ABSTRACT
Objective To investigate the relationship between peripheral blood thyroxine levels and cardiac function in elderly patients with chronic heart failure.Methods Seventy patients with chronic heart failure admitted into our hospital from January 2016 to December 2017 were enrolled as the study group,and 70 healthy subjects were collected as the control group.Left ventricular ejection fraction(LVEF)and serum thyroxine levels were measured in both groups.Results LVEF,serum levels of total triiodothyronine(TT3)and total thyroxine(TT4)were lower in the study group than in the control group[(37.3±2.4)％ vs.(58.5 ± 5.3) ％,(87.4 ± 8.7) mmol/L vs.(120.8±10.4) mmol/L,(8.6±1.7)mmol/L vs.(10.1 ± 1.3)mmol/L,t =30.486,20.609 and 5.864,P =0.000].LVEF,TT3 and TT4 in patients with grade lⅡ 、grade Ⅲ and grade Ⅳ Cardiac insufficiency were [(42.3±2.2)％、(37.9± 1.0)％ and(31.8±1.5)％,(104.2± 15.4) mmol/L、(89.7±4.6) mmol/L and(72.0±7.2)mmol/L,(9.3± 1.8)mmol/L、(8.8± 1.3) mmol/L and (8.1 ± 0.9) mmol/L]respectively.Serum levels of TT3 and TT4 and LVEF steadily declined as cardiac dysfunction grew more severe in patients with chronic heart failure(P =0.000).Conclusions Patients with chronic cardiac insufficiency are often combined with euthyroid sick syndrome,and serum levels of TT3 and TT4 can indicate the degree of abnormal cardiac systolic function.Therefore,low serum levels of T3 and T4 can be used as indicators for poor prognosis in patients with chronic heart failure.
ABSTRACT
The hybrid pencil beam model (HPBM) is an effective algorithm for calculating electron dose distribution in radiotherapy. The mean energy distribution of incident electron beam in phantom is one of the factors that affect the calculation accuracy of HPBM, especially in field edge areas near the end of the electron range. A new fitted formula based on Monte Carlo (MC) simulation data for electron beams with energy range of 6-20 MeV in the homogeneous water phantom is proposed in this paper. The precision of the fitted formula within the scope of the energy was evaluated by comparing the electron dose distribution of ECWG measured data with that obtained from HPBM which took the mean electron energy that calculated by the fitted formula and the existed empirical formula, respectively. The results showed that the accuracy of dose distribution that obtained by the mean electron energy calculated with the fitted formula increased about 1%.