Application of the Magnetron Sputtering Technique to the development of a Contrast Detail Test Object for mammography-Master Thesis BERMUDEZ JUDILKA

Author: BERMUDEZ JUDILKA ; Type of thesis: Master Thesis
Abstract: In the past few decades a large amount of attention has been given to health service’s technology. Advances in electronic components, computer technology, and images processing have contributed considerably to the expansion and improvement of the field. However, there is evidence that several other related topics still need to be explored, such as X-ray imaging in the routine mass screening for medical diagnosis.
Tumors formation is one of the most common human health problems and large efforts have been undertaken world wide to tackle the disease. Breast cancer specifically seems to affect a large percentage of the female population. Research indicates that breast cancer treatment is most effective if the disease is diagnosed in its early stages of development. Traditionally, X-ray technologies have been used for breast screening film mammography and its success in detecting breast cancer has been reconfirmed throughout the past few decades. However, the technique has several limitations, and further improvements are required if we wish to achieve early stage diagnosis. Image formation in radiological diagnosis is the result of the complex interdependence of many factor. Creating an ideal balance among them could improve the image to such a degree that it could be used in a clinical setting, where the minimum radiation dose would be applied to the patient. The factors which increase radiation dose and affect image quality can be grouped as: radiation quality, photon intensity, Xray detection sensitivity, and reduction of background through scattered radiation. Optimum performance is dependent on the improvement of the assessments of these phenomena. In the past, standard methods of quality control have been introduced which have lead to a partial improvement in the image evaluation techniques. Some methods, widely applied, involve the use of test objects or phantoms for the establishment of comparison parameters. However, the methods that use phantoms, are frequently not
as reliable as radiation based diagnoses of asymptomatic woman produce. In addition,the subjective nature of image interpretation by medical professionals can make the assessment process very difficult. Consequently, the currently available tools which are used for breast clinical image formation and interpretation regularly results in an incorrect diagnosis.
In past years, the commercially introduced digital detectors for mammography were seen as an important advancement since they provided both a higher acquisition speed and a lower associated radiation dose. However, up until this point, the quality of the produced images is comparable to the images obtained with film detectors. Even though applying a lower dose represents a great advantage, there is no improvement in image quality production. In addition, has been demonstrated that using traditional phantoms, to evaluate image quality on digital mammography, did not bring enough information about certainties on dose measurements. But a new window is open for innovation, since dose control on digital mammography systems depends on factors where major improvement can be achieved. Theoretically, it is possible to enhance discriminating threshold and therefore improve image interpretation at a higher degree. Although at the moment it has still not been achieved, it is within reach since there is currently underway the development of new instruments which have a better approach for the assessment of digital mammography systems. We propose one of the improvements.
The construction and research of the uniformity and replicability of a contrast detail test object could represent an advance in this research field. Until now, a phantom use for digital mammography has not been provided, that can provide both uniformity and reproducibility such that it could be used as a main interpretational tool. This knowledge would allow for the establishment of standard parameters in both the systematic and even auto