The 10-day rule was established by the International Commission on Radiological Protection to minimize the risk of radiological examinations in pregnant women. The basis of the rule was to carry out radiographic examinations of the abdomen and pelvis only within 10 days after the beginning of menstruation. We now know much more about radiation and pregnancy, and we know that large doses (~10 rem; more than those obtained with routine diagnostic x-rays) are needed to cause birth defects or malformations. Since organogenesis begins 3 to 5 weeks after conception, it has been assumed that radiation exposure in early pregnancy cannot lead to malformations. Now the focus is on a missed period and the possibility of pregnancy. If there is a missed period, a woman should be considered pregnant until proven otherwise. In such a situation, care should be taken to explore other methods of obtaining clinical information by conducting studies that do not use ionizing radiation. Often, due to radiation therapy, a patient`s fetus that has been exposed to radiation therapy may have birth defects that can even lead to abnormal cell proliferation, which could lead to the development of cancer [5]. Where possible, protective devices such as lead shields and lead aprons should be used to minimise the effects of radiation without affecting the region of interest.
In order to reduce the potential damage associated with radiation exposure, several rules have been proposed to protect the fetus. The initial proposal was 14 days, but this was reduced to 10 days to account for the variability of the human menstrual cycle. In most situations, it is increasingly clear that strict adherence to the « ten-day rule » can be unnecessarily restrictive. If 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 be observed in the form of implantation failure or undetectable death of the conceptus; Malformations are unlikely or very rare. Since organogenesis begins 3 to 5 weeks after conception, it has been assumed that radiation exposure in early pregnancy cannot lead to malformations. On that basis, it was proposed to abolish the 10-day rule and replace it with a 28-day rule. This means that a radiological examination, if warranted, can be performed throughout the cycle until a period is missed. Thus, the focus is on a missed period and the possibility of pregnancy.
Don`t forget to ask your patient questions about their LMP and consider the 10-day rule. If there is a missed period, a woman should be considered pregnant until proven otherwise. In such a situation, care should be taken to explore other methods to obtain the required information through non-radiological examinations. A conservative approach used by some radiology institutions is to apply a 10-day rule only for examinations where a high dose can be given to the lower abdomen and pelvis, such as barium enemas and computed tomography of the abdomen or pelvis. These institutions apply a 28-day rule for all other exams. PIP: Procedures to ensure the safe use of X-rays to protect the developing embryo or fetus are described. The effects of radiation on the developing embryo or fetus can lead to developmental disorders and cancer in children or later. The 1st trimester of pregnancy is a particularly critical period, with the exception of the 1.10 days after the beginning of the menstrual cycle when there is no risk of conceptus. The guiding principle is the 10-day rule, which states that the abdominal region (lumbar spine, pelvis, tailbone and hips) should not be irradiated after the 1.10 days of the menstrual cycle. The exceptions are patients on pills, sterilized, with a hysterectomy, or when the referring doctor considers that the X-ray saves lives. This 10-day rule has been modified to allow radiographic examination of patients of childbearing potential, provided that the patient is not pregnant. The responsibility for determining pregnancy rests with the attending physician, radiologist, radiologist or technician.
The date of the last menstruation must be entered in an application form. Any missed or late deadlines are worrisome; The recommendation is to publish a warning about the risk of pregnancy in the diagnostic service. In addition, the radiologist/technician should ask privately if the patient might be pregnant. If the fetal risk is less than the lack of necessary diagnosis, examinations may be carried out, but care must be taken to minimize the radiation time or the number of films or the high dose of radiation to the fetus. Irradiation of other removed areas of the fetus, such as the breast, skull or extremities, can be performed at any time during pregnancy, provided that appropriate shields (lead aprons) are used to protect the fetus from X-rays. Ultrasound examinations are preferred to determine fetal maturation, placental localization and viability of the fetus. This method is safe because it does not use ionizing radiation. If pelvimetry is necessary during pregnancy, it is necessary to determine the cost-benefits and take X-rays in the last trimester of pregnancy. The reminder is that all measures must be taken to avoid exposing the embryo and fetus to ionizing radiation. Safety standards must be met in hospitals and private clinics; The creation of a national radiation protection and regulatory authority is essential. X-ray operators need appropriate qualifications and training.
» What is the ten-day rule and what is its status? For radiology institutions, it is important to have procedures to determine the pregnancy status of patients of childbearing potential before any radiological procedure that could lead to a significant dose to the embryo or fetus. The approach is not uniform across all countries and institutions. One approach is the « ten-day rule, » which states that « as far as possible, radiological examination of the lower abdomen and pelvis should be limited to the interval of 10 days after the onset of menstruation. » The 10-day rule states that radiological examinations can only take place within 10 days of the beginning of menstruation and are suitable for a high-dose radiological examination (computed tomography of the abdomen; simple X-ray of the lumbar spine). It is very important to follow these basic rules in order to minimize the harmful effects of radiation on the unborn fetus [1]. While the 28-day rule applies to radiological examinations, which can take place throughout the 28-day cycle until a patient undergoes a missed period and is suitable for a low dose of radiological examination (chest x-ray). Thus, the focus here is more on the missed period and the possibility of pregnancy [6]. At this stage, the patient is assumed to be pregnant, unless the contrary is proven by a urine test for pregnancy to confirm the state of pregnancy. Radiation from diagnostic radiological examinations is unlikely to have harmful effects on the child, but the possibility of a radiation-induced effect cannot be completely excluded. The effects of radiation exposure on the conceptus depend on the time of exposure in relation to the date of conception and the amount of energy dose.
The following description is intended for scientific professionals and the effects described can only be seen in the situations mentioned. This does not mean that these effects have to occur at doses that occur during joint investigations, as they are quite small. For more details, see ICRP 84. The concept of the 10-day rule was established by the International Commission on Radiological Protection (ICRP) to minimize the risk of radiological examinations on pregnant women. Depending on the type of radiological procedure, the corresponding rule (« 10 days and 28 days rule ») is applied. Patient exposure » Is there safe radiation exposure for a patient during pregnancy? » What is the ten-day rule and what is its status? » Should pregnancy be terminated after radiation exposure? The effects of exposure to high levels of radiation (>100 mGy) depend on the age of the fetus and the total absorbed dose. Radiation risks are highest during organogenesis and the beginning of the fetal period, slightly less in the second trimester and less in the third trimester. CNS sensitivity is highest in the eighth week after conception; Fetal doses of the order of 1,000 mGy lead to a high probability of severe mental retardation. 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 worried. The radiation dose to the fetus/conceptus should be estimated, but only by a medical physicist/radiation protection specialist who has experience with this type of dosimetry. The patient can then be better advised on the possible risks.
In many cases, the risk is low because the radiation occurred within the first 3 weeks after conception. In some cases, the conceptus will be older and the associated dose may be substantial. However, it is extremely rare that the dose is high enough to advise the patient to consider an abortion. With fetal doses greater than 500 mGy, there can be significant fetal damage, the extent and type of which depend on the dose and stage of pregnancy. As shown in Table 1, the radiation doses of the diagnostic radiological examination do not approximate these values.
