Attention Deficit Hyperactivity Disorder Glossary of Medical Terms

Access: 1. In general, a means of approaching something. 2. In health care, the opportunity or right to receive health care. 3. In dialysis , the point on the body where a needle or catheter is inserted to gain entry to the bloodstream.
See the entire definition of Access

Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
See the entire definition of Acute

Addiction: A chronic relapsing condition characterized by compulsive drug-seeking and abuse and by long-lasting chemical changes in the brain . Addiction is the same irrespective of whether the drug is alcohol , amphetamines, cocaine , heroin , marijuana , or nicotine . Every addictive substance induces pleasant states or relieves distress. Continued use of the addictive substance induces adaptive changes in the brain that lead to tolerance, physical dependence, uncontrollable craving and, all too often, relapse . Dependence is at such a point that stopping is very difficult and causes severe physical and mental reactions from withdrawal. The risk of addiction is in part inherited. Genetic factors, for example, account for about 40% of the risk of alcoholism . The genetic factors predisposing to addiction are not yet fully understood.
See the entire definition of Addiction

ADHD: Attention deficit hyperactivity disorder .
See the entire definition of ADHD

Affinity: In immunology , the strength of binding interaction between antigen and antibody molecules.
See the entire definition of Affinity

Aggressive: In oncology, quickly growing, tending to spread rapidly. As, for example, an aggressive tumor.
See the entire definition of Aggressive

Agonist: A drug that binds to a receptor of a cell and triggers a response by the cell. An agonist often mimics the action of a naturally occurring substance.
See the entire definition of Agonist

Amphetamine: A drug with a stimulant effect on the central nervous system that can be both physically and psychologically addictive when overused. This drug has been much abused recreationally. The street term " speed " refers to stimulant drugs such as amphetamine.
See the entire definition of Amphetamine

Anger: An emotional state that may range in intensity from mild irritation to intense fury and rage. Anger has physical effects including raising the heart rate and blood pressure and the levels of adrenaline and noradrenaline.
See the entire definition of Anger

Anorexia: An eating disorder characterized by markedly reduced appetite or total aversion to food. Anorexia is a serious psychological disorder. It is a condition that goes well beyond out-of-control dieting. The person with anorexia, most often a girl or young woman, initially begins dieting to lose weight. Over time, the weight loss becomes a sign of mastery and control. The drive to become thinner is thought to be secondary to concerns about control and fears relating to one's body. The individual continues the endless cycle of restrictive eating, often to a point close to starvation. This becomes an obsession and is similar to an addiction to a drug. Anorexia can be life-threatening. Also called anorexia nervosa .
See the entire definition of Anorexia

Antidepressant: Anything, and especially a drug, used to prevent or treat depression.
See the entire definition of Antidepressant

Antisocial personality: See: Antisocial personality disorder .
See the entire definition of Antisocial personality

Antisocial personality disorder: A pervasive pattern of disregard for and violation of the rights of others and inability or unwillingness to conform to what are considered to be the norms of society.
See the entire definition of Antisocial personality disorder

Anxiety: A feeling of apprehension and fear characterized by physical symptoms such as palpitations , sweating, and feelings of stress . Anxiety disorders are serious medical illnesses that affect approximately 19 million American adults. These disorders fill people's lives with overwhelming anxiety and fear. Unlike the relatively mild, brief anxiety caused by a stressful event such as a business presentation or a first date, anxiety disorders are chronic, relentless, and can grow progressively worse if not treated.
See the entire definition of Anxiety

Anxiety disorder: A chronic condition characterized by an excessive and persistent sense of apprehension with physical symptoms such as sweating, palpitations , and feelings of stress . Anxiety disorders have biological and environmental causes.
See the entire definition of Anxiety disorder

Attention deficit hyperactivity disorder : A family of related chronic neurobiological disorders that interfere with an individual's capacity to:

• regulate activity level (hyperactivity),
• inhibit behavior (impulsivity), and
• attend to tasks (inattention) in developmentally appropriate ways. The term "attention deficit hyperactivity disorder" is abbreviated and usually referred to as ADHD.

The core symptoms of ADHD include an inability to sustain attention and concentration, developmentally inappropriate levels of activity, distractibility, and impulsivity.
See the entire definition of Attention deficit hyperactivity disorder

Baseline: 1. Information gathered at the beginning of a study from which variations found in the study are measured.
2. A known value or quantity with which an unknown is compared when measured or assessed.
3. The initial time point in a clinical trial, just before a participant starts to receive the experimental treatment which is being tested. At this reference point, measurable values such as CD4 count are recorded. Safety and efficacy of a drug are often determined by monitoring changes from the baseline values.
See the entire definition of Baseline

Bipolar disorder : A mood disorder sometimes called manic-depressive illness or manic-depression that characteristically involves cycles of depression and elation or mania . Sometimes the mood switches from high to low and back again are dramatic and rapid, but more often they are gradual and slow, and intervals of normal mood may occur between the high ( manic ) and low (depressive) phases of the condition. The symptoms of both the depressive and manic cycles may be severe and often lead to impaired functioning.
See the entire definition of Bipolar disorder

Blood: The familiar red fluid in the body that contains white and red blood cells , platelets , proteins , and other elements. The blood is transported throughout the body by the circulatory system . Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.
See the entire definition of Blood

Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle . It's measurement is recorded by two numbers. The first ( systolic pressure) is measured after the heart contracts and is highest. The second ( diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called " hypertension ".
See the entire definition of Blood pressure

Brain: That part of the central nervous system that is located within the cranium ( skull ). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."
See the entire definition of Brain

Brain stem: The stemlike part of the brain that is connected to the spinal cord. Or conversely, the extension of the spinal cord up into the brain. The brain stem is small but important. It manages messages going between the brain and the rest of the body, and it also controls basic body functions such as breathing, swallowing, heart rate , and blood pressure. The brain stem also controls consciousness and determines whether one is awake or sleepy.
See the entire definition of Brain stem

Caffeine: A stimulant found naturally in coffee beans, tea leaves, cocoa beans (chocolate) and kola nuts (cola) and added to soft drinks, foods, and medicines. A cup of coffee has 100-250 milligrams of caffeine. Black tea brewed for 4 minutes has 40-100 milligrams. Green tea has one-third as much caffeine as black tea.
See the entire definition of Caffeine

Centers for Disease Control and Prevention: The US agency charged with tracking and investigating public health trends. The stated mission of the Centers for Disease Control and Prevention, commonly called the CDC, is "To promote health and quality of life by preventing and controlling disease, injury, and disability."
See the entire definition of Centers for Disease Control and Prevention

Childhood: (1) The time for a boy or girl from birth until he or she is an adult. (2) The more circumscribed period of time from infancy to the onset of puberty .
See the entire definition of Childhood

Condition: The term "condition" has a number of biomedical meanings including the following:

1. An unhealthy state, such as in "this is a progressive condition."
2. A state of fitness, such as "getting into condition."
3. Something that is essential to the occurrence of something else; essentially a "precondition."
4. As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.

See the entire definition of Condition

Depression : An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
See the entire definition of Depression

Diagnosis: 1 The nature of a disease ; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies . 3 The identification of any problem. The diagnosis was a plugged IV.
See the entire definition of Diagnosis

Dopamine: An important neurotransmitter (messenger) in the brain.
See the entire definition of Dopamine

Dysfunction: Difficult function or abnormal function.
See the entire definition of Dysfunction

ECG: Abbreviation for electrocardiogram or EKG. The K is from "kardio" (in German).
See the entire definition of ECG

Environment: The sum of the total of the elements, factors and conditions in the surroundings which may have an impact on the development , action or survival of an organism or group of organisms.
See the entire definition of Environment

Euphoria: Elevated mood. Euphoria is a desirable and natural occurrence when it results from happy or exciting events. An excessive degree of euphoria that is not linked to events is characteristic of hypomania or mania, abnormal mood states associated with bipolar disorders.
See the entire definition of Euphoria

Family history: The family structure and relationships within the family, including information about diseases in family members.
See the entire definition of Family history

Family medicine: Also called family practice . The medical specialty which provides continuing and comprehensive health care for the individual and family . It is the specialty in breadth which integrates the biological, clinical, and behavioral sciences. The scope of family practice encompasses all ages, both sexes, each organ system, and every disease entity. (From the American Academy of Family Physicians )
See the entire definition of Family medicine

Family therapy: A type of psychotherapy designed to identify family patterns that contribute to a behavior disorder or mental illness and help family members break those habits. Family therapy involves discussion and problem-solving sessions with the family. Some of these sessions may be as a group, in couples, or one on one. In family therapy, the web of interpersonal relationships is examined and, ideally, communication is strengthened within the family.
See the entire definition of Family therapy

FDA: The Food and Drug Administration, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services.
See the entire definition of FDA

Feedback: Many biologic processes are controlled by feedback, just as the temperature in a home from a furnace is regulated by a thermostat.
See the entire definition of Feedback

Feet: The plural of foot, both an anatomic structure and a unit of measure.
See the entire definition of Feet

Film: Slang shortening of X-ray film, an X-ray, a radiograph.
See the entire definition of Film

Food and Drug Administration: The FDA, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services.
See the entire definition of Food and Drug Administration

Generic: 1. The chemical name of a drug. 2. A term referring to the chemical makeup of a drug rather than to the advertised brand name under which the drug may be sold. 3.A term referring to any drug marketed under its chemical name without advertising.

See the entire definition of Generic

Genes: The basic biological units of heredity . Segments of deoxyribonucleic acid (DNA) needed to contribute to a function.
See the entire definition of Genes

Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
See the entire definition of Heart

High blood pressure : Also known as hypertension, high blood pressure is, by definition, a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90.
See the entire definition of High blood pressure

Hyperactivity: A higher than normal level of activity. An organ can be described as hyperactive if it is more active than usual. Behavior can also be hyperactive.
See the entire definition of Hyperactivity

Impulsivity: Inclined to act on impulse rather than thought. People who are overly impulsive, seem unable to curb their immediate reactions or think before they act. As a result, they may blurt out answers to questions or inappropriate comments, or run into the street without looking. Their impulsivity may make it hard for a child to wait for things they want or to take their turn in games. They may grab a toy from another child or hit when they are upset.
See the entire definition of Impulsivity

Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury . The injury may be accidental or deliberate, as with a needlestick injury . The term "injury" may be synonymous (depending on the context) with a wound or with trauma .
See the entire definition of Injury

Insomnia: The perception or complaint of inadequate or poor-quality sleep because of one or more of the following: difficulty falling asleep; waking up frequently during the night with difficulty returning to sleep; waking up too early in the morning; or unrefreshing sleep. Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause problems during the day, such as tiredness, a lack of energy, difficulty concentrating, and irritability.
See the entire definition of Insomnia

Intelligence quotient: An attempt to measure the intelligence of someone. Abbreviated IQ. The IQ score is usually based upon the results of a written test. To calculate the IQ, the person's mental age as determined by a test is divided by chronologic age, and the result is multiplied by 100.
See the entire definition of Intelligence quotient

Intervention: The act of intervening, interfering or interceding with the intent of modifying the outcome. In medicine, an intervention is usually undertaken to help treat or cure a condition. For example, early intervention may help children with autism to speak. "Acupuncture as a therapeutic intervention is widely practiced in the United States," according to the National Institutes of Health. From the Latin intervenire, to come between.
See the entire definition of Intervention

Lab test: A test that is done in the laboratory where the appropriate equipment, supplies, and certified expertise are available.
See the entire definition of Lab test

Lethargy: 1. Abnormal drowsiness, stupor. 2. A state of indifference.
From the Greek lethargia, drowsiness.
See the entire definition of Lethargy

Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.

See the entire definition of Liver

Marker: A piece of DNA that lies on a chromosome so close to a gene that the marker and the gene are inherited together. A marker is thus an identifiable heritable spot on a chromosome. A marker can be an expressed region of DNA (a gene) or a segment of DNA with no known coding function. All that matters is that the marker can be detected and trailed.
See the entire definition of Marker

Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
2. The history of medicine.
See the entire definition of Medical history

Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")
See the entire definition of Medication

Memory: 1. The ability to recover information about past events or knowledge. 2. The process of recovering information about past events or knowledge. 3. Cognitive reconstruction. The brain engages in a remarkable reshuffling process in an attempt to extract what is general and what is particular about each passing moment.
See the entire definition of Memory

Motor: In medicine, having to do with the movement of a part of the body. Something that produces motion or refers to motion. For example, a motor neuron is a nerve cell that conveys an impulse to a muscle causing it to contract. The term "motor" today is also applied to a nerve that signals a gland to secrete. Motor is as opposed to sensory.
See the entire definition of Motor

MRI: Abbreviation and nickname for magnetic resonance imaging . For more information, see: Magnetic Resonance Imaging ; Paul C. Lauterbur ; Peter Mansfield .
See the entire definition of MRI

Neurological: Having to do with the nerves or the nervous system.
See the entire definition of Neurological

Neurotransmitter: A chemical that is released from a nerve cell which thereby transmits an impulse from a nerve cell to another nerve, muscle, organ, or other tissue. A neurotransmitter is a messenger of neurologic information from one cell to another.
See the entire definition of Neurotransmitter

NIMH: Stands for the National Institute of Mental Health, one of the National Institutes of Health in the U.S., whose mission is to "provide national leadership dedicated to understanding, treating, and preventing mental illnesses through basic research on the brain and behavior, and through clinical, epidemiological, and services research."
See the entire definition of NIMH

NINDS: Stands for the National Institute of Neurological Disorders and Stroke, one of the National Institutes of Health in the U.S., whose mission is to "support and conduct research and research training on the normal structure and function of the nervous system and on the causes, prevention, diagnosis, and treatment of more than 600 nervous system disorders including stroke , epilepsy , multiple sclerosis , Parkinson's disease, head and spinal cord injury, Alzheimer's disease, and brain tumors."
See the entire definition of NINDS

Nose: The external midline projection from the face.
See the entire definition of Nose

Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis . There is always an onset to a disease but never to the return to good health. The default setting is good health.
See the entire definition of Onset

Ophthalmic: Pertaining to the eye. An ophthalmic ointment is designed for the eye.
See the entire definition of Ophthalmic

Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia . Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
See the entire definition of Pain

Personality disorder: A disorder characterized by the chronic use of mechanisms of coping in an inappropriate, stereotyped, and maladaptive manner. Personality disorders are enduring and persistent styles of behavior and thought, not atypical episodes. The personality disorders encompass a group of behavioral disorders that are different and distinct from the psychotic and neurotic disorders. The official psychiatric manual, the DSM-IV (Diagnostic and Statistical Manual of the American Psychiatric Association , Fourth Edition), defines a personality disorder as an enduring pattern of inner experience and behavior that differs markedly from the expectations of the individual's culture, is pervasive and inflexible, has an onset in adolescence or early adulthood, is stable over time, and leads to distress or impairment. Personality disorders are a long-standing and maladaptive pattern of perceiving and responding to other people and to stressful circumstances.
See the entire definition of Personality disorder

Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
See the entire definition of Pharmacy

Pregnancy : The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman's last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long.
See the entire definition of Pregnancy

Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.
See the entire definition of Prescription

Primary: First or foremost in time or development. The primary teeth (the baby teeth) are those that come first. Primary may also refer to symptoms or a disease to which others are secondary.
See the entire definition of Primary

Primary care: The "medical home" for a patient, ideally providing continuity and integration of health care. All family physicians and most pediatricians and internists are in primary care. The aims of primary care are to provide the patient with a broad spectrum of care, both preventive and curative, over a period of time and to coordinate all of the care the patient receives.
See the entire definition of Primary care

Primary care provider: In insurance parlance, a physician chosen by or assigned to a patient, who both provides primary care and acts as a gatekeeper to control access to other medical services.
See the entire definition of Primary care provider

Psychiatric: Pertaining to or within the purview of psychiatry , the medical specialty concerned with the prevention, diagnosis , and treatment of mental illness.
See the entire definition of Psychiatric

Psychiatrist: A physician (an M.D.) who specializes in the prevention , diagnosis, and treatment of mental illness . Psychiatrists must receive additional training and serve a supervised residency in their specialty. They may also have additional training in a psychiatric specialty, such as child psychiatry or neuropsychiatry. They can prescribe medication, which psychologists cannot do.
See the entire definition of Psychiatrist

Psychiatry: The medical specialty concerned with the prevention, diagnosis , and treatment of mental illness.
See the entire definition of Psychiatry

Psychosis: In the general sense, a mental illness that markedly interferes with a person's capacity to meet life's everyday demands. In a specific sense, it refers to a thought disorder in which reality testing is grossly impaired.
See the entire definition of Psychosis

Psychotherapy: The treatment of a behavior disorder, mental illness, or any other condition by psychological means. Psychotherapy may utilize insight, persuasion, suggestion, reassurance, and instruction so that patients may see themselves and their problems more realistically and have the desire to cope effectively with them.
See the entire definition of Psychotherapy

Puberty: A complex biologic and psychologic process involving sexual development, accelerated growth, and adrenal maturation heralded by the secretion of gonadotropin releasing hormone (GnRH) from a part of the brain called the hypothalamus . This event is the first known step in the reproductive cascade. It initiates the pulsatile release of gonadotropins , gonadal secretion of sex steroids, pubertal development, and gametogenesis (the production of sperm and ova ).
See the entire definition of Puberty

Quality of life: An important consideration in medical care, quality of life refers to the patient's ability to enjoy normal life activities. Some medical treatments can seriously impair quality of life without providing appreciable benefit, while others greatly enhance quality of life.
See the entire definition of Quality of life

Quotient: The result of mathematical division. The I.Q. (Intelligence Quotient) is arrived at by dividing the person's mental age (as determined on the Binet test) by the person's chronologic age and multiplying by 100. So if a child scores at the 8-year old level but is only 6, the I.Q. is 8/6 X 100=125.
See the entire definition of Quotient

Rebound: Return of the original symptoms when maneuvers or treatment is discontinued.
See the entire definition of Rebound

Resistance: Opposition to something, or the ability to withstand it. For example, some forms of staphylococcus are resistant to treatment with antibiotics.
See the entire definition of Resistance

Restless legs: See: Restless leg syndrome .
See the entire definition of Restless legs

Runny nose: Rhinorrhea is the medical term for this common problem. From the Greek words "rhinos" meaning "of the nose" and "rhoia" meaning "a flowing."
See the entire definition of Runny nose

Serotonin: A hormone , also called 5-hydroxytryptamine , in the pineal gland , blood platelets, the digestive tract, and the brain. Serotonin acts both as a chemical messenger that transmits nerve signals between nerve cells and that causes blood vessels to narrow.
See the entire definition of Serotonin

Short-term memory: A system for temporarily storing and managing information required to carry out complex cognitive tasks such as learning, reasoning, and comprehension. Short-term memory is involved in the selection, initiation, and termination of information-processing functions such as encoding, storing, and retrieving data.
See the entire definition of Short-term memory

Sign: Any objective evidence of disease. Gross blood in the stool is a sign of disease. It can be recognized by the patient, doctor, nurse, or others. In contrast, a symptom is, by its nature, subjective. Abdominal pain is a symptom. It is something only the patient can know.
See the entire definition of Sign

Sleep : The body's rest cycle.
See the entire definition of Sleep

Stage: As regards cancer , the extent of a cancer, especially whether the disease has spread from the original site to other parts of the body. See also: Staging .
See the entire definition of Stage

Stroke : The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA.
See the entire definition of Stroke

Substance: 1. Material with particular features, as a pressor substance .
2. The material that makes up an organ or structure. Also known in medicine as the substantia.
3. A psychoactive drug as, for example, in substance abuse .
See the entire definition of Substance

Substance abuse: The excessive use of a substance, especially alcohol or a drug. (There is no universally accepted definition of substance abuse.)
See the entire definition of Substance abuse

Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.
See the entire definition of Syndrome

Therapy: The treatment of disease .
See the entire definition of Therapy

Womb: The womb (uterus) is a hollow, pear-shaped organ located in a woman's lower abdomen between the bladder and the rectum. The narrow, lower portion of the uterus is the cervix; the broader, upper part is the corpus. The corpus is made up of two layers of tissue.

See the entire definition of Womb

Working memory: Short-term (recent) memory.
See the entire definition of Working memory

X-ray: 1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer . Formerly called a Roentgen ray. 2. An image obtained by means of X-rays.
See the entire definition of X-ray

Most Popular Topics

Explore 80+ Centers

Search Medical Dictionary

or A-Z List

We subscribe to the HONcode principles. Verify here.

©2008 WebMD, Inc. All rights reserved.
eMedicineHealth does not provide medical advice, diagnosis or treatment. See Additional Information.