CT SCAN AND PET SCAN

The positron Emission Tomography Scan(PET Scan) and Computerised Tomography Scan (CT Scan) is considered to be a revolutionary, advanced imaging modality that combines two imaging devices resulting in precisely locating cancer within the body.
But many fear the radiation hazards a patient may face, considering the fact that there is substantial radiation exposure to the patient undergoing PET CT (it detects the metabolic activity of the cancer cells in the body). However, if there is a definite indication for getting a PET CT, then its benefits outweigh the risks involved, PET CT is touted to be one of the 'magical' discoveries of the century. Its advantages are many, compared to conventional imaging modalities. However, this doesn't indicate the need for a PET scan.
It is important for doctors ' to keep the health of the patient as the highest priority' (hippocratic Oath). The doctor should remember ' to do no harm' to the patient and must always consider the following questions before investigating a patient.

• Will the investigation make a meaningful difference?
• Will the investigation have apotential to change the treatment plan?
• With specific reference to oncology, will the investigation help in term survival of the patient?

If the answer to these questions is 'yes', then the investigation is certainly justified.
Extending the boundaries of an investigative modality beyond the established indications is in my opinion, unscientific and unethical. For example, in the follow up of a patient who has completed treatment for early breast cancer, all that is required, is a regular follow up by the treating clinician and an annual mamogram + (plus) ultrasound scan of the breast. But subjecting the patient ot a chest X ray, abdominal scan, and bone scan on a regular basis does not help.
There is now ample evidence to suggest that actively looking for an asymptomatic metastasis (metastasis - cancer spreading elsewhere in the body from the primary organ) by ordering a battery of investigations on a regular basis does not improve the long term survival of the patient.
Subjecting the patient to too many tests of unproven indications is unjustified. The public and the profession must be constantly sensitised to the fact that technology has its limitations.
PET CT is a wonderful imaging modality. IT is extremely useful in some situations and helps in guiding treatment decisions. It is however, important to remember that' the patient is supreme' and doctors must be prudent and judicious when ordering diagnostic tests.