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Tests

• Tests and procedures
  • Audiology
  • Biopsy
  • Blood Tests
  • Bone Marrow aspirate
  • Lumbar Puncture
  • Electrocardiogram
  •  
  • Glomerular Filtration Rate (GFR)
• Imaging
  • Ultrasound
  • Bone Scans
  • Gallium Scan
  • Magnetic Resonance Imaging (MRI) Scan
  • Echocardiogram
  • X-Rays

Tests and procedures

Before doctors decide on the best way to treat your child, various tests will be done to establish an accurate diagnosis, and to determine if the cancer has spread (metastasised) or not. They also assess your child's general health, as this may affect how treatment is started.

The tests enable the specialist:

• To be absolutely sure that the exact type of cancer has been diagnosed. Sometimes it is very difficult to be certain of the exact type of cancer, and for this reason further opinions from other specialists may be sought.
• To find out exactly where the tumour or cancer has arisen from and whether it has spread to other parts of the body. This is called staging. The tests involved may delay the start of treatment for a few days, but it is important to get all the information together so that the right treatment is given.

The following are brief descriptions of some of the tests and procedures, which may be encountered during diagnosis and treatment. Some of these tests are repeated during the course of treatment to monitor progress and check for any effects.

Audiology

Some drugs can affect hearing. Baseline hearing tests (audiology) and regular testing during treatment are done with children receiving these drugs.

Biopsy

If it is suspected that a tumour is malignant (cancerous), the surgeon may first remove a part of it, either by inserting a small needle through the skin (needle biopsy) or by doing a small operation (open biopsy). A CT guided biopsy may also be done by a radiologist. The whole tumour may be removed at the initial surgical procedure. This specimen is then examined by a specialist doctor- a histopathologist - who can tell whether or not it is malignant and exactly what type of tumour it is. It usually takes a few days to get the results. Sometimes specialised tests such as chromosome analysis or special staining tests to look more closely at the tumour tissue may be required to help diagnosis. The type of biopsy done depends on the individual child's specific clinical circumstances.

Blood Tests

Blood tests are done at the time of diagnosis, during treatment and occasionally after treatment, to monitor the effects of treatment. The blood cells are counted in the haematology department. The blood count is one of several different ways to monitor the effects of treatment. Your child's doctor can tell you what your child's blood counts are, what this means and what they are expected to be. Microbiologists may check the blood to see whether there is infection. This is called a blood culture. The chemistry laboratory measures certain salts and chemicals in the blood sample. This gives information about kidney and liver function. Blood samples may also be obtained to cross-match blood in case a transfusion is needed.

Bone Marrow aspirate

The bone marrow is like a factory where all the blood cells in the body are produced. In children bone marrow is in the long bones, ribs, pelvis and hips. To see whether the cancer has affected the bone marrow it is necessary to obtain a sample. This is done by placing a fine needle into the bone in the hip and taking out a small amount of the marrow which is then examined in the laboratory. Occasionally a core of marrow (trephine biopsy) is required to examine the marrow in more detail. Bone Marrow Aspirate is usually done under anaesthetic and a trephine biopsy under a general anaesthetic.

Bone Scans

A bone scan is done in the Nuclear Medicine department to get an image of a bone or bones, to see if there is any cancer present. An injection of a radioactive material (isotope) is given first and then a scan performed a couple of hours later. Where there is increased cell activity the isotope will accumulate.

CT Scan

Computerised Axial Tomography - also called a CAT scan - takes many pictures of soft tissue inside the body, from different directions. A computer integrates the pictures to show any tumours. Scanning is painless but a needle is sometimes required to inject contrast. A CT scan usually takes less than five minutes. A sedative or a general anaesthetic may be needed to ensure that the child stays still for this time.

Echocardiogram

An ultrasound test is used to assess heart function. Some chemotherapy drugs have the potential to affect heart function. Heart function is monitored at regular intervals when these drugs are used.

Electrocardiogram

This records the rate, rhythm and electrical activity of the heart.

Gallium Scan

Gallium scans are done in the Nuclear Medicine department. Before the scan, an injection of Gallium is given. Gallium gathers at sites of infection and malignancy. The first scan is usually done 48 hours later and a second scan a week later.

Glomerular Filtration Rate (GFR)

Some drugs have the potential to affect kidney function. Children having these drugs have their kidney function monitored regularly during treatment. Glomerular Filtration Rate (GFR) is a very specialised nuclear medicine test of kidney function.

Lumbar Puncture

With come cancers, such as leukaemia or lymphoma, malignant cells can pass into the brain and cerebrospinal fluid surrounding the brain. To find out whether this has occurred, a few drops of the fluid are removed by inserting a fine needle between two vertebral bones in the spine.

Magnetic Resonance Imaging (MRI) Scan

Magnetic waves are passed through the body and produce different images depending on the types of cell they pass through. They are harmless. The MRI can give an accurate picture of a tumour and the surrounding structures. The MRI machine is noisy and may be scary because the child has to lie in a tunnel, but having the MRI is painless. A general anaesthetic may be required to keep the child still. A 'mock MRI' (available at RCH only) is used to let the child experience what having an MRI is like. For many children, this practice MRI avoids the need for a general anaesthetic. Sometimes in CT, MRI and X-ray a special fluid called 'contrast' is injected into the blood to get an even better picture of the tumour and its relationship to other structures.

Ultrasound

Ultrasound waves are sound waves that the human ear cannot hear. A special machine directs the waves at a certain part of the body and differences in the way in which they are reflected helps to distinguish a healthy part of an organ from a tumour.

 

 

 

 

 

X-Rays

An ordinary x-ray can show whether there is tumour in the chest, abdomen or bones as tumour tissue appears differently on x-ray from ordinary bone tissue. Sometimes special dyes are injected into one of the child's blood vessels to get an even better picture of the tumour and it's relationship to other structures.