Construction and validation of a low cost paediatric pelvis phantom

Ali, M; Hogg, P; Johansen, S; England, A

Abstract

PURPOSE: Imaging phantoms can be cost prohibitive, therefore a need exists to produce low cost alternatives which are fit for purpose. This paper describes the development and validation of a low cost paediatric pelvis phantom based on the anatomy of a 5-year-old child.

METHODS: Tissue equivalent materials representing paediatric bone (Plaster of Paris; PoP) and soft tissue (Poly methyl methacrylate; PMMA) were used. PMMA was machined to match the bony anatomy identified from a CT scan of a 5-year-old child and cavities were created for infusing the PoP. Phantom validation comprised physical and visual measures. Physical included CT density comparison between a CT scan of a 5-year old child and the phantom and Signal to Noise Ratio (SNR) comparative analysis of anteroposterior phantom X-ray images against a commercial anthropomorphic phantom. Visual analysis using a psychometric image quality scale (face validity).

RESULTS: CT density, the percentage difference between cortical bone, soft tissue and their equivalent tissue substitutes were -4.7 to -4.1% and -23.4%, respectively. For SNR, (mAs response) there was a strong positive correlation between the two phantoms (r>0.95 for all kVps). For kVp response, there was a strong positive correlation between 1 and 8 mAs (r=0.85), this then decreased as mAs increased (r=-0.21 at 20 mAs). Psychometric scale results produced a Cronbach’s Alpha of almost 0.8.

CONCLUSIONS: Physical and visual measures suggest our low-cost phantom has suitable anatomical characteristics for X-ray imaging. Our phantom could have utility in dose and image quality optimisation studies.
Keywords: Pelvis phantom, low-cost, dose optimisation, validation, development.

Citation

Ali, M., Hogg, P., Johansen, S., & England, A. (2018). Construction and validation of a low cost paediatric pelvis phantom. European Journal of Radiology, 108, 84-91. https://doi.org/10.1016/j.ejrad.2018.09.015

• Journal Article Type: Article
• Acceptance Date: Sep 12, 2018
• Online Publication Date: Sep 14, 2018
• Publication Date: Nov 1, 2018
• Deposit Date: Sep 19, 2018
• Publicly Available Date: Sep 14, 2019
• Journal: European Journal of Radiology
• Print ISSN: 0720-048X
• Publisher: Elsevier
• Volume: 108
• Pages: 84-91
• DOI: https://doi.org/10.1016/j.ejrad.2018.09.015
• Publisher URL: https://doi.org/10.1016/j.ejrad.2018.09.015
• Related Public URLs: https://www.journals.elsevier.com/european-journal-of-radiology