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rpop Radiation protection of pregnant women in radiologyPatient exposure » Is there a safe level of radiation exposure for a patient during pregnancy? Dose limits do not apply for radiation exposure of patients, since the decision to use radiation is justified depending upon the individual patient situation. When it has been decided that a medical procedure is justified, the procedure should be optimized. This means that the conditions should achieve the clinical purpose with the appropriate dose. Dose limits are determined only for the staff and not for patients. » What is the ten-day rule and what is its status? 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. The approach is not uniform in all countries and facilities. 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 original proposal was for 14 days, but this was reduced to 10 days to account for the variability of the human menstrual cycle. In most situations, there is growing evidence that a strict adherence to the "ten-day rule" may be unnecessarily restrictive. 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. Since organogenesis starts 3 to 5 weeks post-conception, it was felt that radiation exposure in early pregnancy couldn't result in malformation. Based on this, it was suggested to do away with the 10-day rule and replace it with a 28-day rule. This means that radiological examination, if justified, can be carried throughout the cycle until a period is missed. Thus the focus is shifted to a missed period and the possibility of pregnancy. If there is a missed period, a female should be considered pregnant unless proved otherwise. In such a situation, every care should be taken to explore other methods of getting needed information by using non-radiological examinations. » Should pregnancy be terminated after radiation exposure? According to ICRP 84, termination of pregnancy at fetal doses of less than 100 mGy is not justified based upon radiation risk. At fetal doses between 100 and 500 mGy, the decision should be based upon the individual circumstances. The issue of pregnancy termination is undoubtedly managed differently around the world. 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. This complicated issue involves much more than radiation protection considerations and require the provision of counseling for the patient and her partner. 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. Read more: INTERNATIONAL COMISSION ON RADIOLOGICAL PROTECTION, Pregnancy and Medical Radiation, Annals of the ICRP, Publication 84, Pergamon Press, Oxford (2000). Undergoing medical examinations in pregnancy » What if a patient underwent an abdomen CT before realizing that she is pregnant? In some cases, a patient will not be aware of her pregnancy at the time of an X-ray examination. After realizing that she is pregnant, she will be concerned. 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. The patient can then be better advised as to the potential risks involved. In many cases there is little risk, as the irradiation will have occurred in the first 3 weeks following conception. In a few cases the conceptus will be older and the dose involved may be considerable. It is, however, extremely rare for the dose to be high enough to warrant advising the patient to consider terminating the pregnancy. If a calculation of radiation dose is required in order to advise the patient, the radiographic factors should be noted if known. Some assumptions may be made in the dosimetry, but it is best to use actual data. The patient's date of conception or date of LMP (last menstrual period) should also be determined. » How safe are radiological examinations of chest and extremities in pregnancy? Medically indicated diagnostic studies remote from the fetus (e.g. radiographs of the chest or extremities) can be safely done at any time during pregnancy if the equipment is in proper working order.
Commonly, the risk of not making the diagnosis is greater than the radiation risk involved. Effects of radiation exposure in utero It is unlikely that radiation from diagnostic radiological examinations will result in any harmful effects on the child, but the possibility of a radiation-induced effect cannot be entirely ruled out. The effects of exposure to radiation on the conceptus depend on the time of exposure with respect to the date of conception and the amount of absorbed dose. The following description is for scientific professionals and the effects described are to be seen only under the situations mentioned. It does not imply that these effects shall occur with doses encountered in common examinations, as they are quite small. For further details, please see ICRP 84.
» Can cardiac catheterization be performed on a pregnant patient? Yes. There will be many situations where the benefit of performing the procedure is much greater than any small possible harm that
might arise from the radiation exposure. As with any medical exposure, each particular procedure must be clinically justified, taking into account scheduling of the procedure and the anticipated radiation dose to the fetus.
For well performed procedures, estimated fetal doses are
typically quite small, and well below the level of concern for radiation effects. Calculations of dose by a knowledgeable medical physicist is recommendable in all cases. » Can the patient become sterile after undergoing a diagnostic X-ray examination? The gonads are radiosensitive organs in the human body. The threshold radiation dose for permanent sterility in men is 3500 - 6000 mGy, and for women 2500 - 6000 mGy. As diagnostic X-ray examinations involve small doses (see table below), they imply no risk of sterility. Table: Approximate
foetal doses from common diagnostic procedures in the United Kingdom
» How should I counsel patients on the dose and risk assessment procedures? Patients who have received diagnostic studies while pregnant are often alarmed because of emotional perceptions surrounding radiation. The health professionals should advise patients about the steps that will be taken for risk assessment and provide appropriate information regarding the risk associated with diagnostic (and therapeutic) radiation exposure during pregnancy. The following points should be considered:
Radiation exposure of staff » Can a pregnant employee continue to work in the X-ray department? A pregnant worker can continue working in an X-ray department as long as there is reasonable assurance that the fetal dose can be kept below 1 mGy during the pregnancy. It is important to ensure that pregnant women are not subjected to unnecessary discrimination. Both worker and the employer carry responsibility towards safety. The first responsibility for the protection of the conceptus lies with the woman herself, who should declare her pregnancy to management as soon as the condition is confirmed. The following recommendations are taken from ICRP 84:
» How high is the chance that a staff member will approach the dose limits of exposure? Radiation doses to occupationally exposed staff working with radiological equipment are generally low and it is unlikely that the equivalent dose limit
recommended by the ICRP (see the table below) will be approached. Table: ICRP 60 Recommendations Assumed radiation risksICRP Publication 60
*After its meeting on April 21, 2011 the ICRP issued a statement recommending an equivalent dose limit to the lens of the eye of 20 mSv per year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. Which of the following Xray procedures increases the radiographers risk of exposure to ionizing radiation compared to radiography?What X-ray procedures increases the radiographers risk of exposure to ionizing radiation? Mobile C-arm fluoroscopy, interventional procedures that use high level control fluoroscopy, mobile radiographic examinations.
Which of the following are areas of the body that should be shielded from the useful beam whenever possible?Areas of the body that should be shielded from the useful beam whenever possible are the:. Lens of the eye;. Breasts;. Reproductive organs;. What is the purpose of radiographic beam filtration quizlet?What is the purpose of radiographic beam filtration? a. To reduce exposure to the patient's skin and superficial tissues by absorbing most of the higher-energy photons from the heterogeneous beam.
Which of the following is a tenet of the Alara concept?Which of the following is a tenet of the ALARA concept? A facility that employs a pregnant diagnostic imaging staff member should provide that individual with an additional monitor to be worn at waist level during all radiation procedures.
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