I. Define the meaning of the “X” word.

administer: administration= назначать: x

detect: detection= обнаруживать: x

order: disorder= порядок: x

alter: alteration= изменять: x

local: localize= местный:x

cancer: cancerous= рак:x

short-lived: long-lived= кратковременный: x

seize: seizure= хватать: x

II. Find in the list the following parts of speech: a) nouns, b) adjectives, c) adverbs, d) verbs.

Emission, physiologic, emit, evaluate, responsive, surgery, scanner, multiple, permit, attach, commonly, appropriate, brightness, accumulate, restriction, plenty, exposure, affect, enhance.

III. Complete the sentences with the following words: are not responsive, are displayed, exposure, detection, radioactive, radiologist, colors, brightness, alterations.

1	PET images are based on the … of radiation from the emission of positrons.
2	PET scans detect diseases and disorders that … to medical therapy.
3	Images … on the monitor of a computer.
4	Cyclotron is a machine producing a … substance.
5	Different levels of tissue or organ function are represented by different … or degrees of … .
6	A specialist who has got a specialized training in nuclear medicine is called a … .
7	PET helps physicians to detect … in biochemical processes.
8	During the procedure of PET imaging patient’s radiation … is low.

IV. Read the text and entitle it.

Positron emission tomography, also called PET imaging or PET scan, is a diagnostic examination that involves the acquisition of physiologic images based on the detection of radiation from the emission of positrons. Positrons are tiny particles emitted from a radioactive substance administered to the patient. The subsequent images of the human body developed with this technique are used to evaluate a variety of diseases.

PET scans are used most often to detect cancer and to examine the effects of cancer therapy, heart diseases, brain tumors or seizure disorders that are not responsive to medical therapy and are therefore candidates for surgery.

The PET scanner has a hole in the middle and looks like a large doughnut. Within this machine are multiple rings of detectors that record the emission of energy from the radioactive substance in your body and permit an image of your body to be obtained. While lying on a cushioned examination table, you will be moved into the hole of the machine. The images are displayed on the monitor of a nearby computer, which is similar in appearance to the personal computer you may have at home.

Before the examination begins, a radioactive substance is produced in the machine called a cyclotron and attached, or tagged, to a natural body compound, most commonly glucose, but sometimes water or ammonia. Once this substance is administered to the patient, the radioactivity localizes in appropriate areas of the body and is detected by the PET scanner. Different colors or degrees of brightness on a PET image represent different levels of tissue or organ function. For example, because healthy tissue uses glucose for energy, it accumulates some of the tagged glucose, which will show up on the PET images. However, cancerous tissue, which uses more glucose than normal tissue, will accumulate more of a substance and appear brighter than normal tissue on the PET images.

The procedure may take 30 to 45 minutes. It must be done by a radiologist who has specialized in nuclear medicine and has substantial experience with PET. A radiologist who has specialized training in PET will interpret the images and forward a report to your referring physician. Usually, there are no restrictions on daily routine after the test, although you should drink plenty of fluids to flush the radioactive substance from your body. Because PET allows study of body function, it can help physicians detect alterations in biochemical processes that suggest disease before changes in anatomy are apparent with other imaging tests, such as CT or MRI. Because radioactivity is short-lived, your radiation exposure is low. The substance amount is so small that it does not affect the normal processes of the body.

Finally, the value of a PET scan is enhanced when it is a part of a larger diagnostic work-up. This often entails comparison of the PET scan with other imaging studies, such as CT or MRI.

V. Read the text and say which paragraph contains the information about some common uses of the procedure.

VI. Say whether the following statements are true or false.

1	PET imaging is based on the detection of radiation from emission of electrons.
2	PET scans are used to evaluate only heart disorders.
3	During the examination a patient is moved into the hole of the machine.
4	Similar colors on a PET image represent different levels of tissue.
5	The procedure must be done by a physician.
6	PET scan is usually a part of a larger diagnostic work.

VII. Match parts of the sentences.

1	Positrons are tiny particles	a	to the patient.
2	Within the PET scanner there are	b	radioactivity is short-lived.
3	Radioactive substance is administered	c	emitted from a radioactive substance.
4	There are no restrictions on a daily routine	d	after the test.
5	Your radiation exposure is low, because	e	multiple rings of detectors.

VIII. Give a short summary of text B.

Part C

I. Read the text and define its main idea.