High Dose MicroCT Does Not Contribute Toward Improved MicroPET/CT Image Quantitative Accuracy and Can Limit Longitudinal Scanning of Small Animals

Frontiers in Physics

McDougald, Wendy A.¹  Green, Mark²  Tavares, Adriana A. S.³  Collins, Richard⁴ 

[1]British Heart Foundation/University Centre for Cardiovascular Science (CVS), Queen'

[2]Edinburgh College of Arts, University of Edinburgh, United Kingdom

[3]Radiation Protection Unit, Department of Health and Safety, University of Edinburgh, United Kingdom

[4]s Medical Research Institute, University of Edinburgh, United Kingdom

关键词: Preclinical PET CT;    Hounsfield Units;    Absorbed dose;    Recovery coefficient;    Attenuation coefficient;   

DOI  :  10.3389/fphy.2017.00050

学科分类：物理（综合）

来源: Frontiers

【 摘 要 】

Obtaining accurate quantitative measurements in preclinical Positron Emission Tomography/Computed Tomography (PET/CT) imaging is of paramount importance in biomedical research and helps supporting efficient translation of preclinical results to the clinic. The purpose of this study was two-fold: (1) to investigate the effects of different CT acquisition protocols on PET/CT image quality and data quantification; and (2) to evaluate the absorbed dose associated with varying CT parameters. Methods: An air/water quality control CT phantom, tissue equivalent material phantom, an in-house 3D printed phantom and an image quality PET/CT phantom were imaged using a Mediso nanoPET/CT scanner. Collected data was analyzed using PMOD software, VivoQuant software and National Electric Manufactures Association (NEMA) software implemented by Mediso. Measured Hounsfield Unit (HU) in collected CT images were compared to the known HU values and image noise was quantified. PET recovery coefficients (RC), uniformity and quantitative bias were also measured. Results: Only less than 2% and 1% of CT acquisition protocols yielded water HU values < -80 and air HU values < -840, respectively. Four out of eleven CT protocols resulted in more than 100 mGy absorbed dose. Different CT protocols did not impact PET uniformity and RC, and resulted in <4% overall bias relative to expected radioactive concentration. Conclusion: Preclinical CT protocols with increased exposure times can result in high absorbed doses to the small animals. These should be avoided, as they do not contributed towards improved microPET/CT image quantitative accuracy and could limit longitudinal scanning of small animals.

【 授权许可】

CC BY