ORGAN AND BODY SYSTEMS 487 



Coutard (50, 51) has found that either protracted or simple frac- 

 tional irradiation with a total dose of 4500 to 5000 r is followed by severe 

 damage to the skin and mucous membranes which heal, however, and 

 remain intact for at least 6 to 7 years. The treatment is given in two 

 daily sessions of 1 hr. each (225 to 250 r, the intensity being 7.5 to 20.0 r 

 per min.) for 10 days. There is redness of the skin with edema by the 

 end of this time, and desquamation begins, so that by the twenty-eighth 

 day there is a total loss of the superficial epithelial cells with a denudation 

 of the epidermis, accompanied by pain. The lesion is usually repaired 

 by the forty-second day "without any visible trace" of injury. With 

 greater doses the period of reaction is longer; with smaller doses, the pain 

 is less. 



By appropriate spacing of the exposures, the time of the reaction in 

 the mucous membranes of the mouth and throat can be separated from 

 that of the skin. Mucositis occurs between the fourteenth and the 

 twenty-eighth days, and is practically asymptomatic. Radio-epi- 

 dermitis develops between the twenty-eighth and the forty-second day. 

 This very interesting and puzzling sequence occurs if the radiation is 

 given over a period of 14 days. The difference is probably due to the 

 smaller dose received by the mucosa in contrast to that supplied to the 

 skin. If the period is prolonged to 18 days with proportionately smaller 

 daily doses, the damage to the skin is less and the skin heals sooner. 

 Lesions produced by this method are considerably greater than those 

 which follow a massive dose, but they heal with little damage, leaving 

 the skin thin and flexible and usually free of pigment (61, 241, 324, 392). 

 But telangectasis and permanent edema may ensue (150). For a 

 further discussion of this topic see Zuppinger (402). Holf elder (157) by 

 giving 50 to 60 per cent of an erythema dose every 2 to 5 days over a 

 period of 2 to 6 weeks, was able to administer a total of 1600 to 2400 r. In 

 his procedure, the dosage in successive treatments is gradually decreased, 

 while the intervals are increasingly prolonged. 



McNattin (221) used the Coutard method of treatment with 200-kv. 

 radiation and compared the effects with those obtained with 700 kv. 

 administered by the fractional method, and with the radium pack. He 

 believes that as a first approximation the following doses may be thera- 

 peutically equal if fractionated over a period of 3 weeks or longer : (a) for 

 200-kv. roentgen rays, 6 threshold erythema doses, (6) for 700-kv. 

 roentgen rays, 4.7 erythema doses, (c) for gamma rays, 1.6 to 2.2 erythema 

 doses. The threshold erythema dose is 600 r for 200-kv. radiation 

 (massive dose) filtered by 0.5 mm. Cu and 3.0 mm. Al and includes 

 back-scattering. The skin reaction with the above large (tolerance) 

 doses is very marked with the 200-kv. radiation and with gamma rays, 

 and less severe with the 700-kv. rays. On the other hand, after the skin 

 has healed, the mildest changes are found after the gamma-ray treat- 

 ment (66, 144, 149, 194, 311). 



