Grammaticos Philip, Fountos George
Hell J Nucl Med. 2006 May-Aug;9(2):82-4.
Six hundred years before Christ, Hippocrates said that physicians on exercising their medical duties, should benefit but not harm their patients. Seventy years ago increased medical radiation caused radiologists in the US an excess risk of leukemia, lymphoma and multiple myeloma. Now medical radiation is rather safe for the physician but the question remains if proper prophylactic measures are being taken to make it safe for the subjects examined. Roughly, first trimester of pregnancy radiography has a much greater fatal cancer risk than that of exposures taken later in pregnancy. It is suggested that women should be administered the minimum activity consistent with achieving the desired clinical information, whether or not they are known to be pregnant. The best available risk estimates suggest that pediatric CT diagnostic procedures will induce significantly increased lifetime radiation risk in children. Professor Roger Clarke wrote that there may be a need to reduce or prevent doses of medical radiation up to 3 mSv if there is no benefit to the individual. 30 mSv is described as "a dose which should not be exceeded" and can be approached only if there is a benefit to individuals and the dose is difficult to reduce or prevent. In WHO Category III a) Static brain imaging with technetium-99m pertechnetate, b) Gated cardiac imaging c) Bone imaging with technetium-99m MDP, c) Quantitative haemodynamics with technetium-99m pertechnetate, d) myocardial imaging with thallous-201 chloride and e) abscess imaging with gallium-67 citrate, induce an effective dose equivalent of 5-9 mSv. A CT scan commonly gives 25 mSv to the subject examined. BEIR VI indicated that a 10 mSv single population dose is associated with a lifetime attributable risk for developing a solid cancer or leukemia in 1:1000. Multiple CT examinations have administered to some patients with renal colic a dose of 19.5-153.7 mSv. One may suggest that there should be "justification" and informed written patients' consent for nuclear medicine examinations administering to the patient doses greater than 5 mSv, especially doses around or above 30 mSv / year.
公元前600年，希波克拉底说，医生在履行医疗职责时，应该使患者受益而不是伤害他们。70年前，医疗辐射增加导致美国放射科医生患白血病、淋巴瘤和多发性骨髓瘤的风险增加。现在，医疗辐射对医生来说相当安全，但问题仍然存在，即是否正在采取适当的预防措施，以使接受检查的对象也安全。大致来说，怀孕头三个月进行X光检查导致致命癌症的风险比怀孕后期接受辐射要大得多。建议无论女性是否已知怀孕，都应给予她们与获得所需临床信息相一致的最低辐射量。现有的最佳风险估计表明，儿科CT诊断程序将显著增加儿童一生的辐射风险。罗杰·克拉克教授写道，如果对个人没有益处，可能需要减少或防止高达3毫希沃特的医疗辐射剂量。30毫希沃特被描述为“不应超过的剂量”，只有在对个人有益且剂量难以减少或防止的情况下才能接近这个剂量。在世界卫生组织第三类中，a) 用高锝[99mTc]酸盐进行静态脑显像，b) 门控心脏显像，c) 用锝[99mTc]亚甲基二膦酸盐进行骨显像，c) 用高锝[99mTc]酸盐进行定量血流动力学检查，d) 用氯化铊[201Tl]进行心肌显像，以及e) 用枸橼酸镓[67Ga]进行脓肿显像，会产生5至9毫希沃特的有效剂量当量。一次CT扫描通常会使接受检查的对象受到25毫希沃特的辐射。美国国家科学院医学研究所第六次报告指出，单次10毫希沃特的人群剂量与1000人中1人患实体癌或白血病的终生归因风险相关。一些患有肾绞痛的患者接受了多次CT检查，辐射剂量为19.5至153.7毫希沃特。有人可能会建议，对于给患者施用超过5毫希沃特剂量的核医学检查，尤其是每年剂量在30毫希沃特左右或以上的检查，应该有“正当理由”并获得患者的书面知情同意。
