（中央社記者顏伶如波特蘭14日專電）美國國家癌症研究所最新的研究指出，2007年，全美民眾使用電腦斷層掃瞄達7200萬次，估計導致2萬9000例癌症，其中近1萬5000個癌症病例具有致命風險。電腦斷層掃瞄可以提供清楚的圖像，有助於醫師掌握病情。不過，國家癌症研究所（National CancerInstitute） 最新的研究卻提出警告，病患接受電腦斷層掃瞄時由於曝露於放射線之下，未來幾年可能因此發生成千上萬的癌症病例。美國「國家公共電台」（National Public Radio）今天報導，國家癌症研究所最新的研究指出，光是在2007年一年內，美國民眾使用電腦斷層掃瞄的次數高達7200萬次，估計導致2萬9000例癌症個案，其中將近1萬5000個癌症病例更具有致命的風險。報導指出，除非美國醫學界能降低電腦斷層掃瞄的使用率，或者減少患者每次接受電腦斷層掃瞄時的放射線量，否則電腦斷層掃瞄所引發的致癌風險，每年在美國都會繼續發生國家癌症研究所這項研究將刊登於本週出刊的美國「內科醫學年鑑」（Annals of Internal Medicine）。
The FDA issued an initial safety notification in October 2009 after learning of 206 patients who had been exposed to excess radiation of up to eight times the expected level during their CT perfusion scans at Cedars-Sinai Medical Center in Los Angeles over an 18-month period.
Some of these patients reported hair loss or skin redness following their scans. High doses of radiation can cause cataracts and increase the risk of some forms of cancer.
On the basis of its investigation to date, the FDA is providing interim recommendations for imaging facilities, radiologists, and radiologic technologists to help prevent additional cases of excess exposure. These recommendations apply to all CT perfusion images, including brain and heart, because they use similar procedures and protocols.
These recommendations include:
-Facilities assess whether patients who underwent CT perfusion scans received excess radiation.
-Facilities review their radiation dosing protocols for all CT perfusion studies to ensure that the correct dosing is planned for each study.
-Facilities implement quality control procedures to ensure that dosing protocols are followed every time and the planned amount of radiation is administered.
-Radiologic technologists check the CT scanner display panel before performing a study to make sure the amount of radiation to be delivered is at the appropriate level for the individual patient.
-If more than one study is performed on a patient during one imaging session, practitioners should adjust the dose of radiation so it is appropriate for each study.
