ABSTRACT
Objective To investigate the effects of spine region of interest (ROI),tracking range,and real-time image contrast ratio on the positioning errors of cyberknife.Methods The LTT dynamic phantom was used to develop a spine tracking plan and perform treatment,and the target positioning system was used to preset the phantom and obtain real-time preset image and positioning error.Based on the realtime preset image,spine ROI,tracking range,and real-time image contrast ratio were changed to observe the changes in positioning error and related parameters.Pearson correlation analysis was performed.Results The change in tracking range did not change the positioning error in spine tracking,and tracking range was not correlated with positioning error (R =0,P =1).The changes in ROI and image contrast ratio did not affect the translation error,but affected the rotation error,especially the rotation error in left-right direction (r =0.533 and 0.693,P=0.002 and 0.026).The image contrast ratio had the most obvious effect,with an amplitude of variation up to 2.2°.Conclusions The change in tracking range does not affect the positioning errors in spinal tracking,but the changes in ROI and image contrast ratio can cause varying degrees of changes in positioning errors,which should be taken seriously in cyberknife treatment.
ABSTRACT
STUDY DESIGN: Prospective study based on magnetic resonance (MR) imaging of the lumbar spinal root of the intervertebral foramen. PURPOSE: This study was to compare MR three-dimensional (3D) sequences for the evaluation of the lumbar spinal root of the intervertebral foramen. OVERVIEW OF LITERATURE: The diagnosis of spinal disorders by MR imaging is commonly performed using two-dimensional T1- and T2-weighted images, whereas 3D MR images can be used for acquiring further detailed data using thin slices with multi-planar reconstruction. METHODS: On twenty healthy volunteers, we investigated the contrast-to-noise ratio (CNR) of the lumbar spinal root of the intervertebral foramen with a 3D balanced sequence. The sequences used were the fast imaging employing steady state acquisition and the coherent oscillatory state acquisition for the manipulation of image contrast (COSMIC). COSMIC can be used with or without fat suppression (FS). We compared these sequence to determine the optimized visualization sequence for the lumbar spinal root of the intervertebral foramen. RESULTS: For the CNR between the nerve root and the peripheral tissue, these were no significant differences between the sequences at the entry of foramen. There was a significant difference and the highest CNR was seen with COSMIC-FS for the intra- and extra-foramen. CONCLUSIONS: In this study, the findings suggest that the COSMIC-FS sequences should be used for the internal or external foramen for spinal root disorders.
Subject(s)
Diagnosis , Healthy Volunteers , Magnetic Resonance Imaging , Prospective Studies , Spinal Nerve RootsABSTRACT
Objective:The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography(DSCT) in the evaluation of coronary artery disease(CAD).Methods:Fifty-two patients(44 male,8 female,mean age 70.59) with a high pre-test probability of CAD underwent DSCT coronary angiography and selective coronary angiography(SCA).Two physicians independently assessed the images of all coronary segments.Results:The overall sensitivity,specificity,positive and negative predictive value for evaluating CAD were 92.31%,99.82%,90.57%,and 99.32%,respectively.Conclusion:The result indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD.And it is a better choice for CAD evaluation.
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PURPOSE: The purpose of this study was to evaluate the effect of scatter correction on the assessment of myocardial perfusion and left ventricular function by gated Tc-99m myocardial SPECT. MATERIALS AND METHODS: Subjects were 11 normal volunteers, 20 patients with non-cardiac chest pain and 13 patients with coronary artery diseases. We classified above 3 groups into normal and diseased groups. Scatter correction was done using dual-energy-window scatter correction method (DEW-SC). We compared acquired counts, image contrast, corrected maximum relative counts, indices of left ventricular function, extent and severity of perfusion defects calculated by 'CEqual program' between scatter non-corrected and corrected images. RESULTS: Scatter corrected studies was lower in counts by 18+/-3% than uncorrected studies, but image contrast were improved in all cases. Scatter correction using DEW-SC took 3 minutes to complete, and 512 kB memory to store. There were no significant differences among indices of left ventricular function between scatter non-corrected and corrected images. Although extents of perfusion defects were not significantly different, severity was severer in scatter corrected images. CONCLUSION: Scatter correction using DEW-SC is simple to do, and improves image contrast without changing other indices of myocardial perfusion and function.