The 200‐MeV proton therapy project at the Paul Scherrer Institute: Conceptual design and practical realization

Abstract

The new proton therapy facility is being assembled at the Paul Scherrer Institute (PSI). The beam delivered by the PSI sector cyclotron can be split and brought into a new hall where it is degraded from 590 MeV down to an energy in the range of 85-270 MeV. A new beam line following the degrader is used to clean the low-energetic beam in phase space and momentum band. The analyzed beam is then injected into a compact isocentric gantry, where it is applied to the patient using a new dynamic treatment modality, the so-called spot-scanning technique. This technique will permit full three-dimensional conformation of the dose to the target volume to be realized in a routine way without the need for individualized patient hardware like collimators and compensators. By combining the scanning of the focused pencil beam within the beam optics of the gantry and by mounting the patient table eccentrically on the gantry, the diameter of the rotating structure has been reduced to only 4 m. In the article the degrees of freedom available on the gantry to apply the beam to the patient (with two rotations for head treatments) are also discussed. The devices for the positioning of the patient on the gantry (x rays and proton radiography) and outside the treatment room (the patient transporter system and the modified mechanics of the computer tomograph unit) are briefly presented. The status of the facility and first experimental results are introduced for later reference.

Dosimetric characterization of a synthetic single crystal diamond detector in a clinical 62 MeV ocular therapy proton beam

“…As a result of an improved dose distribution [4,5] and of advances in delivery techniques [6,7], protons are gaining increasing interest worldwide as an elective treatment for specific types of tumors and the number of dedicated proton therapy facilities is rapidly growing [8]. The need of proton dosimetry standardization and of improvement of dosimetric accuracy have motivated the implementation of international dosimetry protocols [9,10], and a challenging optimization of detector technology.…”

CLUSTER: A high-frequency H-mode coupled cavity linac for low and medium energies

“…The usual beam lines and gantries are located at the end of the linac. It can been shown that the time and intensity structure of a cyclinac is better suited to the active dose distribution approach, called "spot scanning" and developed at PSI [7] than those produced by cyclotrons and synchrotrons. A cyclinac is intended to be the heart of IDRA, the "Institute for Diagnostic and RAdiotherapy", which is a multipurpose facility for the production of both radiopharmaceuticals for diagnostic and therapy, and high-energy protons for the radiotherapy of superficial and deep-seated tumours (Fig.…”

Online beam monitoring in the treatment of ocular pathologies at the INFN Laboratori Nazionali del Sud-Catania

“…The MOPI detector covers a sensitive area of 12.8 x 12.8 cm 2 and is divided in two chambers separated by a common cathode plane, as shown in Fig.3. The anode plane of each chamber is segmented in 256 strips, resulting in a pitch of 0.5 mm, oriented along the vertical and horizontal directions.…”