What is PET CT Scanner?
PET CT Scanner is a type of medical imaging equipment that provides an explicit information that allow doctors to see how the body is working inside. It is frequently use on cancer to see if how active the tumor is.
How the PET CT Scan Procedure Works?
Firstly, the scanner takes a CT scan. “CT” stand for Computerized tomography it uses a low dose of xrays to show where the structures are located in the body. The CT scan take about 30 seconds. This is followed by the PET scan which will take about 20-30mins. PET stands for Positron Emission Tomography. The PET scan shows an extra information about how active cells are, and weather maybe they are cancerous tissue in the body.
In order for the PET scan to work, the patient is given an injection of a substance called a radiotracer about an hour before the scan. There are various types of radiotracers that can tell us different things about cancer, but the one is most commonly used is the FDG radiotracers. FDG is a sugar that have been modified to contain a small amount of radiation. Because cancer cells are more active they taking more sugar than surrounding normal tissue. This means when a patient is given an injection of FDG, it builds up in tumor and the radiation that have been absorb by the cancerous tissue shows up on the PET scan. The PET scan image is then combine with the CT scan image on a computer, to allow the doctors see not only where the cancer is but also how active it is.
PET CT before Cancer Treatment
PET CT scan are requested for evaluation of cancer and research. There are 3 main ways that PET CT may be use.
- It can be used to find out of which patient are suitable to enter a particular trial. For example for lung cancer trial a PET CT scan could be given to patients before they enter a study to get detailed of information on the extent of their cancer. This information helps to make sure that the trial is an appropriate choice for a particular patient. It also means researcher know that they have a similar group of patient being studied, so they can be confident in the trial results.
- PET CT can also use in clinical trials to find out whether the treatment is working . PET scan can show chances in the tumor earlier than other type of scan sometimes as soon as two weeks after starting treatment. This means patient who are responding to a treatment can continue the treatment and patient who are not responding to treatment can be identified quickly and may need to change to another treatment options.
- Some trials look at new ways of using PET CT to assess cancer. PET CT scan already give us a lot of information. But researchers always looking for a way to advance for the way how they use. For example a study might focus on assessing a new PET technique, finding out the best timing of the treatment to give a scan or comparing the information you get from PET scan against from the other type of scan.
Patient Information Sheet
The patient information sheet provide us with detailed information about the risk associated with a specific trial. The local ethics committee and radiation experts approved all clinical trials and included PET CT scan to ensure that this are appropriate for the clinical trial.
Patient Preparation
Patient will be advice not to eat for about 6 hour before the appointment. Before the patient has the scan, we should get some general information from them and very importantly we need to know if they had a chemo radiotherapy recently, if they had any biopsies, or if they have any surgery and if they had an imaging procedure recently such a CT or MRI scan. We need to make sure we have an accurate weight specifically for that day, it’s important to know that, so that can we measure out the exact amount of FDG radiotracer and afterward helps the doctor analyse the scan properly.
The radiographer makes the preparation for the scan following the specific instruction given in the clinical trial protocol. In the injecting room the patient receive an injection of the FDG tracer in preparation for the PET CT scan. He will stay there for an hour so that the radiotracer has time to circulate around the body and builds up in any cancer cells.
The radiographer will try not to spend too much time with the patient from this point onwards after the injection. This is because she works with radiation every day and needs to limits the exposure. There were also be a separate toilet for the scan patient to use, after they have had the radiotracer injected because some radiation will pass-out in the urine. While patient wait for the radiotracer to circulate, the radiographer will keep an eye using CCTV in case he needs anything.
