Σχεδιασμός ομοιώματος για χρήση στην κτηνιατρική απεικόνιση ακτίνων-Χ

Abstract

The phantom is a specially designed object that is scanned or is represented in the field of the medical imaging so as to evaluate, analyze and optimize the performance of various ways of imaging. Its contribution is also useful for avoiding a living organism in unnecessary radiation exposure. There are two categories of phantoms; anthropomorphic phantoms and calibration phantoms. Digital radiography is constantly evolving especially in the veterinary field and the use of radiation requires responsibility in order to maintain the high quality of the image. Restraining and positioning of animals are important so as to get quality x-rays. For this particular reason, a large amount of phantoms is utilized to optimize image quality. The purpose of the present study is to create a three-dimensional animal phantom for the utilization of X-ray in the veterinary field, which will describe the required amount of animal volume. The science of three-dimensional (3D) printing consists of three phases: 1) the design of the object by the user, 2) the printing and 3) the insurance of the delicacy of each part of the phantom. In order to design the phantom, the Autodesk Maya program has been used. The presented phantom will have the shape of an animal where in the lower part of it, it will be designed as an hole. This hole will be of specific dimensions and this is where the CDRAD phantom will be displayed during the process of the imaging with the use of X-ray. The CDRAD phantom will be used to obtain the desired radiographic imaging and for the quality control of the final image, based on the contrast and detail of the imaging area. For the purpose of the presented printing, various factors have been taken into account such as the dimensions of the final phantom, the area of interest as well as the cost of the printing material. The phantom that has been designed a length of 715 cm, a width of 1180 cm, and a thickness of 83 cm. The area chosen to be printed is only the body of the animal, due to the fact that this is the desired area that we wanted to visualize and study. The final phantom that has been printed has a length of 30 cm, a width of 36 cm, and a thickness of 7.9 cm. The material that has been chosen for its print is the PLA. For the selection of the material, it has been taken into account as a basic criterion the radiation absorption of the material that would be used for the printing in relation to the radiation absorption of the PMMA material, that the CDRAM phantom is made of, in a combination of both the price and the time that is required for the printing as well as its chemical and mechanical properties. Finally, due to the SARS-CoV-2 pandemic (COVID 19) it was not possible to image the phantom with a spectrum of radiation. For this reason, after the construction of the phantom a theoretical study was carried out regarding the permeability of the phantom during its exposure to X-rays using mono-energetic radiation for two different thickness measures of the phantom.