[en] The improvement in conformal radiotherapy techniques enables us to achieve steep dose gradients around the target which allows the delivery of higher doses to a tumor volume while maintaining the sparing of surrounding normal tissue. One of the reasons for this improvement was the implementation of intensity-modulated radio therapy (IMRT) by using linear accelerators fitted with multi-leaf collimator (MLC), Tomo therapy and Rapid arc. In this situation, verification of patient set-up and evaluation of internal organ motion just prior to radiation delivery become important. To this end, several volumetric image-guided techniques have been developed for patient localization, such as Siemens OPTIVUE/MVCB and MVision megavoltage cone beam CT (MV-CBCT) system. Quality assurance for MV-CBCT is important to insure that the performance of the Electronic portal image device (EPID) and MV-CBCT is suitable for the required treatment accuracy. In this work, the commissioning and clinical implementation of the OPTIVUE/MVCB system was presented. The geometry and gain calibration procedures for the system were described. The image quality characteristics of the OPTIVUE/MVCB system were measured and assessed qualitatively and quantitatively, including the image noise and uniformity, low-contrast resolution, and spatial resolution. The image reconstruction and registration software were evaluated. Dose at isocenter from CBCT and the EPID were evaluated using ionization chamber and thermo-luminescent dosimeters; then compared with that calculated by the treatment planning system (TPS- XiO 4.4). The results showed that there are no offsets greater than 1 mm in the flat panel alignment in the lateral and longitudinal direction over 18 months of the study. The image quality tests showed that the image noise and uniformity were within the acceptable range, and that a 2 cm large object with 1% electron density contrast can be detected with the OPTIVUE/MVCB system with 5 monitor units (MU) protocol. The registration software was accurate within 2 mm in the anterior-posterior, left-right, and superior-inferior directions. The additional dose to the patient from MV-CBCT study set with 5 MU at the isocenter of the treatment plan was 5 cGy. For Electronic portal image device (EPID) verification using two orthogonal images with 2 MU per image the additional dose to the patient was 3.8 cGy. These measured dose values were matched with that calculated by the TPS-XiO, where the calculated doses were 5.2 cGy and 3.9 cGy for MVCT and EPID respectively. (author)

[en] This is the first nationwide survey of bisphenol A (BPA), methylparaben, ethylparaben, propylparaben, butylparaben, and o-phenylphenol, in Egypt’s water. Five hundred fifty-five water samples were collected from source water (SW, 109 samples) and drinking water (DW, 446 samples) of twenty-three Egyptian governorates. These chemicals were determined by direct ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) analysis of a filtered aliquot of samples. The impacts of the measured concentrations on the aquatic organisms and human health were evaluated as well. BPA, methylparaben, propylparaben, and butylparaben were frequently detected in SW and DW, while ethylparaben and o-phenylphenol were not detected whatsoever. The most frequently detected endocrine-disrupting chemical (EDC) was BPA in SW and methylparaben in DW. The recorded highest concentrations of BPA and methylparaben in SW and BPA and methylparaben, propylparaben, and butylparaben in DW were the highest worldwide. Of the investigated twenty-three governorates, the SW and DW of Aswan, Red Sea, Cairo, Sharqia, and Damietta were free of the studied EDCs. Contrarily, BPA, MeP, PrP, and BuP were detected in Sohag’s SW and DW. A detection ratio > 70% was recorded in SW of Faiyum, Dakahlia, and Ismailia, and > 90% in DW of Sohag, Port Said, Dakahlia, and Faiyum. The environmental risk assessment results excluded any human health risk even in the worst-case scenario and showed that BPA represents the highest risk to the aquatic organisms.

[en] 

Purpose

Patients with Her2-positive breast cancer treated with trastuzumab have higher rates of cardiotoxicity (CT). Left-breast radiation might increase the risk for CT from cardiac exposure to radiation. The goal of our study is to evaluate the contribution of radiotherapy (RT) in the development of CT in breast cancer patients receiving trastuzumab.

Methods

Two hundred and two patients were treated with RT and trastuzumab from 2000 to 2014. The RT plans for left-side disease were recalled from archives. The heart, each chamber, and left anterior descending artery (LAD) were independently contoured. New dose-volume histograms (DVH) were generated. Their serial left-ventricular ejection fractions (LVEF) were studied. CT for left and right side were compared using Fisher’s exact test. The DVH data were correlated with the predefined cardiac events using actuarial Cox regression analysis.

Results

Compared to the right sided, the left-side cases showed statistically significant development of arrhythmia (14.2%) versus (< 1%) (p < 0.001). Cardiac ischemia was found in 10 patients in left and one patient in right side (p = 0.011). The equivalent uniform dose (EUD) to the left ventricle (LV), right ventricle (RV), and LAD was significantly associated with decrease in LVEF by > 10% (p = 0.037, p = 0.023 and p = 0.049, respectively).

Conclusions

Among patients treated for left-sided lesions, there were no significant differences in EF decline. However, there was a higher rate of ischemia and arrhythmia compared to those with right-sided disease. The EUD index of LV, RV, and LAD could be considered as a parameter to describe the risk of radiation-induced CT.