Acute radiation syndrome

According to research, radiation can cure you but it can also kill you because although it remains an important part of current medical technology that can be crucial in helping to properly identify and cure serious health conditions, if misapplied, it can cause life threatening issues.

Radiation overdose is one of those problems that patients seldom think will apply to them because they are so focused on their treatment and naturally assume that trained doctors and advanced technology would work in their favour. Unfortunately this was not the case for some patients at the BLCTC, who now have to face the trauma of being assessed for possible effects of an overdose of radiation.

In recent years, there have been fears of radiation exposure from airport scanners, cell phones, and even microwaves. However, the fact is, the source in which most people get the most exposure to radiation is medical tests.

Radiation therapy, or radiotherapy, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation therapy works by damaging the genetic material within cancer cells and limiting their ability to successfully reproduce. When these damaged cancer cells die, the body naturally eliminates them. Normal cells are also affected by radiation, but they are able to repair themselves in a way that cancer cells cannot.

Radiation therapy is used to cure cancer, reduce the risk that cancer will return in a certain area or palliate the symptoms of cancer. Radiation therapy can also be used to treat some benign conditions such as keloids and to prevent cardiovascular re-stenosis. More than half of all people with cancer and other diseases are treated with radiation therapy.

There are two basic types of radiation therapy, external beam and internal radiation. Some people receive both external beam and internal radiation therapy, depending on the type and location of their cancer. In external beam radiation therapy, the source of radiation is outside the body, directed toward the tumour using a machine. The radiation oncologist determines the precise point at which the radiation needs to enter the body, called the treatment portal, and places small tattoo dots to mark its boundaries. These tattoos are permanent and serve as the template for aligning the radiation delivery path.

The machine that delivers the radiation therapy is either a linear accelerator (which is most common) or a cobalt machine. These are similar in appearance to a large x-ray machine. When receiving radiation therapy the person lies on a table beneath the machine, often positioned with supports and blocks to maintain the proper alignment for the radiation to hit the tumour. Each treatment session may take 15 to 30 minutes, though the actual delivery of radiation takes only a few minutes.

Radiation therapy does not hurt or cause any discomfort, though the experience can be somewhat stressful for people who are claustrophobic (become uncomfortable in closed spaces) because the machine is very large and often very close during treatment. Because the source of the radiation is outside the body, the person receives only the directed energy and does not become radioactive. External radiation therapy is often among the treatments for lung cancer, breast cancer, prostate cancer, colorectal cancer, Hodgkin’s lymphoma, thyroid cancer, pharyngeal cancer, and some types of brain cancer.

Another form of external beam radiation therapy is intraoperative radiation, in which the person receives radiation to the surgical bed (site where the surgeon removed the tumour).

Intraoperative radiation takes advantage of direct exposure to the site of the cancer to destroy any cancer cells that may have penetrated the tissue surrounding the tumour.

Internal radiation therapy, also called radiation seeding or brachytherapy, more directly targets the tumour with radioactive pellets (radioisotopes encased in thin wire containers) about the size of grains of rice, implanted in the body into or very near the tumour. Internal radiation therapy delivers a higher dose of radiation more directly to the tumour site, and often for a shorter duration, than would be possible with external beam radiation therapy. Internal radiation may be among the treatments for breast cancer, endometrial cancer, thyroid cancer, cervical cancer, prostate cancer, and some cancers of the head and neck.

Internal radiation therapy may be interstitial, in which the radiation oncologist implants the radioactive pellets into the tumour or the tissue surrounding the tumour; intracavitary, in which the radiation oncologist inserts the radioactive pellets into a natural body cavity such as the uterus or rectum; or intraluminal, in which the radiation oncologist inserts the radioactive pellets into a natural body passage such as the esophagus or vagina.

Radiation affects the body in different ways, but the adverse health consequences of exposure may not be seen for many years.

Adverse health effects range from mild effects, such as skin reddening, to serious effects such as cancer and death. These adverse health effects are determined by the amount of radiation absorbed by the body (the dose), the type of radiation, the route of exposure, and the length of time a person is exposed.

Acute radiation syndrome (ARS), or radiation sickness, is usually caused when a person receives a high dose of radiation to much of the body in a matter of minutes. Survivors of the Hiroshima and Nagasaki atomic bombs and firefighters responding to the Chernobyl nuclear power plant event in 1986 experienced ARS.

The immediate symptoms of ARS are nausea, vomiting, and diarrhea; later, bone marrow depletion may lead to weight loss, loss of appetite, feeling like you have the flu, infection, and bleeding. The survival rate depends on the radiation dose. For those who do survive, full recovery takes from a few weeks to two years.

Children exposed to radiation may be more at risk than adults. Radiation exposure to the unborn child is of special concern because the human embryo or fetus is extremely sensitive to radiation.

Radiation exposure, like exposure to the sun, is cumulative.

People exposed to radiation will get ARS only if:

* The radiation dose was high (doses from medical procedures such as chest x-rays are too low to cause ARS; however, doses from radiation therapy to treat cancer may be high enough to cause some ARS symptoms),

* The radiation was penetrating (that is, able to reach internal organs),

* The person's entire body, or most of it, received the dose, and

* The radiation was received in a short time, usually within minutes.

The first symptoms of ARS typically are nausea, vomiting, and diarrhea. These symptoms will start within minutes to days after the exposure, will last for minutes up to several days, and may come and go. Then the person usually looks and feels healthy for a short time, after which he or she will become sick again with loss of appetite, fatigue, fever, nausea, vomiting, diarrhea, and possibly even seizures and coma. This seriously ill stage may last from a few hours up to several months.

People with ARS typically also have some skin damage. This damage can start to show within a few hours after exposure and can include swelling, itching, and redness of the skin (like a bad sunburn).

There also can be hair loss. As with the other symptoms, the skin may heal for a short time, followed by the return of swelling, itching, and redness days or weeks later. Complete healing of the skin may take from several weeks up to a few years depending on the radiation dose the person’s skin received.

The chance of survival for people with ARS decreases with increasing radiation dose. Most people who do not recover from ARS will die within several months of exposure. The cause of death in most cases is the destruction of the person’s bone marrow, which results in infections and internal bleeding. For the survivors, the recovery process may last from several weeks up to two years.

If a radiation emergency occurs that exposes people to high doses of radiation in a short period of time, they should immediately seek medical care from their doctor or local hospital.