\-K\Y MICROSCOPY 



absorbing x-rays. Intracellular components 

 require a greater magnification for their vis- 

 ualization than that possible in microradi- 

 ography. 



The x-ray industry must understand that 

 now together with macroradiology (diag- 

 nostic and therapy) there exists also micro- 

 radiology (contact microradiography and 

 x-ray projection microscopy) applied tomedi- 

 cobiological research. 



Practical Suggestions for Starting Mi- 

 croradiography in a Laboratory 



Choice of Equipment. The equipment 

 depends on the kind of microradiographical 

 research which one has in mind. The most 

 complicated and expensive eciuipment is 

 necessary for microradiography of non- 

 calcareous tissues per se. This has to consist 

 of a special tube with the inbuilt vacuum 

 camera and a transformer which permits a 

 tension so low as 3 kv (see above in "X-ray 

 factor"). So far as we know" this ecjuipment 

 is made only to special order and is not listed 

 by any manufacturer (see equipment of 

 Lamarque, Fitzgerald, Engstrom and 

 others). 



A much simpler ecjuipment is possible for 





z 



•^ 



Fig. 23. Tube stand (A), tube (B) and cassette 

 (C) in position. X-rays pass through a cone (D). 

 E— Diffraction unit. 



microradiographical research of calcareous 

 tissues, microvasography, etc. It has to 

 consist of a tube and power supply. The 

 above mentioned AEG-50A Machlett tube 

 with 1 mm thick beryllium window may be 

 used. The tube is supplied with hoses per- 

 mitting cooling with flowing water from any 

 water tap. A tube stand for this tube may 

 be made in any workshop (Fig. 23). 



The low voltage necessary for the AEG- 

 50A tube may be obtained either from a 

 diffraction unit or from a special micro- 

 radiographical equipment made by some 

 companies (e.g. Philips). In the latter the 

 midget tube (with beryllium window and 

 air cooling) is built into the transformer 

 housing. The defect of this equipment is its 

 low effectiveness due to the absence of water 

 cooling and other reasons. 



Diffraction unit produces stabilized, recti- 

 fied secondary current. Kv range is from 

 5 to 50. It is costlier than the former but is 

 more powerful. It w^orks also with the 

 Machlett tube. 



One may obtain low voltage also from the 

 usual diagnostic transformer. It is only 

 necessary to regulate input to the primary 

 coil of this transformer. It is known that the 

 coefficient of transformation is in trans- 

 formers of this continent approximately 500. 

 That is to say, 20 v input produces approxi- 

 mately 10 kv. Since autotransformers of 

 usual diagnostic apparatus cannot regulate 

 so low an input, it is necessary to use an 

 additional autotransformer for these low 

 voltages. The switching of this autotrans- 

 former and the calibration of the resulting 

 kv output can be done easily by any en- 

 gineer or even a skilled electrician. Since 

 any obsolete transformer may be used for 

 the equipment this self-made microradio- 

 graphical unit will be within the financial 

 limits of any laboratory. 



Cutting and Coloring of Calcareous Tis- 

 sues. Specimens of calcareous tissues with 

 surrounding soft tissue of the smallest pos- 

 sible size are removed after death and fixed 

 in 10% neutral formalin for at least 1 week, 



620 



