Radium, its physics and therapeutics / [Dawson Turner].

  • Turner, Dawson (Dawson Fyers Duckworth)
Date:
1911
Catalogue details

Licence: Public Domain Mark

Credit: Radium, its physics and therapeutics / [Dawson Turner]. Source: Wellcome Collection.

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    will now be utilized, and the effect produced will be at a maximum, especially in the immediate vicinity of the radium, because the alpha rays will predominate, and they are very powerful, but of feeble penetration. If a subcutaneous. condition is to be treated, use a screen of aluminium of about half a millimetre in thickness, or a silver one of one-fifth of a millimetre, and give a longer exposure. The thicker the screen, the less the skin will be affected, but the longer the exposure. Only the beta and gamma rays will now be of use, for a thin sheet of note-paper is sufficient to stop all the alpha rays. If the disease be still deeper, use a lead screen, one-fifth or less to 1 millimetre in thickness, and give a prolonged exposure. Only the hard beta and gamma rays will get through, and they are few in number; thus the quantity and quality of the radiation has been altered. The deeper and denser tissues will now bear the brunt of the attack, and the skin and softer tissues will be almost unaffected. Very long exposures are necessary. Wickham and Degrais point out that, when primary rays pass through a metal such as a screen, secondary rays discovered by Sagnac are emitted. C.J. Barkla has shown that the Rontgen rays behave similarly. These rays, though of feeble penetrative power, may irritate the skin. They accordingly recommend that, when a metal screen is used, a thin envelope of some non-metallic substance should in addition be interposed to cut off Sagnac’s rays.