TOKYO (AP) — A new study says children living near the Fukushima nuclear meltdowns have been diagnosed with thyroid cancer at a rate 20 to 50 times that of children elsewhere, a difference the authors contend undermines the government's position that more cases have been discovered in the area only because of stringent monitoring. 
 
 Toshihide Tsuda, a professor at Okayama University, speaks during a press conference at Foreign Correspondents' Club of Japan in Tokyo, Thursday, Oct. 8, 2015. A new study says children living near the... (Associated Press) 
 
 FILE - In this March 29, 2011 file photo, children watch their father being screened for radiation at a shelter in Fukushima, northeast of Tokyo. A new study says children living near the Fukushima nuclear... (Associated Press) 
 
 FILE - In this March 15, 2011 file photo, a child is screened for radiation exposure at a testing center in Koriyama city, Fukushima Prefecture, northeast of Tokyo, after a nuclear power plant on the... (Associated Press) 
 
 Toshihide Tsuda, a professor at Okayama University, listens to a reporter's questions during a press conference at Foreign Correspondents' Club of Japan in Tokyo, Thursday, Oct. 8, 2015. A new study says... (Associated Press) 
 
 FILE - In this March 24, 2011 file photo, a young evacuee is screened at a shelter for leaked radiation from the tsunami-ravaged Fukushima Dai-ichi nuclear plant in Fukushima, northeast of Tokyo. A new... (Associated Press) 
 
 Most of the 370,000 children in Fukushima prefecture (state) have been given ultrasound checkups since the March 2011 meltdowns at the tsunami-ravaged Fukushima Dai-ichi nuclear plant. The most recent statistics, released in August, show that thyroid cancer is suspected or confirmed in 137 of those children, a number that rose by 25 from a year earlier. Elsewhere, the disease occurs in only about one or two of every million children per year by some estimates. 
 
 "This is more than expected and emerging faster than expected," lead author Toshihide Tsuda told The Associated Press during a visit to Tokyo. "This is 20 times to 50 times what would be normally expected." 
 
 The study was released online this week and is being published in the November issue of Epidemiology, produced by the Herndon, Virginia-based International Society for Environmental Epidemiology. The data comes from tests overseen by Fukushima Medical University. 
 
 Making sense of the relationship between radiation and cancer is precarious: It's scientifically impossible to link an individual cancer case to radiation. Looking harder with routine check-ups, like the one in Fukushima, leads to quicker discovery of tumors, inflating the tallies in a so-called "screening effect." 
 
 Right after the disaster, the lead doctor brought in to Fukushima, Shunichi Yamashita, repeatedly ruled out the possibility of radiation-induced illnesses. The thyroid checks were being ordered just to play it safe, according to the government. 
 
 But Tsuda, a professor at Okayama University, said the latest results from the ultrasound checkups, which continue to be conducted, raise doubts about the government's view. 
 
 Thyroid cancer among children is one sickness the medical world has definitively linked to radiation after the 1986 Chernobyl catastrophe. If treated, it is rarely fatal, and early detection is a plus, but patients are on medication for the rest of their lives. 
 
 Scientists are divided on Tsuda's conclusions. 
 
 In the same Epidemiology issue, Scott Davis, professor at the Department of Epidemiology in the Seattle-based School of Public Health, said the key limitation of Tsuda's study is the lack of individual-level data to estimate actual radiation doses. 
 
 Davis agreed with the findings of the World Health Organization and UNSCEAR, or the United Nations Scientific Committee on the Effects of Atomic Radiation, both of which have carried out reviews on Fukushima and predicted cancer rates will remain stable, with no rises being discernable as radiation-caused. 
 
 David J. Brenner, professor of radiation biophysics at Columbia University Medical Center, took a different view. While he agreed individual estimates on radiation doses are needed, he said in a telephone interview that the higher thyroid cancer rate in Fukushima is "not due to screening. It's real." 
 
 Conclusions about any connection between Fukushima radiation and cancer will help determine compensation and other policies. Many people who live in areas deemed safe by the government have fled fearing sickness, especially for their children. 
 
 An area extending about 20 kilometers (12 miles) from the nuclear plant has been declared an exclusion zone. The borders are constantly being remapped as cleanup of radiated debris and soil continues in an effort to bring as many people back as possible. Decommissioning the plant is expected to take decades. 
 
 Noriko Matsumoto, 53, who used to work as a nurse in Koriyama, Fukushima, outside the no-go zone, fled to Tokyo with her then-11-year-old daughter a few months after the disaster. She had initially shrugged off the fears but got worried when her daughter started getting nosebleeds and rashes. 
 
 "My daughter has the right to live free of radiation," she said. "We can never be sure about blaming radiation. But I personally feel radiation is behind sicknesses." 
 
 Andrew F. Olshan, professor at the Department of Epidemiology at the University of North Carolina, in Chapel Hill, noted that research on what follows a catastrophe is complex and difficult. 
 
 "Dr. Tsuda's study had limitations including assessment of individual radiation dose levels to the thyroid and the ability to fully assess the impact of screening on the excess cases detected," he said. 
 
 "Nonetheless, this study is critical to initiate additional investigations of possible health effects, for governmental planning, and increasing public awareness." 
 
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 Follow Yuri Kageyama: http://twitter.com/yurikageyama ||||| Fukushima Study Links Children's Cancer To Nuclear Accident 
 
 Enlarge this image toggle caption Chris Meyers/Reuters/Landov Chris Meyers/Reuters/Landov 
 
 Updated at 3:40 p.m. ET 
 
 A new analysis of data from Fukushima suggests children exposed to the March 2011 nuclear accident may be developing thyroid cancer at an elevated rate. 
 
 But independent experts say that the study, published in the journal Epidemiology, has numerous shortcomings and does not prove a link between the accident and cancer. 
 
 The work, led by Toshihide Tsuda of Okayama University, is based on a large public health survey that was set up in Japan's Fukushima prefecture following the accident. As part of the survey, children who were living near the plant at the time of the accident have been offered regular thyroid screenings. 
 
 Thyroid cancer can be caused by radioactive iodine released in a nuclear accident. Children are particularly susceptible because their thyroids are growing rapidly. Thyroid cancer was listed as a possible health risk in a World Health Organization report on Fukushima, though the report stated it would be difficult to link cancer cases to the accident. 
 
 In the past year or so, the Fukushima Health Survey of more than 150,000 children has turned up 25 "suspicious or malignant cases" of thyroid cancer. Thyroid screenings in previous years have also found numerous cases. 
 
 Enlarge this image toggle caption Wally Santana/AP Wally Santana/AP 
 
 Japanese officials believe the screening process itself may be behind the numbers. Increased vigilance might be turning up thyroid abnormalities that otherwise would have gone undetected. 
 
 But the new paper contradicts that view. The increase in cancer is "unlikely to be caused by a screening surge," the paper says. It says thyroid cancer rates are highly elevated throughout Fukushima. 
 
 Other researchers are skeptical of the new result. Geraldine Thomas, a professor at Imperial College who has studied thyroid cancer from Chernobyl, says the analysis incorrectly compares the screening in Fukushima to clinical cases of thyroid cancer in which patients are already sick. The comparison falsely suggests thyroid cancer in Fukushima is elevated by as much as 50 times compared with the general population. "This is not a very good paper to be basing opinions on," she says. 
 
 More accurate comparisons between residents within different parts of Fukushima prefecture show no statistically significant variations in cancer rates, she says. 
 
 David Brenner, director of the Center for Radiological Research at Columbia University, adds that the study makes no effort to trace the exposure of patients. "It's simply relating geographic regions to cancer risks and not looking at individual radiation doses," he says, adding that without that information, it's virtually impossible to connect the screenings to the accident. 
 
 "It really doesn't tell us the whole story," he says. ||||| Background: After the Great East Japan Earthquake and Tsunami in March 2011, radioactive elements were released from the Fukushima Daiichi Nuclear Power Plant. Based on prior knowledge, concern emerged about whether an increased incidence of thyroid cancer among exposed residents would occur as a result. 
 
 Methods: After the release, Fukushima Prefecture performed ultrasound thyroid screening on all residents ages <=18 years. The first round of screening included 298,577 examinees, and a second round began in April 2014. We analyzed the prefecture results from the first and second round up to December 31, 2014, in comparison with the Japanese annual incidence and the incidence within a reference area in Fukushima Prefecture. 
 
 Results: The highest incidence rate ratio, using a latency period of 4 years, was observed in the central middle district of the prefecture compared with the Japanese annual incidence (incidence rate ratio = 50; 95% confidence interval [CI] = 25, 90). The prevalence of thyroid cancer was 605 per million examinees (95% CI = 302, 1,082) and the prevalence odds ratio compared with the reference district in Fukushima Prefecture was 2.6 (95% CI = 0.99, 7.0). In the second screening round, even under the assumption that the rest of examinees were disease free, an incidence rate ratio of 12 has already been observed (95% CI = 5.1, 23). 
 
 Conclusions: An excess of thyroid cancer has been detected by ultrasound among children and adolescents in Fukushima Prefecture within 4 years of the release, and is unlikely to be explained by a screening surge. 
 
 This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. 
 
 Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved. ||||| Gina Baker carefully weighed the pros and cons of a CT scan for her 1-year-old son. 
 
 "His pediatrician said she wanted to do a scan to make sure everything was OK," said Baker, explaining concerns that "the little guy's" head was growing too quickly. "They told me the risks from the radiation were low, but you definitely struggle with those types of decisions as a parent." 
 
 The scan came back normal, giving Baker some peace of mind. But the 31-year-old nurse and blogger from Brigham City, Utah, said she still worries about the test's long term effects -- a fear bolstered by a new study linking childhood CT scans to cancer later in life. 
 
 "Radiation exposure from CT scans was associated with an increased risk of brain cancer and leukemia, and that risk increased with increasing levels of radiation exposure," said Amy Berrington de González, a radiation epidemiologist at the National Cancer Institute in Bethesda, Md., and co-author of the study published today in The Lancet. 
 
 The study, of more than 355,000 children and teens in the U.K., found those exposed to 60 milligrays of radiation -- the cumulative dose of two brain CT scans -- were three times more likely to develop brain tumors. Those exposed to 50 milligrays of radiation were three times more likely to develop leukemia, a cancer of the white blood cells produced in the bone marrow. 
 
 Berrington de González stressed that the absolute cancer risk is very small, accounting for one extra cancer case per 30,000 children scanned. 
 
 "Providing the scan is clinically justified and performed properly with a child size dose of radiation, the benefits should easily outweigh the risks," she said. 
 
 But for parents like Baker, forced to quickly weigh the immediate benefits with the long term risks, the decision is far from easy. 
 
 "You want to do what's best for your family," she said. "I did agonize over it." 
 
 Radiation has long been known to cause DNA damage that can lead to cancer. But the cancer-causing effects of doses doled out during CT scans were purely theoretical. 
 
 "Those estimates drew a lot of controversy because they were based on the cancer risk in atomic bomb survivors," said Dr. David Brenner, director of Columbia University's Center for Radiological Research and lead author of the 2001 study estimating the cancer risk from CT scans. "There was debate about whether the risks were real, and this study shows pretty unequivocally that they are." 
 
 But Brenner said the benefits of CT scans, namely their ability to quickly detect life-threatening problems and guide life-saving surgeries, indeed outweigh the risks. 
 
 "All medical procedures have risks and benefits," he said. "That said, there are situations where CT scans are being used too much." 
 
 Brenner estimates some 20 percent of the country's 80 million CT scans each year are either unnecessary or could be replaced by a radiation-free ultrasound or MRI. 
 
 "That's why we need basic guidelines; decision rules that determine when a CT scan is medically appropriate," he said, adding that such guidelines already exist but are not always used. 
 
 Dr. Andrew Einstein, director of cardiac CT research at Columbia University Medical Center in New York City and author of an editorial accompanying the study, said he hopes doctors to think twice before ordering CT scans in children and parents will ask about alternatives. 
 
 "I think we need to redouble our efforts to ensure patients are getting appropriate tests with the lowest radiation dose possible," he said. "There are good reasons to use CT scans; it's a lifesaving test for many people. But with every good thing in medicine, there's a potential downside. And for CT scans it's the radiation." ||||| TOKYO—Raising concerns over possible contamination from the stricken Fukushima Daiichi nuclear plant, Japan's health ministry said Saturday that an abnormal amount of a radioactive material was detected in spinach grown about 110 kilometers (about 70 miles) northeast of Tokyo. 
 
 The ministry also said that an abnormal amount of the material, called iodine-131, was detected in milk from a dairy farm about 50 kilometers away from the plant. 
 
 Earthquake in Japan See all the graphics on the situation in Japan -- from before and after photos to the status of the reactors to survivors' stories. 
 
 "This is the first time ever that an abnormal amount of radioactive material has been detected in food in Japan," said ministry official Ryusuke Hagiwara. 
 
 Chief Cabinet Secretary Yukio Edano said that the amounts detected in the milk and spinach would not immediately affect human health. Even so, concerns over possible food contamination mark a serious setback in Japan's attempts to contain its worst-ever nuclear accident as it threatens to widen the economic impact of the disaster to Japan's declining farming industry. 
 
 Also Saturday, Japan's science ministry said that small amounts of a radioactive substance not usually present have been detected in tap water in Tokyo and five nearby prefectures, but it said the amounts are too small to pose a threat to human health. The ministry started monitoring tap water for radioactive material Saturday, and will continue to check it every day. 
 
 In raw milk samples collected from a farm in the town of Kawamata in Fukushima prefecture, up to 1,510 becquerel per kilogram of iodine-131 were detected, about five times the limit of 300 becquerel per kilogram set by law. 
 
 "This will be a huge blow to dairy farms all over Fukushima," said Yukimitsu Sato, a spokesman for the prefecture's dairy farm cooperative, which represents about 60% of local dairy farms, including the one in Kawamata. 
 
 The prefecture had not shipped milk for consumption since the earthquake, and the health ministry's announcement came just as the cooperative was preparing to begin shipping again. 
 
 "We were just starting to see a ray of hope," said Mr. Sato, adding that the cooperative was not told about the radioactivity tests. 
 
 According to the cooperative, Fukushima prefecture's 516 dairy farms usually ship 254 tons of milk every day, with annual sales of about ¥10 billion (about $125 million). About 1.3% of dairy cows in Japan were in Fukushima as of 2008, according to the prefecture. 
 
 The health ministry also detected higher-than-normal levels of iodine-131 from spinach samples collected Saturday from farms in six locations in Ibaraki prefecture, south of Fukushima. 
 
 One spinach sample collected from the city of Hitachinaka, located about 120 kilometers south of the plant, contained 8,420 becquerel per kilogram of iodine-131, according to the health ministry. The normal amount set by Japanese law is 2,000 becquerel per kilogram. 
 
 Another spinach sample from Takahagi, a city closer to Fukushima, recorded 15,020 becquerel per kilogram, more than seven times the normal amount. From that sample, radioactive caesium 134 and caesium 137 were also detected in slightly larger amounts than the limits set by law. 
 
 The Ibaraki prefectural government has asked farmers to suspend shipments of spinach, according to the Ibaraki branch of the National Federation of Agricultural Cooperative Associations. 
 
 An official in Ibaraki prefecture said that he couldn't deny the possibility that some spinach from the prefecture has already reached consumers. The prefecture produces about 14,000 tons of spinach a year, about 5% of overall production in Japan. 
 
 Tokyo Electric Power Co. said at a news conference Saturday that it was prepared to offer compensation to farmers. 
 
 Any impact on Japan's agricultural sector will mostly be concentrated on the domestic market. Japan imports far more food than it exports, and even some of the most basic ingredients in Japanese cuisine, such as soy beans, are mostly imported. In 2009, the total value of the country's food imports stood at $53.5 billion, while its exports came to only $3.27 billion, according to the Japan External Trade Organization. 
 
 If fears over contamination grow, the country may have to rely on imports even more. 
 
 Mr. Edano said that the level of radioactive materials detected in the milk means that if a person drank that milk every day for a year, based on average Japanese milk consumption, total exposure to radioactivity would be about the same as one CT scan. If a person ate the spinach in question for one year, the radioactivity would be about one-fifth of one CT scan, he said. 
 
 Mr. Edano said that the health ministry will collect more data to find out whether contaminated foods are limited to certain areas, and whether it is necessary to restrict the consumption or shipment of certain food products. The ministry will also investigate other products besides milk and spinach, he added. 
 
 --Hiroyuki Kachi contributed to this article.
– For four years, nearly all kids living in Japan's Fukushima prefecture have received ultrasounds to gauge the effects of the nuclear disaster there in March 2011. Now a research team says the alarming results are in: Children living near the nuclear plant have thyroid cancer rates that are 20 to 50 times higher than those found in children elsewhere, the AP reports. Per a study being published in the November issue of Epidemiology, of the 370,000 or so kids 18 and under in the Fukushima region who received thyroid exams since the disaster, 137 of them have suspected or confirmed cases of thyroid cancer, a number that rose by 25 from last year, the AP notes. "This is more than expected and emerging faster than expected," lead author Toshihide Tsuda tells the AP. Thyroid cancer cases in children outside the prefecture are estimated to be around one or two out of every million kids per year. Children's thyroids are particularly vulnerable to cancer—radioactive iodine released during nuclear meltdowns can cause it—because they're growing so quickly, NPR notes. Tsuda and his team claim that the numbers aren't simply the result of a "screening effect"—in which more routine checkups like the ones in Fukushima have simply found tumors earlier and more often—as the Japanese government has suggested. Other experts, however, aren't so sure how accurate Tsuda's study is and note the complexity of studying such an issue. The director for Columbia University's Center for Radiological Research, for example, tells NPR that just tying certain geographic areas to higher cancer rates doesn't prove anything without looking at individual radiation exposure, a claim that's echoed in a report by the World Health Organization.(The residents of the Japanese town of Nahara are finally allowed back—but many don't want to go.)