A PET (Positron emission tomography) is a diagnostic modality that takes images of the body helped by detection through radiation from the emission of positrons. A radioactive substance is given to the patient that emits tiny...
Introduction
A PET (Positron emission tomography) is a diagnostic modality that takes images of the body helped by detection through radiation from the emission of positrons. A radioactive substance is given to the patient that emits tiny particles called positrons.
There is a host of measures that need to be taken care of for the safety of the patient and ensuring accurate results from PET scans. The patient should inform the doctor about any allergies or adverse reactions to medicines. If a woman is pregnant or may be pregnant, it should be earnestly reported to the doctor and the team beforehand. All important belongings and jewelry should be left at home or in the facility locker room. If one is an out-patient, he or she should be carrying all the current medications.
Preparing for the PET scan
The doctor is in the best position to advise and prepare the patient for the PET scan. It includes a particular diet and strict adherence to it. A diet, which is low in carbohydrates, is considered best before a PET scan.
Twelve hours before the PET scan the physician is likely to ask the patient to follow a diet that is very low on low carbohydrates. One can eat meat, eggs, hard cheese, butter, tofu, and non-starchy vegetables.
Among foods that are a strict no include cereal, bread, milk, pasta, and other sugars. If the scan is fixed for the afternoon, the patient can have breakfast, but, it should be low on carbohydrate.
So, should you fast before the PET scan?
When there are six hours to the scan, then the patient should abstain from eating anything. But, one can drink water. The person should also have all the recent copies of CT scans and MRIs so that the team can evaluate them.
Foods that are allowed and prohibited before the PET scan
PET is an advanced nuclear medicine technique that uses Positron Emission Tomography (PET). When the diet before a PET scan is inappropriate, it can impact the glucose levels in the body giving inaccurate results. Hence, it is prohibited to eat just before the PET scan.
In a PET-CT scan, PET provides functional status and CT gives us the structural status of the organ or tissue through high-resolution imaging. This helps in the accurate assessment of diseases and subsequent treatment. For the scan, technicians administer radioactive tracers either intravenously or orally. It helps to locate the changes in organs and tissues at a molecular level.
What should the patient eat before the PET scan?
The patient can eat the prescribed diet by the doctor 24 hours before the visit to the PET scan center.
They can usually consume a diet that is protein-rich and low in carbohydrates. The diet is given below:
Protein-rich diet: Meat, fish, chicken, shellfish, nuts, crab, sunflower seeds, and eggs
Non-starchy vegetables: Broccoli, green beans, spinach, cabbage, cucumber, cauliflower, and mushrooms
In beverages: Diet soda or zero-calorie drinks
One should drink a sufficient amount of water to stay hydrated.
One should avoid the food mentioned below before the PET scan:
- Cereals
- Dry beans
- Pasta
- Sugar, honey, desserts, or candy
- Fruit and fruit juices
- Nutritional shakes or smoothies
- Alcohol, beer, wine
- Rice
- Bread
- Syrups and Ketchup
- Jams and jellies
- High-caffeine food like coffee or tea
- Milk or milk products
- Chewing gum, mints, or tobacco products
One should strictly not eat anything or drink juices six hours before the scan.
The procedure
Before the scan, the technician and the team will first verify the identification of the patient and the exam requested.
The patient will then complete a contrast screening form. The doctor may also advise the contrast be given to the patient, which is injected into the vein. It helps in defining the images better throughout the body.
If the radiologist thinks that it would be helpful under the circumstance, a small intravenous (IV) line will be placed in an arm vein. The contrast and the isotope will be injected through this line. The contrast will be excreted through the kidneys.
During the scan
The duration of the scan varies, but the average time required is about two hours.
The technician positions the patient on the examination table and gives instructions to be still or to hold their breath. The patient can ask questions to the technician during the process.
What precautions are necessary before a PET scan?
Precautions before a PET scan are mostly about eating and diet. Usually, the patient should not eat anything for six hours beforehand as mentioned above, but drinking water is allowed. Another important precaution is to avoid strenuous exercise for 24 hours before the scan. The patient should also wear loose, comfortable clothes for the scan.
Risk factors associated with PET scan
During these tests, the patient is exposed to a small amount of radiation. However, this is a low dose of radiation and has not been proven to cause any harm.
However, for children or individuals requiring multiple PET scans, CT scans, and X-rays, there may be a slight potential increase in the risk of developing cancer in the future.
Conclusion
So, we have seen that PET scans are typically conducted as an outpatient procedure, which means a patient won't be required to stay overnight in the hospital or facility. PET scans use positron emission tomography technology to create accurate and detailed 3-D images of the internal structures of the body. The patient should not eat for a lea six hours before the scan, but drinking water is allowed. One should wear loose and comfortable clothes for the scan and avoid doing strenuous exercise for 24 hours ahead of the scan.
FAQs
What is best to eat after a PET scan?
Once the PET scan is over, the patient is free to eat a variety of foods, some of which with very high protein. A high-protein diet and low in carbohydrates ensure that the blood sugar levels remain stable. So, one can eat turkey, duck, steak, chicken, cheese, fish, eggs, mushrooms, asparagus, and broccoli.
Are there any restrictions after a PET scan?
After your PET scan, the patient will have a very small amount of radioactive sugar in the body. So, to flush it out from the system it is advisable to drink plenty of water. Once the PET scan is over the patient doesn’t need to follow any special dietary restrictions or guidelines.
How many PET scans are safe in a lifetime?
Experts opine that there should be no more than three PET/CT scans covered after the first line of treatment. It may be harmful to patients on an individualized basis.
Can one eat bananas ahead of PET scan?
Fruits and Vegetables that should be avoided before a PET scan are all fruits, corn, potatoes, carrots, tomatoes, legumes (other beans), peas, veggie burgers, and squash. Dairy Products like milk, yogurt, and high-fat cheese should also be avoided.
Can you eat on the morning of a PET scan?
The patient should not eat or drink except water for at least six hours before the appointment time. They should even refrain from chewing gum, breath mints, hard candy, and tobacco products.
How long after a PET scan can I eat?
After the PET scan, the radiographer removes the cannula from the arm and the patient can go home and free to eat and drink normally. The radiation in the radioactive tracer is very low, but one should drink plenty of fluids after the scan so that it flushes the radiotracer out of the system.
What is the next step after a PET scan?
After the PET scan, one can resume normal activities immediately without any bar. The injection of the radioactive material used in the scan is not a cause of concern as there are no noticeable changes or drowsiness. Moreover, PET scan uses no sedative drugs or anesthesia during the procedure. The results are however not immediately available and may need some extra time for analysis and interpretation.
Should you avoid people after a PET scan?
A patient doesn’t have to restrict his or her activities after a PET/CT scan. Although a PET scan is conducted by injecting a radioactive substance, which may lead to radiation exposure in persons close by, the amount of radiation coming from the patient after the scan is very low.
Is PET scan cost-effective?
Studies conducted in parallel to randomized clinical trials have shown that PET scans are not only accurate in preoperative staging of non-small cell lung cancer (NSCLC), but they are also good for cost savings. These analyses conducted along with these trials have confirmed the value of utilizing PET scans in the management of NSCLC.
What happens if you eat sugar before a PET scan?
One should avoid eating and drinking beverages that contain sugar for at least 24 hours before the PET scan. This will ensure that the images come out in the best quality. It will also prevent rescheduling the scan due to blood sugar that is too high.
