Ian S Negus1, Robin B Holmes1, Kirsty C Jordan2, David A Nash3, Gareth C Thorne1, Margaret Saunders1. 1. Department of Medical Physics and Bioengineering, University Hospitals Bristol NHS Foundation Trust, Bristol BS28HW, United Kingdom. 2. Department of Biomedical Engineering, University of Strathclyde, Glasgow G11XQ, United Kingdom. 3. Department of Medical Physics, Portsmouth Hospitals NHS Trust, Portsmouth PO63LY, United Kingdom.
Abstract
PURPOSE: To make an adaptable, head shaped radionuclide phantom to simulate molecular imaging of the brain using clinical acquisition and reconstruction protocols. This will allow the characterization and correction of scanner characteristics, and improve the accuracy of clinical image analysis, including the application of databases of normal subjects. METHODS: A fused deposition modeling 3D printer was used to create a head shaped phantom made up of transaxial slabs, derived from a simulated MRI dataset. The attenuation of the printed polylactide (PLA), measured by means of the Hounsfield unit on CT scanning, was set to match that of the brain by adjusting the proportion of plastic filament and air (fill ratio). Transmission measurements were made to verify the attenuation of the printed slabs. The radionuclide distribution within the phantom was created by adding (99m)Tc pertechnetate to the ink cartridge of a paper printer and printing images of gray and white matter anatomy, segmented from the same MRI data. The complete subresolution sandwich phantom was assembled from alternate 3D printed slabs and radioactive paper sheets, and then imaged on a dual headed gamma camera to simulate an HMPAO SPECT scan. RESULTS: Reconstructions of phantom scans successfully used automated ellipse fitting to apply attenuation correction. This removed the variability inherent in manual application of attenuation correction and registration inherent in existing cylindrical phantom designs. The resulting images were assessed visually and by count profiles and found to be similar to those from an existing elliptical PMMA phantom. CONCLUSIONS: The authors have demonstrated the ability to create physically realistic HMPAO SPECT simulations using a novel head-shaped 3D printed subresolution sandwich method phantom. The phantom can be used to validate all neurological SPECT imaging applications. A simple modification of the phantom design to use thinner slabs would make it suitable for use in PET.
PURPOSE: To make an adaptable, head shaped radionuclide phantom to simulate molecular imaging of the brain using clinical acquisition and reconstruction protocols. This will allow the characterization and correction of scanner characteristics, and improve the accuracy of clinical image analysis, including the application of databases of normal subjects. METHODS: A fused deposition modeling 3D printer was used to create a head shaped phantom made up of transaxial slabs, derived from a simulated MRI dataset. The attenuation of the printed polylactide (PLA), measured by means of the Hounsfield unit on CT scanning, was set to match that of the brain by adjusting the proportion of plastic filament and air (fill ratio). Transmission measurements were made to verify the attenuation of the printed slabs. The radionuclide distribution within the phantom was created by adding (99m)Tc pertechnetate to the ink cartridge of a paper printer and printing images of gray and white matter anatomy, segmented from the same MRI data. The complete subresolution sandwich phantom was assembled from alternate 3D printed slabs and radioactive paper sheets, and then imaged on a dual headed gamma camera to simulate an HMPAO SPECT scan. RESULTS: Reconstructions of phantom scans successfully used automated ellipse fitting to apply attenuation correction. This removed the variability inherent in manual application of attenuation correction and registration inherent in existing cylindrical phantom designs. The resulting images were assessed visually and by count profiles and found to be similar to those from an existing elliptical PMMA phantom. CONCLUSIONS: The authors have demonstrated the ability to create physically realistic HMPAO SPECT simulations using a novel head-shaped 3D printed subresolution sandwich method phantom. The phantom can be used to validate all neurological SPECT imaging applications. A simple modification of the phantom design to use thinner slabs would make it suitable for use in PET.
Authors: John C Nouls; Rohan S Virgincar; Alexander G Culbert; Nathann Morand; Dana W Bobbert; Anne D Yoder; Robert S Schopler; Mustafa R Bashir; Alexandra Badea; Ute Hochgeschwender; Bastiaan Driehuys Journal: J Med Imaging (Bellingham) Date: 2019-05-15
Authors: Tilman Läppchen; Lorenz P Meier; Markus Fürstner; George A Prenosil; Thomas Krause; Axel Rominger; Bernd Klaeser; Michael Hentschel Journal: EJNMMI Phys Date: 2020-04-22
Authors: Jonathan C Taylor; Nicholas Vennart; Ian Negus; Robin Holmes; Oliver Bandmann; Christine Lo; John Fenner Journal: Nucl Med Commun Date: 2018-03 Impact factor: 1.690