PMS focused on dental implant planning and design of appropriate drill guides to transfer the planning to the patient. A prototype application was developed on our EasyVision clinical workstation, which includes the following steps