ABSTRACT
Objective To investigate the relationship between image quality of PET/CT in automatic tube current modulation and effective dose(ED) of patients and to determine the optimal acquisition scheme.Methods Scanning was performed on anthropomorphic phantom RS-550 using GE Discovery ST-16 or Discovery Elite PET/CT.The same CT acquisition conditions was used:tube voltage 120 kV,pitch 1.375,rotation speed 0.8 s,noise index ranged from 8 to 30,interval 2,automatic tube current low limit 30 mA,high limit ranged from 200 to 350 mA,interval 50 mA.The images were analyzed,and the noise,signal to noise ratio (SNR) and figure of merit (FOM) of main organs in the abdomen were calculated.The relationship between image quality and ED was analyzed.Two-sample t test was used for data analysis.Results The noise of each organ decreased significantly along with the increase of ED until the ED of ST-16 increased to 15 mSv or Elite increased to 12 mSv,then the image noise decreased gently.SNR of each organ image increased along with the increase of ED.The FOM of liver decreased along with the increase of ED,while the FOM of other organs did not change significantly with ED.All image indicators of Elite PET/CT were better than ST-16 PET/CT at the same ED (5-20 mSv),though there was no significant difference (t:0.133-4.701,all P＞0.05).When ED was 5 mSy,the noise of liver with ST-16 was 12.0％ (28.9 vs 25.8)higher than that with Elite,and the SNR and FOM of liver with Elite was 13.9％ (4.1 vs 3.6) and 66.7％ (0.50 vs 0.30) higher than that with ST-16,respectively.Conclusion When the ED caused by the 2 PET/CT systems was between 5-20 mSy,the image quality is improved along with the ED increasing in a certain range.
ABSTRACT
PET-CT, SPECT, and SPECT-CT examinations could lead to inevitable medical exposure for patients, and the radiation dose of this examinations and whether it was harmful to patients have attracted attention from the public and professionals. At the same time, there was still a controversy about whether the biological effect of low dose radiation was useful to human body. The research investigates and reviews the radiation dose of PET-CT, SPECT, and SPECT-CT scans and their biological effects. Under achieved to the demands of clinical conditions, operators should try to reduce the radiation dose of PET-CT, SPECT, SPECT-CT scans for patients. Although PET-CT, SPECT, SPECT-CT scans deliver inevitable radiation, the dose of single examination will not lead to deterministic effect, and even the view of the random effect of linear no-threshold from these scans also have been questioned.
ABSTRACT
Whole-body PET-CT scanning has been used in the diagnosis and treatment of tumor to providing functional and morphological imaging. As the most widely used semi-quantitative analysis index, the cutoff value of SUV would affect the final diagnosis, therapeutic regimen and prognosis estimation. Therefore, the article reviews the influential factors of SUV, its correction methods, its cutoff values of differential various tumors and the progress of SUV. Although there is no acknowledged cutoff value of SUV in tumor diagnosis, SUV is still an important semi-quantitative index, and its rational and prudent use would increase both of the sensitivity and specificity in tumor diagnosis.
ABSTRACT
Objective To establish a HPLC method for determination of Chlorogenic acid in Liyan Granule. Method The determination was performed on Diamondsil Cl8 (4.6 mm?150 mm, 5 ?m) with mobile phase consisted of acetonitrile-0.4% phosphonic acid solution (13∶87) at a flow rate of 1.0 mL/min. The detective wavelength was set at 327 nm. Result The linear range of Chlorogenic acid was 0.026～0.26 ?g (r =0.999 9) and the average recovery rate of Chlorogenic acid was 101.84% (RSD=0.48%, n =6). Conclusion This method is simple, accurate and with good stabilization, and suitable for the quality control of Liyan gramule.