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Novel point-like Ge-68/Ga-68 radioactive source with spherical positron absorber
https://repo.qst.go.jp/records/46338
https://repo.qst.go.jp/records/46338961e077a-efaa-4527-929a-76a2bc369018
| Item type | 学術雑誌論文 / Journal Article(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2012-06-06 | |||||
| タイトル | ||||||
| タイトル | Novel point-like Ge-68/Ga-68 radioactive source with spherical positron absorber | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | journal article | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Hasegawa, Tomoyuki
× Hasegawa, Tomoyuki× Oda, Keiichi× Murayama, Hideo× Takei, Hideyuki× et.al× 長谷川 智之× 村山 秀雄× 武居 秀行 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Purpose: In the conventional techniques for determining the calibration factors of positron emission tomography (PET) scanners, cylindrical water and resin phantoms with radioisotope 18F or 68Ge/68Ga are used. In these methods, however, the results depend on attenuation and scatter correction. The purpose of this study is to develop a point-like 68Ge/68Ga radioactive source that can be used to determine the calibration factors of PET scanners without the uncertainty of attenuation and scatter correction. Methods: A spherical absorber design was employed to realize a symmetric angular distribution of emitted annihilation photons. A Geant4-based Monte Carlo simulation code was used to compare physics characteristics of point-like sources with various absorber materials. On the basis of this simulation, a point-like 68Ge/68Ga source with a spherical aluminum absorber was manufactured. Its radioactivity was calibrated at an accredited national calibration facility. A calibration factor of a clinical PET scanner was then obtained with a point-like source and compared with that obtained by a standard cross-calibration method. Results: The emission probability of 0.511 MeV annihilation photon pairs per positron decay was typically 0.6-0.8. The fraction of background photon pairs was 6-8% in the energy region of 0.4-0.6 MeV. Considering these two figures, lower density materials such as aluminum and pol(ymethyl methacrylate) (PMMA) were preferable. For the aluminum absorber, a diameter of 8 mm was suitable to prevent positrons from escaping. The calibration factor obtained with the point-like source agreed with that obtained by the standard method within 2-3%. Conclusion: A point-like 68Ge/68Ga radioactive source was successfully designed, manufactured, and used for determining a calibration factor of a PET scanner. It can be considered a practical tool for calibrating and ev- luating the quantitative aspects of PET scanners. | |||||
| 書誌情報 |
IEEE Transactions on Nuclear Science 巻 59, 号 1, p. 24-29, 発行日 2012-02 |
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| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 0018-9499 | |||||
