Investigation on the resolution of a micro cone beam CT scanner scintillating detector using Monte Carlo methods.

Volken, Werner; Zulliger, M A; Koller, B; Manser, Peter; Fix, Michael (2018). Investigation on the resolution of a micro cone beam CT scanner scintillating detector using Monte Carlo methods. Physica medica, 53, pp. 17-24. Elsevier 10.1016/j.ejmp.2018.08.002

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The impact of several physical quantities on the spatial resolution of an X-ray scintillating pixel detector for a micro cone beam CT (µCBCT) is investigated and discussed. The XtremeCT from SCANCO Medical AG was simulated using the EGSnrc/EGS++ Monte Carlo (MC) framework and extensively benchmarked in a previous work. The resolution of the detector was determined by simulating a titanium knife-edge to obtain the edge spread function (ESF) and the modulation transfer function (MTF). Propagation of the scintillation light through the scintillator and its coupling into the fiber optics system was taken into account. The contribution of particles scattered in the main scanner components to the detector signal is very low and does not affect the spatial resolution of the detector. The resolution obtained from the energy deposition in the scintillator without any blurring due to the propagation of the scintillation light into the fiber optics array was 31 µm. By assuming isotropic light propagation in the scintillator, the resolution degraded to 360 µm. A simple light propagation model taking into account the impact of the scintillator's columnar microstructures was developed and compared with the MANTIS Monte Carlo simulation package. By reducing the width of the model's light propagation kernel by a factor of 2 compared to the isotropic case, the detector resolution can be improved to 83 µm, which corresponds well to the measured resolution of 86 µm. The resolution of the detector is limited mainly by the propagation of the scintillation light through the scintillator layer. It offers the greatest potential to improve the resolution of the µCBCT imaging system.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology > Medical Radiation Physics

UniBE Contributor:

Volken, Werner; Manser, Peter and Fix, Michael

ISSN:

1724-191X

Publisher:

Elsevier

Language:

English

Submitter:

Beatrice Scheidegger

Date Deposited:

02 Oct 2018 13:54

Last Modified:

02 Oct 2018 13:58

Publisher DOI:

10.1016/j.ejmp.2018.08.002

PubMed ID:

30241750

BORIS DOI:

10.7892/boris.120255

URI:

https://boris.unibe.ch/id/eprint/120255

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