TY - JOUR
T1 - Technical Note
T2 - Improved CT number stability across patient size using dual-energy CT virtual monoenergetic imaging
AU - Michalak, Gregory
AU - Grimes, Joshua
AU - Fletcher, Joel
AU - Halaweish, Ahmed
AU - Yu, Lifeng
AU - Leng, Shuai
AU - McCollough, Cynthia
N1 - Publisher Copyright:
© 2016 American Association of Physicists in Medicine.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Purpose: The purpose of this study was to evaluate, over a wide range of phantom sizes, CT number stability achieved using two techniques for generating dual-energy computed tomography (DECT) virtual monoenergetic images. Methods:Water phantoms ranging in lateral diameter from 15 to 50 cm and containing a CT number test object were scanned on a DSCT scanner using both single-energy (SE) and dual-energy (DE) techniques. The SE tube potentials were 70, 80, 90, 100, 110, 120, 130, 140, and 150 kV; the DE tube potential pairs were 80/140, 70/150Sn, 80/150Sn, 90/150Sn, and 100/150Sn kV (Sn denotes that the 150 kV beam was filtered with a 0.6 mm tin filter). Virtual monoenergetic images at energies ranging from 40 to 140 keV were produced from the DECT data using two algorithms, monoenergetic (mono) and monoenergetic plus (mono+). Particularly in large phantoms, water CT number errors and/or artifacts were observed; thus, datasets with water CT numbers outside ± 10 HU or with noticeable artifacts were excluded from the study. CT numbers were measured to determine CT number stability across all phantom sizes. Results: Data exclusions were generally limited to cases when a SE or DE technique with a tube potential of less than 90 kV was used to scan a phantom larger than 30 cm. The 90/150Sn DE technique provided the most accurate water background over the large range of phantom sizes evaluated. Mono and mono+ provided equally improved CT number stability as a function of phantom size compared to SE; the average deviation in CT number was only 1.4% using 40 keV and 1.8% using 70 keV, while SE had an average deviation of 11.8%. Conclusions: The authors report demonstrates, across all phantom sizes, the improvement in CT number stability achieved with mono and mono+ relative to SE.
AB - Purpose: The purpose of this study was to evaluate, over a wide range of phantom sizes, CT number stability achieved using two techniques for generating dual-energy computed tomography (DECT) virtual monoenergetic images. Methods:Water phantoms ranging in lateral diameter from 15 to 50 cm and containing a CT number test object were scanned on a DSCT scanner using both single-energy (SE) and dual-energy (DE) techniques. The SE tube potentials were 70, 80, 90, 100, 110, 120, 130, 140, and 150 kV; the DE tube potential pairs were 80/140, 70/150Sn, 80/150Sn, 90/150Sn, and 100/150Sn kV (Sn denotes that the 150 kV beam was filtered with a 0.6 mm tin filter). Virtual monoenergetic images at energies ranging from 40 to 140 keV were produced from the DECT data using two algorithms, monoenergetic (mono) and monoenergetic plus (mono+). Particularly in large phantoms, water CT number errors and/or artifacts were observed; thus, datasets with water CT numbers outside ± 10 HU or with noticeable artifacts were excluded from the study. CT numbers were measured to determine CT number stability across all phantom sizes. Results: Data exclusions were generally limited to cases when a SE or DE technique with a tube potential of less than 90 kV was used to scan a phantom larger than 30 cm. The 90/150Sn DE technique provided the most accurate water background over the large range of phantom sizes evaluated. Mono and mono+ provided equally improved CT number stability as a function of phantom size compared to SE; the average deviation in CT number was only 1.4% using 40 keV and 1.8% using 70 keV, while SE had an average deviation of 11.8%. Conclusions: The authors report demonstrates, across all phantom sizes, the improvement in CT number stability achieved with mono and mono+ relative to SE.
KW - dual-energy CT
KW - monoenergetic
KW - stability
UR - http://www.scopus.com/inward/record.url?scp=84954102229&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84954102229&partnerID=8YFLogxK
U2 - 10.1118/1.4939128
DO - 10.1118/1.4939128
M3 - Article
C2 - 26745944
AN - SCOPUS:84954102229
SN - 0094-2405
VL - 43
SP - 513
EP - 517
JO - Medical physics
JF - Medical physics
IS - 1
ER -