UNLABELLED: Localization of regions with increased uptake of radiotracer in small-animal SPECT is greatly facilitated when using coregistration with anatomic images of the same animal. As MRI has several advantages compared with CT (soft-tissue contrast and lack of ionizing radiation) we developed a SPECT/low-field MRI hybrid device for small-animal imaging. METHODS: A small-animal single-pinhole gamma-camera (pinhole, 1.5 mm in diameter and 12 cm in focal length) adjacent to a dedicated low-field (0.1 T) small MR imager (imaging volume, 10 x 10 x 6 cm(3)) was used. The animal was placed in a warmed nonmagnetic polymethyl methacrylate imaging cell for MR acquisition, which was followed immediately by SPECT after translation of the imaging cell from one modality to the other. 3-Dimensional T1-weighted sequences were used for MRI. Phantom studies enabled verification of a low attenuation (10%) for (99m)Tc and (201)Tl and a very slight increase in Compton scattering due to the radiofrequency coil and polymethyl methacrylate imaging cell. RESULTS: SPECT/MRI data acquisition and image coregistration of selected examples using different radiotracers for lungs, kidneys, and brain were obtained in 3 nude mice with isotropic spatial resolutions of 0.5 x 0.5 x 0.5 mm(3) for MRI and 1 x 1 x 1 mm(3) for SPECT. The total acquisition time for combined SPECT and MRI lasted 1 h 45 min. CONCLUSION: A low-magnetic-field strength of 0.1 T is a simple and useful solution for a small-animal dual-imaging device combining pinhole SPECT with the adjacent MR imager.
UNLABELLED: Localization of regions with increased uptake of radiotracer in small-animal SPECT is greatly facilitated when using coregistration with anatomic images of the same animal. As MRI has several advantages compared with CT (soft-tissue contrast and lack of ionizing radiation) we developed a SPECT/low-field MRI hybrid device for small-animal imaging. METHODS: A small-animal single-pinhole gamma-camera (pinhole, 1.5 mm in diameter and 12 cm in focal length) adjacent to a dedicated low-field (0.1 T) small MR imager (imaging volume, 10 x 10 x 6 cm(3)) was used. The animal was placed in a warmed nonmagnetic polymethyl methacrylate imaging cell for MR acquisition, which was followed immediately by SPECT after translation of the imaging cell from one modality to the other. 3-Dimensional T1-weighted sequences were used for MRI. Phantom studies enabled verification of a low attenuation (10%) for (99m)Tc and (201)Tl and a very slight increase in Compton scattering due to the radiofrequency coil and polymethyl methacrylate imaging cell. RESULTS: SPECT/MRI data acquisition and image coregistration of selected examples using different radiotracers for lungs, kidneys, and brain were obtained in 3 nude mice with isotropic spatial resolutions of 0.5 x 0.5 x 0.5 mm(3) for MRI and 1 x 1 x 1 mm(3) for SPECT. The total acquisition time for combined SPECT and MRI lasted 1 h 45 min. CONCLUSION: A low-magnetic-field strength of 0.1 T is a simple and useful solution for a small-animal dual-imaging device combining pinhole SPECT with the adjacent MR imager.
Authors: Gurpreet Singh Sandhu; Luis Solorio; Ann-Marie Broome; Nicolas Salem; Jeff Kolthammer; Tejas Shah; Chris Flask; Jeffrey L Duerk Journal: Wiley Interdiscip Rev Syst Biol Med Date: 2010 Jul-Aug
Authors: Boris Keil; Graham C Wiggins; Christina Triantafyllou; Lawrence L Wald; Florian M Meise; Laura M Schreiber; Klaus J Klose; Johannes T Heverhagen Journal: Magn Reson Med Date: 2011-03-23 Impact factor: 4.668
Authors: Mark J Hamamura; Seunghoon Ha; Werner W Roeck; Douglas J Wagenaar; Dirk Meier; Bradley E Patt; Orhan Nalcioglu Journal: Technol Cancer Res Treat Date: 2010-02