PET-CT scan today

I have had another PET-CT scan today morning in the Bangalore Institute of Oncology (BIO), which is the only center in Bangalore to have such facility. Given the number of patients lining up for the scan, one needs to always take an appointment at least three or four days prior to the scan day. So, I took the appointment last week (Nov 30), when I had my chemo session.

Today's scan was my seventh in the last one year of my treatment for cancer! Nevertheless, I would like to share with you my experiences of the scan process for a couple of reasons: (a) Most of us might not have heard about what PET part of the scan is, though some of us might already know what CT scan is. (b) I did not share my scan experiences in a public platform such as this blog until now. Thus, I give below more details of the PET-CT scan in the form of FAQs. Hopefully, this might give a few of the readers what a scan process might be! :)

1. What is PET-CT scan? Why should a CT scan be combined with PET scan?
PET is an acronym for Positron Emission Tomography, while CT stands for Computed Tomography. A CT scan usually gives us an idea of the structural changes of the parts/tissues/organs in the body. Thus, CT will give us what is called anatomical imaging. However, CT cannot give us the details of the metabolic activity going on in the specific part/tissue/organ in the body, which can be achieved by PET. Thus, PET will give us what is called functional imaging.
Let us take an example of a cancerous growth in Liver. CT will show the images of the liver with its shape, changes in the size and any other properties such as color, which might be due to the presence of cancer. PET will capture how these cancer tissues or cells are moving or spreading. So, a combination of both PET and CT images of the body not only gives the anatomy and changes in the structure of the part, but also how the part is functioning.

For more technical details on PET-CT scan, interested readers might want to see the following web resources:
(a) PET-CT
(b) Positron Emission Tomography
(c) What is PET-CT scan?

2. Is PET-CT scan the only technique available for effective diagnosis of cancer in the body?
PET-CT scan is the widely used technique world-wide to detect the nature and extent of the cancer in the body. Though there are other kinds of tests used to detect the cancer, such as mammography test (for breast cancer), Pap smear to test (for cervical/uterus cancer), and various others, they only detect the cancer in a specific area of the body. PET-CT scan detects the abnormal activity in any part of the body thus helping an oncologist in effective diagnosis.

3. Is PET-CT scan a painless process?
Yes, the PET-CT scan is mostly a painless process since the actual scan will be performed in a machine where the body is exposed to a painless radiation, similar to that of an X-ray machine.

4. How expensive the scan is?
Given the logistics and investment of the tools and equipment required for the PET-CT scan, it is usually expensive. For instance, BIO charges anywhere between Rs.12000 to Rs.20000, depending on the reference of the doctor and whether you are an internal or external patient. (Of course, one can negotiate always for a discount with the help of your doctor :) )

5. What the process for a typical PET-CT scan is?
The process for a typical PET-CT scan might be as follows:

(a) The patient should be on fasting for at least eight hours before the scan! He can only take water during the fasting period. (In my case, I had my dinner at around 9 PM yesterday and did not have any thing later to that until my scan was complete at 12 noon today.)

(b) The patient when reports to the PET-CT center, is checked for his vitals, such as blood pressure level, sugar level, white blood cell count, weight and height. If any of the first three are abnormal, the scan will not be done on the day and will be rescheduled. (For example, the fasting sugar level should be less than 200 mg/dl i.e., 200 milli grams of glucose per deci liter of the blood.)

(c) An intra-venous (IV) needle will be injected in one of the veins of the patient, usually in one of the hands, which would later carry the radioactive tracer before and during the scan.

(d) The patient is then administered with a small dosage of fluorodeoxyglucose (FDG) through the IV line. (FDG contains the radioactive tracer as fluorine-18, a radioactive isotope of Fluorine, with half-life of around two hours! This tracer is absorbed by the abnormal areas of the body and emit gamma rays, which are captured by the PET-CT machine.)

(e) The patient is quarantined from others since now he carries the radioactive tracer in his blood.

(f) The patient is then asked to have one liter of liquid, usually water, with soluble FDG. This is to ensure that the body will have enough dose of FDG to absorb. The intake of this fluid, also called oral contrast, should be slow and even and should be over a period of 45 minutes to one hour.

(g) The patient is then shifted to the PET-CT machine, where the actual scan of the body will take place. It usually takes 15-20 minutes for the scan to complete. The whole process of scan can take any where between 1.5 - 2 hours.

Once the scan is complete, the patient is advised to be in observation for another couple of minutes before he is let out. (Once he is let out, of course, he is free to break his fast now! :) )

Now that I have had my scan, I am eagerly waiting for its report, which would be available to me tomorrow morning! Hope there are quite positive results in the report and my recovery is complete without any further chemo sessions! :)