[The Impact That SPECT Collection Angle and Collection Orbit Gives to an Image: Myocardial Digital Phantom Study].

PURPOSE: We evaluated the effect that collection angle and collection orbit condition gave to an image quantitatively by simulating the single photon emission computed tomography (SPECT) system. METHOD: Using the Software Package of the Nuclear Medicine Data Processor for Research, we performed making of the myocardial digital phantom, three ways of different simulation of the collection angle and collection orbit, and making of reference of the uniform picture element level. We calculated NMSE for uniformity evaluation and calculated myocardial thickness full width at half maximum (FWHM) for a spatial resolution evaluation. RESULTS: 360 degrees circular orbit collection had best uniformity. 180 degrees noncircular orbit collection had best spatial resolution. CONCLUSION: By using the digital phantom, we focused on only collection angle and collection orbit condition, and focused on two indexes of the uniformity and the spatial resolution and were able to show a quantitative index.

Feasibility of resuscitation contrast-enhanced postmortem computed tomography using cardiopulmonary resuscitation technique with chest compression immediately after death.

PURPOSE: Our purpose was to evaluate image delineation ability of contrast-enhanced post-mortem computed tomography (CEPMCT) using cardiopulmonary resuscitation technique of chest compression, named "resuscitation CEPMCT". MATERIALS AND METHODS: Non-traumatically-deceased 15 subjects (7 men; 8 women) aged 19-87 years (mean 61 years) underwent resuscitation CEPMCT. The contrast-enhanced technique, while injecting 100 ml of contrast media from the right cubital vein at a rate of 1 ml/s, chest compression was performed for 2 minutes at a rate of 100 times/min (a total of 200 times). CT attenuation values (Hounsfield Unit: HU) were measured in 8 target vessels: 1) pulmonary artery, 2) coronary artery, 3) ascending aorta, 4) abdominal aorta, 5) celiac trunk, 6) common iliac artery, 7) superior vena cava, and 8) inferior vena cava. One-sided Student's t-test was performed to assess whether measured values were higher than 140 HU by setting p-value at 0.05. RESULTS: Measured CT values in the 8 vessels were 1) pulmonary artery: 325 ± 140 HU, 2) coronary artery: 240 ± 73 HU, 3) ascending aorta: 321 ± 127 HU, 4) abdominal aorta: 286 ± 96 HU, 5) celiac trunk: 233 ± 62 HU, 6) common iliac artery: 260 ± 114 HU, 7) superior vena cava: 422 ± 187 HU, and 8) inferior vena cava: 301 ± 142 HU, showing significantly higher values than the threshold value of 140 HU. Resuscitation CEPMCT detected one case of pulmonary arterial thromboemboli death. CONCLUSION: Resuscitation CEPMCT using chest compression immediately after death has the possibility of detecting thromboembolus in major vessels, despite the simplicity of the technique.