Home - Education Resources - NDT Course Material - Radiation
 

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Radiation Safety

Introduction
Background Information
X-Radiation
Gamma Radiation
Health Concerns

Radiation Theory
Nature of Radiation
Sources of High Energy
   Rad

Rad for Ind Radiography
Decay and Half-life
Energy, Activity, Intensity   and Exposure
Interaction with Matter
Ionization
Radiosensitivity
Measures Related to   Biological Effects

Biological Effects
Biological Factors
Stochastic (Delayed) Effects
  -Cancer
  -Leukemia
  -Genetic Effects
  -Cataracts

Nonstochastic (Acute) Effects
Symptoms

Safe Use of Radiation
NRC & Code of Federal
   Reg
s
Exposure Limits
Controlling Exposure
  -Time-Dose Calculation
  -Distance-Intensity Calc
HVL Shielding
Safety Controls
Responsibilities
Procedures

Survey Techniques

Radiation Safety Equipment
Radiation Detectors
Survey Meters
Pocket Dosimeter
Audible Alarm Rate Meters
Film Badges
Thermoluminescent
   Dosimeter

Video Clips

References

Quizzes

Cancer

Cancer is any malignant growth or tumor caused by abnormal and uncontrolled cell division.  Cancer may spread to other parts of the body through the lymphatic system or the blood stream. The carcinogenic effects of doses of 100 rads (1 Gy) or more of gamma radiation delivered at high dose rates are well documented, consistent and definitive.

Although any organ or tissue may develop a tumor after overexposure to radiation, certain organs and tissues seem to be more sensitive in this respect than others. Radiation-induced cancer is observed most frequently in the hemopoietic system, in the thyroid, in the bone, and in the skin.  In all these cases, the tumor induction time in man is relatively long - on the order of 5 to 20 years after exposure.

Carcinoma of the skin was the first type of malignancy that was associated with exposure to x-rays. Early x-ray workers, including physicists and physicians, had a much higher incidence of skin cancer than could be expected from random occurrences of this disease. Well over 100 cases of radiation induced skin cancer are documented in the literature. As early as 1900, a physician who had been using x-rays in his practice described the irritating effects of x-rays. He recorded that erythema and itching progressed to hyper-pigmentation, ulceration, neoplasia, and finally death from metastatic carcinoma. The entire disease process spanned a period of 9 years. Cancer of the fingers was an occupational disease common among dentists before the carcinogenic properties of x-rays were well understood. Dentists would hold the dental x-ray film in the mouths of patients while x-raying their teeth.