Linked Life Data

16475776

Source:http://linkedlifedata.com/resource/pubmed/id/16475776

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2006-2-14
pubmed:abstractText
The use of breast computed tomography (CT) as an alternative to mammography in some patients is being studied at several institutions. However, the radiation dosimetry issues associated with breast CT are markedly different than in the case of mammography. In this study, the spectral properties of an operational breast CT scanner were characterized both by physical measurement and computer modeling of the kVp-dependent spectra, from 40 to 110 kVp (Be window W anode with 0.30 mm added Cu filtration). Previously reported conversion factors, normalized glandular dose for CT-DgN(ct), derived from Monte Carlo methods, were used in concert with the output spectra of the breast scanner to compute the mean glandular dose to the breast based upon different combinations of x-ray technique factors (kVp and mAs). The mean glandular dose (MGD) was measured as a function of the compressed breast thickness (2-8 cm) and three different breast compositions (0%, 50%, and 100% glandular fractions) in four clinical mammography systems in our institution. The average MGD from these four systems was used to compute the technique factors for breast CT systems that would match the two-view mammographic dose levels. For a 14 cm diameter breast (equivalent to a 5 cm thick compressed breast in mammography), air kerma levels at the breast CT scanner's isocenter (468 mm from the source) of 4.4, 6.4, and 9.0 mGy were found to deliver equivalent mammography doses for 0%, 50%, and 100% glandular breasts (respectively) at 80 kVp. At 80 kVp (where air kerma was 11.3 mGy/100 mAs at the isocenter), 57 mAs (integrated over the entire scan) was required to match the mammography dose for a 14 cm 50% glandular breast. At 50 kVp, 360 mAs is required to match mammographic dose levels. Tables are provided for both air kerma at the isocenter and mAs for 0%, 50%, and 100% glandular breasts. Other issues that impact breast CT technique factors are also discussed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0094-2405
pubmed:author
pubmed:issnType
Print
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3767-76
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Technique factors and their relationship to radiation dose in pendant geometry breast CT.
pubmed:affiliation
Department of Radiology, University of California Davis Medical Center, Sacramento, California 95817, USA. jmboone@ucdavis.edu
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural