Medical applications of diamond detectors: online control of Hadrontherapy with fast timing and Microbeam Radiation Therapy monitoring
Résumé
This presentation will focus on two applications of diamond detectors in the field of innovative radiotherapies.
The first one consists of a beam hodoscope for hadrontherapy (proton or carbon ion beams). This detector will be used for position and time stamp of the incident particle beam, in order to detect secondary particles (mainly prompt-gammas). Time of Flight is used to reduce background from massive particles, and select photons issued from the patient only. This detector will be made of a mosaic assembly of several diamond plates with double-side strip metallization. The electronic readout design will enable high count rate and high time resolution of the detector.
Preliminary measurements were performed at ARRONAX with 68 MeV protons. Detection efficiency was measured with mono- and polycrystalline diamond detectors. For the latter, up to 95% efficiency (corrected from noise triggering) was obtained for single-proton detection. The time resolution was close to 100ps rms for prompt gamma detection using diamond and fast scintillators for incoming particles and secondary photon detection, respectively. The potential for ultra-fast timing in prompt gamma imaging leads to spatial discrimination and real time reconstruction capabilities for range verification during treatment.
The second application consists in the in vivo monitoring of Microbeam Radiation Therapy. The beam is spatially fractionated with local doses above 1000 Gy/s delivered in narrow peaks of a few tens of μm, separated by 300-500μm. A large area diamond detector with 1D position readout by fast- and high-dynamics charge integration will be used to monitor the transmitted photon beam, and thus evaluate the energy deposited in the patient.