Early Philips Mammography Tube

Looking into the tube from the anode side. Note the back-side perforations of the anode disc.

X-ray view of tube

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 non-screen mammography films came in light-tight paper envelopes, and needed long exposures. The Mammography screen-film technique came several years later.

Modern mammography tubes have two focal spots, generally 0.3mm and 0.1mm, an output generally of 100mA, 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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