How dangerous is CT radiation and how often can such an examination be done?

How dangerous is CT radiation and how often can such an examination be done?

Use and Safety of CT Scans

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answers (6)

Answer 1
June, 2021

Good afternoon!

In the field of maxillofacial diagnostics, when performing an overview circular image of teeth or cone-beam computed tomography, the patient receives a low dose of radiation. Even if X-rays of the teeth were taken yesterday, today another study can be done.

If we take the total radiation exposure from CBCT, OPTG, TRG, then it will be about 70 μSv, provided that images are taken on modern devices. We would like to draw your attention to the fact that the dose that the patient receives during fluorography is approximately 400-600 μSv, which significantly exceeds the load during dental X-ray examination.

According to SanPin and NRB-99 to the population , i.e. practically healthy persons, who undergo X-ray examinations for prophylactic purposes, are allowed to receive radiation exposure of up to 1000 μSv per year. CBCT of two jaws - up to 50 μSv. Therefore, about 20 CBCTs can be done per year.

Answer 2
June, 2021

You can do a CT scan of the brain without strict restrictions. This is primarily due to the importance and urgency of research into brain pathologies. In addition, this organ is protected by bone tissue, due to which the negative effects of radiation are minimized. The same applies to the diagnosis of other bone structures.

How often can CT scan of the abdomen be done? In this case, the body receives the highest dose of radiation, so the number and frequency of such procedures is minimized as much as possible. It is recommended to repeat the procedure up to 3 times within 1 year.

How often can CT of the lungs be done? The radiation exposure in this case is lower than during the examination of the abdominal cavity, but it is still very high. The recommended frequency of CT diagnostics is no more than 4 times a year.

CT examinations performed:

Answer 3
June, 2021

Good afternoon! The computed tomography method is based on X-ray radiation. It is ionizing and damages cells. Despite this, the dose of radiation used in the study is relatively safe. In terms of its negative impact, it is less than certain electronic devices. Thanks to this, the examination with a computed tomograph can be completed after short periods of time.

At the same time, there are certain contraindications. For example, a CT scan cannot be done during pregnancy. Another contraindication is the patient's serious condition.

The main contraindications are associated with computed tomography with contrast. This type of examination is prescribed for a more detailed study of organs. It is often prescribed for the diagnosis of cancer.

Contraindications to CT with contrast are:

  • drug allergy;
  • some thyroid problems;
  • impaired renal function;
  • severe bronchial asthma;
  • arrhythmias that cannot be managed with medication (contraindication for CT with contrasting coronary arteries of the heart);
  • if treatment with radioactive iodine preparations is planned in the near future.

In addition, the examination cannot be performed if the patient's body weight is greater than that for which the tomograph is designed. It differs and differs depending on the type of scanner, manufacturer.

The frequency of examinations is determined by the attending physician. It depends on the patient's state of health, the type of examination, as well as on the technical characteristics of the computer tomograph. For example, the radiation power depends on the type of examination, as well as the clarity of the images.

You can read more about this type of examination by following the link

Answer 4
June, 2021

Hello !

Computed tomography (CT) is a highly informative, relatively safe, non-invasive and affordable research method. It is widely used in many branches of medicine, helping to diagnose various pathological processes in the body and carry out dynamic control. For oncologists, computed tomography is especially valuable , as it allows even very small tumors to be seen with a diameter of only a few millimeters. Thanks to the use of this method, doctors can timely find primary malignant formations, their metastases and relapses.

Of course, computed tomography is an irreplaceable technique if it is prescribed by a doctor and strictly according to indications. But its irrational and frequent use is considered unacceptable and can lead to undesirable consequences for a person. Since CT refers to X-ray examination methods, it carries radiation exposure. In particular, when performing one examination of the chest organs , the patient receives radiation equal to 11 millisieverts (mSv).

For an adult, the total annual radiation dose up to 50 mSv. In exceptional cases, for example, if the patient has an oncological pathology, it is allowed to increase this limit to 150 mSv. Going beyond this limit may have, albeit very small, but danger to human health and life. Therefore, if a patient undergoes many X-ray examinations, including CT scan, during a year or several years in a row, he should clearly monitor the received radiation dose. This parameter must be indicated in the conclusion of the study. Another thing is that exceeding these limits only slightly increases certain risks for the patient, and does not mean that something bad is guaranteed to happen to his health.

It is also desirable to maintain a interval of 2-3 months between repeat scans. Naturally, for medical reasons, for example, with lung cancer or severe pneumonia, these periods can be reduced. Sometimes, within one month, the patient undergoes so many X-ray examinations that in aggregate he receives an annual dose of radiation.

In some cases, the doctor may prohibit the patient from performing a computed tomography if there are justified reasons for this. The technique is contraindicated for pregnant women and children under 12 years of age.

Answer 5
June, 2021

CT of the chest ~ 7mSv

the annual limit of workers whose work is associated with radiation - 50mSv

The lowest annual dose that is guaranteed to increase the risk of cancer - 100mSv

Source (there are many interesting things) - translation of the chart from xkcd. xkcd, although it is an entertaining source, but I would classify it as a reliable scientific pop and trust almost completely.

Answer 6
June, 2021

During the examination, an estimate of the dose received is written.

Depending on the device and the type of examination, the dose may vary.

Roughly - the minimum equivalent of the order of several fluorographies.

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