Design and Construction of a Simple Applicator for 1,000 Curies of Cobalt 60

The Effect of Source Size upon Integral Dose in Teletherapy Units

“…It is evident from the tables that the large cobalt 60 units with souree diameters less than 3 em deliver integral doses per r at the tumour less than those delivered by conventional roentgen apparatus. An exception is the Los Angeles unit (12), where the source is a cylinder 4.33 em high by 3.5 em diameter and a side view of the cylinder is presented to the treatment cone. It also appears that although the walls of the treatment cones may playa small part in limiting the beam, the main lead defining aperture is 40 em from the skin when the S. S. D. is 70 em.…”

Sensitivities of Different Bacteriophage Species to Ionizing Radiations

“…Often several different phage lysates were exposed simultaneously, mixed together in the same gelatin cake, titrations being performed on differential indicators. For all irradiations the Co60 source of the Los Angeles Tumor Institute (Neil et al, 1953) was employed,3 the samples being exposed at approximately the same distance from the source as used by Weigle and Bertani (1956). Their measurement of the radiosensitivity of phage T2 (their table 1, lowest multiplicities of infection) agrees within 10 per cent with the estimate obtained here (table 1), when correction is made for the decay of the radioactive source (half life = 5.3 years).…”