What are the key parameters of a medical X-ray equipment tube?


The parameters of the tube include structural parameters (tilt angle, focal point, external dimensions, weight, filtration equivalent of the tube wall, anode rotation speed, operating temperature and cooling form, etc.) and electrical parameters (filament heating voltage & current, maximum tube voltage, tube current, maximum allowable power and anode heat capacity, etc.), of which the key parameters are the necessary prerequisites for the realization of the requirements of X-ray equipment for imaging high definition, high reliable operation, and so on.

① kV and mA values

The combination of these two parameters constitutes the ability of the tube to release electrons and X-rays to effectively penetrate the photographed object, and determines the amount of heat released inside the tube.

The greater the mA and kV, the more heat is released. Predicting the amount of heat generated helps to determine whether the dome tube is overheating during operation, and thus maintains and extends the life of the dome tube.

② Tube Power

The rate of heat generation within the tube is equal to the electrical power given by the tube and is usually related to the formula (Power (W) = w x kVp x mA).

The higher the power, the shorter the life of the tube. However, if there is not enough power, there may not be enough X-ray intensity to do the job, so operating the tube at the lowest available power extends its life.

Influence of tube voltage and tube current on X-ray intensity

③Anode target

The anode target links the focal width, the projected spot size and the focal heat capacity.

In the case of a certain effective focal point, the smaller the target angle, the larger the actual focal point, the more unfavorable to the target surface heat dissipation, so the target angle is generally 6-17.5 °, and the anode target requires a large heat capacity, good resistance to thermal expansion.

④Anode heat capacity

Focus (0.6~1.2) heat capacity, 200kHU, 300kHU, 400kHU and so on are more reasonable; Focus (0.3~0.8) heat capacity is 600kHU, 700kHU and above are more reasonable. Among them, the heat capacity of the bulb represents the bearing capacity of the whole tube sleeve, which is related to the heat dissipation curve; the larger the diameter size of the target surface, the more obvious the heat dissipation effect.

⑤ Focus size

Focus size is used to measure the spatial resolution presented by the tube, in order to obtain high quality image resolution, it is usually necessary to use a smaller focus size (micro-focus: less than 0.4mm; smaller focus: less than 1mm, micro-focus is usually used as a cardiovascular fluoroscopy tube more).

When shooting images, the smaller the focal point, the higher the resolution, but the power will also be reduced, the balloon can be a good solution to improve the power and reduce the contradiction between the focal point is extremely important.

Imaging at different focal points

Spatial resolution

Reflected in the medical clinic as the ability to image small lesions or structures, it represents the ability to distinguish the smallest geometric detail specific to an X-ray machine’s image, and is commonly measured in line pairs per centimeter per millimeter (lp/cm, lp/mm).

The higher the spatial resolution of the image, the better the X-ray machine can demonstrate the details of the area being photographed, although the spatial resolution is the result of the synergistic effect of multiple components of the equipment, such as the size of the ray focal point (the smaller the focal point, the higher the resolution), the detector pixel size and material, the accuracy of electromechanical scanning, and the method of calculating the image reconstruction.

The tube is the core component of medical X-ray equipment. However, even for professional medical X-ray equipment manufacturers, only a few of them have the ability to independently research and develop the production of tubes, and Nanjing Perlove Medical is one of them. Adherence to independent research and development of the core technology of the production concept, is Perlove brand equipment over the past two decades, a major dependence on the enduring.


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