Design and Fabrication Process of MTF Phantom CT Scan

Document Type: Conference Proceedings

Authors

1 Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran TEL: 09120510601, E-mail: behzad.mohsenzadeh@sbmu.ac.ir

2 Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran

Abstract

Introduction:
One of the main steps in the optimization process in diagnostic imaging is the quality control of radiology devices. The usual method of CT scan calibration is used of a phantom. The phantom created a certain weakening for the radiation through which it passes. One of the most suitable methods for quantitative analysis of the resolution and contrast in CT scan images is to calculate MTF chart. Modulation in imaging is means contrast and the transfer function to the concept of the contrast ratio of the output to the contrast of the input system. The modulation transfer function of an imaging system is reflecting the contrast of the system at various space frequencies. The aim of this study is created phantom MTF for a CT scan.
Materials and Methods:
For phantom design, firstly, the number of pairs of lines required for CT scan images was evaluated and 2 to 14 LP/cm were selected for this phantom. Then, to create these pair of lines, you need a metal with a low atomic number until the amount of artifact decreases that aluminum was selected in this regard. Then using the AutoCAD software, the MTF calculation tool was designed as L-shape. Finally, the MTF calculation tool was combined into the groove created in the acrylic disk using the LOEXAL glue.
Results:
This phantom was tested for various CT scan devices. The results obtained from this phantom are equal to the external samples. The MTF chart obtained from this phantom corresponds to the MTF Phantom Pro-CT chart.
Conclusion:
This phantom has much less weight than other phantoms. The thickness of these lines is high and it can be captured in a slide CT scan of all the lines. In this phantom, the modulation function or MTF is calculated with high precision and more points. This phantom can be used for limiting spatial resolution.

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