Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 1342–1345 A patient positioning system for the ESRF medical imaging facility Y. Dabin a, *, A. Draperi a , H. Elleaume a , A-M. Charvet b , T. Brochard a , M. Perez a , C. Nemoz a , G. Blattmann a , M. Renier a , F. Fournier c , J-L Dupuy c , B. Lemoine c , P. Bouhaniche c , W. Thomlinson a , P. Suortti a a (ESRF) European Synchrotron Radiation Fac. Machnical Engineering TSD BP 220, 6 rue Jules Horowitz, Zip 38000, F-38043 Grenoble C ! edex 09, France b R.S.R.M., MRI Unit, CHRUG, BP 217, 38043 Grenoble c ! edex 09, France c SPRETEC, 19 rue des Ciments, 38180 Seyssins, France Abstract The medical imaging facility of the ESRF is devoted to human coronary angiography, computed tomography, diffraction enhanced imaging (DEI), bronchography, and also radiation therapy programs. Most of the imaging is performed in a satellite building located at 150 m from the wiggler source (H. Elleaume et al., Nucl. Instr. and Meth. A 428 (1999) 513). A multi-purpose device known as the Patient Positioning System (PPS or medical chair) has been designed to perform in different modes of research on patients. This device operates in the angiography mode, with alternating up and down movements in 1.6 s cycles over a period of about 30 s. The tomography mode is used mainly for the imaging of the brain. It consists of turning the patient around an axis perfectly perpendicular to the beam plane. A dual-energy scan involves two rotations with one image recorded each turn at a different energy (Phys. Med. Biol. 45 (2000) L39). The first angiography imaging on patients was undertaken in January 2000 after successful pre-clinical tests on animals. # 2001 Elsevier Science B.V. All rights reserved. 1. Introduction This paper presents the specific engineering aspect of the PPS device in its main operating modes: angiography and tomography. The design aspects of the two scan movements are presented along with the necessary stiffness of the structure, and finally the commissioning tests that show the quality of the scan axis and the noise damping. Investigations of safe operation and energy re- dundancy in the angiography mode give evidence of a smooth operation even in the event of a breakdown. For human imaging experiments, particular attention is paid to the safety of the patient. The PPS is a critical component in that regard. A dedicated Patient Angiography Safety System (PASS) has been designed and commis- sioned for the angiography project (P. Berkvens, ESRF, private communication). It monitors such parameters as the speed of translation, imaging position, and radiation dose. In the event of a problem, the PASS terminates the imaging and *Corresponding author. Tel.: +33-476-882276; fax: +33- 476-882585. E-mail address: dabin@esrf.fr (Y. Dabin). 0168-9002/01/$-see front matter # 2001 Elsevier Science B.V. All rights reserved. PII:S0168-9002(01)00657-X