RADIATION
IN MEDICINE
What should a patient know?

Every person undergoes dozens of diagnostic and, if needed, therapeutic procedures using radiation sources during a lifetime. The procedures related to medical exposure are prescribed by a physician, performed in special medical institutions and shall be planned. Most often, diagnostic examination is performed using X-ray machines: mammographs, fluorographs, computer tomographs, angiographs, dental X-ray machines.

Every year, each of us is subject to at least one X-ray diagnostics. Usually, these procedures are needed for preventive examination in order to detect diseases, including cancer in the early stages, to confirm the diagnosis and prescribed treatment. In addition, such examinations have negative impact on the human body. Thus, there is a possibility of mutation of cells that can eventually result into malignant tumors. Another negative consequence is the probability of genetic changes in germinal cells.

The physicians shall avoid unjustified appointment of X-ray and radiological procedures. Besides, they shall ensure radiation protection of the patient during such procedures.

Is medical X-ray diagnostics harmful?

The exposure dose in X-ray diagnostics is very small. However, the risks for somatic-stochastic effects (tumors, leukemia, genetic diseases such as Down’s disease, Turner’s syndrome) increase with the value of dose received by a person.

Patients receive relatively high exposure doses as a result of diagnostics on computer tomographs, angiographs and through interventional procedures with radiopharmaceuticals. Therefore, these procedures are subject to certain regulatory restrictions and the necessity of conducting them shall be justified by the doctor on the basis on medical evidences.

What does an exposure dose stands for?

The notion of exposure dose is used to assess the damage caused by radiation on the human body. It is measured in sieverts, millisieverts and microsieverts. During a preventive examination, the annual effective dose of a person should not exceed 1 millisievert (mSv).

What are natural and man-made radiation sources?

Cosmic radiation, radioactive substances on the surface and in the depths of the earth, in atmosphere, water, plants, all living organisms that inhabit our planet, are natural sources of radiation.

Depending on the area in which the person lives, the dose of exposure from the natural background can reach up to 3 mSv annually.

Man-made radiation sources are used in industry, energy, medicine.

Do all types of diagnostic procedures have high exposure doses?

No. Different types of diagnostic procedures can lead to different exposure doses. On average, this dose is 0.2 mSv and it is quite low as compared with natural radiation.

 

Procedure Effective dose, mSv Risk of cancer Period of obtaining a similar dose from natural radiation
No doses

• Magnetic resonance imaging (MRI);

• Ultrasound diagnostics

Not applied

Unknown

Not compared

Low doses

• Dental X-ray diagnostics;

• Examination of the chest;

• Mammography;

• Examination of limb and foot bones

< 0,1

1 per 1 000 000

Several days

Average doses

• Fluorography of the chest;

• Research of the spinal column;

• Examination of the gastric cavity

1 – 5

1 per 10 000

From several months to several years

High doses

• CT of the head and neck;

• CT of the chest;

• Radionuclide diagnostics;

• Angiography

5 – 20

1 per 2 000

From two to several years

Do doses received in X-ray diagnostics comply with the table ranges?

Not always. The actual dose received by the patient depends on many factors: the technical condition of equipment, qualification of the medical staff, features of examination, etc. One way or another, medical staff should always remember that any X-ray diagnostic procedure should be conducted with as low dose load as possible. Sufficient quality of X-ray images can be achieved through the use of up-to-date equipment, which eliminates the need for duplication of the same type of diagnostic procedures and which causes less harm to the human body.

Why mammography is not recommended for young women as a screening?

Mammography is not an effective method for the screening of asymptomatic young women (up to 40 years old) to detect breast cancer. Mammography screening may by appropriate for some women in high-risk groups. For example, for women whose close relatives had breast cancer at a young age or with some other clinical signs. Screening for these women is justified in terms of achieving the obvious benefit from the medical exposure taking into account the increased risk of breast cancer when being older.

Is it permitted for a pregnant woman to undergo X-ray diagnostics?

If necessary, a pregnant woman can undergo X-ray examination of the head, legs, neck, shoulders and chest with modern equipment. All other procedures should be well justified and planned for the embryo or fetus to receive the lowest possible dose.

Women must notify medical staff about pregnancy (probable pregnancy) when they need an X-ray examination of the abdominal cavity and pelvis. Pregnant women should obligatory consult with a physician during procedures with relatively high exposure doses.

Is it permitted for children to undergo X-ray diagnostics?

The organs and systems of children body are more sensitive to radiation than those of adults. Therefore, it is better to use technologies without radiation for children diagnostics. X-ray examination of a child is reasonable only in the event that it is impossible to establish a diagnosis otherwise and this poses a danger for the life of a child.

Are there alternatives to X-ray diagnostics?

Yes. Despite the fact that the risk of single X-ray examination is rather low, it is possible to minimize it by the alternative technologies. One of such alternatives is ultrasound diagnostics and magnetic resonance imaging (MRI). However, sometimes there are cases where these types of examination are not enough to establish a diagnosis.

Memo to the patient undergoing X-ray examination

Medical staff is obliged to provide the patient with individual protective means to reduce negative impact of X-ray. Such individual protective means include: a protective tunnel for small children; dental apron for both children and adults; shield for protection of gonads (testicles, ovaries); collar to protect the thyroid glands; sets of plates to protect exposed areas.

Data on effective doses received by the patient shall be registered by the radiologist in the dose record sheet or in the computer accounting system label. After that, the letter or the label shall be included into the patient’s medical card. Medical institutions are required to store such data for 50 years.

If the patient wants to understand the degree of radiation during a year, it is necessary to take care several years or several decades before of the radiation passport and present it during each medical or diagnostic procedure.