An ultrasound will burn your organs

Ultrasound examination - instructions for patients

The ultrasound examination is particularly popular with parents-to-be, as it enables an initial picture of the unborn child. But ultrasound is also firmly anchored in many other medical sub-areas.

Many patients repeatedly ask the question about the importance and danger of modern ultrasound examinations. In the following, we will explain the effects of the ultrasound examination on the patient and explain the ban on 3D and 4D ultrasound from 2021.

Table of Contents

The importance of modern ultrasound

With around 500 devices per 1 million inhabitants, ultrasound devices are among the most widely used medical imaging technology in German medical practices and clinics. In classic ultrasound diagnostics, high-frequency sound impulses are generated, which penetrate the patient's body without damage and are reflected to different degrees at certain interfaces.

Thanks to constant further developments, precise information about the size, shape and exact location of organs (localization diagnostics) can now be made. Thanks to the Doppler method, analyzes of blood flow speeds are also possible (functional diagnostics). Pathological changes in the size of organs, cyst formations or accumulations of fluid can therefore be recognized just as much as vascular stenoses and septal defects.

Nowadays, ultrasound systems that have a certain degree of mobility are almost exclusively manufactured. Be it the compact design for rescue or home visit use or installation on a trolley for clinic wards: the trend is clearly towards miniaturization. In addition to the diagnostic, there are also therapeutic ultrasound devices.

In contrast to x-rays, for example, ultrasound devices produce real-time cross-sectional images of the patient's body. Above all, statements can be made about depth gradations. The fields of application of medical ultrasound are therefore broad. In addition to the medical ones, there are a number of cosmetic applications for ultrasound devices (micromassages, heat applications, stimulation of metabolic activities, etc.)

How dangerous is an ultrasound examination?

Ultrasound diagnostics, or sonography for short, is extremely popular in medicine. Because due to the non-invasive, painless treatment, but also because this procedure is not associated with any radiation exposure, sonography is the preferred imaging procedure for patients and doctors.

Treatment with an ultrasound therapy device can lead to both thermally and non-thermally induced side effects. These can sometimes lead to considerable physical damage, which is why safe and professional handling is essential. If all risk-minimizing measures have been taken, then ultrasound therapy can be seen as a basically harmless treatment method with few side effects.

The medical fields of application of diagnostic ultrasound decide which sound frequency has to be used. Not all organs can be examined with the same frequency: While the head area should only be examined with a frequency of no more than 3 MHz, the examination of the eyes allows up to 11 MHz. The following table is intended to give you an overview of the different frequency ranges of diagnostic ultrasound in their respective applications.

Ultrasound applicationFrequency range
head1 - 3 MHz
Prenatal care2 - 5.5 MHz
Abdominal area2.5-5.5 MHz
gynecology2.5 - 6 MHz
Pediatrics3 - 6.5 MHz
Thyroid and prostate3.5 - 7.5 MHz
Breast diagnostics3.5 - 8 MHz
peripheral vessels4.5-10.5 MHz
eyes7-11 MHz
Echocardiography2.5-5.5 MHz

Depending on the set frequency of the ultrasound, the sound waves penetrate the body tissue to different extents. At this point, however, medicine encounters a dilemma, because the penetration depth and the axial resolution are diametrically opposed to each other: This means that the axial resolution improves with increasing frequency, but the penetration depth decreases. Unfortunately, the only solution here is to find a compromise. The following table is intended to clarify the relationship between frequency range and resolution / penetration depth.

Sound frequencyresolutionPenetration depth
2 MHz1.8 mm20-25 cm
3.5 MHz1.3 mm15-18 cm
5 Mhz1 mm10-12 cm
7.5 MHz0.7 mm6 - 8 cm
10 MHz0.3 mm3 - 4 cm

How often can you have an ultrasound?

In principle, the ultrasound examination is considered to be risk-free and painless for the patient and the practice team. Even studies lasting more than 40 years cannot prove any danger from ultrasound, only a few side effects are known. As a rule, however, these only occur if the ultrasound therapy is used improperly.

The heat development in the sonicated tissue can lead to hyperemia, inflammatory reactions or even tissue necrosis, if used for too long or too intensively. In addition, heat-independent damage, such as in the case of so-called cavitation, can occur. The sonication causes gas bubbles to form, which lead to bleeding and injuries in the tissue.

Even if the medical use of ultrasound appears to be fundamentally harmless, a precautionary safety level is used in ultrasound therapy and especially in the area of ​​pregnancy care: the ALARA principle. This designation stands for “As low as reasonably achievable” and is intended to ensure that the sound power is kept as low as possible for the patient.

In general, ultrasound therapy should always be avoided if - e.g. in the case of acute infections - the use of heat is contraindicated. In addition, the uterus of pregnant women, the eyes or the central nervous system should never be exposed to sound. Treatment in the immediate vicinity of a joint replacement should also be avoided, as it could heat up unexpectedly.

Ultrasound soon banned for pregnant women

The all-clear right away: Even after many years of studies and intensive research in the field of sonography, real dangers from an ultrasound examination are not known today. Nevertheless, the use of ultrasound devices without medical relevance poses a potential risk.

Accordingly, 3D and 4D ultrasound for pregnant women is to be banned from 2021. The reason for the prohibition of 3D and 4D ultrasound during pregnancy is the new radiation protection ordinance, which came into force at the beginning of 2019. From January 1, 2021, this prohibits 3D and 4D ultrasound examinations without medical necessity.

The 3D / 4D ultrasound device can not only be purchased by trained doctors, but also by non-medical professionals. Non-medical companies that offer 3D and 4D sonography for unborn babies have also established themselves on the free health market. Experts warn against too frequent and amateurish use of ultrasound in unborn babies. The ban on 3D / 4D ultrasound results from this consideration, less from concerns about permanent damage or side effects.

Reasons for an ultrasound in pregnancy

The main purpose of the ultrasound examination during pregnancy is to determine whether the embryo is developing normally or whether there are any abnormalities. For this reason, the ultrasound is internationally part of the basic care during pregnancy. For example, heart defects in the unborn child are often discovered during pregnancy through the ultrasound examination.