Diagnostic Testing and Procedures
Many procedures and tests are used to see if and where cancer cells are present in the body. The exact combination of tests that are used to diagnose a patient depends on the symptoms that are present and the type of cancer that is suspected. In order to decrease pain during and/or discomfort during tests and procedures doctors and nurses may recommend local anesthesia (simply numbing the skin with medicine), conscious sedation or deep sedation/general anesthesia. Some of the most commonly-prescribed diagnostic tests and procedures include:
A biopsy is a test in which a small piece of tumor or tissue is taken out of the body to be examined for cancer cells. Biopsies are done to determine the exact type of cancer that is present, if any. A biopsy can be performed using a small needle to obtain a piece of the lump, or it may be done during surgery. This procedure may require the use of anesthesia or numbing medicine (a local anesthetic) in the area to be biopsied. The exact procedure depends upon the area that needs to be biopsied, and the age of the child.
A test called a bone marrow aspirate is done to see if cells in the bone marrow are healthy. Bone marrow is the liquid/spongy part inside bone, where blood cells are made. For this test, a needle is placed in a bone (usually the hipbone) and a small amount of bone marrow is pulled into a syringe. It is sent to the laboratory to be tested for cancer cells. The child may feel some pain when the needle is placed in the bone, and may feel pressure when a syringe removes the bone marrow cells.
While a bone marrow aspirate is performed to look at the blood cells in the bone marrow, a bone marrow biopsy is used to study an actual piece of the bone. It may be completed at the same time as a bone marrow aspirate. For this test, a needle is placed in a bone (usually the hipbone); a small piece of bone is removed and sent to the pathology laboratory to be tested. The child may feel some pain when the needle is placed in the bone and may feel pressure or "tugging" when the needle removes a small piece of bone.
A lumbar puncture (also known as a spinal tap) is performed to see if there are cancer cells or an infection in the fluid around the brain and spinal cord. The child will usually lay on his or her side during this test, with the chin tucked to the chest and knees pulled up to the chest. When the back is in a curved position, a needle is placed between the bones of the spine (vertebrae) below the level of the spinal cord. Fluid from the spinal canal is then removed through the needle and collected into a tube that is sent to the laboratory for testing. For some types of cancer, chemotherapy may be given into the spinal canal through the same needle after the cells are removed for testing.
A CT scan (Computerized Axial Tomography scan) is a special x-ray that uses a computer to make a three-dimensional picture of the inside of the body. These scans are performed in the department of radiology. The patient lies still on a table while the scanner takes pictures around the body. Some children need sedation to be able to relax and lie still for the whole test. Contrast day may be given through the bloodstream or by mouth.
An MRI (Magnetic Resonance Imaging) uses a special machine to take pictures of the inside the body. The scanner uses magnetic waves to create an image of the inside of the body. The MRI can take from 30 minutes or up to two hours. Some children may need sedation to lie still for the whole test.
An ultrasound works by bouncing sound waves off solid parts of the body. The sound waves create an image of the tissue or organ that is being studied. The image can be seen on a screen on the ultrasound machine. Clear jelly is placed on the part of the body that is being studied. A small round handle is then placed on the jelly and moved around to get a clear picture of the tissue or organ that is being studied.
A bone scan looks at the bones to see if there is a tumor or infection present. A special dye called a radioactive marker is given through an IV before the pictures are taken. This dye contains a small amount of radiation, about the same amount as an x-ray. The dye goes to the spots in the bones that are not normal. It may take up to an hour to take the pictures and because it is important for the child to lie still during this test some children may need sedation. This test must be done in the Nuclear Medicine Department. Other Nuclear Medicine tests include PET scans, Gallium scans and MIBG scans.
An echo (echocardiogram) test helps doctors evaluate the strength and function of a child's heart. The test uses sound waves to create a picture of the heart. In preparation, a clear jelly is placed on the chest. The person doing the test will apply a small round handle to the chest, to send sound waves to the heart. A picture of the heart will be seen. Echo tests are conducted by the Division of Pediatric Cardiology.
Pulmonary function tests (PFT) evaluate how well the lungs are working. The test measures how much air the lungs can hold, and how well your child can let air out of his or her lungs. The machine that performs the PFT is a confined space with clear walls and a seat inside. The child is be asked wear a nose plug and blow into a plastic mouthpiece connected to the machine. The machine measures the amount of air breathed in and the force of the air breathed out. The child will probably be asked to repeat the test a few times to get an accurate reading. PFTs are conducted by the Pediatric Pulmonary Division.
An audiogram is a hearing test. Since some chemotherapy drugs can affect hearing, patients may be periodically monitored throughout treatment. For this test, earphones will be placed on the child. He/She will be asked to raise the right hand when the sound is heard in the right ear and the left hand when the sound is heard in the left ear. The child will be asked to repeat a list of words to test speech. Very young children will not wear headphones. If the child is too young to communicate, play audiometry is used. For example, the child may be asked to throw a block into a box. This test takes 10 to 15 minutes and parents may stay in the room during the test.