Radiological Protection in Diagnostic Radiology
General Aspects of Radiological Protection in Diagnostic Radiology
The objective of radiological protection is to provide the necessary information for diagnosis with minimal risk. The realization of this objective should consider other diagnostic methods that do not involve the use of radiation.
General Aspects Influencing Radiological Protection
- The largest dose saving is achieved by not performing unnecessary explorations. A radiodiagnostic installation plays a part in the balanced application of radiological protection in the equipment selection, project design, installation, and operation phase.
- Facilities should have appropriate architectural designs, such as dressing rooms, lobbies, and corridors. Large-sized rooms and their structural and non-structural barriers (screens and mobile control) should be fully shielded for use (secondary barriers).
- Traders should look at general aspects that influence their own radiological protection, that of the patient, and the public in general. They should utilize equipment correctly in each examination, preventing the repetition of plates due to being past due, cut, moved, or decentered, and complying with the rules of radiological protection. Optimizing radiological techniques should be a permanent part of the work of users, from technicians to maintenance personnel. The only purpose is that exposure to radiation for patients and operators is always the minimum possible, so it is necessary to take into account the distribution of equipment within the room. The right situation is for the operator to be in the best-protected position from the radiation, with easy circulation within the room and easy access from the outside, providing operator-source distances.
Basic Standards of Protection for Exposed Professional Staff
- Professionals exposed to radiation should always avoid introducing any part of the body within the useful field of the radiation beam unless strictly necessary. They should strive to remain adequately protected against primary radiation for the shortest time possible. Primary radiation (direct radiation and useful beam leakage) and high radiation (scattered radiation) barriers (primary and secondary).
- The primary radiation beam should never be turned toward the operator’s position, even if a partition barrier is considered primary protection. It is worth remembering that lead aprons used as protection material should always be considered secondary barriers.
- During a trip or a radiographic examination, no one should be in the radiographic room except the patient, except for those scans that require the presence of medical staff and/or technical personnel. In such cases, the necessary minimum number of people will be present.
- Each room should have the necessary and sufficient protection means for all who may need it, routinely or sporadically, especially in the case of aprons. Each person who works in a room with radiation should be aware of the risk posed by ionized radiation. The main business is responsible for avoiding that those in the courtroom without adequate protection stay there for as long as the radiation emission is active.
Basic Rules for Routine Work in Rooms with Fluoroscopy
- While performing fluoroscopy, only the necessary staff will remain in the room.
- Do not press the fluoroscopy button more than necessary to obtain information. This is known as discontinuous fluoroscopy.
- The use of image intensifiers is recommended, and direct fluorescent screens should be gradually eliminated. While they do not present great inconvenience, it is a fact that most teams are now working with fluoroscopy coupled with image intensification systems.
- When the tube is placed above the table and the intensifier below, the scattered radiation that can reach the operator is greater than when the order is reversed. This involves greater exposure to the gonads, so whenever possible, it is preferable to place the intensifier above the tube and the table below.
- Before beginning the exploration, the doors of the room should be closed to prevent unnecessary irradiation of both staff and the public.
- Never direct the primary radiation beam directly to windows from the control room or dark chamber.
- The radiation field should be the lowest achievable by using tube diaphragms, which should always be used and should not interfere with the diagnosis. Gonadal shields should also be used.
- The focus-skin distance should be no less than 30 cm, while the best minimum distance is considered to be 45 cm.
- If, due to the type of examination (e.g., angiography), it is essential to place the hands under the direct action of the primary beam, leaded gloves are required for protection.
- When the technique used makes it likely that some body structure will receive a higher radiation dose than others, and the difference is significant (as might occur with the hand lens), it will be necessary to use a personal dosimeter, always located behind the apron. Another dosimeter should be used for other areas, especially those located in exposed zones.
Operational Rules for Mobile Teams and Work Routines
Rules relating to the construction and design of mobile equipment, seen previously, will be meaningless if the work routine (protection systems) is not followed. Therefore, it is required that technical staff operating these teams exercise extreme caution in applying the rules of protection. These are:
- When making the radiographic shot, the operator should seize the opportunity afforded by the extension cord to move away, trying to be placed as far as possible from the X-ray tube and acting as a protection barrier. Doors, walls, and the distance from the technician to the tube should be no less than 2m.
- The technician will always wear a leaded apron with an equivalence of at least 0.25 mm of lead. The apron should always be worn for fluoroscopy explorations during the entire time of the exploration, and the dosimeter should be placed under the apron.
- During a radiographic shot, no one should remain in the room except the patient and the technician.
- When the procedure is performed, someone should remain near the patient to assess the dose and ensure that it is the smallest possible.
- The radiographic chassis should never be adjusted by any person. Appropriate devices should always be used for each case.
- Diaphragms should always be consistent with the size of the zone to be radiographed. This operation should be performed whenever the tube-patient distance is adjusted.
- The data collection system must have the maximum possible sensitivity.
- When using mobile devices, the dosimeter should always be placed under the leaded apron.