PMID- 29729075
OWN - NLM
STAT- MEDLINE
DCOM- 20190313
LR  - 20240328
IS  - 1526-9914 (Electronic)
IS  - 1526-9914 (Linking)
VI  - 19
IP  - 4
DP  - 2018 Jul
TI  - Relationship between size-specific dose estimates and image quality in computed 
      tomography depending on patient size.
PG  - 246-251
LID - 10.1002/acm2.12340 [doi]
AB  - This study investigates the relationship between contrast-to-noise ratio (CNR) 
      and size-specific dose estimate (SSDE) in computed tomography (CT) depending on 
      patient size. In addition, the relationship to the auto exposure control (AEC) 
      techniques is examined. A tissue-equivalent material having human-liver energy 
      dependence is developed and used to evaluate these relationships. Three exposure 
      dose levels (constant CT dose index, constant SSDE, and with AEC) are tested 
      using four different phantom sizes (diameter: 15, 20, 25 and 30 cm) in two 
      different CT scanners (SOMATOM Definition Flash, Siemens, and LightSpeed VCT, 
      GE). The contrast-to-noise ratios (CNRs) are measured using the developed 
      phantom. It is found that the CNR increases with decreasing phantom size at 
      constant SSDE, although the increase ratio is smaller than that of the constant 
      CT dose index. This result indicates that the image characteristics differ even 
      when the patient dose received from the CT examination is equivalent for each 
      patient size. In the case of AEC use, the CNR results of the Siemens scanner 
      exhibit a similar trend to those obtained for constant SSDE, for each phantom 
      size. This suggests that the AEC technique that maintains a constant image 
      quality (CARE Dose 4D) for each patient size corresponds well to the image 
      quality obtained for constant SSDE. These findings facilitate further 
      understanding of the relationship between image quality and exposure CT dose 
      depending on patient size.
CI  - (c) 2018 The Authors. Journal of Applied Clinical Medical Physics published by 
      Wiley Periodicals, Inc. on behalf of American Association of Physicists in 
      Medicine.
FAU - Kawashima, Hiroki
AU  - Kawashima H
AD  - Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health 
      Sciences, Kanazawa University, Kanazawa, Japan.
FAU - Ichikawa, Katsuhiro
AU  - Ichikawa K
AD  - Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health 
      Sciences, Kanazawa University, Kanazawa, Japan.
FAU - Hanaoka, Shinsuke
AU  - Hanaoka S
AD  - Radiology Division, Kanazawa University Hospital, Kanazawa, Japan.
FAU - Matsubara, Kosuke
AU  - Matsubara K
AD  - Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health 
      Sciences, Kanazawa University, Kanazawa, Japan.
FAU - Takata, Tadanori
AU  - Takata T
AD  - Radiology Division, Kanazawa University Hospital, Kanazawa, Japan.
LA  - eng
PT  - Journal Article
DEP - 20180504
PL  - United States
TA  - J Appl Clin Med Phys
JT  - Journal of applied clinical medical physics
JID - 101089176
SB  - IM
MH  - Humans
MH  - Japan
MH  - Phantoms, Imaging
MH  - Radiation Dosage
MH  - Retrospective Studies
MH  - *Tomography, X-Ray Computed
PMC - PMC6036365
OTO - NOTNLM
OT  - auto exposure control
OT  - computed tomography
OT  - contrast-to-noise ratio
OT  - image quality
OT  - patient size
OT  - size-specific dose estimates
EDAT- 2018/05/08 06:00
MHDA- 2019/03/14 06:00
PMCR- 2018/05/04
CRDT- 2018/05/06 06:00
PHST- 2017/12/17 00:00 [received]
PHST- 2018/03/04 00:00 [revised]
PHST- 2018/03/27 00:00 [accepted]
PHST- 2018/05/08 06:00 [pubmed]
PHST- 2019/03/14 06:00 [medline]
PHST- 2018/05/06 06:00 [entrez]
PHST- 2018/05/04 00:00 [pmc-release]
AID - ACM212340 [pii]
AID - 10.1002/acm2.12340 [doi]
PST - ppublish
SO  - J Appl Clin Med Phys. 2018 Jul;19(4):246-251. doi: 10.1002/acm2.12340. Epub 2018 
      May 4.