Chest
Original ResearchChest ImagingThe Effects of Radiation Dose and CT Manufacturer on Measurements of Lung Densitometry
Section snippets
Subject Selection
Subjects for this study were selected from the British Columbia Cancer Agency Lung Health Study.20 The study was approved by the clinical ethics review boards of the British Columbia Cancer Agency and the University of British Columbia. All subjects signed informed consent forms to allow their spirometry and CT scan images to be used for research. This study comprises a cohort of heavy smokers who have been screened for the presence of lung nodules using “low-dose” CT scans. If suspicious
Subjects
The subjects' demographic data are summarized in Table 1 . There were more men in the CT dose study than in the CT scanner manufacture study, and there were more current smokers than former smokers in each study group. There were no significant differences (p > 0.05) in the spirometry measurements between study groups.
Radiation Dose Study
A summary of the measurements of total lung volume, total lung mass, mean lung density, %Emphysema, and percentile points obtained using the low-dose and high-dose CT scan images
Discussion
Quantitative CT scan imaging has become a very important tool for quantifying the extent of emphysema in subjects with COPD. However, most published studies arise from a single institution scanning small numbers of subjects using a single CT scanner and a site-specific scanning protocol. It is now apparent that to advance the knowledge of how the lung changes with time, either in a diseased state or with an intervention, quantitative CT scanning must be applied to larger cohorts acquired from
ACKNOWLEDGMENT
The authors wish to acknowledge Dr. Elizabeth Tench for statistical analysis; Anh-Toan Tran and Ida Chan, MD, for technical assistance in developing and supporting the lung analysis application; and Claudine Storness-Bliss, Dianna Louie, and Sukhinder Khattra for logistical assistance.
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This work was supported by National Cancer Institute grants N01-CN-85188, 1U01-CA-96109 and P01–96964 (to Dr. Lam); a Canadian Institutes of Health Research-Industry Partnership Grant (GlaxoSmithKline) No. DOP#76813 (PDP), and a British Columbia Lung Association/Canadian Institutes of Health Research New Investigator Award (to Dr. Coxson).
Dr. Coxson has received honoraria, consultant fees, and contract service agreements from GlaxoSmithKline for research studiesinvolving quantitative CT scanning and COPD. A percentage of his salary between 2003 and 2006 derived from contract funds provided to a colleague (Dr. Paré) by GlaxoSmithKline for the development of validated methods to measure emphysema and airway disease using CT scanning. There is no financial relationship between any industry and the current study. Dr. Paré is the principal investigator of a project jointly funded by the Canadian Institute of Health Research (CIHR) and GlaxoSmithKline (one third by the CIHR and two thirds by industry). This grant application was funded after peer review by the regular CIHR mechanism, and the funds received from industry are directly related to the operating costs of the study. Dr. Paré is also principal investigator of a Merck Frosst-supported research program to investigate gene expression in the lungs of patients who have COPD. These funds have supported the technical personnel and expendables involved in the project. Dr. Hogg served as a consultant to Altana Pharmaceuticals in 2003, 2004, and 2005, and also served on the Canadian advisory board for GlaxoSmithKline for 1 year in 2003. He has participated as a speaker in scientific meetings and courses organized and financed by various pharmaceutical companies including AstraZeneca, Altana Pharmaceuticals, and GlaxoSmithKline. He serves as the principal investigator on a grant jointly funded by the CIHR and GlaxoSmithKline (one third by the CIHR and two thirds by industry). This grant application was funded after peer review by the regular CIHR mechanism, and the funds received from industry are directly related to the operating costs of the study. Drs. Yuan, Mayo, Lam, and McWilliams have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.