A CT scan (or CAT scan as it is called in some hospitals) stands for Computerised (Axial) Tomography. The CT scanner is a big machine which is in Alder Hey’s Radiography Department. A CT scan doesn’t hurt and uses x-rays to take the picture. It is shaped like a big doughnut and has a sliding couch to lie on. The couch slides backwards and forwards through the round hole and pictures are taken as the patient moves through. A CT scan takes pictures from all around the body at different angles. These are then put into the computer and it makes a set of cross sections or “slices” through the part of the body being scanned. This gives a very detailed picture of inside the body. It can show exactly where a tumour is and how big it is.
These are used to look at soft parts of the body such as the tummy and kidneys. It is important that the patient lies quite still while cold jelly is placed on the area to be scanned. The scan tells us the site and size of normal organs, glands and tumours. It can also be used to see how a tumour has responded to treatment.
This is a test which looks at the heart using ultrasound. It doesn’t hurt but the patient having the scan needs to stay still while jelly is put on the chest. This test checks on the heart and how it is working as some drugs can affect how the heart works.
This is a special type of scan which looks for tumours or metastases (spread of the tumour) in bones. If we suspect a bone tumour or a tumour which has spread to bone, this type of scan can show how much of the bone is affected. The scan involves injecting a small dose of a radioactive dye into a vein.
This is quite harmless and the scan itself does not hurt. The patient having the scan needs to lie on a table with a special camera above. Unfortunately, we cannot put the dye into a patient’s central line/port-a-cath as this can affect the results of the scan. It may therefore be necessary to have a cannula put in to inject the dye. This will be taken out after the test.
MRS (Magnetic Resonance Spectroscopy)
MRS is a procedure similar to an MRI scan. Unlike MRI scans, which can only give a picture of what the brain looks like, MRS can also provide information about the activity of the brain tissue. With this information, our doctors are able to identify the type and grade of brain tumour.
MRI Scan (Magnetic Resonance Imaging)
This is a type of scan which uses magnetic waves. These waves change as they pass through the body depending on the type of cell. An MRI scan makes up a selection of cross section pictures of the body. The scan doesn’t hurt but the machine is quite loud and it makes a hammering noise. Sometimes it can be a bit frightening as the patients must lie very still in a tunnel with a loud noise. It is often difficult for our patients to stay still during the test so a general anaesthetic may be needed before the scan.
PET Scan (Positron Emission Tomography)
This type of scan produces three-dimensional colour images of the body using radiation. It can be used to diagnose a health condition or to find out more about how a condition is developing. It can also be used to measure how well treatment for a condition is working. Alder Hey does not perform this type of scan so patients who need it go to another hospital for the procedure.
Some chemotherapy drugs can have an effect on the kidneys. We will test kidney function at regular intervals. This involves an injection of a small amount of radioactive dye and a number of blood tests over a few hours. A double lumen central line can be used and the dye is put in one side of the line while the blood tests are taken from the other. If a single lumen central line is used, the dye is injected into the back of the hand. A local anaesthetic (magic cream) will be used so that the injection does not hurt. Kidney tests are often called a GFR or EDTA. GFR means glomerular filtration rate (how good the kidneys are at filtering). EDTA (ethylene diamine tetra-acetic acid) is the shortened name of the dye used in the test.
If the chemotherapy given is known to affect hearing, we check our patient’s hearing before, during and after treatment. This usually involves the patient wearing a set of headphones and watching responses to sounds of various tones and volume. Sometimes we will use another type of hearing test where the patient has to wear a small earplug (like those on a personal stereo) while a computer works out the hearing.
Urine tests are used to check a patient’s response to treatment or identify complications. Fluid balance (how much fluid goes in and comes out of a person) may be recorded. Patients may be asked to write down on a chart how much they have drank and passed out as urine. If this is needed, a nurse will show you how this is done.