PMID- 29296042
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20220311
IS  - 0971-6203 (Print)
IS  - 1998-3913 (Electronic)
IS  - 0971-6203 (Linking)
VI  - 42
IP  - 4
DP  - 2017 Oct-Dec
TI  - A Study to Determine Whether the Volume-Weighted Computed Tomography Dose Index 
      Gives Reasonable Estimates of Organ Doses for Thai Patients Undergoing Abdomen 
      and Pelvis Computed Tomography Examinations.
PG  - 266-272
LID - 10.4103/jmp.JMP_91_17 [doi]
AB  - INTRODUCTION: Values for the CTDI(vol), which is displayed on scanner consoles, 
      give doses relative to a phantom much larger than most Thai patients, and the 
      CTDI(vol) does not take account of differences in patient size, which affect 
      organ doses. OBJECTIVE: The purpose of this study was to evaluate relationships 
      for size specific dose estimate (SSDE) and volume weighted computed tomography 
      (CT) dose index (CTDI(vol)) with patient size for CT scanners operating under 
      automatic tube current modulation (ATCM). METHODS: Retrospective data from 244 
      patients who had undergone abdomen and pelvis examination on GE and Siemens CT 
      scanners were included in this study. The combination of anteroposterior (AP) and 
      lateral dimensions at the level of the first lumbar vertebra (L1) was used to 
      represent patient size. Image noise within the liver was measured, and values of 
      the absorbed dose for organs covered by the primary beam such as the liver, 
      stomach and kidney were calculated using methods described in the literature. 
      Values of CTDI(vol) were recorded and SSDE calculated according to the American 
      Association of Physics in Medicine (AAPM) Report No.204. Linear regression models 
      were used to evaluate the relationship between SSDE, CTDI(vol), image noise and 
      patient size. RESULTS: SSDE is 20%-50% larger than the CTDI(vol), with values for 
      larger patients being more representative. Both the CTDI(vol) and image noise 
      decreased with patient size for Siemens scanners, but the decline in SSDE was 
      less significant. For the GE scanner, the CTDI(vol) was a factor of 3-4 lower in 
      small patients compared to larger ones, while the SSDE only decreased by a factor 
      of two. Noise actually decreased slightly with patient size. CONCLUSION: Values 
      of SSDE were similar to the doses calculated for the liver, stomach and kidney, 
      which are covered by the primary beam, confirming that it provides a good 
      estimate of organ-absorbed dose.
FAU - Sookpeng, Supawitoo
AU  - Sookpeng S
AD  - Department of Radiological Technology, Faculty of Allied Health Sciences, 
      Naresuan University, Phitsanulok, Thailand.
FAU - Martin, Colin J
AU  - Martin CJ
AD  - Department of Clinical Physics, University of Glasgow, Glasgow G12 8QQ, UK.
FAU - Butdee, Chitsanupong
AU  - Butdee C
AD  - Department of Radiological Technology, Faculty of Allied Health Sciences, 
      Naresuan University, Phitsanulok, Thailand.
LA  - eng
PT  - Journal Article
PL  - India
TA  - J Med Phys
JT  - Journal of medical physics
JID - 9441104
PMC - PMC5744456
OTO - NOTNLM
OT  - Automatic exposure control
OT  - computed tomography dosimetry
OT  - size-specific dose estimate
COIS- There are no conflicts of interest.
EDAT- 2018/01/04 06:00
MHDA- 2018/01/04 06:01
PMCR- 2017/10/01
CRDT- 2018/01/04 06:00
PHST- 2018/01/04 06:00 [entrez]
PHST- 2018/01/04 06:00 [pubmed]
PHST- 2018/01/04 06:01 [medline]
PHST- 2017/10/01 00:00 [pmc-release]
AID - JMP-42-266 [pii]
AID - 10.4103/jmp.JMP_91_17 [doi]
PST - ppublish
SO  - J Med Phys. 2017 Oct-Dec;42(4):266-272. doi: 10.4103/jmp.JMP_91_17.