Objective: In this study, we used the concept of organ-equivalent dose (OED) to evaluate the excess absolute risk (EAR) for secondary cancer in various organs after radiation treatment for breast cancer. Methods: Using CT data set of 12 patients, we generated three different whole-breast radiation treatment plans using 50 Gy in 2 Gy fractions: three-dimensional conformal radiotherapy with a field-in-field (FinF) technique, intensity modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT). The OEDs were calculated from differential dose–volume histograms on the basis of the “linear–exponential,” “plateau,” and “full mechanistic” dose–response models. Secondary cancer risks of the contralateral breast (CB), contralateral lung (CL), and ipsilateral lung (IL) were estimated and compared. Results: The lowest EARs for the CB, CL, and IL were achieved with FinF, which reduced the EARs by 77%, 88%, and 56% relative to those with IMRT, and by 77%, 84%, and 58% relative to those with VMAT, respectively. The secondary cancer risk for FinF was significantly lower than those of IMRT and VMAT. OED-based secondary cancer risks for CB and IL were similar when IMRT and VMAT were used, but the risk for CL was statistically lower when VMAT was used. Conclusion: The overall estimation of EAR indicated that the radiation-induced cancer risk of breast radiation therapy was lower with FinF than with IMRT and VMAT. Therefore, when secondary cancer risk is a major concern, FinF is considered to be the preferred treatment option in irradiation of whole-breast. Advances in knowledge: Secondary malignancy estimation after breast radiotherapy is becoming an important subject for comparative treatment planning.When secondary cancer risk a major concern, FinF technique is considered the preferred treatment option in whole breast patients.

This study aimed to compare the secondary cancer risk (SCR) between the sequential boost (SEQ) technique and simultaneous integrated boost (SIB) technique in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with nasopharyngeal carcinoma (NPC) using the concepts of organ equivalent dose (OED) and excess absolute risk (EAR). Patients and Methods: IMRT-SEQ, VMAT-SEQ, IMRT-SIB, and VMAT-SIB plans were created with identical objective functions for five patients with early-stage NPC. Three different planning tumor volumes (PTVs; PTV 1 , PTV 2 , and PTV 3) were delineated for each patient, and the prescribed doses were 50 Gy, 60 Gy, and 70 Gy (2 Gy/fraction), respectively, for the SEQ technique and 52.8 Gy, 59.4 Gy, and 69.3 Gy (33 fractions), respectively, for the SIB technique. Results: All plans were clinically acceptable. There was no difference in most OED-based SCRs between IMRT and VMAT when the same fractionation scheme was used. Compared with the SEQ technique, the SIB technique in IMRT and VMAT was associated with the lowest OEDs for the oral cavity, pharynx, parotids, and submandibular glands, resulting in SCR reduction. SCR for the parotids was much lower than that for the other assessed organs when the SIB technique was used. Conclusion: Our findings suggest that OED-based SCRs are lower with the SIB technique than with the SEQ technique in IMRT and VMAT in most organs for which SCR was calculated; furthermore, SCR for the parotids is much lower than that for other organs when the SIB technique is used in patients with NPC.

No abstract

No abstract

Abstract In recent years, environmental safety associated with heavy metal levels of a tourism area and its surrounding areas has been one of the basic security for tourists health. Various methods have been used for measuring concentrations of heavy metal levels in these areas. Biomonitoring organisms such as mosses provide quantitative information on the quality of the environment around them, and they respond to pollution by altering their physiology or their ability to accumulate heavy metals. The aim of this study is to assess  the concentration of aluminum, manganese, iron, nickel, copper, and zinc levels in five different moss species collected around Camlihemsin district of Rize, by using Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometry. The average concentrations of heavy metals in moss samples were found ranged from 3.8-8.3% for aluminum, 0.1-0.47% for manganese, 2.3-3.8% for iron, 38.8-74.2 ppm for nickel, 92.1-495.3 ppm for copper, 187.3-334 ppm for zinc. This study has shown that Abietinella abietina, Hypnum cupressiforme, Plagiomnium undulate, Rhytidium rugosum, and Thuidium tamariscinum samples were used to assess the potential contamination of Al, Mn, Fe, Ni, Cu, and Zn contamination in the region and made important contributions toward the understanding of Al, Mn, Fe, Ni, Cu, and Zn baseline data can be used for identification of changes in the levels of these heavy metals in the studied area. Keywords: Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometry, heavy metals, moss, biomonitor, environment.