Tests

The oncology doctors will probably want to conduct at least a few radiological tests to assess the status of your child's disease. Some of the more common types of tests are:

Bone Scan

This type of X-ray is done if your child has bone pain of unknown origin, to evaluate osteomyelitis, and in general, to search for bony metastases. A radioactive material is injected intravenously and the child must wait approximately two hours before the test is actually done (to allow the radioactive dye to circulate through the blood stream and attach to areas of new bone formation).

CT Scan

Computed Tomography (CT) is a type of X-ray by which cross-sectional pictures of the body are taken. This can give the doctors far more detail than do conventional X-rays, and can be very helpful to the radiotherapist in planning treatment fields. A dye may or may not be injected through the child's vein. The CT scanner is a large machine, and the size and noise may scare your child, but it will not cause other discomfort. If your child is young, a sedative may be given so that he/she remains still during the scan.

Scans may be be made of the brain, abdomen or chest. For brain tumour follow-up, or when the child has had a history of headaches or seizures, a dye will probably be required, but the doctor will decide whether or not this is necessary.

For abdominal scans, an oral contrast agent is often given to colour the intestines, and so differentiate them from other intra-abdominal contents.

Gallium Scan

This type of scan is done to evaluate an abcess or an inflammatory process, and to identify sites where metastasis has occurred, particularly in the case of lymphoma, Hodgkin's Disease, hepatoma, or other solid tumours. A dye made from the element Gallium (Ga67) is injected intravenously on the first day, and the scan is made on the third or possibly the fourth day after.

Intravenous Pyelogram (I.V.P.)

This test is done to help the doctors visualize the urinary tract, which includes the kidneys. It is done by the intravenous injection of an iodine-based contrast medium. If the child's intestine is empty, the doctors can obtain a more accurate picture of the urinary tract, so some cleansing procedures (such as laxatives or enemas) may be ordered. The test may take between one and three hours.

Lymphangiogram

The lymphatic system is the body's system of fighting infection by producing lymphocytes, which are a type of white blood cell. The lymphangiogram is used to diagnose patients who may have lymphatic cancer, such as Hodgkin's Disease. A dye (typically a methylene blue dye) is injected and is absorbed into the lymphatic system, which makes it more visible on X-rays and enables the doctor to see whether the lymph nodes appear abnormal.

Magnetic Resonance Imaging (M.R.I.)

Through magnetic resonance imaging, magnets are used to create computer scans of body tissues. This test generates an image similar to a CT scan, but without the use of X-rays or radioactive substances, and gives different kinds of information than does a CT scan. M.R.I. creates an image of the distribution of the nuclei in the tissue being tested.

Lumbar Puncture

This is a procedure by which the doctors can obtain a sample of your child's cerebro-spinal fluid. The child lies on his/her side and curls up by putting knees to chest and tucking chin to chest. A small amount of fluid is removed through a needle inserted into the lower spine and the fluid is checked to see if cancer is present in the central nervous system.

Myelogram

This test is done to enable the doctors to visualize the entire spine for the presence of abnormalities such as slipped discs or solid tumour masses. A contrast medium (usually an iodine derivative called iohexol, which is water-soluble) is injected via a lumbar puncture, and is followed by X-rays, or, sometimes, a CT scan of the spine and/or head. Only local anesthesia is needed at the site of the lumbar puncture.

This test usually takes 1 - 2 hours. Your child will be required to lie down for a period of about 6 hours after the test, to prevent headaches. The child will also be encouraged to drink a lot of fluids after the test to help dissolve the dye.

Tissue Biopsy

A tissue biopsy may be required if your child has a tumour. A portion of the tumour or affected tissue is removed surgically, and the pathologists examine the cells under a microscope to identify the type of cancer.

Ultrasound

Ultrasound uses high frequency sound waves to locate abnormal growths, to evaluate therapy, and to outline target areas (for radiotherapy, for example). It is painless and there is no prior preparation required, except that a full bladder helps in visualizing pelvic structures such as the uterus, lymph nodes, masses, etc.

The child must lie down, and a water-soluble gel is spread over the area to be scanned. A hand-held device (the transducer) is then rubbed gently over the area being scanned, and a video image is produced on a television screen. Photographs can be produced from the video image to assist in the evaluation.

Other Tests

There are also less common tests which may be done, but which have not been discussed here. Feel free to ask your doctor or nurse about what these tests involve, if such a test has been ordered by the doctor.