Sec. 19.2] THE SAFE HANDLING OF RADIOACTIVE MATERIALS 451 



to remain fixed in the human body when breathed in the form of dust, 

 ingested, or introduced through lesions. Among these, certain alpha 

 emitters are the most dangerous because of the great damage inflicted on 

 tissues by the heavy ionization produced by alpha particles. 



The elaborate protective measures developed and practiced in the national 

 laboratories where large quantities of radioactive materials are processed 

 clearly demonstrate by their practically perfect record in health physics that 

 every precaution taken to minimize the health hazard and danger from con- 

 tamination is fully warranted. The general principles and much of the detail 

 of these practices is now sufficiently well known to enable any laboratory 

 contemplating the use of radioactive materials to institute the necessary 

 procedures and install the proper facilities for its particular needs. The follow- 

 ing sections are intended to outline these problems and practices, but refer- 

 ence to the literature cited is suggested for more exhaustive discussions. 



19.2. Medical Considerations. 1 Perhaps the most obvious hazards to the 

 health of laboratory personnel from radioactive materials are external 

 irradiation by gamma rays and beta particles and internal irradiation from 

 active material inadvertently taken into the body by inhalation, ingestion, 

 or other means. The types of injuries or subsequent pathological changes 

 following such exposures depend upon the radiation dose, the tissues irra- 

 diated, and various other factors such as the physical characteristics of the 

 radiation involved and duration of exposure. The medical treatment of 

 radiation damage is not well developed; some of the changes induced are 

 insidious in onset, and some are associated with grave consequences. Since 

 every effort must be made to ensure against significant exposure, emphasis 

 should be placed on prophylaxis. The situation may be compared in some 

 ways to the handling of infectious diseases in the laboratory or the use of 

 poisonous reagents. Provided that guesswork as to radiation exposure is 

 supplanted by measurement of radiation intensity and personnel monitoring 

 and such possibilities as air contamination are explored, with adequate pre- 

 cautions taken, work may proceed with confidence and safety. 



In addition to safeguarding laboratory personnel, thought should be given 

 to the possibility of contaminating other areas and involving persons outside 

 the laboratory, e.g., by sending contaminated laboratory coats to the laundry 

 or spreading activity through contaminated clothing and shoes. These 

 considerations, the problem of radioactive waste disposal, and others are 

 treated in the succeeding sections. 



In many instances it is not possible to avoid some degree of external 

 irradiation while working with radioisotopes; hence the need for knowledge 

 of "safe" exposures or tolerance doses has arisen. Much has been written 

 about this question, and reference may be made to a recent review by 



1 This section is by R. Lowry Dobson. 



