Imaging

Many diseases affect the body by changing the anatomy, or structure, of some body part. The ability to"see" inside the body is very important for accurate diagnosis. Endoscopes are tubes with many fibreglass bundles that both transmit and collect light. These devices are inserted into the body through natural openings or incisions and provide pictures of tissues.

Ultrasound is sound energy at frequencies above the level of normal human hearing (that is above 20,000 hertz). Like X rays, ultrasound can present an image of body structures. Unlike X rays, however, well controlled ultrasound is harmless to tissue, and can be used repeatedly over a long time period.

Biological measurement with ultrasound is possible because its propagation, or transmission, varies with the mechanical properties of the tissue. Because various tissues absorb and scatter ultrasonic energy differently, ultrasound is often used for the detection of boundaries between various types of tissue, such as that between skin and muscle. Standard two-dimensional and prototype three-dimensional ultrasonic imaging can also detect changes in organs due to disease. Such changes include the buildup of atherosclerotic plaques in arteries or the development of tumours in the liver and other organs. Very high frequency ultrasound transducers are also mounted on the tips of catheters that can be inserted into specific blood vessels to obtain images of the insides of arteries. Furthermore, the constant motion of blood cells changes the frequency with which ultrasound is reflected off of them.

Thus, bioengineers can determine the speed of blood flow in any part of the body by measuring the frequency of reflected ultrasonic waves and converting this into colour-coded flow images.

In addition to standard X-ray devices, computed X-ray tomography (CT) scanners can provide greater detail using advanced radiographic techniques. Using multiple X-ray sources and detectors arranged in a hollow ring, high resolution images can be obtained of the body in cross section. By combining several cross-sectional images along the body's long axis (the line from head to foot), three-dimensional images can be generated.

Nuclear medicine procedures allow selective imaging of body regions that have absorbed specialized radioactive materials. By scanning over these regions with gamma-ray detectors, it is possible to generate an image based on the uptake or metabolism of certain "tagged" compounds, such as barium.

A newer technique involves the production of images using the magnetic properties of various elements. The element hydrogen, which is contained in all organic molecules, can be monitored with magnetic resonance imaging (MRI). The procedure begins by inserting the body into a large magnet. This causes the magnetic spin of the hydrogen nuclei to align with the magnet. Radiofrequency signals are then used to alter that spin alignment temporarily, producing a distinctive magnetic echo when the signal is discontinued. Emitted echoes from throughout the body can then be used to make images of certain organs based upon the hydrogen concentration of each organ.

Positron-emission tomography (PET) and single-photon-emission tomography (SPECT) utilize the release of high-energy gamma rays from radioactive particles transmitted through the body to form an image based on the location of the emitting source.

Exercise 28.Give Ukrainian equivalents to the following words and word combinations:

To transmit light, to collect light, fibreglass bundles, to affect the body, accurate diagnosis, to absorb, boundaries between various types of tissue, detect changes in organs, to scatter ultrasonic energy, to determine the speed of blood flow, ultrasound transducers, to be mounted on the tips of catheters, to obtain images, to be reflected off, to combine several cross-sectional images, advanced radiographic techniques, reflected ultrasonic waves, to determine the speed of blood flow, body's long axis, selective imaging, to generate an image, magnetic spin, to alter, emitted echoes, hydrogen nuclei, to insert into the body, incisions, to provide pictures of tissues, anatomy, ability to"see", to release energy, buildup, to align, “tagged” compounds, to vary, human hearing, harmless to tissues, propagation, transducer, incisions, endoscopes.

Exercise 29. Give English equivalents to the following words and word combinations:

Змінювати, розміри, поглинати енергію, представляти зображення, вирівнювати, виявляти пухлини, розсіювати, зосередження, збирати світло, ендоскоп, скловолокно, передавати хвилі, високочастотні звукові хвилі, точний діагноз, виміри, вражати тіло, відображати хвилі, людський слух, ядро, трьохвимірні зображення, радіографічні методи, атеросклеротична бляшка, різні типи тканин, компоненти.

Exercise 30. Answer the questions:

1. What ways do diseases affect the human body?

2. What is an endoscope?

3. What do endoscopes provide?

4. What can ultrasound present?

5. What are advantages of ultrasound?

6. What imaging can detect changes in organs due to disease?

7. What do CAT scanners provide?

8. What can clinicians obtain using multiple X-ray sources and detectors?

9. What do nuclear medicine procedures allow?

10. What do the magnetic properties of various components provide?

11. What does PET utilize to form an image based on the location of emitting source?

Exercise 31. Form plural of the following nouns.

Density, tissue, image, frequency, medium, graph, technique, ray, variety, body, property, issue, diagnosis, isotope, abnormality, cavity, slice, fluid, disease, inability, kidney, screen, emulsion, intrusion.

Exercise 32. Form nouns from the following verbs.

To detect, to swallow, to expand, to annihilate, to yield, to create, to reconstruct, to provide, to show, to arrange, to release, to absorb, to improve, to align, to involve, to locate, to utilize, to generate, to emit, to mount, to harm, to insert, to collect, to affect, to change, to transmit, to carry, to perform, to increase, to reduce, to treat, to use, to convert.

Exercise 33. Open the brackets and use the correct form in Passive Voice.

1. Detectors …..(to arrange) in a hollow ring.

2. The body …..(to affect) by many diseases changing the anatomy.

3. The element hydrogen …(to monitor) with magnetic resonance imaging (MRI).

4. Three-dimensional images ..(to generate) by combining several cross-sectional images along the body's long axis (the line from head to foot).

5. An image …(to base) on the location of the emitting source.

6. The element hydrogen…..(to contain) in all organic molecules.

7. Emitted echoes …(to use) to make images of certain organs.

8. The radioactive substance …(to produce) in a laboratory near the PET scanner.

9. PET …...(to do) by a radiologist who has specialized in nuclear medicine.

10. The release of energy …(to detect) by the PET scanner.

Exercise 34. Fill the gaps with a proper word.

structural	defining	vertebrae
verify	kidneys	are used
changes	analyze	parts
intervertebral	contrast material	be identified

CAT scans are performed to __________ the internal structures of various _________ of the body. This includes the head, where traumatic injuries, (such as blood clots or skull fractures), tumours, and infections can __ _______. In the spine, the bony structure of the __________ can be accurately defined, as can the anatomy of the ___________ discs and spinal cord. Occasionally, _______ ________ (an x-ray dye) is placed into the spinal fluid to further enhance the scan and the various ___________ relationships. CAT scans ____ ________in the chest to identify tumours, cysts, or infections that may be suspected on a chest x-ray. CAT scans of the abdomen are extremely helpful in __________ body organ anatomy, including visualizing the liver, gallbladder, pancreas, spleen, aorta, ____________, uterus, and ovaries. CAT scans in this area are used to ________ the presence or absence of tumours, infection, abnormal anatomy, or __________ of the body from trauma.

Exercise 35. Put all possible special questions to the sentences.

1. A CAT scan is used to define normal and abnormal structures in the body.

2. CAT scan procedure combines many x-ray images with the aid of a computer to generate cross-sectional views.

3. A large donut-shaped x-ray machine takes x-ray images at many different angles around the body.

4. These images are processed by a computer to produce cross-sectional pictures of the body.

5. Contrast material may be injected intravenously.

6. The technique is painless and can provide extremely accurate images of body structures.

7. Contrast material (an x-ray dye) is placed into the spinal fluid to further enhance the scan.

8. Many of these procedures are minimally invasive and have markedly decreased the need to perform surgery to accomplish the same goal.

9. The amount of radiation a person receives during a CAT scan is minimal.

10. The actual procedure can take from a half an hour to an hour and a half.

11. All metallic materials and certain clothing around the body are removed because they can interfere with the clarity of the images.

12. Newer intravenous contrast agents have been developed, such as Isovue, which have nearly eliminated the complication.

13. Patients are placed on a movable table, and the table is slipped into the centre of a large donut-shaped machine.

14. The technologist directly watches the patient through an observation window during the procedure.

15. This significantly increases the clarity of the x-ray images.

16. CAT scans have vastly improved the ability of doctors to diagnose many diseases earlier in their course and with much less risk than previous methods.

Exercise 36. Retell the text.

UNIT 2

Exercise 1. Read and translate the text using the Glossary below the text.