Dose-effect curves have been established for the various endpoints (erythema, dry or moist desquamation, permanent ulcer or healing) from experiments in animal models and from observations in radiotherapy patients. These studies have provided a suitable basis for improving radiological protection criteria for the skin, The pathogenesis of different late effects, including atrophy, fibrosis and sclerosis, observed after local exposure of skin and underlying tissues, has been assessed in the pig, the rabbit and the mouse in the first 18 months after exposure. Skin has been widely used in radiation carcinogenesis studies because of the accessibility and visibility of the tumors in the tissue. Both rat and mouse models have proved to be sensitive, reproducible systems to study the dose and time response of cancer induction following different mode and qualities of radiation exposure.
All these responses have been documented in human skin after accidental overexposure; the clinical studies on the Chernobyl and Goiania accidents victims made obvious combined injury, adding the effects of local and regional or total exposures. The problem of hot particles has been posed in these cases more acutely than as a hazard in the nuclear power plants.
Localized overexposure accidents are rather rare and generally due to industrial sources manipulation; their clinical evolutions are dramatic and surgical interventions are accepted rather bilatedly by the patients because of the extremely painful and hopeless nature of the pathological process in these injuries. Experience and knowledge supplied by both clinical following up of such lesions and experimental observations should be useful to give scientific basis for setting a common and well accepted management protocole of these radiological injuries. Studies on the pathogeny, the prevention and the treatment of fibrosis, the pretransformation of certain sort of skin cells, will be directly applicable to the management of the late effects of radiotherapy. Combining clinical and experimental researches worked out by the different contractants seems to be more efficient way to obtain rapidly practical methods for localized radiation injuries management.
ACUTE LOCALIZED IRRADIATION AND EXTERNAL CONTAMINATION ARE THE MOST FREQUENT ACCIDENTAL EVENTS IN RADIATION PROTECTION HAZARDS, CASES OF OVER-EXPOSURE OF THE SKIN AND UNDERLYING TISSUES. INCLUDING SKELETAL MUSCLES, CAN OCCUR IN BOTH MEDICINE AND INDUSTRY,IN A MAJOR ACCIDENT SITUATION, AS INDICATED BY EXPERIENCES FROM CHERNOBYL AN GOIANIA, SIGNIFICANT NUMBERS OF PERSONS WOULD BE AFFECTED, THE GRAVITY OF A RADIOBIOLOGICAL DAMAGE DEPENDS ON THE ENERGY DEPOSITED IN THE TISSUES, AND THE DOSE HAS TO BE DETERMINED AS ACCURATELY AS POSSIBLE IN ORDER TO EVALUATE THE PROGNOSIS AND TO MANAGE THE TREATMENT,
THE PATHOGENESIS OF DIFFERENT EFFECTS, INCLUDING ATROPHY; FIBROSIS AND SCLEROSIS, OBSERVED AFTER LOCAL EXPOSURE OF SKIN AND UNDERLYING TISSUES, HAS BEEN ASSESSED IN THE PIG, THE RABBIT AND THE MOUSE IN THE FIRST 18 MONTHS AFTER EXPOSURE, ALL THESE RESPONSES HAVE BEEN DOCUMENTED IN HUMAN SKIN AFTER ACCIDENTAL EXPOSURE; THE STUDIES ON THE CHERNOBYL ACCIDENT VICTIMS MADE OBVIOUS COMBINED INJURIES, ADDING THE EFFECTS OF LOCAL AND TOTAL OR REGIONAL EXPOSURES,
IN THE CLINICAL RESEARCH, WE HAVE THE POSSIBILITY TO USE ACCIDENTAL EXPOSED PATIENTS AND CASES IN RELATION TO PLANED RADIATION TREAMENT, ANIMAL EXPERIMENTS, ESPECIALLY IN PIGS WILL ENABLE US TO TEST NEW METHODS OF DIAGNOSIS AND TREATMENTS, AS CONCERNING PATHOGENESIS, FURTHER RESEARCHES HAVE TO BE PERFORMED ON THE IDENTIFICATION OF TARGET CELLS RESPONSIBLE FOR THE DIFFERENT TYPES OF EFFECTS OBSERVED AND THE DETAILED UNDERLYING CELLULAR AND MOLECULAR MECHANISMS, THE EXPERIENCE GAINED AS MUCH BY CLINICAL OBSERVATIONS AS BY ANIMAL EXPERIMENTS WOULD BE USEFUL AS SCIENTIFIC BASIS FOR DIAGNOSIS AND TREATMENT OF LOCAL OVEREXPOSURE OF THE SKIN AND THE SUBCUTANEOUS TISSUES,
Funding SchemeCSC - Cost-sharing contracts
EC1M 6BQ London
OX3 7LJ Oxford