Autoradiography 



AUTORADIOGRAPHY OF TISSUE* 



This article discusses techniques used for 

 autoradiography of human and animal tis- 

 sues and, to a limited extent, plant tissues. 

 Methods are outlined which will enable 

 those relatively inexperienced in autoradi- 

 ography to plan an experiment in\'olving 

 alpha, beta and gamma emitters and to pro- 

 ceed with the experiment confident of ob- 

 taining meaningful autoradiograms. A cur- 

 rent bibliography for the period 1954 to 

 1959 is that of Johnston (1). Boyd (2) has 

 cited numerous literature references. Foreign 

 journals often cany detailed papers relating 

 to autoradiography which should not be 

 overlooked as a source of information. 



The technique which produces an image 

 on a photographic plate or film when radio- 

 active material is opposed to it is called 

 autoradiography. The result of the exposure 

 of an emulsion to a radioactive specimen is 

 called an autoradiogram. The autoradiogram 

 supplies a graphic record of the sites of depo- 

 sition of radioactive isotopes within or on a 

 tissue and may be macroscopic, as in the 

 case of plant leaves, or in some cases micro- 

 scopic, at or below the cellular level. Au- 

 toradiography of tissues containing alpha, 

 beta and gamma emitters may be performed. 



Suggested Autoradiographic Tech- 

 niques for Alpha Emitters; Pluto- 

 nium 



In industries where contamination of per- 

 sonnel with radioactive substances is pos- 



* Work performed under Contract No. AT(45- 

 1)-1350 between the Atomic Energy Commission 

 and the General Electric Company. 



sible, low level detection procedures are 

 necessary. Plutonium, an alpha (5.14 Mev) 

 emitting radionuclide with some gamma ra- 

 diation and a 24,300 year half-life, may be 

 used as an example to illustrate one auto- 

 radiographic technique by which either par- 

 ticulate or soluble material may be graphi- 

 cally localized. 



A 24-hour sputum sample (3) from a per- 

 son known to have inhaled plutonium was 

 taken and fixed in 10% formalin, as was a 

 human biopsy of skin removed from a punc- 

 ture wound in the hand. The samples were 

 dehydrated in "Cellosolve" (glycol mono- 

 ethyl ether), cleared in xylene, and em- 

 bedded in paraffin. Sections were cut and 

 floated on a water bath, transferred by a 

 clean slide to a crystalhzing dish containing 

 distilled water. Working under light filtered 

 by a Wratten OA filter, a 5 /x NTA emulsion 

 coated on a 1 x 3 inch slide with a thin gela- 

 tin protective "T" coat was shpped under 

 the section. The excess water was drained on 

 to filter paper; the slides were then placed in 

 a Hght-tight plastic box made for this pur- 

 pose. A small vial of a desiccant (CaS04) 

 lightly closed with a cotton plug was added. 

 The appearance of the tracks from pluto- 

 nium which was in solution is characterized 

 in Figure 1 (a human sputum specimen), 

 where individual alpha tracks proceed in a 

 straight line. The appearance of the tracks 

 in sputum when plutonium is in the par- 

 ticulate form is illustrated in Figure 2, in 

 which alpha tracks arise from a central 

 point, with some random single tracks in the 

 field. 



Thirty-three sections from the plutonium- 



