The development process of CT tubes: The structure of CT tubes is basically the same as that of the tubes used on ordinary X-ray machines. There are also two types: fixed anode tubes and rotating anode tubes. At present, the commonly used type is the rotating anode ball tube. In 1895, the German physicist Rontgen discovered X-rays while experimenting with cold cathode tubes. The tube he used at that time was called a "Crookes tube", which was a sealed glass tube containing two electrodes (anode and cathode) and a small amount of gas. When the Crookes tube is connected to high voltage, the gas inside the tube ionizes, and the electrons, after being accelerated, strike the target surface to produce X-rays. The tube current and tube voltage of the Crucible tube cannot be adjusted separately, and it has low power, short lifespan and unstable X-ray quality.

In 1896, C.H.F.Muller created the world's X-ray tube with practical application significance. It was a very simple tube without a clear focus point. After the filament is powered on, X-rays are emitted throughout the bottom, and the received image is very blurry. In the same year, Muller created an X-ray tube with a focus, also known as the Muller tube. This kind of spherical tube has a concave mirror placed at the cathode to converge X-rays at one point. After current is passed through both ends, an electron stream is emitted from the cathode and strikes the anode, generating X-rays.

In 1913, Coolidge created the stationary anode X-ray tube with high vacuum thermal cathode, also known as the Coolidge tube. This CT tube has a high vacuum degree inside. Electrons are emitted from the hot cathode and are accelerated by the high voltage applied at both the anode and cathode to impact the anode target surface, generating X-rays. The Coolidge tube only needs to change the working temperature of the cathode to adjust the size of the tube current. In addition, the tube current and tube voltage of the Coolidge tube can be adjusted separately. In 1923, the dual-focus fixed anode tube was successfully developed, enabling a single tube to simultaneously possess two different focus sizes and power characteristics. Since the anode target of the fixed anode tube is stationary, the high-speed electron flow bombards the fixed position of the anode target, which has the characteristics of low power and large focus. At present, fixed anode tubes are only used in low-power mobile X-ray machines or dental X-ray machines.

In 1927, the rotating anode X-ray tube was successfully developed. The high-speed moving electron beam is emitted from the cathode deviated from the central axis of the tube and bombards the rotating target surface. Due to the heat generated by the high-speed moving electron beam bombarding the target surface, it is evenly distributed on the rotating annular surface. The area bombarded by the electron beam is greatly increased due to the rotation of the anode (the actual focus and spatial position remain unchanged), and the heat distribution area is greatly increased. Due to the characteristics of high power and small focal point of the rotating anode tube, it has developed rapidly since its introduction. In the 1960s, the rotational speed of the rotating anode reached 9,000 r/min. The metal-cased rotating anode tube was presented in the 1970s.

In 2003, Siemens launched the straton electron beam controlled tube. straton electron beam controlled tubes adopt an anode direct cooling design, which can release up to ten times the heat compared with traditional CT tubes. Rapid cooling means that smaller anodes can be installed, thus the equipment is lighter in weight, further improving mechanical stability while achieving higher rotational speeds. In addition, straton electron beam control tubes also feature "flying focus" technology, which can record each projection of each scan from multiple angles, improving the sampling rate and significantly enhancing the clarity of the image.

In 2013, GE launched a liquid bearing ball tube named Performix Plus, and in 2015 it launched a new Performix 40 Plus liquid bearing ball tube for Revolution EVO CT. The liquid bearing ball tube not only achieves high-speed rotation and provides high-quality images, but also reduces the noise during rotation. More importantly, it extends the service life of the CT ball tube.