Highlights
- •Monte Carlo implementation of a micro-CT scanner (XtremeCT)
- •Validation of MC model using measurements.
- •Extensions of MC model to enable the analysis of scatter components.
- •Scatter component analysis for different situations.
Abstract
Micro computed tomography (µCT) scanners are used to create high-resolution images
and to quantify properties of the scanned objects. While modern µCT scanners benefit
from the cone beam geometry, they are compromised by scatter radiation. This work
aims to develop a Monte Carlo (MC) model of a µCT scanner in order to characterize
the scatter radiation in the detector plane.
The EGS++ framework with the MC code EGSnrc was used to simulate the particle transport
through the main components of the XtremeCT (SCANCO Medical AG, Switzerland). The
developed MC model was based on specific information of the manufacturer and was validated
against measurements. The primary and the scatter radiation were analyzed and by implementing
a dedicated tracing method, the scatter radiation was subdivided into different scatter
components.
The comparisons of measured and simulated transmission values for different absorber
and filter combinations result in a mean difference of 0.2% ± 1.4%, with a maximal
local difference of 3.4%. The reconstructed image of the phantom based on measurements
agrees well with the image reconstructed using the MC model. The local contribution
of scattered radiation is up to 10% of the total radiation in the detector plane and
most of the scattered particles result from interactions in the scanned object. The
MC simulations show that scatter radiation contains information about the structure
of the object.
In conclusion, a MC model for a µCT scanner was successfully validated and applied
to analyze the characteristics of the scatter radiation for a µCT scanner.
Keywords
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Article info
Publication history
Accepted:
November 4,
2017
Received in revised form:
October 5,
2017
Received:
June 10,
2017
Identification
Copyright
© 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
