Last Updated on November 27, 2025 by Bilal Hasdemir

Nearly 2 million PET scans are done every year in the United States. They are key in diagnosing and managing many health issues.

Getting ready for a PET scan is more than just showing up. It means following dietary restrictions and managing medications carefully. This is to get accurate results.

It’s important to know what to wear, what to eat, and which medications to avoid. This knowledge is key for a good PET scan.

Key Takeaways

• Understand the importance of following pre-PET scan instructions.
• Learn about dietary restrictions required for a PET scan.
• Discover which medications may interfere with PET scan results.
• Find out what to wear and what to avoid wearing during a PET scan.
• Gain insights into the PET scan preparation process.

What Is A PET Scan And How Does It Work?

A PET scan, or Positron Emission Tomography scan, is a high-tech medical imaging method. It helps doctors find and treat some diseases. It uses a radioactive tracer to show where the body’s metabolic processes are happening.

Definition and Purpose of PET Scans

PET scans give detailed info about the body’s internal functions, like metabolic activity. They are used to find and track diseases like cancer, neurological issues, and heart problems.

The main goal of a PET scan is to help doctors:

• Find diseases early
• Track how a disease grows
• See if treatments are working
• Spot areas where the body isn’t working right

The Science Behind PET Imaging

PET imaging detects energy from a radioactive tracer injected into the body. This tracer goes to areas with high activity, like growing cancer cells. The PET scanner then picks up these signals, making detailed images of the body’s inner workings.

The science of PET imaging is simple. It’s based on the fact that sick tissues have different metabolic rates than healthy ones. By showing these differences, PET scans help doctors diagnose and plan treatments.

Differences Between PET, CT, and PET-CT Scans

PET scans look at metabolic activity, while CT scans show detailed body structures. A PET-CT scan combines both, giving a full view of the body’s metabolic and anatomical details.

The main differences are:

1. PET scans: Focus on metabolic activity
2. CT scans: Show detailed body structures
3. PET-CT scans: Offer a complete view of both metabolic and anatomical aspects

Knowing the differences between these scans is key to picking the right one for a patient’s needs.

Preparing For Your PET Scan: An Overview

To get the most out of your PET scan, it’s vital to follow the preparation guidelines provided by your healthcare provider. Proper preparation ensures that the scan produces accurate and reliable images. These images are key for diagnosis and treatment planning.

Timeline For PET Scan Preparation

The preparation timeline for a PET scan can vary. Generally, patients are advised to start preparing 24 to 48 hours before the scan. This may include dietary restrictions, adjustments to medication, and other lifestyle changes.

It’s essential to follow the specific instructions given by your healthcare provider. They may have particular requirements based on your medical history and the type of PET scan you’re undergoing.

Communication With Your Healthcare Provider

Effective communication with your healthcare provider is critical in preparing for a PET scan. Be sure to inform them about any medications you’re currently taking, as well as any allergies or sensitivities you may have.

Your healthcare provider will give you detailed instructions on how to prepare for your scan. If you have any questions or concerns, don’t hesitate to reach out to them for clarification.

What To Bring To Your Appointment

On the day of your PET scan, it’s a good idea to bring any relevant medical records. Also, bring a list of your current medications and any other information that your healthcare provider has requested.

Comfortable clothing and any necessary identification should also be brought to your appointment. Your healthcare provider will inform you if there’s anything specific you need to bring or wear.

Clothing Requirements For A PET Scan

When getting ready for a PET scan, knowing what to wear is key. The clothes you pick can affect the scan’s image quality.

Do You Leave Your Clothes On During The Procedure?

Patients are usually told to wear comfy clothes. But, they might need to switch to a hospital gown for the scan. This choice depends on the PET scan type and the hospital’s rules.

Always follow the exact instructions from your doctor or the PET scan center about what to wear. This ensures the best results.

Hospital Gowns vs. Personal Clothing

Often, patients are asked to wear a hospital gown for the scan. This is to avoid any interference from metal or thick clothes. But, some places might let you wear your own clothes if they’re okay.

What Type Of Clothing Is Recommended

If you can wear your own clothes, choose loose, comfy ones without metal. Stay away from clothes with metal zippers, buttons, or accessories. They could mess up the scan.

Metal Objects And Accessories To Remove

Whether you wear a hospital gown or your clothes, you’ll need to take off metal things. This includes jewelry, glasses, and clothes with metal parts.

By knowing and following these tips, you can make sure your PET scan goes well.

What To Wear To Your PET Scan Appointment

Choosing the right clothes for a PET scan is key for a good experience. The right outfit can greatly affect how you feel during the test.

Comfortable Clothing Options

Wear comfortable, loose clothing for your scan. This lets you move easily and stay relaxed. Tight clothes can be uncomfortable.

Wearing layers is a good idea. It helps you stay at a comfortable temperature in the scanning room. Being too hot or cold can be distracting.

Temperature Considerations In The Scanning Room

The scanning room’s temperature can change. Wearing layers helps you stay comfortable. It’s important for your comfort during the test.

The room might be cooler than other parts of the facility. Being ready for this can help you avoid discomfort.

Clothing Items To Avoid Completely

There are clothes you should not wear to your PET scan. Metal objects and accessories can mess with the scan. This includes jewelry, belts with metal buckles, and clothes with metal parts.

• Avoid clothes with metal zippers or buttons.
• Take off any jewelry or accessories with metal.
• Choose clothes without metal for a smooth scan.

Dietary Restrictions Before A PET Scan

Before a PET scan, knowing what to eat is key. The right diet helps make sure the scan works well. This ensures the results are clear and useful.

Fasting Requirements And Duration

Fasting is a big part of getting ready for a PET scan. You need to fast for a while before the scan. This helps the body absorb the radiotracer right.

General Guidelines:

• Fast for 4-6 hours before the scan for most PET scans.
• Avoid any food or drink with calories during fasting.
• Water is usually okay, but check with your doctor first.

Foods To Avoid Before Your Scan

Some foods can mess with your PET scan results. Foods with a lot of sugar, caffeine, and certain nutrients can be bad. They can change how the radiotracer works.

Foods to Avoid:

1. Sugary foods and drinks.
2. Caffeine in any form.
3. High-fat foods.

Recommended Diet For 24-48 Hours Prior

In the 24 to 48 hours before your PET scan, eat a special diet. A diet low in carbs and sugars is best.

“A low-carb, high-fat diet can help improve the quality of PET scan images by reducing glucose levels in the body,” says a leading nuclear medicine specialist.

Recommended Foods:

• Lean proteins.
• Vegetables.
• Nuts and seeds.

Following these dietary tips helps make sure your PET scan results are good. This gives your healthcare team the info they need to help you.

Hydration Guidelines: What Can You Drink?

When getting ready for a PET scan, knowing the hydration rules is key. It’s important to drink the right amount of water and avoid certain drinks.

Water Consumption Rules

Mostly, doctors tell patients to drink water before a PET scan. Water is safe and won’t mess up the scan results. But, always listen to what your doctor says about drinking fluids.

“Drinking enough water helps spread the radiotracer,” says, a nuclear medicine expert. “Drink water as your doctor tells you to.”

Beverages To Avoid

While water is okay, some drinks are not. Caffeine in coffee and tea might be off-limits because it could mess with the scan. Also, sugary and high-calorie drinks are not recommended.

• Coffee and tea (due to caffeine)
• Sugary drinks (e.g., soda, sports drinks)
• High-calorie beverages

Special Instructions For Diabetic Patients

For people with diabetes, managing drinks before a PET scan is tricky. Talk to your doctor about your diabetes plan and how it might change before the scan. Some might need to adjust their fluid or medicine.

By following the hydration rules, you help make sure your PET scan is accurate. Always do what your healthcare provider tells you.

Medications To Avoid Before PET Scan

Before getting a PET scan, it’s key to know which medicines might mess with the results. Some drugs can change how the scan works, so telling your doctor about your meds is important.

Common Medications That Interfere With PET Results

Some medicines can change where the scan’s special dye goes. This can make the scan not show the right things. Here are some common ones to watch out for:

• Diabetes medications: Some diabetes meds, like those that change blood sugar, might need to be changed or stopped.
• Stimulants and sedatives: These can change how your body works, which might mess with the scan’s results.
• Certain antidepressants: Some antidepressants can change how the brain works, which might be important for brain scans.

Timing Of Medication Adjustments

When to change your meds is important and depends on the medicine and the scan. Usually, you should:

1. Tell your doctor about all the medicines you take.
2. Follow their advice on when to stop or change your meds before the scan.
3. Know that some meds might need to be stopped 24 to 48 hours before the scan.

Special Considerations For Chronic Medications

For people on long-term meds, there are special things to think about. It’s important to:

• Talk to your doctor about managing your chronic conditions before the scan.
• Understand that some long-term meds might not need to be stopped but might need to be adjusted.
• Know that some chronic conditions might need special prep or care before the scan.

Knowing which meds to avoid or adjust before a PET scan helps make sure your scan is accurate and reliable.

Can You Take Tylenol Or Other Pain Relievers?

When getting ready for a PET scan, knowing about pain relievers like Tylenol is key. You might need to manage pain but also avoid medicines that could mess up your scan results.

Safe Pain Management Options

Always talk to your doctor about your pain plan before a PET scan. Tylenol (acetaminophen) is usually okay, but check with your doctor first. Some pain meds might mess with the scan or the tracer used.

Make sure to discuss how often and when you take your pain meds with your doctor. They might suggest changing your schedule to avoid any issues with the scan.

When To Consult Your Doctor About Pain Medication

Before taking any pain meds, including Tylenol, for a PET scan, talk to your doctor. They’ll look at your health, pain, and meds to give you the best advice.

Your doctor will think about the PET scan type, your health history, and other meds you’re on. This helps them find the best way to handle your pain.

Alternative Pain Management Strategies

In some cases, your doctor might suggest other ways to manage pain before a PET scan. This could be deep breathing, meditation, or other non-medical methods.

By working with your doctor, you can find a safe and effective pain plan. This ensures you’re comfortable while getting ready for your PET scan.

Physical Activity Restrictions Before A PET Scan

Before a PET scan, it’s key to limit physical activity. This ensures the scan’s accuracy. Exercise can change how the tracer is distributed, affecting the scan’s results.

Why Exercise Should Be Limited

Exercise boosts blood flow and changes tissue metabolism. This can alter the tracer’s uptake. Limiting physical activity ensures the tracer is distributed correctly.

For example, intense exercise increases glucose uptake in muscles. This can mess with the tracer’s distribution if the scan uses a glucose-based tracer.

Recommended Rest Period

Avoid strenuous exercise for at least 24 hours before your PET scan. This lets your body rest, ensuring the tracer is distributed accurately.

Patients should keep up with normal daily activities but skip vigorous exercise. This avoids fatigue or discomfort.

Daily Activities To Avoid

Here are some activities to avoid before your PET scan:

• Strenuous exercise, such as running or weightlifting
• High-intensity interval training (HIIT)
• Long-distance cycling or other aerobic activities

Staying away from these activities ensures your PET scan results are accurate and reliable.

The Day Before Your PET Scan: A Checklist

The day before your PET scan is very important. It’s a time to follow certain guidelines to get the best results.

Diet And Hydration Reminders

It’s key to stick to the diet your doctor tells you. You should avoid foods high in sugar and fast for a while before the scan.

• Drink lots of water to stay hydrated.
• Stay away from drinks with sugar or caffeine.
• Listen to any special diet advice from your doctor.

Medication Management

Managing your medications is very important. Some can affect the PET scan results.

1. Check with your healthcare provider about your medications.
2. Change your medication schedule if your doctor says so.
3. Tell your doctor about any supplements or vitamins you take.

Rest And Activity Guidelines

Getting enough rest and avoiding hard activities is key. It helps your body be ready for the scan.

• Try to sleep well.
• Don’t do heavy exercise or hard activities.
• Don’t take too many stimulants that can keep you awake.

Personal Hygiene Considerations

Keeping clean is important, but there are things to remember.

• Don’t use lotions, creams, or perfumes that could mess with the scan.
• Take a shower or bath as usual, but don’t use any products on your skin.
• Wear loose, comfy clothes.

By following this checklist, you can make sure your PET scan goes well. And the results will be accurate.

What Happens During A PET Scan Procedure

Knowing what happens during a PET scan can make you feel less anxious. A PET scan is a detailed imaging test. It helps doctors find and manage different health issues.

Arrival And Check-in Process

When you arrive, you’ll check in at the reception desk. You might need to show your ID. It’s important to be on time to avoid delays.

Key steps during check-in include:

• Verifying patient information
• Reviewing preparation instructions
• Signing consent forms

Radiotracer Administration

A radiotracer is given to you through an IV line. This tracer sends out positrons. These positrons help create detailed images of your body’s inside.

The radiotracer used depends on the type of PET scan:

• FDG (Fluorodeoxyglucose) for cancer, infection, and inflammation
• Other tracers for specific conditions, such as heart disease or neurological disorders

The Scanning Process

After getting the radiotracer, you’ll go into the PET scanner. It’s a big, doughnut-shaped machine. The scan usually takes 30 to 60 minutes.

During the scan:

1. The patient lies on a comfortable bed
2. The bed is slowly moved into the scanner
3. Images are captured as the radiotracer emits positrons

Duration And Positioning Requirements

PET scans usually last 30 to 60 minutes. You’ll need to stay very quiet and follow breathing instructions. This helps get clear images.

Positioning requirements include:

• Lying flat on the scanning bed
• Remaining very quiet during the scan
• Following technologist instructions

Understanding PET Scan Dye And Contrast Agents

PET scans use special tracers to see how the body works. These tracers, known as PET scan dye or contrast agents, help show how the body’s cells are working.

Types Of Tracers Used

The most common tracer is Fluorodeoxyglucose (FDG). It’s a sugar molecule with a radioactive tag. FDG goes to cells that use a lot of energy, like cancer cells. Other tracers are used for different needs, like checking the heart or brain.

The right tracer depends on what the doctor wants to check. For example, Fluorodopa looks at brain chemistry, and Sodium Fluoride helps see bones.

Potential Side Effects And Reactions

PET scan tracers are usually safe. But, like any medical test, there can be side effects. Rarely, some people might have an allergic reaction.

• Most side effects are mild, like a little discomfort where the tracer was given.
• But, serious allergic reactions are very rare.

Post-Procedure Care Related To Contrast Agents

After a PET scan, drinking lots of water is important. Drinking water helps get rid of the tracer and can prevent side effects.

Most people can go back to their usual activities right after. But, some might need to avoid being close to pregnant women or young kids for a bit.

Special Considerations For Cancer Patients

For cancer patients, getting ready for a PET scan is more than just following basic steps. Their unique situation and ongoing treatments require a customized approach. This ensures the scan is both accurate and safe.

Additional Preparation Requirements

Cancer patients often have to do more before a PET scan. They might need to change their medication, follow a special diet, and know how their treatments could affect the scan.

• Informing their healthcare provider about any recent cancer treatments
• Adjusting their medication as advised by their doctor
• Following specific dietary instructions

How Cancer Treatments May Affect Scan Preparation

Cancer treatments, like chemotherapy and radiation, can change how a patient prepares for a PET scan. For example, some treatments might affect blood sugar or interact with the PET scan’s radiotracer.

It’s vital for patients to talk about their treatment history with their healthcare provider. This helps make sure the PET scan preparation is adjusted as needed.

Communicating With Your Oncology Team

Talking well with the oncology team is key for cancer patients getting ready for a PET scan. They should tell their team about the scan and share any worries or questions.

“Clear communication between patients and their healthcare providers is key to ensuring that PET scans are conducted safely and effectively.”

– Medical Expert

PET Scan Frequency During Cancer Treatment

The number of PET scans during cancer treatment depends on the cancer type, its stage, and the treatment plan. Regular scans help track how well the treatment is working and spot any changes in the cancer.

Understanding these special needs helps cancer patients prepare better for their PET scans. This way, they get the most accurate and useful diagnostic results.

After Your PET Scan: What To Expect

After a PET scan, many patients wonder what comes next. The time after your scan is important. Knowing what to expect can ease any worries you might have.

Immediate Post-Scan Activities

Right after your PET scan, you can usually go back to your normal day unless told not to. It’s smart to have someone with you during the scan. This is because you might need to wait a bit to make sure you’re okay after the scan.

Drink lots of water to get rid of the radiotracer from your body. Your doctor will tell you what to do after the scan. Make sure to follow their advice.

Radiation Safety Considerations

The PET scan uses a small amount of radiation. Even though it’s safe, there are steps you can take to protect others. This is important for kids and pregnant women.

• Avoid being close to others for a few hours after the scan.
• Drink lots of fluids to get rid of the radiotracer.
• Go to the bathroom often to lower radiation exposure.

When To Resume Normal Activities

Most people can go back to their usual activities soon after the scan. But, it’s key to listen to your doctor’s advice. Some things might need to wait a bit.

Rest if you’re feeling tired after the scan. The scan can take a while, and fasting or special diets might make you feel weak.

Follow-up Appointment Information

Your doctor will set up a follow-up to talk about the scan results. This meeting is very important. It helps figure out what to do next in your treatment.

Don’t hesitate to ask questions during this meeting. You can ask about your results, more tests, or treatment plans. Your doctor is there to help you through this.

Conclusion

Getting ready for a pet scan is very important. It helps get accurate results. Several things can make the scanning process a success.

Before a pet scan, it’s key to follow some rules. You should wear clothes without metal and avoid certain foods and drinks. This can really help the scan’s quality.

Knowing what to do before a pet scan can also make you feel less anxious. By following the right steps, you help make the scan a success. This leads to a better diagnosis.

In conclusion, being well-informed and prepared is essential for a good pet scan. By following the advice in this article, you can make sure your pet scan goes smoothly and effectively.

FAQ