Development and validation of a bespoke phantom to test accuracy of Cobb angle measurements

Alrehily, F, Hogg, P ORCID: https://orcid.org/0000-0002-6506-0827, Twiste, M ORCID: https://orcid.org/0000-0003-2724-3283, Johansen, S and Tootell, AK ORCID: https://orcid.org/0000-0002-8567-8659 2020, 'Development and validation of a bespoke phantom to test accuracy of Cobb angle measurements' , Radiography, 26 (2) , e78-e87.

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Abstract

Introduction: Adolescent idiopathic scoliosis (AIS) is a spinal deformity that causes the spine to bend laterally. Patients with AIS undergo frequent X-ray examinations to monitor the progression of the disorder by through the measurement of the Cobb angle. Frequent exposure of adolescents poses the risk of radiation-induced cancer. The aim of this research was to design and build a bespoke phantom representing a 10-year-old child with AIS to allow optimisation of imaging protocols for AIS assessment through the accuracy of Cobb angle measurements.
Method: Poly-methyl methacrylate (PMMA) and plaster of Paris (PoP) were used to represent human soft tissue and bone tissue, respectively, to construct a phantom exhibiting a 15olateral curve of the spine. The phantom was validated by comparing the Hounsfield unit (HU)of its vertebrae with that of human and sheep. Additionally, comparisons of signal-to-noise ratio (SNR) to those from a commercially available phantom. An assessment of the accuracy of the radiographic assessment of the Cobb angle measurement was performed.
Results: The HU of the PoP vertebrae was 628 (SD= 56), human vertebrae was 598 (SD= 79) and sheep vertebra was 605 (SD= 83). The SNR values of the two phantoms correlated strongly (r = 0.93 (p = 0.00)). The measured scoliosis angle was 14 degrees.
Conclusion:The phantom has physical characteristics (in terms of spinal deformity) and radiological characteristics (in terms of HU and SNR values) of the spine of a 10-year-old child with AIS. This phantom has utility for the optimisation of x-ray imaging techniques in 10 year old children.
Implications for practice: A phantom to investigate new x-ray imaging techniques and technology in the assessment of scoliosis and to optimise currently used protocols.

Item Type: Article
Schools: Schools > School of Health and Society
Journal or Publication Title: Radiography
Publisher: Elsevier
ISSN: 1078-8174
Related URLs:
Depositing User: AK Tootell
Date Deposited: 13 Nov 2019 14:11
Last Modified: 06 Apr 2020 11:45
URI: http://usir.salford.ac.uk/id/eprint/53026

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