Decoding PET CT

The PET CT Scan is one of the sought after diagnostic tests. Lets find out more on what is a PET CT and why is it preferred over other diagnostic tests, such as an MRI, CT Scan or an ultrasound.

What is a PET Scan ?

A PET Scan is a nuclear medicine technique which produces images of the human body at a molecular level.

A PET CT, uses radioactive tracers in conjugation with isotopes such as oxygen, nitrogen, carbon etc. These radio isotopes act at a molecular level and work as probes which seek out disease, cancer in the body while giving out radio signals which are captures to produce an image.

PR

PET CT Scan
PET CT

This can help in diagnosis of even the tiniest lesions, thus increasing the accuracy of investigation, subsequent diagnosis and hence cancer treatment.

A PET CT Scan, therefore reveals a lot more about the body than standard diagnostic tests such as MRI, CT Scan or an ultrasound.

What happens during a PET Scan ?

A PET CT Scan, is always on a price appointment basis as the radio isotopes, having a a very short half life need to be brought in just before the scan.

A PET CT, is usually carried out empty stomach on overnight or ateast 6 hrs fasting.

The creatinine levels, need to checked prior to conducting the PET CT by a simple blood tests called KFT or Kidney function test

If the creatinine levels are in order, the patient is  tested for blood sugar and if found in order , the patient is given an injection of glucose with a radioactive tracer.

After the injection, the patient is made to rest for about 90 mins and then taken for the actual scan which takes about 30 mins to 45 mins depending upon the imaging required.

During the scan, the patient is made to lie on a comfortable table that moves slowly through the ring like PET scanner.

After the scan, the patient can leave immediately. However close contact with others especially children and pregnant women is best avoided for the next 4-6 hrs.

It is also good to drink a lot of water, to flush out the radio active tracer from the body.

The imaging can be seen by the doctors and the nuclear medicine specialists almost immediately for evaluation, though a formal written report takes a day to be handed over to the patient.

Are there any side effects or discomfort due to the scan ?

There are no sid effects or discomfort due to the PET  CT Scan, except the minor prick while injecting the tracer.

The PET CT scanner, also does not make any sounds while the scan is going on unlike a few other diagnostics tests.

What are the diseases for which a PET CT Scan can be used ?

The most common use case for a PET CT Scan is for detecting and treating cancer. However other applications, include diagnosing cardiac or heart problems and also neurology.

Cancer/Oncology :

During the initial stages of the disease, a PET CT helps distinguish between benign and malignant disease and also cancer staging, that is knowing  and determining the stage of the disease and also its characteristics, which further helps oncologists decide the best treatment option for the patient.

During course of treatment, it helps determine response to therapy or cancer treatment and if the metabolic activity decreases on the PET CT Scan, the oncologists know that the drugs being administered are working.

On the other hand, if the metabolic activity on the scan increases, it indicates that the treatment option is losing its efficacy or is not working and helps oncologists change the line of treatment to benefit the patient.

Cardiac Care: Post a heart attack, a PET CT Scan can be used to determine myopathy , need for CABG or open heart surgery and if there would be any benefit from CABG or would a heart transplant or an LVAD be a better treatment option.

Neurology: Alzeheimer’s at an early stage can be diagnosed using a PET Scan leading to early intervention.

A PET CT Scan helps locate tumours, distinguish between benign and malignant tumours and also scar tissue for brain surgery.

A PET CT  is also useful for treatment of epileptic seizures. It can help locate the origin and focus of seizures and assess sites for intervention if any is required.

What is the difference between a PET CT and an MRI or a CT ?

A CT or an MRI works on the physical level and can give the size and location of the tumour with accuracy.

However since both tests donot work on the molecular level, they cannot indicate metabolic activity of the tumour which only a PET CT Scan can indicate, thereby making a PET CT, a diagnostic test of choice for oncologists, cardiologists, cardiac or heart surgeons and interventional neurologists.

To know more on PET CT Scans, cost and implications, from the best cancer hospitals in India, write to us on info@ihealthkonnect.com or send us a query.

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PRRT and the promise it holds for cancer treatment

As we continue our conversation on Precision Medicine for cancer, a popular therapy used to treat NET tumours or Neuro Endocrine Tumours is PRRT or Peptide Receptor Radionuclide therapy.
Neuroendocrine tumours are a rare form of cancer and originate from Neuro endocrine cells in the body and hence the name.They are different from adenocarcinoma’s and often do not do not respond well to chemotherapy, the 1st line of treatment for most cancers.

By administering radioactive protein lutetium octreotate, it is possible to treat NET tumours or neuro endocrine carcinoma with precision and offset progression of disease.

PRRT for neuroendocrine tumour
PRRT treatment for metastatic cancer cells spreading and growing. Tailor-made precision medicine based on genetic profile and molecular structure of the tumour.

In PRRT a peptide or a cell targeting protein is combined with a small amount of radio active nuclide creating what is called as a radio peptide. The radio peptide when injected into the patients blood stream travels and binds to a neuro endocrine tumour, delivering a high dose of radiation to the tumours. This also limits damage to the nearby healthy tissue and hence lesser and milder side effects than chemotherapy.

What kind of cancers can be treated by PRRT?

Along with Neuroendocrine tumours, carcinoids, islet cell carcinoma of the pancreas, small cell carcinoma of the lung a form of lung cancer, pheochromocytoma (a rare tumor that forms in the adrenal glands), gastro-enteropancreatic (stomach cancer , intestine cancer and pancreas) neuroendocrine tumors, and rare thyroid cancers that are unresponsive to treatment with radio iodine are often treated with PRRT.

Role of PRRT is also being explored for treatment of prostate cancer.

When is a patient a candidate for PRRT ?

Patients with following conditions are often proposed for PRRT

  • When neuro endocrine tumours are not responsive to other lines of cancer treatment
  • When surgical removal of tumours is not possible at current stage, PRRT may be used to reduce size of the tumours.
  • PRRT is also a treatment option for last stage inoperable cancers when metastasis has set in.
    The main aim of PRRT is then to slow down progression of disease, offer relief and prolong life.

However, not all neuroendocrine tumours respond to PRRT. First an OctreoScan is done. If the patient is found to have a positive OctreoScan and meets other requirements, PRRT is proposed.

What happens during PRRT ?

For patients having a positive octreoscan, to start with an amino acid solution is delivered to protect the kidneys.

As most net tumours have a lot of a specific type of surface receptor, a protein called somatostatin. Octreotide, is a lab version of somastostatin. During PRRT, a dose of radio nuclides such as Lutetium, Yttrium are often combined with octreotide and injected into the blood stream.

Molecular imaging and scans follow to see whether the radio peptide has latched on of the tumour sites correctly.

The entire session usually lasts for about 4 hrs and is often done as an out patient procedure.

The main goals of PRRT hence are to provide symptom relief, to stop or slow tumor progression and to improve overall survival.

Advantages of PRRT ?

PRRT along with other molecular therapies or targeted therapies offer excellent results as they are tailor made keeping in mind molecular properties of the tumour and also biologic characteristics of the patient.

PRRT is offered in Germany , USA, UK and other developed countries at a significant cost, In India, a single session of PRRT costs approx USD 6300.

Get in touch with us for a second opinion on cancer treatment, write to us on info@ihealthkonnect.com or send us a query

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