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Purpose: There are few areas in the world where ionizing radiation (IR) dose received by the public from radon gas and other radioactive elements are much higher than recommended limits. Telomere length is a potential biomarker of genomic instability due to oxidative stress from IR exposure. In this study, we investigated the impact of chronic exposure to environmental IR on relative telomere length (RTL) in white blood cells (WBC) among inhabitants of high background radiation areas (HBRA) of Ramsar, Iran. Materials and methods: One hundred and four individuals from HBRAs of Ramsar and 104 age-matched subjects from normal background radiation areas (NBRA) of Iran were enrolled in the study. The RTLs of WBC DNA samples were measured by a quantitative polymerase chain reaction (q-PCR) approach. Results: Mean RTL in HBRA and NBRA groups did not show any significant difference (1.21 ± 0.71 versus 1.22 ± 0.66, p = .306). After controlling for all demographic variables, less than 1% of the variances in RTL values were related to background radiation exposure. Conclusion: We conclude that chronic exposure to natural IR has no statistically significant effect on RTL among the inhabitants of HBRAs of Ramsar compared with a control group.

Purpose: One of the promising radiosensitizers is the ultrasmall gold nanoparticle (GNP) with a hydrodynamic diameter vβ3) in the murine ALTS1C1 glioma cell line. Materials and methods: We investigated the uptake, toxicity and radiosensitivity of GNP–PEG–cRGDfKs in ALTS1C1 cells exposed to protons, kilovoltage photons and megavoltage photons. The in vitro uptake and toxicity of GNPs in the hepatocytes and Kupffer cells were assessed for murine AML12 hepatocyte and RAW 264.7 macrophage cell lines. The in vivo biodistribution of GNPs in the ALTS1C1 tumor model was tested using the inductively coupled plasma mass spectrometry. Results: Results indicated GNPs accumulated in the cytoplasm with negligible toxicity for a moderate concentration of GNPs. Observed sensitizer enhancement ratios and dose enhancement factors are 1.21–1.66 and 1.14–1.33, respectively, for all radiations. Conclusion: Ultrasmall GNP–PEG–cRGD can be considered as a radiosensitizer. For radiotherapy applications, the delivery method should be developed to increase the GNP uptake in the tumor and decrease the uptakes in undesirable organs.

Antimony-122, having a half-life of 2.723 d and I?-=97.59%, is an important radiotracer in studies of environmental contamination and food crops. For the work discussed in this paper, the production of 122Sb was done via the natSn(p, xn)122Sb nuclear reaction. Radiochemical separation was performed by silica gel column chromatography and liquid-liquid extraction methods. Excitation functions for the 122Sb radionuclide, via 122Sn(p, n)122Sb, natSn(p, xn)122Sb, 122Sn(d, 2n)122Sb, natSn(d, xn)122Sb, 124Sn(p, 3n)122Sb and 124Sn(d, 4n)122Sb reactions, were calculated by ALICE/91, ALICE/ASH, and TALYS-1.2 codes and compared with existing data.

Yttrium-88 (T1/2 = 106.6 d, Ib+ = 0.2% and IEC = 99.8%) is used in mixed gamma efficiency calibration standards and also as a substitute for 90Y to quantify the biodistribution of Y-pharmaceuticals in animals. Yttrium-88 and strontium-85 as gamma emitting radiotracers were produced via natSrCO3(p, xn) and natRbCl(p, xn) nuclear processes at AMIRS, with 18 and 15 MeV protons, respectively, at a current of 20 ?A for 10 hours. The deposition of natSrCO3 on the Cu backing was carried out by means of the sedimentation method. Yt- trium-88 was separated in a 92 ? 5% radiochemical yield using the precipitation technique by precipitating natSr as SrSO4 (strontium-85 as a tracer) while radioyttrium passed through the filter paper. Also, a theoretical study of the nuclear reaction cross-sections for proton and deuteron induced reactions on natSr and natRb for the production of 88Y and 85Sr, respectively, was performed using the EMPIRE (version 3.1 Rivoli), TALYS-1.26 codes and the TENDL-2010 database.

Auger electron emitting radionuclides have potential for the therapy of small-size cancers because of their high level of cytotoxicity, low-energy, high linear energy transfer, and short range biologic effectiveness. Auger emitter 165Er (T1/2 = 10.3 h, IEC = 100%) is a potent nuclide for targeted radionuclide therapy. 165Er excitation function via 165Ho(p,n)165Er, 165Ho(d,2n)165Er, 166Er(p,2n)165Tm→165Er, 166Er(d,3n)165Tm→165Er, natEr(p,xn)165Tm→165Er and 164Er(d,n)165Tm→165Er reactions were calculated by ALICE/91, ALICE/ASH (GDH Model & Hybrid Model) and TALYS-1.2 (Equilibrium & Pre-Equilibrium) codes and compared to existing data. Requisite for optimal thicknesses of targets were obtained by SRIM code for each reaction.

Cancer is a leading cause of morbidity and mortality in the modern world. Treatment modalities comprise radiation therapy, surgery, chemotherapy and hormonal therapy. Radiation therapy can be performed by using external or internal radiation therapy. However, each method has its unique properties which undertakes special role in cancer treatment, this question is brought up that: For cancer treatment, whether external radiation therapy is more efficient or internal radiation therapy one? To answer this question, we need to consider principles and structure of individual methods. In this review, principles and application of each method are considered and finally these two methods are compared with each other.