Technical Note: Development of a 3D printed subresolution sandwich phantom for validation of brain SPECT analysis. Issue 9 (9th August 2016)

• Record Type: Journal Article
• Authors: Negus, Ian S.; Holmes, Robin B.; Jordan, Kirsty C.; Nash, David A.; Thorne, Gareth C.; Saunders, Margaret
• Is Part Of: Medical physics. Volume 43:Issue 9(2016)
• Page Start: 5020
• Page End: 5027
• Publication Date: 2016-08-09
• Subjects: biomedical MRI -- brain -- cameras -- computerised tomography -- image reconstruction -- image segmentation -- medical image processing -- phantoms -- polymers -- radioisotope imaging -- single photon emission computed tomography -- three‐dimensional printing; Single photon emission computed tomography (SPECT) -- Computed tomography -- Reconstruction -- MRI: anatomic, functional, spectral, diffusion; Involving electronic [emr] or nuclear [nmr] magnetic resonance, e.g. magnetic resonance imaging -- Computerised tomographs -- Biological material, e.g. blood, urine; Haemocytometers -- Details of cameras or camera bodies; Accessories therefor -- Cameras -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Transforming light or analogous information into electric information -- Scintigraphy -- Measuring radioactive content of objects, e.g. contamination (whole‐body counters G01T011/63); 3D printing -- nuclear medicine -- phantoms -- quantitative imaging -- brain; Brain -- Single photon emission computed tomography -- 3D printing -- Positron emission tomography -- Medical image reconstruction -- Computed tomography -- Cameras -- Three dimensional image processing -- Image scanners; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4960003
• Languages: English
• ISSNs: 0094-2405

Abstract

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.