gh eenote tenn, woul RADEABPION INJURY. PPS PATHOGEN ESis AND PHELRAPY Pu tent period. infection= and hemorthages will become more prominent. In the Japanese, infections were particularly apparent 5 too weeks after exposure and hemorrhagic phenomena four to 6 weeks after exposure (LeRoy. SRR sey “Eade pe ps Details of the serial blood chatiges have been covered ina previous chapter. With large amount~ of radiation (2000 to 50,000 ry the signs and svniptonis appearin an inteus#fied form with mean survival time of about 3 to 4 days. With doses in excess of 30,000 r sudden deaths oceur in mice preceded by convulsions, central nervous system svinptonis, or respiratory difhenlty (Langham ef al). 9.4 Acute Illness from Partial Exposure to Penetrating Radiations The acuteness that is produced by exposure of part of the body to penetrating radiations is seen characteristically in patients undergoing high voltage x-ray therapy for cancer, With respect to the imitial so-called “toxic symptoms,” they are similar to the syndrome produced bya single intense exposure of the whole body to penetrating radiation. Radiation of certain areas of the body will produce the illness with greater frequency, or with less radiation than for exposure of other parts of the body. Exposure of a relatively small area of the body does not produce the severe pancytopenia that results from exposure of the whole body to the same amount and type of radiation, Irradiation of the thorax and abdomen, particularly the upper abdomen, produces a high incidence of nausea, vomiting, and anorexia. In contrast to this, irradiation of the head and extremities rarely produces these symptoms. Since the clinical course and handling of this type of reaction to penetrating irradiation have heen amply covered in recent text books and reviews of clinical radiology, further discussion is not necessary. These initial “toxic symptoms” should be distinguished sharply from the serious syndromes that can develop in days or weeks if sizeable regions of the body are exposed to high doses of radiation. For instance in the Lockport accident (Howland c¢ al.) a variety of signs and symptoms in- cluding severe pancytopenia developed after exposure of the head, thorax, and abdomento large doses of x-radiation. In general, following partial or surface exposure, the organism is able to react locally and generally to injury, in accordance with the concept of adaptation (Selye). Bond ef al. have demonstrated that local irradiation of the abdomen and elsewhere in the body produces the alarm reaction as described by Selye. In contrast to this, exposure of the whole body to large amounts of penetrating radia- tion produces diffuse injury of varving degrees to all tissues and the organism may be less able or unable to react with the usual protective and adaptive mechanisms. IGizZboS