Positron Emission Tomography – sounding like a Hebrew phrase, right? But if I say, it is an expanded form of PET, many readers will immediately understand. PET scan is an important diagnostic tool used at the best cancer treatment hospital in Kolkata. This test is performed on cancer patients to figure out if the cancer has spread from its original site (medically called metastases) and if yes, where it has spread, tumour size and many other important details.
Advantages of PET Scan
High Sensitivity: When it comes to identifying malignant cells, PET scan is more effective than MRI or CT. PET scan can pick up the cancerous cells that don’t appear on CT or MRI images.
Improved Evaluation of Treatment Effectiveness: Changes in the metabolic activities in a malignant tumour precede the changes in the size of the tumour and hence, can effectively demonstrate if a patient’s cancer is responding to a particular treatment. When it comes to treatment evaluation, PET is more effective than other imaging methods. Patients responding to treatments, as suggested by PET Scan report, have a better prognosis than those having disease progression.
Differentiating Tumours and Fibrosis: Radiation therapy may cause fibrosis in radiation areas. PET is an advanced imaging method and so can differentiate between tumour and fibrosis whereas other imaging techniques fail to do so.
How Is PET Scan Performed?
For PET scan, a syringe containing a low level of radioactive tracer is injected into the patient’s body. This tracer is actually a radioactive content. After a waiting period, which allows tissues and organs to absorb the tracer, it releases photons that become visible and get translated into images by the scanner.
Do Patients Undergo Any Special Preparations for PET Scan?
- Pregnant woman cannot have PET scan.
- Breastfeeding women should stop feeding their babies for 8-10 hours before undergoing PET scan.
- Patients have to undergo fasting for at least 4 hours before an 18 F-FDG PET scan. They cannot take beverages such as tea, coffee, juice or other sugar containing drinks. However, drinking water is allowed.
- A patient’s morning blood sugar level must be less than 150mg/dl. In fact, sugar test is a must before PET scan. If the report is okay, only then booking can be done for the scan.
What Are the Advantages of PET Scan Along with CT?
The most advanced machines, installed at the best cancer hospital in Kolkata, have a built-in CT scanner. The CT scanners emit a series of narrow beams that create an arc-shaped path when passing through the body. In contrast, X-ray machines emit only a single beam. Hence, CT scanners produce a clear picture than X-ray machines. An added CT scanner offers additional benefits. These are:
- It delivers more accurate PET images.
- It is possible to superimpose PET images on to the CT images. It helps the oncologists localize the site of PET abnormality more precisely.
- PET along with CT images gives plenty of information about tumour metabolism and characteristics.
Are PET/CT Effective in Detecting All Tumours?
Not all tumours show the same kind of metabolism activities. Furthermore, they also differ in sizes. Effectiveness in tumour detection is based on all these factors along with the site of the tumours. PET can accurately detect all tumours>=1 cm. Tumours between 5mm-1cm are categorized under the grey zone and may not appear on PET images. Microscopic diseases and tumours<5mm are detected by PET and other imaging methods.