Manufacturing method of rat model for small animal position emission tomography (PET) scattering fraction measurement

Abstract

The invention provides a manufacturing method of a rat model for small animal position emission tomography scattering fraction measurement. The rat model is divided into a main cylinder and auxiliary mandrels. The manufacturing method comprises the following steps of: firstly, manufacturing a right cylinder polyethylene bar with the diameter of 50 mm and the length of 150 mm, drilling an eccentric circular hole with the aperture of 10 mm and the length of 150 mm at a position which is 17.5 mm away from the section center of the right cylinder polyethylene bar along a direction parallel to the long axis of the right cylinder polyethylene bar by adopting a method of drilling at two ends to manufacture the main cylinder; then preparing three auxiliary mandrels with the diameter of 10 mm and the length of 50 mm, wherein the center of each auxiliary mandrel is provided with a central circular hole with the diameter of 3.2 mm and the length of 50 mm; and sequentially filling the three auxiliary mandrels into the eccentric hole on the main cylinder to finish the manufacturing. In the manufacturing, the H / d value is greatly reduced so that the manufacturing difficulty is greatly reduced, and the precision requirement is easy to achieve. After the manufacturing is finished, disassembly manufacture is not needed for the model, thereby the operation is simple, and the model has good stability and long service life.

Description

technical field [0001] The invention relates to a method for preparing a model for measuring scattering fraction in small animal positron emission tomography (Positron Emission Tomography, PET) performance testing, in particular to a method for preparing a rat model for measuring PET scattering fraction for small animals. Background technique [0002] NEMA (National Electrical Manufacturers Association) put forward clear requirements for the production of the scattering fraction measurement model in its 2008 edition of "Small Animal PET Performance Measurement Standards". According to several commonly used experimental animals (mice, rats, Monkey), the NEMA standard specifies three measurement models of scattering fraction with different sizes in turn: mouse model, rat model, and monkey model. These three types of models are similar in structure but different in size. Among them, the rat model is a regular cylinder with a diameter of 50 mm and a length of 150 mm, and the ma...

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Problems solved by technology

In the process of making the rat model, the machining of this round hole is faced with a difficult problem: in actual production, the difficulty of machining the hole is usually measured by the ratio of the drilled hole depth H to the hole diameter d, H / If the value of d is too large, many problems will occur: such as twist drill breaking, swinging, large hole position and size deviation, large hole diameter deviation, etc.

For the round hole processing of the rat model, the ratio of H / d is too large (about 47), and it is difficult to achieve the processing results that meet the precision requirements by the method of one-time drilling.

At present, there is no unit that produces this model in China. One way to solve this problem internationally is to cut the cylinder to be processed into three sections and process them separately. In this way, the H / d value of the drilled hole is reduced to the original 1 / 3, thus reducing the difficulty of processing and meeting the precision requirements, but the disadvantage of this method is that a central screw needs to be prepared for the series connection of three cylinders to make a detachable rat model, Due to the instability of the central screw used in this model, the overall specifications of the model will be incoherent after being made, and it is troublesome to use

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