TY - GEN
T1 - Comparative assessment of different energy mapping methods for generation of 511-KEV attenuation map from ct images in pet/ct systems
T2 - 2008 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, ISBI
AU - Shirmohammad, M.
AU - Ay, M. R.
AU - Sarkar, S.
AU - Ghadiri, H.
AU - Rahmim, A.
PY - 2008
Y1 - 2008
N2 - The use of X-ray CT images for CT-based attenuation correction (CTAC) of PET data results in the decrease of overall scanning time and creates a noise-free attenuation map (μmap). The linear attenuation coefficient (LAC) measured with CT is calculated at the x-ray energy rather than at the 511 keV. It is therefore necessary to convert the linear attenuation coefficients obtained from the CT scan to those corresponding to the 511 keV. Several conversion strategies have been developed including scaling, segmentation, hybrid, bilinear and dual-energy decomposition methods. The aim of this study is to compare the accuracy of different energy mapping methods for generation of attenuation map form CT images. An in-house made polyethylene phantom with different concentrations of K2HPO4 was used in order to quantitatively measure the accuracy of the nominated methods, using quantitative analysis of created μmaps. The generated μmaps using different methods compared with theoretical values calculated using XCOM cross section library. Accurate quantitative analysis showed that for low concentrations of K2HPO4 all these methods produce acceptable attenuation maps at 511 keV, but for high concentration of K2HPO4 the last three methods produced the lowest errors (10.1% in hybrid, 9.8% in bilinear, and 4.7% in dual energy method). The results also showed that in dual energy method, combination of 80 and 140 kVps produces the least error (4.2%) compared to other combinations of kVps.
AB - The use of X-ray CT images for CT-based attenuation correction (CTAC) of PET data results in the decrease of overall scanning time and creates a noise-free attenuation map (μmap). The linear attenuation coefficient (LAC) measured with CT is calculated at the x-ray energy rather than at the 511 keV. It is therefore necessary to convert the linear attenuation coefficients obtained from the CT scan to those corresponding to the 511 keV. Several conversion strategies have been developed including scaling, segmentation, hybrid, bilinear and dual-energy decomposition methods. The aim of this study is to compare the accuracy of different energy mapping methods for generation of attenuation map form CT images. An in-house made polyethylene phantom with different concentrations of K2HPO4 was used in order to quantitatively measure the accuracy of the nominated methods, using quantitative analysis of created μmaps. The generated μmaps using different methods compared with theoretical values calculated using XCOM cross section library. Accurate quantitative analysis showed that for low concentrations of K2HPO4 all these methods produce acceptable attenuation maps at 511 keV, but for high concentration of K2HPO4 the last three methods produced the lowest errors (10.1% in hybrid, 9.8% in bilinear, and 4.7% in dual energy method). The results also showed that in dual energy method, combination of 80 and 140 kVps produces the least error (4.2%) compared to other combinations of kVps.
KW - CTAC
KW - Energy mapping
KW - PET/CT
KW - μMap
UR - http://www.scopus.com/inward/record.url?scp=51049098487&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=51049098487&partnerID=8YFLogxK
U2 - 10.1109/ISBI.2008.4541078
DO - 10.1109/ISBI.2008.4541078
M3 - Conference contribution
AN - SCOPUS:51049098487
SN - 9781424420032
T3 - 2008 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, Proceedings, ISBI
SP - 644
EP - 647
BT - 2008 5th IEEE International Symposium on Biomedical Imaging
Y2 - 14 May 2008 through 17 May 2008
ER -