Body Size-Specific Organ and Effective Doses of Chest CT Screening Examinations of the National Lung Screening Trial

Document Type

Article

Publication Date

5-1-2017

Publication Title

AJR. American journal of roentgenology

Abstract

OBJECTIVE: We calculated body size-specific organ and effective doses for 23,734 participants in the National Lung Screening Trial (NLST) using a CT dose calculator.

MATERIALS AND METHODS: We collected participant-specific technical parameters of 23,734 participants who underwent CT in the clinical trial. For each participant, we calculated two sets of organ doses using two methods. First, we computed body size-specific organ and effective doses using the National Cancer Institute CT (NCICT) dosimetry program, which is based on dose coefficients derived from a library of body size-dependent adult male and female computational phantoms. We then recalculated organ and effective doses using dose coefficients from reference size phantoms for all examinations to investigate potential errors caused by the lack of body size consideration in the dose calculations.

RESULTS: The underweight participants (body mass index [BMI; weight in kilograms divided by the square of height in meters] < 18.5) received 1.3-fold greater lung dose (median, 4.93 mGy) than the obese participants (BMI > 30) (3.90 mGy). Thyroid doses were approximately 1.3- to 1.6-fold greater than the lung doses (6.3-6.5 mGy). The reference phantom-based dose calculation underestimates the body size-specific lung dose by up to 50% for the underweight participants and overestimates that value by up to 200% for the overweight participants. The median effective dose ranges from 2.01 mSv in obese participants to 2.80 mSv in underweight participants.

CONCLUSION: Body size-specific organ and effective doses were computed for 23,734 NLST participants who underwent low-dose CT screening. The use of reference size phantoms can lead to significant errors in organ dose estimates when body size is not considered in the dose assessment.

Medical Subject Headings

Aged; Body Size; Female; Humans; Lung Neoplasms; Male; Mass Screening; Middle Aged; Organ Size; Phantoms, Imaging; Radiation Dosage; Radiography, Thoracic; Smoking; Tomography, X-Ray Computed; United States

PubMed ID

28267354

Volume

208

Issue

5

First Page

1082

Last Page

1088

Find It @ Sladen

Share

COinS