Iatrogenic effects of diagnostic and therapeutic uses of X’ray and different radiations are matters of constant concern for the clinicians. Simultaneous attempts continue to prevent and cure such hazards. Cautious and vigilant application of these agents add to the benefit of their uses. A careless attitude is definitely harmful and dangerous.
General harmful effects of radiation –
Acute manifestations –
1. Nausea, vomiting, general indisposition occur in the initial phase.
2. A symptom free period follows.
3. Systemic involvement with excoriation of skin, erythema, blistering, followed by dermatitis and in a few of these cases prolonged ulceration of the skin; G. I. tract disturbances; Haemorrhagic condition.
4. Secondary infections.
Chronic manifestations –
In some cases delayed effects of radiation occur after a long period of therapy or exposure. The gap of time may even be a few years in some. In these subjects, malignant changes may occur in different organs, apart from other problems. To name the delayed complications of radiation, these are:
1. Malignant changes in different organs and systems, namely, haemopoetic system, lung, liver.
2. Exposure during pregnancy may lead to congenital abnormalities in the child.
3. Conditions like sterility, cataract may develop.
Dangers of exposure to X’ray –
The harmful effects may be on the patients, subjected to X’rays and on the radiologists and radiographers.
Early reactions in patients –
X’ray burn in the form of erythema with surface capillary dilatation and pigmentation.
Late reactions in patients –
Bluish discolouration of the subcutaneous tissue with necrosis and slough formation.
In radiologists and radiographers –
Continued prolonged exposure may cause epithelioma.
LASER BEAM INJURY
Laser (Light amplification by stimulated emission of radiation) beam may cause damage of the tissue, in subjects who work, in the laboratories or institution where LASER is in use. The commonest of the danger is damage to the retinal vessels.
EFFECTS OF RADIATION
The following factors have influence on the effects of radiation on human body –
1. Age – Young subjects are more vulnerable to the exposure of radiation.
2. Dose of the radiation – With 500 rads, chance of death is 50% ; with 1000 rads, the danger is 100%.
3. Sensitivity of the organs to radiations – Certain tissues or organs are highly sensitive to radiation, namely, bone marrow or germinal cells. On the other hand some of the body tissues are quite resistant to the effects of radiation, namely, the connective tissue.
4. Mode of administration – A dose received in a short period is more dangerous than the same dose taken, being spreaded over a long period.
5. Period of effectivity – This depends on Half life of different radiations, their elimination etc.
The half life of a radioactive substance is the period required for reduction of the radioactivity to half of its original strength. Half life may be expressed as:
(a) Radioactive half life – Time required for reduction of radio-activity by 50%, by way of decay of radio-activity.
(b) Biological half life – Time required by the body for natural elimination of 50% of the substance.
(c) Effective half life – Time required for reduction of the radioactivity of the substance to 50% of original, by the combined process of decay and elimination.
6. Type of radiation – Type of radiation (e.g., X’ray, radium needles etc) is very important in that, not all types are equally harmful.
7. Level of precaution adapted during the use.
1. Dose should be carefully decided.
2. To avoid accidental ingestion, inhalation etc. of the used radioactive substance.
3. Those who are exposed to radio-active substances, should be subjected to regular check up investigation, so as to be sure that there has not been any over-exposure or there is no sign of any damaging effect.
Medicolegal aspects –
Usually victims of Radiation injuries do not come to a medicolegist. However, legal problems may arise in the following circumstances.
a) With questions of negligence against a treating doctor for over exposure and causing damage to the patient.
b) Compensation cases, where workers vulnerable to radiation exposure, do suffer the harm due to the fault of establishment.