Positron emission tomography, commonly known as PET scan, is an imaging test to diagnose diseases using radioactive material. It is a non-invasive technique that helps doctors detect tumours and diagnose heart disease, brain disorders and other conditions, at times in the early stages of the disease. In this blog, we will delve into the details of PET scans, understanding their types, purpose, procedures, and the insights they provide.

How does a PET scan work?

A PET scan uses a scanning machine and injects radioactive material. A minimal amount of radioactive material or glucose (sugar) is injected into the vein. The glucose is radiolabeled, and the scanner rotates around the body, imaging the brain's active parts where this radiolabeled glucose gives off energy in the body.

Based on the rate at which a tissue or cell takes up the sugar in the body indicates how active the tissue or cell is. For example, if a cancer cell is present in the body, it will need a lot of energy as it multiplies. Hence, it will consume a lot of glucose. These increased sugar levels in the specific area show up as bright hot spots in the scan, indicating the presence of a disease in those areas.

Types of PET scans

Brain PET scan: The primary goal of a Brain PET scan is to assess the metabolic activity of the brain, providing valuable information about its functioning and highlighting areas of abnormal activity. Some key purposes of PET scans include diagnosing neurological disorders. In the case of dementia, a PET scan helps in differentiating Alzheimer's disease from vascular dementia or other forms of cognitive impairment in detecting brain tumours and their evaluation, assessment of stroke, and epilepsy localisation for monitoring the response for the treatment.

F-18 Choline PET scan: This scan is primarily used in the field of oncology. The essential purpose of this imaging technique is to detect and evaluate prostate cancer. F-18 Choline is an effective radiotracer specifically used to image the prostate gland.
FDG - PET scan: The Fluorodeoxyglucose (FDG) PET scan's primary purpose is to provide valuable information about the metabolic status of cells, helping in the diagnosis, staging, and monitoring of various medical conditions such as the detection and stage of cancer, evaluation of tumours, neurological disorders, cardiac imaging, assessment of infection and inflammation, evaluation of fever of unknown origin (FUO)
DOTA PET CT scan: Gallium-68 DOTATATE, or the DOTA PET CT scan, is a tool for detecting and caring for Neuroendocrine Tumours. The DOTA PET CT scan is a sensitive technology that helps detect even the most minor lesions early. NETs have receptors for somatostatin, a hormone; unlike other cancers, they do not consume glucose. Thus, NETs are not detected on routine FDG-PET CT scans. The DOTA PET CT scan offers higher accuracy of NET detection and enhanced patient comfort due to lesser scan time.
Whole body PET scan: A whole-body PET scan is an imaging technique designed to examine the entire body to detect, evaluate, and monitor various medical conditions. Its primary purpose is to assess metabolic activity in tissues and organs. The valuable information obtained from whole-body PET scans helps diagnose and manage diseases.

PSMA PET scan: Prostate-Specific Membrane Antigen Positron Emission Tomography or PSMA PET scan is an advanced imaging method. It combines PET and computed tomography (CT) technologies that target the prostate-specific membrane antigen (PSMA) through a radiotracer. PSMA PET scan helps in detecting, staging, and monitoring prostate cancer. It provides detailed and sensitive imaging of prostate cancer lesions, including primary tumours, lymph node involvement, and distant metastases.
DOPA brain PET scan: DOPA PET CT scan is a molecular imaging. The primary purpose of this scan is to diagnose and manage neurodegenerative diseases such as Parkinson's disease, Alzheimer's changes and dementia. This technique helps in detecting early Parkinson's disease.

Need For PET Scan

PET scan is an advanced imaging procedure. It offers insights into vital physiological functions, including blood flow, oxygen use, and glucose metabolism. These scans are non-invasive and provide a comprehensive assessment of organs and tissues, aiding in identifying areas that may not function optimally. Doctors ask for PET scans when:

Cancer Detection: Healthcare professionals recommend a PET scan to detect and diagnose cancerous lesions. The scan provides information on abnormal metabolic patterns, giving crucial data to the diagnostic process.
Assess Metastasis: Doctors not only ask for PET scans for detection but when a person is already diagnosed with cancer, PET scans are used throughout treatment. They help the doctors to assess metastasis, treatment effectiveness, potential recurrence, and overall prognosis, giving information and understanding of the progression of the disease.
Heart-Related Issues: Doctors may also need a PET scan for heart-related issues. It helps them to assess the aftermath of a heart attack in different areas of the heart. These scans reveal the regions of the heart muscle that could benefit from interventions like angioplasty or coronary artery bypass surgery.
Neurological Issues: A PET scan is also needed for people experiencing neurological symptoms. It helps to evaluate potential abnormalities in the brain. They aid in revealing the tumours, assessing seizures, and evaluating conditions affecting the central nervous system.
Real-time Metabolic Information: PET scans are versatile tools in modern medicine, providing real-time metabolic information. Their ability to measure vital functions and identify abnormalities makes them invaluable for effective patient care and informed treatment decision-making.
Diagnostic Tool: PET scans serve as powerful diagnostic allies, offering a nuanced understanding of physiological functions and playing a crucial role in cancer diagnosis, treatment monitoring, cardiac evaluations, and neurological assessments.

How Do You Prepare For The PET Scan?

Going for a PET scan involves several essential steps to ensure accurate and reliable results. Here's what you need to know:

Discuss Your Medical History
Fasting Guidelines
Take It Easy
Blood Sugar Management (for Diabetics)
Stay Hydrated
Comfortable Clothing
Remove Jewelry and Accessories
Pregnancy and Breastfeeding Considerations

Results Of A PET Scan

When it comes to PET scan results, a normal one is like a clean bill of health. It means everything looks good – no issues with your organs' size, shape, or position, and the tracer hasn't collected any unusual spots.

However, abnormal results can mean a few things, depending on the area studied. It might point to cancer, infection, or a hiccup in how an organ does its job. These results are like red flags that signal your healthcare team to investigate further and determine your care's next steps.

Conclusion

To conclude, PET scans have revolutionised medical imaging. It helps to provide an in-depth understanding of how our bodies work on a metabolic level. These scans are gearing up to become even more crucial in spotting issues early, keeping tabs on treatments, and tailoring medicine to fit each person. Understanding the ins and outs of this diagnostic technology puts people in the driver's seat. It helps them make smart health choices and ensure medical interventions happen at the right time. It's a real team effort between healthcare heroes and proactive patients, painting a bright future for how we approach healthcare with the help of PET scans.

Sources:

https://www.ganeshdiagnostic.com/blog/why-take-dopa-pet-ct-scan
https://radiology.ucsf.edu/psma-pet-scan-for-prostate-cancer
https://www.petscaninmumbai.com/blog/dota-scan-in-mumbai/
https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/positron-emission-tomography-pet
https://www.healthdirect.gov.au/pet-scan
https://www.healthline.com/health/pet-scan