DEVELOPMENT AND VALIDATION OF PHANTOM FOR ULTRASONOGRAPHIC SIMULATOR FOR PULMONARY TISSUES

• Main Author: Alfa Nabila, Citra
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/84415
• Institution: Institut Teknologi Bandung

Ultrasonography (USG) is one of the medical diagnostic methods that utilizes high- frequency acoustic waves. Ultrasound can be used as an alternative method of examining the condition of the lungs, although it has some challenges such as air- containing lung tissue, significant impedance differences between thoracic muscle tissue and pulmonary tissue as well as ribbons that can absorb almost the entire ultrasonic wave delivered by the ultrasound probe. In order to produce accurate diagnosis in the lung ultrasound, the accuracy of the operator's analysis is required in the testing. Before testing, the operator is required to understand basic knowledge of ultrasounds, have technical capabilities to operate the targeting ultrasound device, and know the features of the ultrasonic imaging produced in specific lung conditions. Operators also need to observe some abnormal conditions of the lungs in order to have a pulmonary ultrasound. In the learning process of medical personnel, the need for lung phantom for ultrasound becomes quite significant. This research is intended to develop a lung phantom that can be made on a laboratory scale with affordable material and can be stored for a long time. The Phantom is designed with three phantom module structures connected to a propulsion pump with reference to the structure of the thoracic intersection to simulate the respiratory movement of the lungs. The structure is made from a PLA+ material printed with 3D printing intended as a template and framework for tissue mimicking material (TMM). The TMM material for the pulmonary tissue simulator uses gelatin material that is processed in such a way that the gelatine material can follow the principle of acoustic reverberation and acoustical trap techniques so that it can produce lung ultrasound features in normal and sick conditions. In this study, there are 1 muscle module and 3 lung modules that are structured to simulate normal lung conditions, lung edema, non-translobar lung consolidation, lung sliding, and lung pulse. In addition, F-Clamps clamps are used to lock the ordering of thorax models and lung models at the time of testing. The test is performed in two conditions, static and dynamic. Static is when the propulsion pump is turned off while dynamic is the condition of the propellant pump being turned on. The static condition test is done using a variation of the frequency parameter and focus point to determine the optimal parameter of the observation of ultrasound features in the lung condition being simulated. The dynamic condition testing is carried out using a time delay variation from the propeller pump and the depth of the ultrasonic image to adjust the focus of a particular area of the lung. Validation of the phantom test results is performed with visual inspection as well as analysis of the digital image features of the test image. The analysis of the digital image features should be consistent with the pulmonary ultrasound features. The analysis carried out in this study was texture analysis with a grey-level co- occurance matrix (GLCM), pixel analysis, and spectral frequency analysis of a region of interest (ROI) of different areas. Using the analysis, the phantoms developed in this study could simulate normal lung conditions, lung edema, non- translobar lung consolidation, lung sliding, and lung pulse. The results of the analysis refer to the peak pattern of the plot pixel value on the normal lung phantom image that shows the same interval of the echo pattern on the acoustic reverberation phenomenon of the A-line. The visual inspection indicates a change in the shred sign at the time the lungs inspire and exhale. Phantoms have the advantage of being stored for several months in refrigeration at a temperature of 4-5 °C. Although in some time after being removed from the refrigerator the phantom texture becomes softer and it affects the simulation image result, the texture will re-moderate if refrigerated again in the coolant. This refers to the stability of the phantom against temperature. Keywords: Acoustic Trap, Phantom, Gelatin, Acoustic Reverberation, Respiratory Simulation, Pulmonary Ultrasonography