Radiotherapy in the context of "Radiation burn"

The gray (symbol: Gy) is the unit of ionizing radiation dose in the International System of Units (SI), defined as the absorption of one joule of radiation energy per kilogram of matter.

It is used as a unit of the radiation quantity absorbed dose that measures the energy deposited by ionizing radiation in a unit mass of absorbing material, and is used for measuring the delivered dose in radiotherapy, food irradiation and radiation sterilization. It is important in predicting likely acute health effects, such as acute radiation syndrome and is used to calculate equivalent dose using the sievert, which is a measure of the stochastic health effect on the human body.

Oncology, from Ancient Greek ὄγκος (ónkos), meaning "tumor, bulk", and λόγος (lógos), meaning "study", is a branch of medicine that deals with the study, treatment, diagnosis, and prevention of cancer. A medical professional who practices oncology is an oncologist.

Oncology is focused on the diagnosis of cancer in a person, therapy (e.g., surgery, chemotherapy, radiotherapy and other modalities), monitoring of people after treatment, palliative care for people with advanced-stage cancers, ethical questions surrounding cancer care, screening of people who may have cancer, and the study of cancer treatments through clinical research.

In medicine, a side effect is an unintended effect caused by a medicinal drug or other treatment's capacities or properties, and these effects are often adverse but sometimes beneficial. Herbal and traditional medicines also have side effects.

A drug or procedure usually used for a specific effect may be used specifically because of a beneficial side-effect; this is termed "off-label use" until such use is approved. For instance, X-rays have long been used as an imaging technique; the discovery of their oncolytic capability led to their use in radiotherapy for ablation of malignant tumours.

Xerostomia, also known as dry mouth, is a subjective complaint of dryness in the mouth, which may be associated with a change in the composition of saliva, reduced salivary flow, or have no identifiable cause.

This symptom is very common and is often seen as a side effect of many types of medication. It is more common in older people (mostly because individuals in this group are more likely to take several medications) and in people who breathe through their mouths. Dehydration, radiotherapy involving the salivary glands, chemotherapy and several diseases can cause reduced salivation (hyposalivation), or a change in saliva consistency and hence a complaint of xerostomia. Sometimes there is no identifiable cause, and there may sometimes be a psychogenic reason for the complaint.