Category: L

A material commonly used for thermolu-minescent dosimetry.  

A device that uses microwave energy to accelerate electrons down a tube with ever increasing energy. The electrons may exit through a window and be directly applied to patients undergoing radiation treatment. Alternatively, the electrons may be aimed at a target that releases x rays when struck. The x rays can then be used to…

In any x-ray-producing equipment, the desired beam of radiation is emitted through the collimator. There is always some additional radiation that escapes through the shielding of the head of the machine. This is leakage radiation. Radiation refers to the emission of energy from sources other than the intended radiating system. An example frequently encountered is…

The ability of an x-ray imaging system to produce acceptable images over a range of exposures. If a system has wide latitude it is possible to image parts of the body that vary in thickness or density with only one exposure. A system of lesser latitude would require a lower exposure over the thin section…

Inability of the larynx (voice box) to produce normal speech. A person can lose his or her ability to speak when the nerve supply that normally pushes the two vocal cords together is damaged or destroyed. The most common causes of voice loss are viral infections and overuse of the voice. The voice usually returns…

Anovulation; the inability of the ovaries to produce mature eggs or to release mature eggs on a regular basis. Among the most common causes of infertility in women, anovulation usually results from hormone imbalances, which may be caused by excessive weight loss, obesity, stress, or strenuous exercise. It also frequently occurs in women with polycystic…

A persistent absence of the climax phase during sexual activity despite adequate sexual stimulation. Lack of orgasm is also known as anorgasmia, and it can affect both men and women. The condition may be lifelong or it may arise only in certain situations. Causes can be physical or psychological. Physical causes include diseases such as…

Forgetfulness that can result from brain damage or severe emotional trauma; amnesia. Pathological loss of memory can be caused by dementia, Alzheimer’s disease, alcoholism, head injury, seizures, stroke, brain surgery, ECT (electroconvulsive therapy), the use of barbiturates or other tranquilizers, and other physical events or conditions. Depending on the cause, loss of memory can occur…

A surgical procedure performed under general anesthesia to cut away adhesions, which are composed of scar tissue formed after earlier surgery. Those adhesions are most common in the abdomen. Because fibrous scar tissue is inelastic, adhesions in the abdomen can cause pain when they are stretched. In addition, adhesions involving the intestine can block or…

A complicated, high-risk surgical procedure in which a healthy lung or lungs replace damaged or diseased lungs. Lung transplantation is performed only as a lifesaving measure on people who have not responded to other treatment options, will not survive without the transplant, and have a high probability of a positive outcome from the transplant. Most…