![]() ![]() If a calculation of radiation dose is required in order to advise the patient, the radiographic factors should be noted if known. It is, however, extremely rare for the dose to be high enough to warrant advising the patient to consider terminating the pregnancy. In a few cases the conceptus will be older and the dose involved may be considerable. ![]() In many cases there is little risk, as the irradiation will have occurred in the first 3 weeks following conception. The patient can then be better advised as to the potential risks involved. The radiation dose to the fetus/conceptus should be estimated, but only by a medical physicist/radiation safety specialist experienced in this type of dosimetry. After realizing that she is pregnant, she will be concerned. In some cases, a patient will not be aware of her pregnancy at the time of an X-ray examination. » What if a patient underwent an abdomen CT before realizing that she is pregnant? Undergoing medical examinations in pregnancy INTERNATIONAL COMISSION ON RADIOLOGICAL PROTECTION, Pregnancy and Medical Radiation, Annals of the ICRP, Publication 84, Pergamon Press, Oxford (2000). At fetal doses in excess of 500 mGy, there can be significant fetal damage, the magnitude and type of which is a function of dose and stage of pregnancy. This complicated issue involves much more than radiation protection considerations and require the provision of counseling for the patient and her partner. It is complicated by individual ethical, moral, and religious beliefs as well as perhaps being subject to laws or regulations at a local or national level. The issue of pregnancy termination is undoubtedly managed differently around the world. At fetal doses between 100 and 500 mGy, the decision should be based upon the individual circumstances. » Should pregnancy be terminated after radiation exposure?Īccording to ICRP 84, termination of pregnancy at fetal doses of less than 100 mGy is not justified based upon radiation risk. These facilities use a 28-day rule for all other examinations. In such a situation, every care should be taken to explore other methods of getting needed information by using non-radiological examinations.Ī conservative approach used by some radiology facilities is to apply a 10-day rule only for examinations with the potential to deliver a high dose to the lower abdomen and pelvis, such as barium enemas and CT of the abdomen or pelvis. If there is a missed period, a female should be considered pregnant unless proved otherwise. Thus the focus is shifted to a missed period and the possibility of pregnancy. This means that radiological examination, if justified, can be carried throughout the cycle until a period is missed. Based on this, it was suggested to do away with the 10-day rule and replace it with a 28-day rule. Since organogenesis starts 3 to 5 weeks post-conception, it was felt that radiation exposure in early pregnancy couldn't result in malformation. When the number of cells in the conceptus is small and their nature is not yet specialized, the effect of damage to these cells is most likely to take the form of failure to implant, or of an undetectable death of the conceptus malformations are unlikely or very rare. In most situations, there is growing evidence that a strict adherence to the "ten-day rule" may be unnecessarily restrictive. The original proposal was for 14 days, but this was reduced to 10 days to account for the variability of the human menstrual cycle. One approach is the 'ten day rule,' which states that "whenever possible, one should confine the radiological examination of the lower abdomen and pelvis to the 10-day interval following the onset of menstruation." The approach is not uniform in all countries and facilities. It is important for radiology facilities to have procedures to determine the pregnancy status of female patients of reproductive age before any radiological procedure that could result in a significant dose to the embryo or fetus. ![]() » What is the ten-day rule and what is its status?
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |