When did the clinical application of CT machine begin?

CT is "computed tomography" or "computed tomography". The abbreviation of CT is the biggest breakthrough of X-ray diagnosis since Roentgen discovered X-ray in 1895, which is the product of the combination of computer control technology and X-ray inspection photography technology. CT was successfully developed by British physicist hounsfield in 197 1 year. It was first used for the diagnosis of brain diseases, and then extended to general examination in 1976. This is a great revolution of X-ray in radiology. China also introduced this new technology in the late 1970s. In a short period of 30 years, thousands of various types of CT machines have been installed in hospitals all over the country, even at the county and town levels. CT examination has become an indispensable equipment for medical diagnosis.

Edit the basic structure of this paragraph. X-ray tomography device and computer system. The former is mainly composed of a generator and a bulb for generating X-ray beams and a detector for receiving and detecting X-rays. The latter mainly includes data acquisition system, central processing system, tape drive, console and so on. In addition, the CT machine should also include image display, multiple cameras and other auxiliary equipment.

Basic knowledge and clinical application of CT machine

I. Generation of CT The full name of CT in Chinese is "X-ray computed tomography", which was invented by British engineers on the basis of previous research in 1967. The first head CT machine was successfully applied in the UK on 197 10.

1972, British Radiological Society and North American Radiological Society announced the birth of CT machine respectively. 1974, American engineers designed a whole-body CT machine, which opened a new era of imaging diagnostics.

1990, domestic whole-body CT machine D3 1 domestic, began to be widely used in domestic hospitals.

Second, the imaging principle and basic structure of CT machine 1, the imaging principle of CT machine is simply to scan the examination part along the long axis of human body by using pen-shaped or fan-shaped X-rays.

X-rays are received by the detector after passing through a certain layer of human tissue. Different densities of tissues have different absorption of X-rays. The higher the tissue density, the more X-rays absorbed and the weaker the signal received by the detector. The reduced X-rays are converted into electrical signals and input into an electronic computer. After the data is processed by electronic computer, the image of the whole process is finally displayed on the TV screen.

2.CT machine consists of four parts, 1, X-ray generator system (high voltage generator and X-ray tube); 2.x-ray detection system (detector, detection loop and analog-to-digital converter); 3. Computer systems (computers, disks and tapes, display devices, cameras); 4. Manipulate the control system.

Third, the emergence and development of CT machines The so-called "emergence" of CT machines refers to a sign of the development of CT machines.

The generation of CT machine is mainly divided into the relationship between C-ray tube and detector, the arrangement of detector number and the movement between them. In fact, the generation of ct machine can not fully reflect the performance of ct machine itself, but the performance of X-ray tube system, detector and computer operation speed is the main component that determines the performance of CT machine.

Generation 65438 +0:

The X-ray beam is in the shape of a straight pen, and the single or multiple detectors adopt a combination of linear scanning and rotary scanning, so the scanning speed is slow, which can be as long as 3-6 minutes. Head scan only.

The second generation:

There is no qualitative difference with 1 generation CT machine, except that X-rays are taken more, the number of detectors is increased to dozens, the scanning time is shortened to 10-90 seconds, and the cost is suitable for whole body scanning.

The third generation:

X-rays are fan-shaped beams, and hundreds of detectors are also fan-shaped. The scanning time is only 1-5 seconds. However, it has more reconstruction procedures, local magnification scanning, dynamic scanning, scanning photography and gas imaging. It is a practical machine with excellent performance, and its application is still not much.

The 4th generation spiral CT machine: basically the same as the 3rd generation. The detectors are arranged circumferentially around the scanning frame, and only the X-ray tube rotates. This machine has fast scanning speed, more information and clear images.

The fifth generation CT machine;

It is characterized by using electron beam tomography system instead of X-ray tube rotary tomography system, and the scanning time is 1/20 seconds, which opens up a new application field of CT.

Expensive.

The development direction of CT machine The number of rows of multi-row spiral CT detectors is quite low. Our hospital will buy four-row spiral CT, three-dimensional imaging, dislocation and coronal images next year.

Four, the basic terms of CT 1, scanning:

The X-ray tube rotates around the detected layer of human body and irradiates once.

2. Plain scan is the basic method of CT examination, which only depends on the natural difference of tissue density such as tissues, organs and lesions, and does not produce contrast agent. Abdominal examination often needs oral or iodine water washing, and it is also within the scope of plain scanning to distinguish gastrointestinal tissues and organs.

3. Enhanced scanning: an inspection method of scanning by intravenous injection of ionic or nonionic contrast agent. For some tissues and organs or lesions, it is difficult to distinguish them by plain scan because of their similar CT values. Enhanced scanning can increase the density of cardiovascular system, tissues and internal structures of lesions, which is beneficial to identify tissues and organs and some lesions and improve the diagnostic accuracy.

4.CT value indicates that the unit (relative value) of X-ray absorption in this part is water absorption value, X-ray absorption value of compact bone or calcification is+1000, and air is-1000. This absorption system is called CT value. The higher the density of a substance, the greater the X-ray absorption, while the lower the density, the smaller the CT value and the greater the CT value.

5. Window position, indicating the center position of CT value; C6。 Window width: indicates the range W7 and thickness of CT value of the image, and the thickness of each layer in CT scanning, and the unit is mm 10 mm 5 mm 2 mm.

8, layer spacing:

The distance between slices in CT scanning is mm25 10209, and the density is equal: the scanned image is displayed based on a certain CT value.

10. Artifact: There are various non-existent image shapes in the ct scanning images, CT film marking and film reading methods in our hospital.

000007745— 1 Chinese pinyin name month/day/year s 1 04.5srlp+547w100a0+30v. Clinical application of CT examination1,the most suitable organs and tissues for CT examination are mainly brain and spinal cord, liver, spleen and so on.

2. The organs and tissues suitable for CT mainly include lung, mediastinum, head and neck, retroperitoneal pelvic cavity, spine and bones of limbs.

3.CT is not suitable for organs and tissues, mainly esophageal, stomach, small intestine, large intestine and other pipeline tissues. You can choose to transfer around.

Indications and limitations of brain CT examination 1. Brain CT examination has the advantages of relatively non-invasive, painless, rapid, safe and accurate, and almost all brain diseases and injuries have certain diagnostic value. These signs are as follows:

1) brain tumor:

CT can accurately show the location, size, cystic change, necrotic calcification bleeding, peripheral edema and number of tumors, and whether there is contrast and enhancement. It is suitable for occupying lesions such as glioma, meningioma metastasis, sellar region tumor and infratentorial tumor.

The detection rate of brain tumors is 85%-98%.

2) Cerebrovascular accident:

CT can diagnose subarachnoid hemorrhage caused by hypertensive cerebral hemorrhage, cerebral infarction, aneurysm or hemorrhage.

CT can diagnose the location, size, shape, range and degree of brain edema in the above diseases.

3) Craniocerebral trauma:

CT can diagnose and distinguish intracranial hemorrhage from brain contusion and laceration, subdural and epidural hematoma (acute, mild and slow), mild and severe craniocerebral injury, intracranial pressure and so on.

4) Degenerative brain pain:

CT can treat brain tissue degeneration caused by various reasons (injury, bleeding, ischemia, inflammation, poisoning, etc.). ). There are brain atrophy and ventricular system enlargement, which can provide valuable diagnostic basis, myelin loss.

5) Brain inflammation: It is of great significance for the diagnosis of intracranial inflammation, brain tuberculoma, tuberculous meningitis and CT, and indirectly suggests nonspecific inflammation of the brain.

6) Other brain diseases: congenital brain malformation and neonatal diseases. Such as brain development disorder, hypoplasia, congenital atresia of the middle and lateral foramen of the fourth ventricle, etc.

CT examination can provide diagnostic basis.

7) The observation of brain diseases after surgical treatment, the observation of curative effect after radiotherapy and drug treatment, and ct examination have certain reference significance.

2. The limitation of brain examination is 1), and it is easy to miss the diagnosis due to volume effect, such as posterior cranial fossa, saddle area and Heinz's dark area.

2) for cerebrovascular diseases. Which blood vessels, locations, numbers, collateral circulation, etc. cannot be accurately displayed by CT scanning.

3) Limitation of qualitative diagnosis. The qualitative diagnosis of brain tumors is only 70%-80%.

Indications and limitations of chest CT 1, mediastinum: mediastinal mass (differential in nature, neutral and solid), mediastinal lymph nodes (normal or pathological). Myasthenia gravis. You can learn about thymus or thymic hyperplasia.

2. Lung: The reason of enlarged hilum:

CT can find out whether it is physiological or pathological.

Lung: define the nature of lung lesions; B, tumor cells were found in the disease, but no lesions were found by X-ray or fiberoptic bronchoscopy; C, pleural effusion or pleural hypertrophy, affecting the lungs.

d、