Between 1996 and 2010, according to a study published in 2012, the use of computed tomography (CT)  scans nearly increased by three times as much, from 52 scans per 1,000 patients to 149 scans per 1,000 patients. And those images certainly provided valuable information to help doctors diagnose  hidden conditions that wouldn't have been possible without the added insight. But CT scans produce those detailed images using small amounts of radiation, and while the   risk of that exposure is small, on a population level, increased reliance on the scans could drive a slight bump in cancer risk from CT. That's exactly what the latest study, published in the British Medical Journal, found. It's the largest study to date -- involving 10.9 million Australians born between 1985 and 2005. A team of researchers from Australia and Europe studied the cancer rates of Australian patients from birth to 19 years old who had CT scans in early childhood, and compared them to those who did not receive the scans. Most of the cases were followed for 10 to 17 years, and by the end of the study period, 3,150 of the 680,000 patients exposed to CT scans during childhood and young adulthood developed cancer and 57,542 of the remaining participants, who were not exposed, developed cancer. Those who were scanned had a 24% greater risk of cancer than those who did not receive them, with the risk increasing by 16% for each additional CT. The risk was highest for children who received scans before age five; they showed a 35% increased chance of developing a cancer during the study period than those who weren't scanned at this age. That research is still ongoing, however, and in the meantime, doctors and patients are left to find the delicate balance between how necessary scans are to diagnose disease, and their potential risk of causing cancer, which, most experts say, is still very small. "All parties, including patients and families, need to work together to make sure that CT scans are limited to situations where there is a definite  clinical  indication," the authors write. Only then will the benefits, they say, outweigh the risks of exposure. What can we learn about the participants of the study?
They came from both Australia and Europe. Most of them are between 10 to 17 years old. Some of them had developed cancer at the age of 19. About 10.22 million of them hadn't received CT scans.
Question: Between 1996 and 2010, according to a study published in 2012, the use of computed tomography (CT)  scans nearly increased by three times as much, from 52 scans per 1,000 patients to 149 scans per 1,000 patients. And those images certainly provided valuable information to help doctors diagnose  hidden conditions that wouldn't have been possible without the added insight. But CT scans produce those detailed images using small amounts of radiation, and while the   risk of that exposure is small, on a population level, increased reliance on the scans could drive a slight bump in cancer risk from CT. That's exactly what the latest study, published in the British Medical Journal, found. It's the largest study to date -- involving 10.9 million Australians born between 1985 and 2005. A team of researchers from Australia and Europe studied the cancer rates of Australian patients from birth to 19 years old who had CT scans in early childhood, and compared them to those who did not receive the scans. Most of the cases were followed for 10 to 17 years, and by the end of the study period, 3,150 of the 680,000 patients exposed to CT scans during childhood and young adulthood developed cancer and 57,542 of the remaining participants, who were not exposed, developed cancer. Those who were scanned had a 24% greater risk of cancer than those who did not receive them, with the risk increasing by 16% for each additional CT. The risk was highest for children who received scans before age five; they showed a 35% increased chance of developing a cancer during the study period than those who weren't scanned at this age. That research is still ongoing, however, and in the meantime, doctors and patients are left to find the delicate balance between how necessary scans are to diagnose disease, and their potential risk of causing cancer, which, most experts say, is still very small. "All parties, including patients and families, need to work together to make sure that CT scans are limited to situations where there is a definite  clinical  indication," the authors write. Only then will the benefits, they say, outweigh the risks of exposure. What can we learn about the participants of the study?
A. They came from both Australia and Europe.
B. Most of them are between 10 to 17 years old.
C. Some of them had developed cancer at the age of 19.
D. About 10.22 million of them hadn't received CT scans.
Answer: