Early Philips Rotating Anode
Mammography
Tube
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Looking into the tube from the anode side. Note the
back-side perforations of the anode disc. |
X-ray
view of tube |
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Dating back to the early
or mid-seventies, this oil-immersed metal-shielded tube has a single 0.6 mm
focal spot, fed by a six pulse generator, with an output of 25 to 50 kV and
200 mA. The tube has a Beryllium window and a rotating Molybdenum
faced anode disc, and is fitted with an additional Molybdenum filter. In the
tube housing, there was a provision for water-cooling. The 200mA power, and
the water-cooling were necessary because initially mammography films came in
light-tight paper envelopes, and needed long exposures. The Mammography
Screen-Film procedures came several years later. |
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Modern mammography tubes have two focal spots,
generally 0.3mm and 0.1mm, an output generally of 100 mA,
and are fed by a high frequency generator. Besides the molybdenum target,
some tubes are also fitted with a Rhodium target and/or a Rhodium filter. |
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