Japanese
Title脳血流SPECT定量測定における頭蓋骨等による吸収の影響と補正法
Subtitle原著
Authors岩瀬幹生*, 黒野賢仁*, 飯田昭彦**
Authors(kana)
Organization*豊川市民病院放射線科, **名古屋市総合リハビリテーションセンター放射線科
Journal核医学
Volume35
Number2
Page61-69
Year/Month1998/2
Article原著
Publisher日本核医学会
Abstract「要旨」脳血流SPECTにおける画像再構成時の吸収補正は, 一般的に頭部全体を水等価として行われるが, 被検者間の頭蓋骨等による吸収差の影響は考慮されていない. われわれは, 被検者間の吸収差を求め, 脳血流の定量値を補正する方法を検討した. IMP静注前に頭部左右方向の吸収量を測定し, 測定値より水換算した左右径(Ta)を求める. SPECT収集後, ソレンソンにて吸収補正を行い画像再構成をする. この時得られた輪郭より, Taと同一位置の左右径(Tt)を求める. 2Ts = Ta - Tt よりTsを求め, 補正因子 λ = exp(μ1Ts) より, rCBFを求めるときの補正因子として乗算する. 結果は, TtとTa間において有意差を認めた. 男女間においては, Ttは有意差がなく, TaおよびTsにおいて有意差を認めた. よって頭蓋骨等の吸収差は定量値に無視できない影響を与えており, 正確な定量値を得るには, 被検者間の補正は必要である.
Practice臨床医学：一般
KeywordsAttenuation correction, rCBF, SPECT, Cranium, 123I-IMP
English
TitleEffect of Attenuation by the Cranium on Quantitative SPECT Measurements of Cerebral Blood Flow and a Correction Method
SubtitleOriginal Articles
AuthorsMikio IWASE*, Kenji KURONO*, Akihiko IIDA**
Authors(kana)
Organization*Department of Radiology, Toyokawa City Hospital, **Department of Radiology, Nagoya City Rehabilitation and Sports Center
JournalThe Japanese Journal of nuclear medicine
Volume35
Number2
Page61-69
Year/Month1998/2
ArticleOriginal article
PublisherTHE JAPANESE SOCIETY OF NUCLEAR MEDICINE
AbstractAttenuation correction for cerebral blood flow SPECT image reconstruction is usually performed by considering the head as a whole to be equivalent to water, and the effects of differences in attenuation between subjects produced by the cranium have not been taken into account. We determined the differences in attenuation between subjects and assessed a method of correcting quantitative cerebral blood flow values. Attenuations by head on the right and left sides were measured before intravenous injection of 123I-IMP, and water-converted diameters of both sides (Ta) were calculated from the measurements obtained. After acquiring SPECT images, attenuation correction was conducted according to the method of Sorenson, and images were reconstructed. The diameters of the right and left sides in the same position as the Ta (Tt) were calculated from the contours determined by threshold values. Using Ts given by 2Ts = Ta - Tt, the correction factor λ = exp(μ1Ts) was calculated and multiplied as the correction factor when rCBF was determined. The results revealed significant differences between Tt and Ta. Although no gender differences were observed in Tt, they were seen in both Ta and Ts. Thus, interindividual differences in attenuation by the cranium were found to have an influence that cannot be ignored. Inter-subject correlation is needed to obtain accurate quantitative values.
PracticeClinical medicine
KeywordsAttenuation correction, rCBF, SPECT, Cranium, 123I-IMP

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