What kind of check is PET / CT?Putuo experts answer for you →

As the incidence of tumors becomes higher and higher, everyone’s awareness of preventing tumors is getting stronger.During the diagnosis and treatment of tumors, doctors and patients are often mentioned at PET/CT.So, what is PET/CT?What is the difference between enhancement CT?What are the help of the diagnosis and treatment of tumors?What are the issues need to pay attention to before the inspection?Let’s understand together.

What is PET/CT?

PET/CT is an advanced medical imaging inspection technology. As the name suggests, PET/CT is PET+CT.Patients perform CT (anatomical structure) before a check -up process, and then PET (functional metabolism).CT can accurately determine the lesion and display its morphological structure. PET reflects its metabolic changes through the intake of the lesion.The PET/CT scanning equipment integrates the two technologies to display the functional metabolism and anatomical form of the lesion, that is, the PET/CT image is formed.

Compared with the common enhancement CT,

What are the advantages of PET/CT?

Enhanced CT is a comparison of a certain dose in the patient’s intravenous vein, and then CT examination is performed.Due to the different intake of the lesion and the surrounding tissue comparison agent, the degree of enhancement is different, which helps to find the lesion that the flat sweeping CT cannot find or the scope and nature of the lesion.

However, PET/CT commonly uses visual aids (18F-FDG) are glucose analogs of radioactive nuclear fluorine labels.Because most of the glucose of most malignant tumors is very strong, the intake of the visually (18F-FDG) is often higher than that of the surrounding tissue, so it can be displayed clearer in images.PET/CT and enhanced CT appearance principles are different. They have their own advantages in tumor diagnosis and treatment.

PET/CT examination, as an important means in the diagnosis and treatment of tumor, adopts multiple parts of the whole body, can fully reflect the distribution of primary lesions and metastatic lesions.The enhanced CT examination can only be used for local appearances, and has certain limitations in the diagnosis and treatment of tumor.

Pet/CT commonly uses an image (18F-FDG) generally does not have an allergic reaction, while some patients have an allergic reaction to enhanced CT comparison agents (mostly iodine-made agents).In addition, PET/CT inspection prices are more expensive and have not been included in the scope of medical insurance payment. Increasing CT’s relative inspection costs are low and belong to the scope of medical insurance payment.

In what circumstances,

Maybe you need to do PET/CT?

◆ Patients who have diagnosed malignant tumors can judge whether there are metastatic lesions in other parts of the body except the primary lesions, so as to guide the formulation of treatment plans;

◆ Discover lymph nodes or other organs in the body, such as lung, bone metastases, and find primary lesions through PET/CT;

◆ After the treatment of malignant tumors, follow -up review and efficacy assessment;

◆ Guide a malignant tumor lesions puncture biopsy;

◆ Assist high -risk population, such as pre -cancer lesions, family history of tumor family, and multiple tumor markers continue to rise and early screening.

Specially point out

PET-CT is not universal. It is still not ideal for the diagnosis of early, small lesions, and low-level malignant tumors. It is not sensitive to gastrointestinal lesions and brain tumors.Therefore, it is not recommended as a conventional physical examination method for screening tumors.

Before PET/CT check,

What are the problems after inspection?

1. Control blood sugar

As mentioned earlier, the principle of PET/CT examination is to use the sugar metabolism that is abnormally increased by malignant tumors. In the state of high blood sugar, the tumor tissue has decreased to the iconic agent, and the chance of fake negative results will increase.Therefore, whether or not patients with diabetes are controlled below 11mmol/L.After 10 pm the day before, the morning was fast, and the morning was empty, oral hypoglycemic or insulin was suspended.Before the injection of the imaging agent, the subject’s finger blood glucose test will also be performed.

2. Remove the "internal causes" and "external causes" of interference images as much as possible

In order to reduce the interference of the image, we need to remove the "internal causes" and "external causes" as much as possible.The diaphragm examination, the use of leukocyte drugs, and the women’s menstrual cycle will interfere with the image. When making an appointment, the nurse should be informed; 24 hours before the examination should avoid strenuous exercise, do not drink strong tea and coffee;There is no metal zipper on the clothing. Women should be replaced before the underwear inspection of steel rings. Metal accessories such as jewelry, fake teeth, keys, and mobile phones can be removed.

3. Drink plenty of water

During the waiting period of the injection and before checking, drinking water is very important. Moisturizing can promote the circulation of the body in the body, increase the removal of non -target tissue, reduce the patient’s radiation dose and the tracer concentration pseudohadow.Therefore, please bring a good water cup during inspection. There are hot water and toilets in the waiting area.After the examination, drinking plenty of water can accelerate the residual radioactive drugs from the body.

4. Other matters that need attention

Since the image of PET/CT is radioactive drugs, women who need to confirm whether they are pregnant before checking for childcare women; avoid close contact with pregnant women and infants on the day of examination.PET/CT takes 2-3 hours throughout the inspection process. Among them, the on-board inspection requires lying for 30 minutes. The elderly and weak people need family members to accompany them. Patients with severe illnesses need to consider whether they can persist as appropriate.

Finally, it is worth noting that PET/CT examination cannot completely replace CT, MR, ultrasound, and endoscopic examinations. Pathological diagnosis is still the gold standard for tumor diagnosis.The principle of PET-CT examination is that the image agent participates in glucose metabolism in the body, and some tumors with low metabolism with lower glucose are not good.High glucose metabolism is easy to cover the smaller intracranial lesions; some tumor lesions are small and exceed the limit of the device resolution, and may not be involved or visible.

about the author:

Ji Xiaowen, the attending physician of the Department of Nuclear Medicine, and a master’s degree, graduated from Shanghai Second Medical University, and a member of the third phase of the "Popular Popular Popularity" plan of Putuo District Central Hospital.He has been engaged in nuclear medicine for more than 10 years and is good at diagnosis of ECT and PET/CT image.Published 2 academic papers.Popular science is good at PET/CT check -related introduction.

Section introduction:

The Division of the Putuo District Central Hospital was established in 1975. It is a comprehensive department that integrates molecular imaging diagnosis, functional testing, nuclear therapy, and in vitro analysis diagnosis.At present, there are 2 chief physicians; 2 attending physicians; 1 deputy chief technician, 5 in charge of technicians; 2 technicians and 3 nurses.There is a molecular imaging diagnosis department and in vitro analysis diagnosis department.Equipped with various inspection instruments, including: Lianying PETCT, Siemens E.cam Duet SPECT, a dual -capable X -ray bone density detector, more than ten chemical emitting detection equipment, and one Ximenzi flow line.The department is currently the "Yangtze River Delta Nuclear Medicine and Molecular Imaging Specialist Alliance" unit, and the title of "Endogenic Analysis Laboratory Quality Management Demonstration Lab" was awarded by the Nuclear Medicine Branch of the Chinese Medical Association.

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