Investigation On CT Dynamic Phantom Based On Displacement-controllability

Computer Tomography is one of the important methods in medical imaging field.With the continuous development of this technology,dynamic imaging was insteaded of static imaging gradually and the scanning speed was faster.Multisliecs helieal CT(MSCT)has been applied in examinations of cardiac and other moving organs,which needs more accurate measuring precision.In order to improve measuring accuracy furtherly,CT dynamic phantom has been investigated extensively.However,the lack of standard measurements of high-speed dynamic phantom used for quality control of cardiac imaging,especially coronary angiography,limited the development of CT dynamic phantom.This investigation aimed at studying a CT dynamic phantom based on displacement-controllability and quantitative detecting quality control indexes.Besides,this investigation provided a reliable and effective methods on quality detection and evaluation for coronary angiography.The CT dynamic phantom based on displacement-controllability in this paper which met the requirements of clinical quality control was designed according to GB17589-2011X-CT quality control standard.Inputting voltage signal can stimulate change of liquid volume inside the heart signal simulator to realize displacementcontrollability.The dynamic phantom was debugged by methods of visible light simulation.Besides,the control design,precision and image processing method of the phantom were investigated.This investigation preprocessed each module image that was obtained by scanning the device under inspection,which including transforming dicom images,segmenting interesting ragion,enhancing images,extracting edges and so on.And,the image quality was scored by the physician.The influence of heart rate,spatial resolution,density resolutionon,temporal resolution and pulsatile amplitude on the quality of coronary imaging was discussed and analyzed.Lastly,the quantitative data of each module was applied in clinical diagnosis and the setting of clinical scan parameters.The best image quality was obtained.The results showed that there was a significant negative correlation between image quality and heart rate(P=0.001)when only heart rate was considered.In terms of the tested equipment,the best image quality was achieved when the heart rate was less than70 beats per minute.In the same way,only when the tested factors are considered,the spatial resolution,density resolution,temporal resolution and pulsatile amplitude were of statistically significant and had an influence on the image quality.The test results are consistent with the results of GE dynamic phantom and literature study.Thus it can be seen,the self-made phantom can be used to detect some technical indicators of MSCT.Also,it can be used as a tool to evaluate the quality of coronary artery imaging,which helps to improve the success rate of coronary artery disease examination.