BONE SCAN A bone scan is used to look for abnormalities in bones. In cases where there is concern for retinoblastoma outside of the eye, a bone scan can be used to look for tumor cells that may have spread to the bones. Not all children with retinoblastoma will need a bone scan. It may be done only once, or it may need to be repeated to monitor the effect of treatment. A small amount of radioactive dye (isotope) is given through an IV line and travels around the body. This isotope is picked up by tumor cells, which allows for the tumor’s location in the body to be seen. Pictures are taken about 2-3 hours after the injection. The test is painless, but some children require sedation to lie still for the scan. The radioactive isotope leaves the body in the urine over 2–3 days. There is very little radiation exposure from a bone scan.
BLOOD TESTS
Blood tests help diagnose medical problems and monitor for side effects of treatment. A specially trained nurse or technician uses a needle to collect blood from a vein. The blood samples are collected in tubes that are sent to a laboratory to be closely examined. In some cases, a finger prick may give enough blood for a test. These tests are usually done at the time of diagnosis to rule out other diseases and serve as a baseline for your child. COMPLETE BLOOD COUNT Blood is made up of plasma (the liquid part of the blood) and cells floating in the plasma. There are three types of blood cells: white blood cells, red blood cells, and platelets. The white blood cells fight infection as part of the body’s immune system. The red blood cells carry oxygen throughout the body. The platelets stop bleeding by rushing to the site of an injury to form a clot. A complete blood count, or CBC, is a blood test that measures the amount and the health of these three types of cells. Your child’s CBC results may change with each test because of other things going on in the body, such as infections or nutritional problems, or in response to some medications like chemotherapy. BLOOD CHEMISTRY A blood chemistry test measures the balance of fluid, electrolytes, and blood sugar. These measurements can provide information about the health and function of the kidneys and liver and about the body’s metabolism; they can also help diagnose certain diseases, such as diabetes. They can indicate how a disease is responding to treatment and monitor for possible side effects. Blood tests may be done to: Measure creatinine and blood urea nitrogen (BUN) to monitor changes in kidney function Detect changes in liver function by measuring bilirubin, alanine transaminase (ALT), and aspartate transaminase (AST) Common chemistry tests are a basic metabolic panel (BMP) or a comprehensive metabolic panel (CMP). These test results may change due to other things going on in the body, such as nutritional changes or side effects of treatment.
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