TY - JOUR
T1 - Optimization of transmission scan duration for 15O PET study with sequential dual tracer administration using N-index
AU - Kudomi, Nobuyuki
AU - Watabe, Hiroshi
AU - Hayashi, Takuya
AU - Oka, Hisashi
AU - Miyake, Yoshinori
AU - Iida, Hidehiro
N1 - Funding Information:
Acknowledgments The authors would like to thank Ms Atra Ar-dakani for her invaluable help on preparing this article. The authors gratefully acknowledge the staff of the Department of Nuclear Medicine, Hospital and the Department of Investigative Radiology, Research Institute, National Cardiovascular Center. The present work was supported by the Program for Promotion of Fundamental Studies in Health Science of the Organization for Pharmaceuticals and
PY - 2010/6
Y1 - 2010/6
N2 - Purpose: Cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of O2 (CMRO2) can be quantified by PET with the administration of H 2 15 O and 15O2. Recently, a shortening in the duration of these measurements was achieved by the sequential administration of dual tracers of 15O2 and H 2 15 O with PET acquisition and integration method (DARG method). A transmission scan is generally required for correcting photon attenuation in advance of PET scan. Although the DARG method can shorten the total study duration to around 30 min, the transmission scan duration has not been optimized and has possibility to shorten its duration. Our aim of this study was to determine the optimal duration for the transmission scan. We introduced 'N-index', which estimates the noise level on an image obtained by subtracting two statistically independent and physiologically equivalent images. The relationship between noise on functional images and duration of the transmission scan was investigated by N-index. Methods: We performed phantom studies to test whether the N-index reflects the pixel noise in a PET image. We also estimated the noise level by the N-index on CBF, OEF and CMRO2 images from DARG method in clinical patients, and investigated an optimal true count of the transmission scan. Results: We found tight correlation between pixel noise and N-index in the phantom study. By investigating relationship between the transmission scan duration and N-index value for the functional images by DARG method, we revealed that the transmission data with true counts of more than 40 Mcounts results in CBF, OEF, and CMRO2 images of reasonable quantitative accuracy and quality. Conclusion: The present study suggests that further shortening of DARG measurement is possible by abridging the transmission scan. The N-index could be used to determine the optimal measurement condition when examining the quality of image.
AB - Purpose: Cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of O2 (CMRO2) can be quantified by PET with the administration of H 2 15 O and 15O2. Recently, a shortening in the duration of these measurements was achieved by the sequential administration of dual tracers of 15O2 and H 2 15 O with PET acquisition and integration method (DARG method). A transmission scan is generally required for correcting photon attenuation in advance of PET scan. Although the DARG method can shorten the total study duration to around 30 min, the transmission scan duration has not been optimized and has possibility to shorten its duration. Our aim of this study was to determine the optimal duration for the transmission scan. We introduced 'N-index', which estimates the noise level on an image obtained by subtracting two statistically independent and physiologically equivalent images. The relationship between noise on functional images and duration of the transmission scan was investigated by N-index. Methods: We performed phantom studies to test whether the N-index reflects the pixel noise in a PET image. We also estimated the noise level by the N-index on CBF, OEF and CMRO2 images from DARG method in clinical patients, and investigated an optimal true count of the transmission scan. Results: We found tight correlation between pixel noise and N-index in the phantom study. By investigating relationship between the transmission scan duration and N-index value for the functional images by DARG method, we revealed that the transmission data with true counts of more than 40 Mcounts results in CBF, OEF, and CMRO2 images of reasonable quantitative accuracy and quality. Conclusion: The present study suggests that further shortening of DARG measurement is possible by abridging the transmission scan. The N-index could be used to determine the optimal measurement condition when examining the quality of image.
KW - Image quality
KW - O-15 gas
KW - PET
KW - Transmission scan
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U2 - 10.1007/s12149-010-0374-x
DO - 10.1007/s12149-010-0374-x
M3 - Article
C2 - 20401548
AN - SCOPUS:77954416684
VL - 24
SP - 413
EP - 420
JO - Annals of Nuclear Medicine
JF - Annals of Nuclear Medicine
SN - 0914-7187
IS - 5
ER -