Organ Doses from Chest Radiographs in Tuberculosis Patients in Canada and Their Uncertainties in Periods from 1930 to 1969

Abstract

This paper describes a study to estimate absorbed doses to various organs from film-based chest radiographs and their uncertainties in the periods 1930 to 1948, 1949 to 1955, and 1956 to 1969. Estimated organ doses will be used in new analyses of risks of cancer and other diseases in tuberculosis patients in Canada who had chest fluoroscopic and radiographic examinations in those periods. In this paper, doses to lungs, female breast, active bone marrow, and heart from a single chest radiograph in adults and children of ages 1, 5, 10, and 15 y in the Canadian cohort and their uncertainties are estimated using (1) data on the tube voltage (kV), total filtration (mm Al), tube-current exposure-time product (mA s), and tube output (mR [mA s] −1 ) in each period; (2) assumptions about patient orientation, distance from the source to the skin of a patient, and film size; and (3) new calculations of sex- and age-specific organ dose conversion coefficients (organ doses per dose in air at skin entrance). Variations in estimated doses to each organ across the three periods are less than 20% in adults and up to about 30% at younger ages. Uncertainties in estimated organ doses are about a factor of 2 to 3 in adults and up to a factor of 4 at younger ages and are due mainly to uncertainties in the tube voltage and tube-current exposure-time product.

Organ-specific dose coefficients derived from Monte Carlo simulations for historical (1930s to 1960s) fluoroscopic and radiographic examinations of tuberculosis patients

“…In the province of Nova Scotia, fluoroscopic imaging in the anterior-posterior (AP) direction was most common while physicians in other provinces preferred to image primarily in the posterior-anterior (PA) direction, sparing the breast tissues from undue radiation (Howe and Yaffe 1992). Chest radiographs were routinely performed in the PA direction (Kocher et al 2019).…”

Estimation of Heights and Body Masses of Tuberculosis Patients in the Canadian Fluoroscopy Cohort Study for Use in Individual Dosimetry

“…The Canadian Fluoroscopy Cohort Study (CFCS) was designed to estimate excess risks of cancer and other diseases in tuberculosis patients due to repeated exposures to ionizing radiation from fluoroscopy procedures and chest radiographs during the course of treatment in government-funded tuberculosis sanatoria ( Miller et al 1989 ; Howe 1995 ; Howe and McLaughlin 1996 ; Zablotska et al 2014 ; Borrego et al 2019 ; Kocher et al 2020 ). The time period of interest for the CFCS is 1930–1969; all patients entered the cohort between 1930 and 1952, when improved treatments became available, but use of pneumothorax or pneumoperitoneum and monitoring by fluoroscopy, and thus exposures to some members of the cohort, continued until the end of 1969.…”

“…The time period of interest for the CFCS is 1930–1969; all patients entered the cohort between 1930 and 1952, when improved treatments became available, but use of pneumothorax or pneumoperitoneum and monitoring by fluoroscopy, and thus exposures to some members of the cohort, continued until the end of 1969. More than 28,000 patients (44%) in a total cohort of about 64,000 received radiation from fluoroscopy procedures, and more than 60,000 (94%) received chest radiographs ( Borrego et al 2019 ; Kocher et al 2020 ); both types of radiation exposures are included in the analyses of the CFCS cohort.…”