Comparison of conventional and CT-based planning for intracavitary brachytherapy for cervical cancer: target volume coverage and organs at risk doses

<p>Abstract</p> <p>Background</p> <p>To compare intracavitary brachytherapy (ICBT) planning methods for cervical cancer, based on either orthogonal radiographs (conventional plan) or CT sections (CT plan); the comparison focused on target volume coverage and dose volume analysis of organs at risk (OARs), by representing point doses defined by the International Commission on Radiation Units and Measurement (ICRU) and dose volume histograms (DVHs) from 3D planning.</p> <p>Methods</p> <p>We analyzed the dosimetric data for 62 conventional and CT-based ICBT plans. The gross tumor volume (GTV), clinical target volume (CTV) and organs at risk (OAR)s were contoured on the CT-plan. Point A and ICRU 38 rectal and bladder points were defined on reconstructed CT images.</p> <p>Results</p> <p>Patients were categorized on the basis of whether the >95% isodose line of the point-A prescription dose encompassed the CTV (group 1, n = 24) or not (group 2, n = 38). The mean GTV and CTV (8.1 cc and 20.6 cc) were smaller in group 1 than in group 2 (24.7 cc and 48.4 cc) (<it>P <</it>0.001). The mean percentage of GTV and CTV coverage with the 7 Gy isodose was 93.1% and 88.2% for all patients, and decreased with increasing tumor size and stage. The mean D2 and D5 rectum doses were 1.66 and 1.42 times higher than the corresponding ICRU point doses and the mean D2 and D5 bladder doses were 1.51 and 1.28 times higher. The differences between the ICRU dose and the D2 and D5 doses were significantly higher in group 2 than in group 1 for the bladder, but not for the rectum.</p> <p>Conclusion</p> <p>The CT-plan is superior to the conventional plan in target volume coverage and appropriate evaluation of OARs, as the conventional plan overestimates tumor doses and underestimates OAR doses.</p

A Sensitive Voltammetric Method for Chromium(VI) in Presence of Chromium(III) and its Application to Leather

WOS: 000294096900003The presence of chromium(VI) in leather is a subject of considerable interest in the tannery sector. Cr(VI) is usually controlled by standard spectrophotometric methods that utilize 1:5 diphenyl carbazide. However, the detection limit of this method is around the prohibited limit of Cr(VI) set for most of the leather products, being 3mgkg(-1). Present study describes the Catalytic Cathodic Adsorptive Stripping Voltammetric method for Cr(VI) determination in the presence of Cr(III). The Cr(VI) content of leather samples was extracted according to the IUC 18 standard method and it was reduced to Cr(III) in the presence of diethylenetriaminepentaacetic acid (DTPA) on a hanging mercury drop electrode (HMDE) at -0.90V. The catalytic effect of nitrate ions on the reduction peak of DTPA-Cr(III) complex was exploited for Cr(VI) analysis at sub-ppb level. Ion exchange resins were used to eliminate the interference of Cr(III) ions and their efficiency for removal was examined by ICP-OES. The voltammetric method was proved to be sensitive for Cr(VI) determination in leather samples in the presence of Cr(III)

A study to investigate the relationship between difficult intubation and prediction criterion of difficult intubation in patients with obstructive sleep apnea syndrome

Background and Aim: Obstructive sleep apnea (OSA) syndrome is predisposed to the development of upper airway obstruction during sleep, and it poses considerable problem for anesthetic management. Difficult intubation (DI) is an important problem for management of anesthesia. In this clinical research, we aim to investigate the relationship between DI and prediction criteria of DI in cases with OSA. Materials and Methods: We studied 40 [OSA (Group O, n = 20) and non-OSA, (Group C, n = 20)] ASA I-II, adult patients scheduled tonsillectomy under general anesthesia. Same anesthetic protocol was used in two groups. Intubation difficulties were assessed by Mallampati grading, Wilson sum score, Laryngoscopic grading (Cormack and Lehane), a line joining the angle of the mouth and tragus of the ear with the horizontal, sternomental distance, and tyromental distance. Demographic properties, time-dependent hemodynamic variables, doses of reversal agent, anesthesia and operation times, and recovery parameters were recorded. Results: Significant difference was detected between groups in terms of BMI, Mallampati grading, Wilson weight scores, Laryngoscopic grading, sternomental distance, tyromental distance, doses of reversal agent, and recovery parameters. Conclusion: OSA patient′s DI ratio is higher than that of non-OSA patients. BMI Mallampati grading, Wilson weight scores, Laryngoscopic grading, sternomental distance, and tyromental distance evaluation might be predictors for DI in patients with OSA