Table 4.
Distribution of non-CT imaging exams in the fetal-exposure cohort and childhood-exposure cohort from 1996–2016
| Fetal-Exposure Cohort | United States | Ontario, Canada | Total | |||
| n | Col % | n | Col % | n | Col % | |
| Total Children | 881,205 | 100.0% | 2,592,795 | 100.0% | 3,474,001 | 100.0% |
| Radiography | ||||||
| Number of exams during mother’s pregnancy per child | ||||||
| 0 | 840,329 | 95.4% | 2,493,338 | 96.2% | 3,333,667 | 96.0% |
| 1 | 36,267 | 4.1% | 87,109 | 3.4% | 123,376 | 3.6% |
| 2 | 3,456 | 0.4% | 9,385 | 0.4% | 12,841 | 0.4% |
| 3–10 | 1,132 | 0.1% | 2,936 | 0.1% | 4,068 | 0.1% |
| >10 | 21 | <0.05% | 27 | <0.05% | 48 | <0.05% |
| Fluoroscopy | ||||||
| Number of exams per child | ||||||
| 0 | 879,143 | 99.8% | 2,579,341 | 99.5% | 3,458,484 | 99.6% |
| 1 | 1,848 | 0.2% | 12,607 | 0.5% | 14,455 | 0.4% |
| 2 | 149 | <0.05% | 664 | <0.05% | 813 | <0.05% |
| 3–10 | 65 | <0.05% | 180 | <0.05% | 245 | <0.05% |
| >10 | 0 | 0.0% | 3 | <0.05% | 3 | <0.05% |
| Angiography | ||||||
| Number of exams per child | ||||||
| 0 | 880,843 | 100.0% | 2,591,757 | 100.0% | 3,472,600 | 100.0% |
| 1 | 314 | <0.05% | 967 | <0.05% | 1,281 | <0.05% |
| 2 | 29 | <0.05% | 53 | <0.05% | 82 | <0.05% |
| 3–10 | 19 | <0.05% | 18 | <0.05% | 37 | <0.05% |
| >10 | 0 | 0.0% | 0 | <0.05% | 0 | <0.05% |
| Nuclear Medicine | ||||||
| Number of exams per child | ||||||
| 0 | 879,874 | 99.8% | 2,586,475 | 99.8% | 3,466,413 | 99.8% |
| 1 | 1,284 | 0.1% | 6,023 | 0.2% | 7,307 | 0.2% |
| 2 | 45 | <0.05% | 289 | <0.05% | 334 | <0.05% |
| 3–10 | 2 | <0.05% | 8 | <0.05% | 10 | <0.05% |
| >10 | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| Childhood-Exposure Cohort | United States | Ontario, Canada | Total | |||
| n | Col % | n | Col % | n | Col % | |
| Total Children, n | 931,120 | 100.0% | 2,793,512 | 100.0% | 3,724,642 | 100.0% |
| Radiography | ||||||
| Number of exams per child | ||||||
| 0 | 455,469 | 48.9% | 993,715 | 35.6% | 1,449,130 | 38.9% |
| 1 | 190,897 | 20.5% | 547,692 | 19.6% | 738,565 | 19.8% |
| 2 | 97,829 | 10.5% | 355,402 | 12.7% | 453,224 | 12.2% |
| 3–10 | 166,992 | 17.9% | 795,178 | 28.5% | 962,221 | 25.8% |
| >10 | 19,933 | 2.1% | 101,525 | 3.6% | 121,502 | 3.3% |
| Fluoroscopy | ||||||
| Number of exams per child | ||||||
| 0 | 889,364 | 95.5% | 2,610,327 | 93.4% | 3,499,691 | 94.0% |
| 1 | 33,106 | 3.6% | 146,750 | 5.3% | 179,856 | 4.8% |
| 2 | 5,510 | 0.6% | 23,017 | 0.8% | 28,527 | 0.8% |
| 3–10 | 3,044 | 0.3% | 12,434 | 0.4% | 15,478 | 0.4% |
| >10 | 96 | <0.05% | 984 | <0.05% | 1,080 | <0.05% |
| Angiography | ||||||
| Number of exams per child | ||||||
| 0 | 928,972 | 99.8% | 2,782,498 | 99.6% | 3,711,470 | 99.6% |
| 1 | 1,557 | 0.2% | 7,496 | 0.3% | 9,053 | 0.2% |
| 2 | 279 | <0.05% | 1,539 | 0.1% | 1,818 | <0.05% |
| 3–10 | 277 | <0.05% | 1,856 | 0.1% | 2,133 | 0.1% |
| >10 | 35 | <0.05% | 123 | <0.05% | 158 | <0.05% |
| Nuclear Medicine | ||||||
| Number of exams per child | ||||||
| 0 | 921,543 | 99.0% | 2,748,058 | 98.4% | 3,669,581 | 98.5% |
| 1 | 7,372 | 0.8% | 36,278 | 1.3% | 43,668 | 1.2% |
| 2 | 1,378 | 0.1% | 5,829 | 0.2% | 7,218 | 0.2% |
| 3–10 | 821 | 0.1% | 3,297 | 0.1% | 4,119 | 0.1% |
| >10 | 6 | <0.05% | 50 | <0.05% | 56 | <0.05% |