2003 Fiscal Year Final Research Report Summary
High-resolution, high sensitivity SPECT for small animal imaging using ultra-cone-beam collimators
| Project/Area Number |
13557073
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Radiation science
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KUBO Naoki Hokkaido Univ., School of Med., Inst., 医学部, 助手 (80241389)
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| Co-Investigator(Kenkyū-buntansha) |
TAMAKI Nagara Hokkaido Univ., Grad. School of Med., Prof., 大学院・医学研究科, 教授 (30171888)
KATOH Chietsugu Hokkaido Univ., Grad. School of Med., Asso. Prof., 大学院・医学研究科, 寄附講座教員 (10292012)
MOTOMURA Nobutoku Toshiba Medical systems, Chief., 核医学部開発担当, 開発部主務
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| Project Period (FY) |
2001 – 2003
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| Keywords | converging collimator / pinhole collimator / positron emitter / 超高エネルギーコリメータ / SPECT |
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| Research Abstract |
We have designed novel pinhole and converging collimators for cone-beam SPECT of small objects. Particularly, these collimators were designed to cope with ultrahigh energy gamma photons. Cone-beam collimators, including pinhole and converging collimators, magnify an acquired image using gamma cameras. Consequently, spatial resolution of the image is improved. For the pinhole collimator, the diameter of the knife-edge pinhole aperture was 1.3 mm and the acceptance angle was 1゜. The thickness of the lead shielding was 30 mm. In SPECT experiments, spatial resolution, expressed as full-width-at-half maximum (FWHM), was 2.4±0.4 and 3.2±0.3 mm for Tc-99m and F-18 SPECT, respectively. In calculated simulations, as the pinhole-object distance decreased, geometric sensitivity geometrically increased. However, as the pinhole-object distance decreased, field-of-view decreased linearly. SPECT of a rat using Tc-99m and F-l8 enabled successful in vivo visualization of the myocardium. The converging
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collimator had a focal length of 200 mm, a hole length of 110 mm at the center and a hole diameter of 1.5 mm. Magnification was 1.9 times at a source-to-collimator distance of 10 mm. Planar spatial resolution was 1.7±0.2 mm and 2.8±0.8 mm (FWHM) for Tc-99m and F-18, respectively. A small myocardial phantom was clearly visualized by both Tc-99m and F-18 SPECT. Thus, we have demonstrated that high-resolution SPECT images can be acquired at ultra-high energy using our cone-beam collimators. Moreover, the most remarkable feature of our converging collimators is applicability to conventional rotating gamma camera SPECT systems. In addition, we have evaluated the spatial resolution of a commercial converging collimator which had a very short focal length (200 mm). The spatial resolution of the converging collimator was superior to that of the parallel-hole collimator. Thyroid scintigraphy using the commercial converging collimator better visualized cold lesions than the parallel-hole collimator. Less
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Research Products
(7 results)
