Detector Seminar

PRaVDA to OPTIma: The trials and tribulations of Proton CT

by Nigel M Allinson, MBE, ScD, FIET, CEng - Distinguished Professor of Image Engineering (University of Lincoln, UK)


The PRaVDA instrument produced some excellent results and more importantly taught us lots of lessons – what to do again and what not!  In designing the next generation of Proton CT instrumentation, we realised that we had to meet a new range of constraints if our work would eventually be accepted by the medical community and by industry if they were going to commercially develop it.
OPTIma had to be designed for pencil beam scanning delivery, work within the normal operational envelope of the accelerator and the delivery nozzle, fit with clinical workflows and provide a benefit that could not be met by other imaging techniques.
The two essential components of a CT system are sets of proton trackers – to record the individual trajectories of incident and traversing protons – and an energy detector – to record the corresponding residual energy of the proton after it has passed through a patient.  The trackers are based on four layers of silicon strips at differing orientations and a new ASIC-FPGA combination capable of recording up to 256 comparator outputs at speeds up to about GHz.  The ASIC contains an integral calibration system to set individual comparator levels. OPTIma will employ a positional calorimeter in place of a range telescope as the residual energy detector.
Finally, we discuss the relevance of time in data capture and the demands of data processing prior to CT reconstruction.

Zoom connection details are given in the invitation email. If you have not received this and would like to attend please contact

Organized by

Michael Campbell (EP-ESE)