open access

Vol 25, No 5 (2020)
Original research articles
Published online: 2020-09-01
Submitted: 2020-01-03
Get Citation

Estimation and evaluation of pseudo-CT images using linear regression models and texture feature extraction from MRI images in the brain region to design external radiotherapy planning

Niloofar Yousefi Moteghaed, Ahmad Mostaar, Keivan Maghooli, Mohammad Houshyari, Ahmad Ameri
DOI: 10.1016/j.rpor.2020.05.005
·
Rep Pract Oncol Radiother 2020;25(5):738-745.

open access

Vol 25, No 5 (2020)
Original research articles
Published online: 2020-09-01
Submitted: 2020-01-03

Abstract

Aim

The aim of this study is to construct and evaluate Pseudo-CT images (P-CTs) for electron density calculation to facilitate external radiotherapy treatment planning.

Background

Despite numerous benefits, computed tomography (CT) scan does not provide accurate information on soft tissue contrast, which often makes it difficult to precisely differentiate target tissues from the organs at risk and determine the tumor volume. Therefore, MRI imaging can reduce the variability of results when registering with a CT scan.

Materials and methods

In this research, a fuzzy clustering algorithm was used to segment images into different tissues, also linear regression methods were used to design the regression model based on the feature extraction method and the brightness intensity values. The results of the proposed algorithm for dose-volume histogram (DVH), Isodose curves, and gamma analysis were investigated using the RayPlan treatment planning system, and VeriSoft software. Furthermore, various statistical indices such as Mean Absolute Error (MAE), Mean Error (ME), and Structural Similarity Index (SSIM) were calculated.

Results

The MAE of a range of 45–55 was found from the proposed methods. The relative difference error between the PTV region of the CT and the Pseudo-CT was 0.5, and the best gamma rate was 95.4% based on the polar coordinate feature and proposed polynomial regression model.

Conclusion

The proposed method could support the generation of P-CT data for different parts of the brain region from a collection of MRI series with an acceptable average error rate by different evaluation criteria.

Abstract

Aim

The aim of this study is to construct and evaluate Pseudo-CT images (P-CTs) for electron density calculation to facilitate external radiotherapy treatment planning.

Background

Despite numerous benefits, computed tomography (CT) scan does not provide accurate information on soft tissue contrast, which often makes it difficult to precisely differentiate target tissues from the organs at risk and determine the tumor volume. Therefore, MRI imaging can reduce the variability of results when registering with a CT scan.

Materials and methods

In this research, a fuzzy clustering algorithm was used to segment images into different tissues, also linear regression methods were used to design the regression model based on the feature extraction method and the brightness intensity values. The results of the proposed algorithm for dose-volume histogram (DVH), Isodose curves, and gamma analysis were investigated using the RayPlan treatment planning system, and VeriSoft software. Furthermore, various statistical indices such as Mean Absolute Error (MAE), Mean Error (ME), and Structural Similarity Index (SSIM) were calculated.

Results

The MAE of a range of 45–55 was found from the proposed methods. The relative difference error between the PTV region of the CT and the Pseudo-CT was 0.5, and the best gamma rate was 95.4% based on the polar coordinate feature and proposed polynomial regression model.

Conclusion

The proposed method could support the generation of P-CT data for different parts of the brain region from a collection of MRI series with an acceptable average error rate by different evaluation criteria.

Get Citation

Keywords

MRI-only treatment planning; Pseudo-CT; Polynomial regression model; Dose evaluation

About this article
Title

Estimation and evaluation of pseudo-CT images using linear regression models and texture feature extraction from MRI images in the brain region to design external radiotherapy planning

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 25, No 5 (2020)

Pages

738-745

Published online

2020-09-01

DOI

10.1016/j.rpor.2020.05.005

Bibliographic record

Rep Pract Oncol Radiother 2020;25(5):738-745.

Keywords

MRI-only treatment planning
Pseudo-CT
Polynomial regression model
Dose evaluation

Authors

Niloofar Yousefi Moteghaed
Ahmad Mostaar
Keivan Maghooli
Mohammad Houshyari
Ahmad Ameri

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