Radiology

Standard radiology (radiography)

Standard radiology or radiography is the study of joints at bone level. As a first-line examination, radiography makes it possible to visualise specific parts of the human body (bones and certain organs) and detects fractures and osteoarthritis. It uses X-rays (high-frequency waves), which – when passing through the body – are absorbed by different structures (e.g. bones, soft tissues). On X-rays, bones will appear white, while soft tissue will appear grey.

Interventional radiology

Interventional radiology combines both radiology (using X-rays) and disciplines such as surgery, medical oncology and urology. The advantage of this new technique is to carry out minimally invasive, imaging-guided procedures to:

a) Stop bleeding (by plugging the bleeding vessel from the inside)

b) Destroy tumours

Interventional radiology uses percutaneous techniques that, using different types of probes and medical imaging (scanners, MRI, ultrasound), locate and reach the tumour. Then, depending on the chosen technique and probe, the tumour will either be burned from the inside (heat emitted by radiofrequencies or microwaves) or frozen to -80 °C (cryotherapy: the liquid injected by the probe will freeze the cancer cells, which will eventually burst)

Even some previously incurable tumours can now be treated with a new technique called radioembolisation, where radioactive particles are injected into the tumour and irradiated from the inside until it is destroyed.

c) Another very promising technique is to inject modified viruses into the tumour, which will then only attack the cancer cells. Naturally, the virus is modified in such a way that it cannot develop into healthy cells.

CT scan

The CT scanneris a device that rotates around the patient using an X-ray tube. Sensors scan all or part of the human body and provide data to reconstruct the image digitally. CT scans can also be used for biopsies, drainage and radiofrequency cancer treatments (interventional radiology: destruction of the tumour using heating or cooling).

For irradiation, only low doses are used and every precaution is taken to limit the exposure to X-rays in the area under examination to an absolute minimum. For example, a single image corresponds to the average natural (cosmic) exposure during a four-hour flight. However, for pregnant women, special precautions must be taken on a routine basis. This is why it is important to notify the medical team about any potential pregnancy.

Mammogram

Mammograms, recommended for all women between the ages of 50 and 75 years, are designed to detect abnormalities in breast tissue as early as possible, before they even cause clinical symptoms. This allows breast cancer to be detected, ruled out or diagnosed before it becomes palpable. This radiological examination has evolved considerably in recent years, therefore the doses given during the examination are extremely low. Mammograms are equipped with tomosynthesis, a technique allowing for sectional imaging, which improves the resolution of the image produced and facilitates the detection of any abnormality.

During the mammogram, which only lasts a few minutes, the patient will be accompanied by an experienced radiologist who will explain the procedure in detail and answer any questions she may have. For a so-called diagnostic examination, it is likely that the patient will undergo an ultrasound scan in addition to the mammogram.

The patient will receive the results of the mammogram by post within eight working days. The results will also be sent to the GP whose name was given on the health questionnaire. This is sufficient time for two experienced radiologists to analyse and interpret the mammogram in detail, so that no abnormalities are missed.

Most of the Swiss Medical Network’s radiology centres actively support and collaborate in breast cancer screening. These examinations are coordinated by screening centres or cantonal bodies (Swiss Cancer Screening).

Densitometry

Bone densitometry (or osteodensitometry or mineralometry) is a radiological technique that measures bone mineral density to determine bone strength. It thus makes it possible to:

• measure the amount of minerals in the bones (calcium)
• detect bone calcium deficiencies, such as osteopenia (early stage) or osteoporosis (advanced stage)
• assess the fracture risk
• check for bone loss

Sites measured are typically the lumbar spine, proximal femurs (hips and femoral necks) and sometimes forearms (radius). In rare cases, a full body measurement may also be taken. During the examination, using the same apparatus, lateral spine imaging (vertebral morphometry) is usually carried out in order to look for any spinal defects or compression fractures. Furthermore, it is important to be able to assess not just the amount of calcium in the bones (quantitative) but also its distribution (qualitative) by analysing vertebral microarchitecture.

This is done using a software programme that allows for a vertebral trabecular bone score to be calculated. Based on all these parameters and a targeted medical questionnaire, the 10-year fracture risk may be determined for all major osteoporotic fractures or hip fractures. These are essential factors in establishing when and which treatment should be put in place.     

Magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) is a technique that does not use X-rays. The device consists of a magnet characterised by its power (1, 1.5 or 3 Tesla) and an examination bed which glides down its centre. The examination creates images of the human body thanks to the hydrogen atoms it contains. In a strong magnetic field, all hydrogen atoms move towards this field. They are then excited by radiofrequency waves for a very short period of time. When the wave emission stops, the atoms return to the equilibrium state and the accumulated energy produces a signal that is recorded and processed as an image. Specific antennas according to the area studied are connected and used to collect the emitted signal. These signals are mathematically analysed to produce images.

According to the technique or sequences, MRI enables the morphology of the organs studied to be brought to light in a detailed way. It demonstrates an increased sensitivity in detecting different pathologies of the soft tissues, making vessels, cartilage and nerve pathways stand out. The acquisition of three-dimensional images allows for their reconstruction on all planes.

Ultrasound

This painless and non-radiation imaging technique allows a diagnosis to be made or a rapid intervention to be carried out alongside the patient. It can be repeated as often as necessary without any health risks. It is very useful in many fields of radiology (ENT, breasts, musculoskeletal system, blood vessels, liver, gall bladder, pancreas, kidneys, bladder and pelvis).

Technically, it is a beam of ultrasound whose frequency is adapted to the organ to be examined. This beam is reflected more or less depending on the anatomical structures it encounters. In turn, this allows for an image of the organ in question to be reconstructed. It is shown directly on the screen of the apparatus for an immediate and dynamic interpretation.

PET/CT examination (positron emission tomography)

A PET/CT scan is used for oncological, cardiological and neurological examinations and to investigate sources of infection. In oncology, this technique can be used to confirm the presence of a cancer. As the patient’s whole body is examined, it can also detect tumour cells present in other organs (metastasis). With the PET/CT scan, quantitative values can be obtained and used to track tumour cells in order to determine if a treatment is working and evaluate if the cancer is improving.

From a therapeutic point of view, nuclear medicine uses radioactive pharmaceuticals to destroy diseased cells. A pre-treatment scintigraphy or PET/CT scan ensures the radiation correctly targets the diseased cells. Afterwards, the patient is administered radioactive pharmaceuticals that are specific to the cells that need to be destroyed.

Scintigraphy

The device records the gamma rays emitted by the patient to create functional images. Activity curves can be generated, for example to map kidney function or compare the activity of a body part on the left with a body part on the right. This is often used to examine stress fractures or bone disorders.

Two radioactive tracers are used to examine the lungs; one is inhaled and the other injected. This technique is used to explore lung function before an operation, in cooperation with a pulmonologist, and to detect pulmonary embolisms.

To confirm a diagnosis of Parkinson’s disease, a cerebral scintigraphy scan may be carried out at the request of a neurologist.

In endocrinology, scintigraphy can be carried out on the thyroid or parathyroid glands. This is the preferred examination for hormonal issues, or to investigate thyroid or parathyroid nodules.

In the case of symptoms that can suggest coronary artery disease (feelings of suffocation, chest pain, shortness of breath), cardiac scintigraphy is indicated. For this examination, a cardiac stress test is carried out with a cardiologist once the radiotracer is administered. The result shows the activity of the cardiac muscle and allows doctors to diagnose ischaemia or infarct.