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The Leukemia/Bone Marrow Transplant Program of BC

Hematology Dictionary
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R

Radiology
The use of x-rays in the diagnosis of a disease.

Radiotherapy
The use of x-rays and other forms of radiation in treatment. It kills cancer cells in the area of the body being treated and is therefore effective treatment for localized disease, particularly in lymphoma and multiple myeloma. Side effects vary according to the type of treatment and will be discussed with the patient by the hospital staff.

Rai System
A system for classification of chronic lymphocytic leukemia based on the symptoms, if any, and on laboratory tests. It is used to decide whether to start treatment.

Recombinant
A term used to describe drugs, which have been produced using the techniques of genetic engineering. The products are exact equivalents of compounds produced naturally by the body.

Red Blood Cells
The cells of the blood, which contain the red, pigment hemoglobin and carry oxygen to all the tissues of the body. Normal red cell count in the blood, 4.5-5.0 x 1012 per liter.

Reed-Sternberg Cell
A distinctive abnormal cell seen in Hodgkin's disease.

Refractory Anemia
A form of myelodysplasia, which primarily affects red cell production by the bone marrow. In some cases the developing red cells show an internal ring of iron granules. These cells are called sideroblasts. Refractory anemia (RA) and refractory anemia with sideroblasts (RAS) are the most common forms of myelodysplasia.

Refractory Anemia With Excess Blasts (RAEB)
is a form of myelodysplasia characterized by the build up of immature white blood cells (blast) in the bone marrow. If the immature cells are particularly numerous it may indicate a chance of transformation to acute leukemia and the condition is called RAEB in transformation (RAEBt).

Relapse
The recurrence of disease. In leukemia this may be indicated by changes in the blood, bone marrow, CNS or testicle even before the patient experiences any symptoms.

Remission
Restoration of the blood, bone marrow and general health of the patient to normal. Induced by chemotherapy and/or radiotherapy.

Remission Induction
The initial course of treatment given to patients on admission to hospital to remove all clinically detectable cancer.

Reticulocytes
Immature red blood cells normally restricted to the bone marrow and present in the blood stream in very low numbers (0.2-2%). An increase in numbers indicates increased proliferation in the bone marrow, for example following chemotherapy.

Retinoic Acid
A synthetic compound related to vitamin A, which can stimulate cells to become fully mature. It may be used clinically to treat some forms of leukemia, notably a sub-type of acute myeloid leukemia called acute promyelocytic leukemia.

Retrovirus
A type of virus, which is related to the AIDS virus. One rare form of human leukemia is caused by the HTLV-1 retrovirus.

Richter's Syndrome
Development of lymphoma in a patient who has chronic lymphocytic leukemia.

RNA (Ribonucleic acid)
A copy of the genetic code used by cells as a template for making proteins. It copies the message given out by the DNA.

 

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The information in this glossary is cited with permission from the Leukemia Research Foundation web site.

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