Cohort Description

When the U.S. Radiologic Technologists (USRT) Study began in 1982, we enrolled 143,517 radiologic technologists who were certified by the American Registry of Radiologic Technologists (ARRT) for at least two years between the registry's inception in the mid-1920s through 1982. The vast majority were certified in radiology only (92%); small percentages were certified in nuclear medicine (<3%), radiation therapy (<1%), or more than one specialty (5%). Most were female (73%), born during the 1940s (32%) or 1950s (41%), certified during the 1960s (28%) or 1970s (48%).

The USRT Cohort and Activities Diagram shows the target populations and response to each of three surveys conducted since 1983. The First Survey (baseline) was sent during 1983-89 to all registrants who were living and located at the time (n=132,454) (Boice et al, 1992). There were 90,305 technologists (68%) who completed the full-length questionnaire, providing data on employment history (individual jobs - employers, type of facility, years began and ended; procedures performed - start year, number of years; apron or shield use), cancer outcomes, history of thyroid conditions or myocardial infarction (MI), selected cancer risk factors (education, cigarette smoking, height, weight, personal diagnostic and therapeutic radiation procedures, gynecologic and reproductive factors, family history of breast cancer), and cancer and birth defects in offspring. An additional 14,028 (11%) technologists completed an abbreviated telephone survey that inquired about medical outcomes (cancer, thyroid conditions and MI) only. From the mail questionnaire responses, we learned that U.S. radiologic technologists are predominantly Caucasian (93%), 87% had been married, and 40% had attended college. Most (47%) worked less than 10 years, 36% worked 10-19 years, and 14% worked 20 or more years as a radiologic technologist. More than 90% of radiologic technologists worked with fluoroscopy, portable radiograph, routine radiograph, and/or multi-film procedures. One-third worked with diagnostic radioisotopes, and fewer than one-quarter worked with radiotherapy procedures. Most (48%) radiologic technologists began working in 1970 or later, 30% began working in the 1960s, 13% in the 1950s, and 6% before 1950. The vast majority (68%) began working between the ages of 18 and 21.

An additional 2,505 radiologic technologists were determined to be eligible and added after the first survey, bringing the total cohort to 146,022. The Second Survey was undertaken during 1994-98 to identify incident cancers diagnosed since the First Survey. At that time, 8% of the cohort had died and 8% were not located. Among 126,628 living and located technologists who were sent the Second Survey, 90,972 (72% overall; 83% of First Survey responders) participated, providing updated and more detailed information on employment history (years trained and worked; frequency performed various procedures, apron and shield use, and holding patients by calendar period), cancer and numerous other medical outcomes, and cancer risk factors (religion, height, weight, gynecologic and reproductive factors, breast biopsies, personal diagnostic and therapeutic radiation procedures by calendar period, census of children and cancers and birth defects, census of siblings and first-degree family cancer outcomes, multivitamins and selected medications, abbreviated dietary questionnaire, and physical activity).

The Third Survey was initiated at the end of 2003, with the oldest cohort members (i.e. those who began working <1950) being interviewed by telephone about all of their jobs working as a radiologic technologist. A total of 2,468 out of 3,441 (72%) of the living and located 'Pioneers' were successfully interviewed. They provided updated medical histories (cancer and many non-cancer outcomes); job-specific information on type of facility, frequency performed various procedures (diagnostic x-rays, fluoroscopy, diagnostic radioisotope, internal therapeutic radioisotope, and external beam radiotherapy), associated apron and shield use, and other work practices; and cancer risk factor data (cigarette smoking, weight (by age), weight gain (by body location), physical activity (intensity by age), sun exposure and sunburns (by age), and residential history (for UV dosimetry)). In September 2004, a mail version of the telephone questionnaire was sent to the living and located technologists who began working in 1950 or later (n=98,253). The mail (long) questionnaire sought employment data for the longest job in each decade, rather than for individual jobs; all other questions were the same. After two mailing waves, 58,628 technologists (56%) had responded. To increase overall response to the Third Survey, an abbreviated version (short) was sent with a $1.00 bill to 38,120 remaining non-responders, of whom 12,492 (33% of non-responders; 13% overall) responded, bringing the overall response to the third survey to 73,657 out of 102,088 (72%). Excluded from the short mail questionnaire were the majority of non-cancer medical outcomes. Questions about decade-specific jobs and cancer risk factors were the same.