What is a pet ct examination?

PET-CT perfectly combines pet and CT. PET provides detailed molecular information, such as the function and metabolism of the lesion, while CT provides the precise anatomical location of the lesion. One imaging can obtain all the sectional images of the whole body, which is sensitive, accurate, specific and accurate, and can understand the overall situation of the whole body at a glance, so as to achieve the purpose of early detection of lesions and diagnosis of diseases. The appearance of PET-CT is another revolution in medical imaging, which has been recognized and widely concerned by the medical community and can be called "the crown of modern medical high technology".

PET-CT is the perfect integration of the most advanced PET scanner and advanced spiral CT equipment, which is mainly used for early detection and diagnosis of major diseases in tumor, brain, heart and other fields.

1 Features and advantages

1, morning

PET-CT can diagnose tumors and other diseases at an early stage. Because of the active metabolism of tumor cells, the ability to take up imaging agent is 2- 10 times that of normal cells, and obvious "light spots" are formed on the image, so hidden tiny lesions (more than 5mm) can be found before the early anatomical structure of the tumor changes.

2. Safety

Check for safety and non-invasiveness. Most of the nuclides used in the examination are basic elements or very similar nuclides that constitute human life, with a short half-life. The dose received is slightly higher than that of chest CT scan, which is safe, efficient and repeatable in a short time.

3, accurate

The test results are more accurate. Qualitative and quantitative analysis can provide valuable functional and metabolic information, and provide accurate anatomical information, which is helpful to determine and find the exact location of the tumor. The examination results are more accurate than simple PET or CT, especially improving the diagnostic ability of small lesions.

Step 4 be quick

Perform a quick general examination. Other imaging examinations scan selected parts of the body, while PET-CT scans the whole body (neck, chest, abdomen and pelvic cavity) in about 20 minutes, and can obtain cross-sectional, sagittal and coronal images of PET, CT and their fusion respectively, and can directly see the affected parts and conditions of the whole body lesions.

5, high cost performance

Tumors can be found early and their properties can be determined. It was found that the late treatment cost decreased by 1-5 times, and the survival time increased by 1-5 times or even 10 times. One examination can accurately judge whether most tumors are benign or malignant and whether they have metastasis, so as to avoid delaying disease diagnosis or making wrong treatment plans after multiple examinations; Can accurately stage the tumor, evaluate the therapeutic effect, and reduce unnecessary treatment methods and doses; It can accurately judge the tumor recurrence after tumor treatment. Although the cost of a single examination is slightly higher, it actually avoids unnecessary surgery, radiotherapy and chemotherapy and hospitalization, and the overall cost performance is outstanding.

2 adapt to the crowd

1, social elites are under great pressure and physical overdraft.

Top civil servants, corporate executives, artists and other elites, as the pillars of society and family, have great responsibilities, heavy work pressure, irregular daily life, many social activities, long-term overdraft, some diseases are in the incubation period, and it is too late to check after symptoms appear.

Medical experts suggest that social elites with high work pressure and heavy responsibilities should go to the hospital for physical examination on a regular basis, and it is best to do cancer prevention examination once a year, such as PET-CT examination, to eliminate major hidden dangers, maintain health and create greater value. At the same time, strengthen physical exercise, improve the body's immune system and adjust the law of life.

2. Long-term disease history

Because of long-term illness, such as hepatitis B and chronic atrophic gastritis, it is often controlled by drugs on weekdays. Such people need to pay special attention to physical examination, especially when the symptoms are getting worse.

Experts pointed out that people with a long history of chronic diseases should have regular PET-CT examinations to eliminate some aggravations and complications, so as to find them early and avoid greater losses.

3. People with a family history of cancer

Family history of cancer refers to the family history of cancer for several generations. According to scientific research, cancer is hereditary, especially common malignant tumors such as esophageal cancer, lung cancer, breast cancer, gastric cancer and intestinal cancer. If parents have such a medical history, their children are several times more likely to have the disease. Therefore, early detection and monitoring of people with family history of cancer is very necessary.

Experts believe that the family history of cancer is an important index to evaluate the risk of gene mutation and conduct reasonable examination. It is suggested that this group of people maintain a healthy lifestyle and form a good habit of regular PET-CT cancer screening.

4. Bad habits.

Long-term irregular work and rest, overeating, drinking and smoking, irregular bleeding in the lower body of middle-aged and elderly women, and no good hygiene habits; Often cough, expectoration, chest pain, blood in sputum, dyspnea and other symptoms on weekdays; Irregular stool, bloody stool, abdominal mass; Progressive emaciation, obvious weight loss, etc. All these situations need to attract people's attention. Through accurate examination and diagnosis, the probability of tumor occurrence can be reduced, or early detection and early treatment can be achieved.

3 function

The unique function of PET is based on metabolic imaging and quantitative analysis. Using short-lived nuclides such as 1 1C, 13N, 15O, 18F as tracers, it can not only quickly obtain multi-level tomographic images, three-dimensional quantitative results and three-dimensional whole-body scanning, but also dynamically observe metabolism at the molecular level. In recent years, PET has shown unique advantages in the diagnosis and treatment of tumor, coronary heart disease and brain diseases.

Four characteristics

PET/CT organically combines PET and CT (Computed Tomography), and uses the same examination table and the same image processing workstation to fuse PET and CT images, which can simultaneously display the pathophysiological changes and morphological structure of the lesions, and obviously improve the accuracy of diagnosis.

1.PET-CT can be used for early diagnosis and differential diagnosis of tumors, distinguishing whether tumors recur, staging and re-staging tumors, finding primary and metastatic tumors, guiding and determining the treatment plan of tumors, and evaluating the curative effect. Among tumor patients, a considerable number of patients changed their treatment plans because they were diagnosed by PET-CT. PET-CT can accurately evaluate the curative effect, adjust the treatment plan in time and avoid ineffective treatment. Generally speaking, the medical expenses are greatly saved and valuable treatment time is gained.

Secondly, PET-CT can accurately locate epileptic foci, and it is also a unique examination method to diagnose depression, Parkinson's disease, Alzheimer's disease and other diseases. The treatment of epilepsy is one of the top ten medical problems in the world, and the difficulty lies in the accurate location of epileptic focus. PET-CT solved this medical problem. Under the guidance of PET-CT, X-knife or γ-knife was used for treatment, and good therapeutic effect was achieved.

3.PET-CT is also a means of health examination. It can complete the whole body examination at one time, and can find tumors and heart and brain diseases that seriously endanger people's health at an early stage, so as to achieve the purpose of early treatment and disease-free prevention.

Fourthly, PET-CT can also evaluate the curative effect very well: after some treatments, such as surgery, radiotherapy and chemotherapy, PET-CT can judge whether the tumor has changed, whether the activity of cancer cells has decreased, and whether other parts of the body have expanded, thus judging the previous therapeutic effect. [ 1]

Modern medicine believes that most diseases are the result of imbalance of biochemical process in vivo, and PET-CT can dynamically and quantitatively observe biochemical changes at molecular level in vivo under physiological conditions. With the decryption of human genes, we will fundamentally understand the occurrence, development and prognosis of tumors, heart and brain diseases and various hereditary diseases that endanger human health, and hope to find an effective treatment plan fundamentally. PET-CT gene imaging is a "bridge" connecting clinical and basic gene research.

The following is an article recommended by the professor: Journal of Nuclear Medicine, Volume 46, Issue 3, Page 385.

Undoubtedly, the era of PET/CT has arrived. At present, for every four ECT machines sold, at least three are PET/CT featuring hardware fusion. However, since the clinical application of PET based on 18F-FDG imaging was put into routine commercial operation in the early 1990s, the development of PET technology has been tightly controlled by the nuclear medicine industry, and no one has touched other fields. In the past five years, PET technology, including the commercial manufacture of PET/CT, has developed rapidly. The advantages of PET/CT over special PET come from the perfect combination of two imaging technologies that provide structural information and functional information respectively. These advantages and the improvement of the ability to locate and characterize diseases have now been mastered by medical professionals, and their scope is far greater than that of nuclear medicine. In this case, some members of nuclear medicine-professional doctors-may be in danger of being eliminated. The reason is obvious. Just as PET/CT will replace special PET on a large scale, PET/CT equipped with diagnostic CT that can apply oral and interventional enhancers and has higher electric power will also replace single CT. Because many nuclear medicine doctors are not proficient in CT sectional anatomy, they can't interpret CT information in PET/CT professionally at present. However, if PET/CT examination only needs to stay at the primary level of attenuation correction and lesion location in 18F-FDG PET imaging, there is no need for diagnostic CT examination and formal interpretation of CT information. For radiologists who are not proficient in PET imaging, they face the opposite problem. In view of this, it is suggested that PET and CT should be interpreted by qualified doctors in their respective fields. However, in the long run, this proposal will not solve the problem. In order to ensure that patients undergoing PET/CT examination can get the best treatment, doctors engaged in this work must be equally proficient in PET and CT. The highest level of this comprehensive work requires doctors to use diagnostic CT imaging information and PET imaging information together when diagnosing patients. This goal can only be achieved by professionals who have received strict training in these two fields and reached a considerable level. Unfortunately, at present, the university education of nuclear medicine and radiology is not related to each other, and it cannot provide the experience and training needed to meet the above professional standards. The lack of such courses makes it impossible for patients and professionals to achieve their desired goals.

To correct this situation, we should start from two levels. At the level of university education, there must be courses with sufficient length and coverage so that residents can receive education and training in tomography and PET. In clinical practice, there must be sufficient and mixed continuing education and experience summary, so that practitioners can reach the same high level of diagnosis, interpretation and comprehensive ability in these two fields. For residents, it is necessary to evaluate and adjust the training and experience level provided by university courses to meet the requirements of PET and CT education in the new situation. For clinicians, it is necessary for relevant professional associations to discuss and establish specific measures for continuing education and experience summary, so as to improve and professionalize the qualifications of clinical practitioners of PET/CT and make them widely recognized and respected. These measures and approaches are being put into action, which will surely become the victory in the field of nuclear medicine and the gospel for patients.

PET-CT is by no means omnipotent, but it is definitely a revolutionary breakthrough in imaging technology, and it will play an increasingly important role in the clinical diagnosis and treatment of tumors!

5 medical prospects

In recent years, the number of PET/CT instruments in China has increased rapidly. By the end of August 2006, 54 sets of PET/CT equipment had been installed. At present, the existing problems are: uneven development and unreasonable allocation in various places; Lack of inspection guidelines and diagnosis and treatment norms for PET/CT; Scientific research lacks innovation, multi-center research results and summary reports of a large number of cases, and the research on health economics evaluation has just started; There is an obvious shortage of professionals in comprehensive imaging and radiopharmaceuticals, and the urgent need can be solved through continuing education.

PET/CT is mainly used for malignant tumor, which has become the main killer of people's health in China, but it is not uncommon for families with poor relatives to suffer from tumor. In fact, although PET/CT is a high-end equipment, it is very helpful for the diagnosis and treatment of patients, but a considerable number of patients have to give up using it because they can't afford the expensive examination fees. For this reason, except for a few of the above 54 centers, it is difficult for the annual inspection volume of 1 center to exceed 1500 person-times, so that most PET/CT and accelerators have not played a role. It can be expected that with the gradual maturity of PET/CT application, the clinical value of PET/CT will be recognized. Once the examination expenses of some diseases (such as some malignant tumors) are included in medical insurance, the demand for PET/CT examination will greatly increase and it will play a greater role in clinic.

6 principles

First, the basic principle of PET imaging

PET is the abbreviation of positron emission tomography. The clinical imaging process is as follows: the radionuclide emitting positron (such as F- 18) is labeled on the compound that can participate in the blood flow or metabolic process of human tissues, and the radionuclide labeled with positron compound is injected into the subject. Let the subjects conduct PET imaging in the effective field of vision of PET. The positron emitted by radionuclide moves about 65438±0mm in the body and then combines with the negative electron in the tissue to produce annihilation radiation. Two equal energies (5 1 1 KeV) are generated,

Gamma photons in the opposite direction. Because the two photons have different paths in the body, the time to reach the two detectors is also different. If the detection system detects two photons with an angle of 180 degrees (0.25 degrees) within a specified time window (generally 0- 15 US). That is, a coincidence event, the detector sends out a time pulse, the pulse processor turns the pulse into a square wave, and the coincidence circuit classifies the data and sends it to the workstation for image reconstruction. Images of cross-section, coronal plane and sagittal plane of various parts of human body can be obtained.

The main components of PET system include frame, ring detector, coincidence circuit, examination table and workstation. The detection system is the main part of the whole positron emission imaging system, and its blocking detection structure is beneficial to eliminate scattering and improve counting rate. Many block structures form a ring, and then dozens of rings form the whole detector. Each block structure consists of about 36 small bismuth germanate (BGO) crystals, followed by two (4) pairs of photomultiplier tubes (PMT) (see figure 1). BGO crystals convert high-energy photons into visible light. PMT converts optical signals into electrical signals, and then converts the electrical signals into time pulse signals. The coincidence circuit test between the probes in each layer judges the time coupling of the probe signals, eliminates the interference of other radiation sources, gives the position of positrons through calculation, and the computer completes the image reconstruction by using scattering, accidental coincidence signal correction and photon time-of-flight calculation. The reconstructed image improves the overall resolution of PET to about 2 mm

PET adopts coincidence detection technology for electronic collimation correction, which greatly reduces random coincidence events and backgrounds. The electron collimator has very high sensitivity (not affected by lead shielding) and resolution. In addition, the size of. BGO crystal is positively correlated with sensitivity. Block structure PET probe. Capable of 2D or 3D acquisition. In 2D acquisition, lead plates or tungsten plates are placed between rings to reduce the influence of scattering on image quality. In 2D image reconstruction, only counting in several adjacent rings (generally 2-3 rings) is calculated, which has high resolution and low counting rate. 3D data collection is different. The interval between rings is cancelled, and the coincidence calculation is carried out in all rings, which obviously improves the counting rate, but the scattering is serious, the image resolution is also low, and a lot of data operations are needed for data reorganization. Another important difference between these two acquisition methods is the different sensitivity. The sensitivity of 3D acquisition is the highest in the center of the field of view.

Second, the working principle of multi-slice spiral CT

The basic principle of CT is image reconstruction. According to the unequal absorption of various tissues (including normal tissues and abnormal tissues) in human body, the selected layer of human body is divided into many cubes (also called voxels). After X-rays pass through voxels, the measured density or gray value is called a pixel. When the X-ray beam passes through the selected slice, the detector receives the sum of attenuation values of voxels arranged in the direction of the X-ray beam after absorbing X-rays, which is a known value, and the X-ray attenuation values of voxels forming the total amount are unknown values. When the X-ray generator and detector move around the human body in an arc or a circle. Iterative method

Calculate the X-ray attenuation value of each voxel, reconstruct the image, and get the black-and-white images of different density tissues at this level.

Spiral CT breaks through the design of traditional CT, adopts slip ring technology, and connects power cables and some signal lines with different metal rings in the fixed frame. X-ray tube and detector move with sliding brush and metal ring wire. The tube and detector are not limited by the length of the cable, and continuously rotate at a constant speed along the long axis of the human body. The scanning bed advances synchronously and uniformly (the traditional CT scanning bed is stationary during the scanning process), and the scanning trajectory spirals forward, which can complete the volume scanning quickly and uninterruptedly.

Multi-slice spiral CT is characterized by multi-layer arrangement of detectors. It is the best combination of high speed and high spatial resolution. The wide detector of multi-slice spiral CT is made of high-efficiency solid rare earth ceramic materials. Each unit is only 0.5, 1 or 1.25 mm thick, and the photoelectric conversion efficiency of the thin-layer scanning detector is as high as 99%, which can continuously receive X-ray signals. The afterglow is short and the stability is good. Multi-slice spiral CT can complete large-scale volume scanning at high speed, with good image quality, fast imaging speed, high longitudinal resolution and good time resolution. It greatly broadens the application scope of CT.

Scope of use, compared with single-slice spiral CT. Collecting the same volume of data, the scanning time is greatly shortened, and one part can be scanned every 15 S without increasing the X-ray dose. The whole chest scan with a thickness of 3 mm can be completed within 5S; Using a large pitch p value and holding your breath for 20 S at a time can complete the whole body scan; Under the same layer thickness, the scanning range is increased by 4 times in the same time. The unit time coverage of scanning is obviously improved, the radiation dose received by patients is obviously reduced, and the service life of X-ray tube is obviously prolonged. At the same time, the amount of contrast agent is saved, the low contrast resolution and spatial resolution are improved, and the noise, artifact and hardening effect are obviously reduced. In addition, the width of X-ray cone beam can be automatically adjusted according to the needs of different layer thicknesses. The collimated X-ray beam is focused on a corresponding number of detectors, which are connected with four data acquisition systems (DAS) through electronic switches. Each DAS can collect a set of images independently, depending on the matching method between DAS and detector. Through electronic switching, images of 1, 2 or 4 layers can be selectively acquired, and the thickness of each layer can be freely selected (0.5, 1.0, 1.25 mm or 5, 10 mm). The collected data can be used for conventional image display and post-processing in the workstation to complete three-dimensional reconstruction, multi-level reconstruction and so on. And can be displayed in real time or near real time. In addition, different rotation angles and different color marks make the image more stereoscopic, intuitive and realistic. Virtual endoscopy and three-dimensional CT angiography technology are also more mature and fast.

3. Image fusion of PET-CT

The combination of PET and CT equipment with different imaging principles is not a simple addition of their functions. But on this basis, image fusion is carried out. The fused image not only has fine anatomical structure, but also has rich physiological and biochemical function information, which can provide quantitative and qualitative diagnosis basis for determining and finding the exact location of tumors and other lesions. X-rays can be used to correct the attenuation of nuclear medical images.

The core of PET-CT is fusion. Image fusion refers to matching the spatial position and spatial coordinates of images with the same or different imaging methods through certain transformation processing. The image fusion processing system uses the characteristics of their respective imaging methods to register and combine two images in space, and then synthesizes the image data into one image. The fusion of PET-CT on the same machine (also called hardware fusion and non-image registration) has the same positioning coordinate system, so the patient can acquire PET-CT on the same machine without changing the position during scanning, thus avoiding the error caused by the patient's displacement. The collected two images do not need to be aligned, transformed and registered, and the computer image fusion software can be conveniently carried out.

Accurate fusion of 2D and 3D, the fused image shows the human anatomical structure and metabolic activities of organs at the same time, which greatly simplifies the technical difficulties in the whole image fusion process, avoids complicated labeling methods and a lot of calculation after collection, solves the registration problem of time and space to a certain extent, and greatly improves the reliability of the image.

Due to Compton effect, scattering, accidental coincidence events, dead time and other attenuation factors, the collected data is inconsistent with the actual situation and the image quality is distorted. In order to get more realistic medical images, effective measures must be taken to correct them. The resolution of penetration image system obtained by isotope correction is generally 12 mm, while the resolution of X-ray penetration image system is about 1mm, and the amount of image information is much larger than that of isotope method. The attenuation correction of PET with CT image greatly improves the definition of PET image, and the image quality is obviously better than that of isotope penetration source correction (see Figure 2). The resolution is improved by more than 25%, the correction efficiency is improved by 30%, and the operation is simple. The corrected PET image and CT image are fused, and more information about the relationship between anatomical structure and physiological function is obtained after the information is complementary, which is of great clinical significance for the location of surgery and radiotherapy for tumor patients.

7 Clinical application

PET-CT provides more information about prediction and treatment than PET and CT alone. It surpasses the existing fields where PET and CT are used alone, and can complete all the functions of ultra-high-grade CT, complete whole-body CT scanning within 20 minutes, which is more than 60% higher than that of PET alone, and can also provide more accurate and faster images of myocardial and cerebral blood perfusion function than CT. Pet-CT fusion images can well describe the role of diseases in biochemical process, distinguish physiological and pathological uptake, detect the early symptoms of diseases before obtaining anatomical evidence, and even detect subclinical tumors smaller than 2 mm, thus providing the best treatment scheme and screening the most effective treatment drugs for correctly determining the planned target area of radiotherapy (combining clinical target area with biological target area), detecting drugs and radiotherapy effect during treatment. Anatomical localization and functional imaging of lesion site.

Specific application

1. Epilepsy location: accurately locate the epileptic focus in the brain, and provide the basis for surgical operation or gamma knife resection of epileptic focus;

2. Qualitative and recurrence judgment of brain tumor: benign and malignant characterization of brain tumor, determination of malignant glioma boundary, differentiation of radiation necrosis and recurrence after tumor treatment, selection of tumor biopsy site, etc.

3. Early diagnosis of dementia: early diagnosis and staging of Alzheimer's disease and its differentiation from other types of dementia such as vascular dementia.

4. Brain receptor research: brain receptor analysis of Parkinson's disease, diagnosis and treatment of the disease.

5. Cerebrovascular diseases: PET-CT can sensitively capture the changes of brain metabolism caused by ischemic attack, so it can be used for early diagnosis and localization of transient ischemic attack (TIA) and cerebral infarction, as well as curative effect evaluation and prognosis judgment.

6. Drug research: pharmacological evaluation and guidance of neuropsychiatric drugs, observation of cerebral glucose metabolism changes in patients with obsessive-compulsive disorder, etc. To provide preoperative basis and postoperative follow-up for stereotactic surgery.

7. Advanced physical examination: Early tumors can be cured, but most tumors are found in the middle and late stages, so the routine screening of tumors can not be ignored. PET-CT is simple, safe, comprehensive and accurate, and it is the best means of physical examination for people. [ 1]

8. Lung cancer examination: 70% of lung cancer has reached the middle and advanced stage when it is diagnosed, and the middle and advanced lung cancer has passed the best treatment period. Obviously, the most advanced imaging instrument that can detect lung cancer lesions at an early stage is PETCT. The ultra-high inhalation of PET-CT makes it possible to detect the micro-functional metabolism of human nervous system, which not only improves the clarity and specificity of lesions, but also greatly improves the detection ability and diagnostic rate of micro-lesions, making the location more accurate. [ 1]

Eight kinds of risks

In fact, the risk of PET-CT is often overlooked when it is extremely popular.

An appointment website vividly shows that the radiation amount of a PET-CT full-body scan is equivalent to two chest X-ray scans; It is equivalent to the natural radiation dose received by living at home for five years; It is equivalent to a round trip from Beijing to new york 100.

Ding Yong, director of the Department of Nuclear Medicine, 307 Hospital of the People's Liberation Army, gave a special explanation on the radiation dose of contrast agent used in PET-CT. He pointed out that the radiation produced by the effective dose of whole body scanning is about 10.5 millisieverts, which is only one tenth of the emergency exposure limit of 100 millisieverts in the Radiation Protection Regulations, and far below the value of non-random radiation damage.

However, a research report published in the Journal of Radiomedicine of the Radiological Society of North America in April 2009 stated that whole-body PET-CT scanning was accompanied by a large amount of radiation dose and cancer risk.

Professor Bai Lankang, director of the Department of Radiological Diagnosis at the University of Hong Kong, and other researchers have adopted three mainstream PET-CT instruments. The results show that the radiation dose is between 13-32 millisieverts, and the incidence of cancer related to PET-CT is 0.2%-0.8%. The younger the age, the greater the risk. Therefore, the researchers suggest that PET-CT examination should be carried out after sufficient clinical reasons, and measures should be taken to reduce the dose.

Professor Robert E. Reiman, from the radiation safety department of Duke University Medical Center in the United Kingdom, said in an interview with Southern Weekend, "It is recognized by the scientific community that the damage caused by radiation will accumulate with the increase of exposure to radiation. Therefore, every PET-CT examination will increase the risk and eventually bring significant radiation dose after a period of time. " Robert e Lehman emphasized that children will face greater risks.

However, few reservation websites actively suggest that people who have just finished PET-CT examination should be used as potential radioactive sources to avoid excessive contact with pregnant women and children in a short time. Therefore, after the examination, in addition to the above avoidance, patients should drink more water after returning home to facilitate urination, and flush the toilet several times when urinating, which can make the effective half-life shorter and decay faster.

Japan is one of the few countries to promote PET-CT physical examination, and it has also promoted the "healthy journey" project in China. Even so, the Japanese people's controversy over PET-CT physical examination is inevitable.

In addition to the risks, the effectiveness of PET-CT in early tumor detection is also controversial.

A chief physician in the Department of Gastroenterology and Oncology, Beijing Cancer Hospital pointed out that PET-CT has a blind spot in finding lesions in hollow organs (stomach, intestine, etc.). ), so it can't replace routine examinations such as gastroscopy and colonoscopy.

"PET-CT is very popular at present, and it is considered that tumors can be found earlier, and the diagnosis is malignant or benign. This is just wishful thinking. " Xian, chief radiologist of Tongren Hospital, said that at the recent 20 12 European Radiology Annual Conference, a multicenter study showed that PET-CT was not superior to CT or MRI in these two aspects.

In 20 1 1 year, Lin Hongwei, a tumor surgeon in the 306 Hospital of the People's Liberation Army, took the lead in publicly criticizing the abuse of PET-CT in Weibo. [2]

9 inspection process

1. Appointment registration: make an appointment by hotline or online appointment;

Second, medical history collection: please show all inspection reports, X-rays, CT, MRI or ultrasound;

Third, measure body weight and blood sugar: ensure that the examination can get the best effect;

Four. Injection: intravenous injection of imaging agent, different imaging agents are selected according to different inspection purposes;

Fifth, rest before inspection: the purpose is to distribute the developer throughout the body. Generally, PET-CT will have a special lounge;

Six, computer scanning: emptying urine before PET-CT examination; Go into battle lightly, without any ornaments;

Seven, image acquisition: computer fusion and comparison of PET and CT images;

Eight, experts read the film: in order to be responsible for the patient's examination results, experts met the next morning to discuss reading the film;

Report distribution: Generally, you can get the report within three working days. If there are any special circumstances, please explain them to the director in detail.