CT scan, MRI scan and PET scan- what's the difference?
A CT scan is a series of xrays that builds up a 3-dimensional picture of inside your body. CT stands for Computerised Tomography. You will need to lie down on a couch which moves through a tunnel. This is a painless procedure and usually takes about 30mins. You may need to take a drink or be injected with dye. This allows your doctors to see areas of your body more clearly. The dye might make you feel hot but this will pass.
An MRI scan uses magnetic fields and not xrays to build up a series of cross sectional pictures of inside your body. MRI stands for Magnetic Resonance Imaging. Again you will have to lie on a couch, this time inside a metal cyclinder. An MRI scan is very noisy and you will be given earplugs or headphones. Some patients find an MRI claustrophobic. If you are worried about this discuss it with your doctor. They can prescribe medication to help keep you calm. You may also be given a drink or injection of dye before an MRI scan.
A PET scan stands for Positron Emisson Tomography. You will be given a radioactive injection prior to your scan and this will highlight areas in the body that are abnormal. A PET scan is often used for parts of the body that other scans don't give enough information about. This scan is also painless, however it can take up to two hours to perform. Again you will be required to lie on a couch that moves through a scanner. This scanner contains sensors that read the signals from the radioactive substance injected into your body. It is important to be very relaxed prior to a PET scan. Your doctor might prescribe some medication to help you with this. It is unusual to become claustrophobic during a PET scan.
All of these scans take pictures of inside the body. Your doctor will decide which scan is best suited for you. These scans are usually performed for investigative purposes and are not normally performed on healthy people.
You will be advised before your scan whether or not you need to fast. Also the staff in the radiology department will explain whether or not you are radioactive following your scan. If so it is advisable to avoid contact with young children and pregnant women for 24hours.
Hi, Hard to know where to begin with this one. My mother was diagnosed with secondary breast cancer in the region of her hip. Got the news on Monday. She had an x-ray of the area in Feb. which was negative. A 2nd x-ray three months later was diagnosed as a possible necrosis of the bone warranting a hip replacement. Her blood tests were all clear as was her bone scan and cat scan. All looked well until a bone biopsy was carried out.
At this point she was told she had cancer and in more than one location. My question then is.. given that the biopsy is so specific location wise, how can it be determined that the cancer is in more than one location.
Secondly, if the bloods, bone scan and cat scan were all clear is this a positive sign i.e. could it be concluded that her condition is currently quite mild or should we be worried that in the space of three months her x-ray went from clear to suspicious in such a short space of time. We're very confused