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The effect of CT reconstruction filter selection on Hounsfield units in radiotherapy treatment planning

Published online by Cambridge University Press:  19 June 2023

Oussama Nhila Open the ORCID record for Oussama Nhila [Opens in a new window] ,
Mohammed Talbi ,
M’hamed El Mansouri ,
Moulay Ali Youssoufi ,
Morad Erraoudi ,
El Mahjoub Chakir  and
Mohamed Azougagh
Oussama Nhila*
Affiliation:
Ibn Tofail University, Faculty of Sciences, Department of Physics, Laboratory of Materials and Subatomic Physics, Kenitra, Morocco
Mohammed Talbi
Affiliation:
Moulay Ismail University, Faculty of Sciences, Physical Sciences and Engineering, Meknes, Morocco
M’hamed El Mansouri
Affiliation:
Ibn Tofail University, Faculty of Sciences, Department of Physics, Laboratory of Materials and Subatomic Physics, Kenitra, Morocco
Moulay Ali Youssoufi
Affiliation:
National Institute of Oncology, University Hospital Center, Rabat, Morocco
Morad Erraoudi
Affiliation:
Mohammed V University, Faculty of Sciences, Department of Physics, Rabat, Morocco
El Mahjoub Chakir
Affiliation:
Ibn Tofail University, Faculty of Sciences, Department of Physics, Laboratory of Materials and Subatomic Physics, Kenitra, Morocco
Mohamed Azougagh
Affiliation:
Mohammed V University, National Graduate School of Arts and Crafts, Rabat, Morocco
*
Corresponding author: Oussama Nhila; Email: nhila.oussama@gmail.com
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Abstract

Introduction:

This work aims to evaluate the effect of Hitachi 16-slice scanner reconstruction filters on Hounsfield unit (HU) variations. In the literature, there is a lack of information from a wide variety of scanners in this regard. In addition, not all studies have investigated the effect of reconstruction filters on HU in an exhaustive way.

Methods:

The computerised imaging reference system electron density phantom (model 062M) was scanned with different substitute materials of different density from Hitachi 16-slice computed tomography. The raw images were obtained with four tube voltage settings: 80 kVp, 100 kVp, 120 kVp and 140 kVp. The raw images for each energy level were then reconstructed using different reconstruction filters.

Results:

The HU values of dense bone were significantly different when changing the reconstruction filters without beam hardening correction (BHC). Nevertheless, when selecting the BHC, this variation decreases heavily for 80 kVp and decreases slightly for 140 kVp, but it remains outside the tolerance of ±50 HU. However, for 100 kVp and 120 kVp, the differences in HU values become within the tolerances indicated for dense bone.

Conclusions:

Changing image reconstruction filters during a dosimetric scan had a significant effect on HU in dense bone. Therefore, it is recommended to evaluate this effect during the commissioning phase. As a result, this study provides a methodology to comprehensively investigate the effect of reconstruction filters on HU.

Keywords

computed tomographyCT-RED calibration curveHounsfield unitradiotherapyreconstruction filters
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 22 , 2023 , e102
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Copyright
© The Author(s), 2023. Published by Cambridge University Press

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