A radiological examination is usually performed based on a referral issued for the patient by a physician. In fact, this is a legally sanctioned requirement in the case of examinations performed with the use of X-ray radiation. No referral is required only in the case of some assessments using X-ray radiation, such as screening mammography, intraoral dental exams and diagnostic examinations carried out using densitometers. These are the rules whether the cost of the service is covered by the patient or the healthcare system. Therefore, if no doctor's referral is presented, the staff of radiological laboratory must refuse to perform the service even if the patient wants to pay for it.

    Different principles apply to examinations performed with such techniques as medical ultrasound or magnetic resonance (MR) imaging. In this case doctor's referral is required only if the cost of the service is to be covered by the healthcare system.

    However, doctor' referral is always required if a radiological examination involves the use of a contrast agent. It should also be emphasised that all types of radiological examination  can be performed with greater precision if the patent presents a doctor's referral (whether or not it is required) along with complete detailed clinical data as well as results and images from examinations performed earlier. This information makes it easier for the radiologist to produce detailed description of the result.

    In the case of diagnostic procedures associated with increased risk (any examinations in which a contrast medium is administered), the patient is required to sign a statement expressing consent for the examination. This type of document presents a description of the procedure, preparations for the examination, as well as possible complications and contains necessary sections documenting the patient's informed consent.

    In the case of some radiological examinations, the patient must prepare appropriately for the procedure. Detailed information is usually provided by the referring doctor or can be obtained from the laboratory where the examination is to be performed.

    The related requirements in the case of the procedures involving administration of contrast agents are described in the section "Contrast media".

    It should be pointed out that not all radiological devices have a sufficiently large 'carrying capacity', which is important in the case of patients with obesity. Similarly, CT and MR scanners with a small-diameter bore will not allow obese patients to be examined. Therefore, if there are any doubts, it is necessary to contact the relevant radiology laboratory to make sure whether the examination will be possible. In the case of MR examinations, patients with claustrophobia may not be able to enter the tunnel of the apparatus.

   Women of childbearing age (menstruating) should report pregnancy or suspected pregnancy. This must be done whether or not the radiology lab staff is required to ask this question. This is because medical imaging procedures using ionising radiation should not be applied to pregnant women. An exception to this rule is when no alternative diagnostic techniques can be used and when the examination cannot wait until after the baby is born whereas the benefits outweigh the hazards. Also, such examinations are performed when the patient's life is at risk. The exposure of the unborn child to radiation should then be minimised.  

   Before a radiological examination you should not apply beauty products such as body creams, lotions (especially with metal contents, so called brightening lotions), deodorants, powder, talcum powder and ointments. If you have any large moles, warts, tattoos or piercings (especially in the case of MR examinations), you should report this to the laboratory staff. If possible, metal elements should be removed from the area subject to the examination. Separate procedures are applicable in relation to this for MR examinations.

    When a doctor decides to refer a patient for a diagnostic radiological examination, the selection of an appropriate technique is crucial. This is particularly important when X-rays, a type of ionising radiation, are used in the examination. By selecting an appropriate imaging technique it is possible to acquire more precise results and to avoid or reduce exposure to X-rays. Although this risk during radiological examinations is low, a number of procedures have been developed to control radiation doses. The guiding principle related to radiation safety is ALARA (acronym for As Low As Reasonably Achievable). It means that the required effects, i.e., useful diagnostic images, are to be acquired by using only the minimum doses of radiation which make it possible to accomplish the task. In other words, a higher image quality than required to make a diagnosis may be associated with the patient's exposure to an unnecessarily high dose. On the other hand, when insufficient radiation is applied, the image acquired may lack information necessary to make an accurate diagnosis. As a consequence, there may be a need to repeat the examination.