Daniel Gillett1,2, Daniel Marsden3, Safia Ballout4, Bala Attili5, Nick Bird4, Sarah Heard4, Mark Gurnell6,7,8, Iosif A Mendichovszky4,9, Luigi Aloj4,9. 1. Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK. dg538@medschl.cam.ac.uk. 2. Cambridge Endocrine Molecular Imaging Group, University of Cambridge, Addenbrooke's Hospital, Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK. dg538@medschl.cam.ac.uk. 3. Clinical Engineering, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK. 4. Department of Nuclear Medicine, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK. 5. Clinical Pharmacology & Safety Sciences, AstraZeneca, Darwin Building, Cambridge Science Park Milton Road, Cambridge, CB4 0WG, UK. 6. Cambridge Endocrine Molecular Imaging Group, University of Cambridge, Addenbrooke's Hospital, Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK. 7. Metabolic Research Laboratories, Wellcome-MRC Institute of Metabolic Science, University of Cambridge, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Hills Road, CB2 0QQ, Cambridge, UK. 8. NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK. 9. Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK.
Abstract
PURPOSE: Phantoms are routinely used in molecular imaging to assess scanner performance. However, traditional phantoms with fillable shapes do not replicate human anatomy. 3D-printed phantoms have overcome this by creating phantoms which replicate human anatomy which can be filled with radioactive material. The problem with these is that small objects suffer to a greater extent than larger objects from the effects of inactive walls, and therefore, phantoms without these are desirable. The purpose of this study was to explore the feasibility of creating resin-based 3D-printed phantoms using 18F. METHODS: Radioactive resin was created using an emulsion of printer resin and 18F-FDG. A series of test objects were printed including twenty identical cylinders, ten spheres with increasing diameters (2 to 20 mm), and a double helix. Radioactive concentration uniformity, printing accuracy and the amount of leaching were assessed. RESULTS: Creating radioactive resin was simple and effective. The radioactive concentration was uniform among identical objects; the CoV of the signal was 0.7% using a gamma counter. The printed cylinders and spheres were found to be within 4% of the model dimensions. A double helix was successfully printed as a test for the printer and appeared as expected on the PET scanner. The amount of radioactivity leached into the water was measurable (0.72%) but not visible above background on the imaging. CONCLUSIONS: Creating an 18F radioactive resin emulsion is a simple and effective way to create accurate and complex phantoms without inactive walls. This technique could be used to print clinically realistic phantoms. However, they are single use and cannot be made hollow without an exit hole. Also, there is a small amount of leaching of the radioactivity to take into consideration.
PURPOSE: Phantoms are routinely used in molecular imaging to assess scanner performance. However, traditional phantoms with fillable shapes do not replicate human anatomy. 3D-printed phantoms have overcome this by creating phantoms which replicate human anatomy which can be filled with radioactive material. The problem with these is that small objects suffer to a greater extent than larger objects from the effects of inactive walls, and therefore, phantoms without these are desirable. The purpose of this study was to explore the feasibility of creating resin-based 3D-printed phantoms using 18F. METHODS:Radioactive resin was created using an emulsion of printer resin and 18F-FDG. A series of test objects were printed including twenty identical cylinders, ten spheres with increasing diameters (2 to 20 mm), and a double helix. Radioactive concentration uniformity, printing accuracy and the amount of leaching were assessed. RESULTS: Creating radioactive resin was simple and effective. The radioactive concentration was uniform among identical objects; the CoV of the signal was 0.7% using a gamma counter. The printed cylinders and spheres were found to be within 4% of the model dimensions. A double helix was successfully printed as a test for the printer and appeared as expected on the PET scanner. The amount of radioactivity leached into the water was measurable (0.72%) but not visible above background on the imaging. CONCLUSIONS: Creating an 18F radioactive resin emulsion is a simple and effective way to create accurate and complex phantoms without inactive walls. This technique could be used to print clinically realistic phantoms. However, they are single use and cannot be made hollow without an exit hole. Also, there is a small amount of leaching of the radioactivity to take into consideration.
Entities:
Keywords:
18F; 3D printing; PET; Phantoms; Quality control
Authors: Benjamin L Cox; Stephen A Graves; Mohammed Farhoud; Todd E Barnhart; Justin J Jeffery; Kevin W Eliceiri; Robert J Nickles Journal: Am J Nucl Med Mol Imaging Date: 2016-07-06
Authors: Andrew P Robinson; Jill Tipping; David M Cullen; David Hamilton; Richard Brown; Alex Flynn; Christopher Oldfield; Emma Page; Emlyn Price; Andrew Smith; Richard Snee Journal: EJNMMI Phys Date: 2016-07-13