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208 R a d i u m
GENERAL RECOMMENDATIONS
It is the duty of those in charge of X-ray and radium departments
to ensure efficient protection and suitable working conditions for the
personnel.
The following precautions are recommended:
I. Not more than seven working hours a day.
2, Sundays and two half-days off duty each week, to be spent as
much as possible out of doors.
3. An annual holiday of one monlh or two separate fortnights.
Sisters and nurses, employed as whole-time workers in X-ray and
radium departments, should not be called upon for any other hospital
service.
PROTECTIVE MEASURES
It cannot be insisted upon too strongly that a primary precaution
in all X-ray work, whether with stationary or portable sets, is to surround
the X-ray bulb itself as completely as possible with adequate protective
material, except for an aperture as small as possible for the work in hand.
The protective measures recommended are dealt with under the following
sections:
I. X-rays for diagnostic purposes.
II. X-rays for superficial (low-voltage) therapy.
III. X-rays for deep (high-voltage) therapy.
IV. Electrical precautions in X-ray departments.
V. Ventilation of X-ray departments.
VI, X-rays for industrial and research purposes.
VII. Radium therapy.
It must be clearly understood that the protective measures recommended
for these various purposes are not necessarily interchangeable;
for instance, to use for dee]' therapy the measures intended for superficial
therapy would probably subject the worker lo serious injury.
It should be further pointed out that the protective values of certain
materials are much affected by a change in the voltage applied to
the X-ray tube. This applies particularly to materials in which lighter
elements than lead furnish the chief protection. The importance of
obtaining a National Physical Laboratory test in this connection is emphasized.
In the case of protective slabs or plasters made up of a mixture
of materials, the difficulty of securing uniform mixing should be
met by a generous margin of safety in estimating the required thickness.
I. X-RAYS FOR DIAGNOSTIC PURPOSES
1. Screen Examinations
(a) The X-ray bulb should be enclosed completely as possible
with protective material equivalent to not less than 2 mm. of lead. The
material of the diaphragm should be equivalent to not less than 3 mm.
of lead. The design of the diaphragm should be such as to permit it to
be completely closed. The simpler rectangular forms of diaphragm
will, in general, be found preferable to the iris type.
In the case of installations which are incapable of generating peak
voltages exceeding 70,000, the lead value of the tube enclosure may be
reduced to 1.5 mm. and of the diaphragm to 2 mm.