Calculation of beta induced Bremsstrahlung exposure from therapeutic radionuclide 198Au in tissues, DNA and RNA

Gold-198 (βmax=0.96MeV (98.6%), γmax=0.412MeV (95.5%) and T1/2=2.7 days) is a well-known therapeutic beta emitter in the field of nuclear medicine, and is being used for the treatment of many different cancers. In the present study, the Bremsstrahlung exposure induced by 198Au in different human tissues, DNA and RNA has been calculated. The specific Bremsstrahlung constant (ΓBr), Probability of energy loss by beta during Bremsstrahlung emission (PBr) and Bremsstrahlung activity (Arelease)Br were estimated. We strongly recommend these parameters should be considered in absorbed dose calculations of radionuclide therapy via 198Au.

Nuclear data for cyclotron production of 114mIn/114In and 140Nd/140Pr used in gamma camera monitoring, RIT, ERT and PET

Aim of the presented study is to compare the calculated cross sections for the production of 140Nd/140Pr and 114mIn/114In via different reactions with incident particle energy up to 50 MeV as a part of systematic studies on particle-induced activations on metal target, theoretical calculation of production yield, calculation of target thickness requirement and suggestion for optimum reaction to produce Neodymium-140 and Indium-114m. 140Nd/140Pr and 114mIn/114In excitation functions via natCe(3He, xn)140Nd → 140Pr, 141Pr(p,2n)140Nd → 140Pr, 141Pr(d,3n)140Nd → 140Pr, 114Cd(p, n)114mIn → 114In, 114Cd(d,2n)114mIn → 114In and 116Cd(p,3n)114mIn → 114In 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.

Targetry of Y2O3 on a copper substrate for the non-carrier-added 89Zr production via 89Y(p, n)89Zr reaction

A thick layer of Yttrium oxide was deposited on cupper substrate via two special sedimentation methods for the production of 89Zr. For deposition of Y2O3 on cupper substrate, 435 mg of Y2O3, 152.25 mg of ethyl cellulose and 4 ml of acetone were used to prepare a Y2O3 layer of 11.69 cm2. Also, 435 mg of Y2O3, 174 mg of methyl cellulose and 7.25 ml of water were used. The targets were checked by SEM and thermal shock test. The deposited target was irradiated for 20 min at a current of 20 μA and a proton beam of 15 MeV.

Nuclear model calculation on charged particle induced reactions to produce 85Sr for diagnostic and endotherapy

85Sr, having a half-life of 64.8 d, is an important radionuclide in nuclear medicine diagnostic and endotherapy. The ALICE/ASH code was used to calculate excitation functions for proton, alpha and deuteron induced on various targets that lead to the production of 85Sr radioisotopes using intermediate energy accelerators. Recommended thickness of the targets according to SRIM code was premeditated. The application of those data, particularly in the calculation of integral yields, is discussed and theoretical integral yields for different reactions were computed. To consider precision of ALICE/ASH code calculations, experimental excitation functions in several decay channels was compared with ALICE/ASH code data. The 85Rb(p, n)85Sr process was determined as most interesting one due to radionuclidic purity. The ALICE/ASH code predicts a maximum cross-section of about 798 mb at 11 MeV for this reaction.

Novel dose calculation and characterization of 32P intravascular brachytherapy stent source

Derived from AAPM task group No. 60/149 protocol, applicable in treatment planning In this study, the two-dimensional dose distributions in water for a 32P intravascular brachytherapy stent have been calculated. The pure beta emitter source 32P which has been coated on Palmaz-Schatz stent is discussed. The dosimetric parameters required by the AAPM TG-60/149 formalism are discussed and calculated. Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source. The Monte Carlo calculated dose rate at the reference point is found to be 2.8 Gy/μCi. Also in this study, the geometry function, G(r,θ), radial dose function, g(r), and the anisotropy function, F(r,θ), have been calculated at distances from 1.8 to 9 mm. The results of these calculations have been compared with other published calculated and measured values for an actual same source. High dose variants were visible near the 32P stent surface, but these values decreased with depth in water rapidly. There is an acceptable agreement between the calculated data in this study and other published data for the same source, which validate our simulations method.

Cyclotron production of 85Sr by proton irradiation of natRb

Excitation functions for protons induced on 85/natRb targets that lead to the production of 85Sr radioisotopes using TALYS 1.0 and ALICE/ASH codes were calculated. Rubidium chloride deposition on copper substrate was carried out via sedimentation method in order to produce Strontium-85. 520 mg RbCl, 208 mg ethyl cellulose (EC) and 4 mL acetone were used to prepare a layer of enriched rubidium chloride of 11.69 cm2 area and 62.2 mg · cm−2 thickness. The deposited target was irradiated at 20 A current and 15 MeV proton beam for 10 h and no degradation was observed. The 85Sr production yield was 1.4 MBq/mA · h. The target material was dissolved by 50 mL acetone. Dissolved Strontium-85 was separated from rubidium by Chelex 100 ion exchanger.

Dosimetric characteristics of three new design 125I brachytherapy sources

For roughly 25 years, 125I sources have been used in the treatment of various malignant diseases such as prostate cancer. Three new brachytherapy sources, IR01-125I, IR02-125I and IR03-125I, have been developed and are designed for permanent implant application. The Monte Carlo radiation transport code version MCNP 5 was used to calculate the dosimetry parameters around the sources in accordance with the updated report of the American Association of Physicists in Medicine (AAPM), Task Group No. 43. For each source, the dose rate constant Λ, the radial dose function gL(r), and the anisotropy function F(r, θ), were obtained. The results indicated a dose rate constant of 0.932 ± 0.01, 0.934 ± 0.01 and 0.939 ± 0.01 Gy h−1 U−1 for the IR01-125I, IR02-125I and IR03-125I sources respectively. With the goal of determining an optimal design for a 125I source, each seed's parameters were compared with other seeds. In this study, the optimal source IR03-125I provides the most isotropic dose distribution in water. Finally, the results for optimal source were compared with published results for those of other commercial sources.

Novel method to produce 109Cd via proton irradiation of electroplated silver on a gold-coated copper backing

Silver electrodeposition on gold layer was carried out by the alkaline plating baths to produce cadmium-109 via natAg(p, n)109Cd nuclear reaction. Gold was electrodeposited on copper backing in the beginning; the bath content consisted of 17.7 gl−1 KCN, 6.6 gl−1 Au, 6.6 gl−1 K2CO3 and 3.3 gl−1 Na2CO3 while acidity and temperature of the bath adjusted at 10 and 45°C respectively. A DC current density of ca 2.08 mA · cm−2 was used to electroplate gold. A gold layer of 63 μm thickness with suitable morphology was obtained after the electrodeposition. Silver was electrodeposited on the gold layer with 100% efficiency using a cyanide bath. The silver target was irradiated with 15 MeV proton beam and current of 150 μA; the 109Cd production yield was 2.0 μCi/μA · h (0.074 MBq/μA · h). The target material was dissolved by 14 M HNO3. Cadmium-109 in the dissolved target solution was separated from silver by evaporation process. Cadmium recovered with more than 88% efficiency involved non-detected silver impurity.

Determination of 89Zr production parameters via different reactions using ALICE and TALYS codes

89Zr is an important positron-emitting radionuclide for positron emission tomography (PET) and used in the field of tumor diagnostics, tumor therapy and the investigation of the bio-kinetic. The ALICE-91 and TALYS-1.0 codes were used to calculate excitation function for proton, alpha, deuteron and neutron induced on various targets that lead to the production of 89Zr radioisotopes using intermediate energy accelerators. Requisite thickness of the targets was obtained by SRIM code. The 89Zr production yield was evaluated using excitation function and stopping power. For the 89Y(p, n)89Zr reaction, the calculation data were compared with the experimental data. The 89Y(p, n)89Zr process was determined as most interesting one due to radionuclide purity. The ALICE-91 and TALYS-1.0 codes predict a maximum cross-section of about 939.86 mb at 15MeV and 860 mb at 13MeV respectively for this reaction.

Cyclotron production of 101Pd/101mRh radionuclide generator for radioimmunotherapy

101mRh is one of such radionuclides that has been considered as a potential candidate for targeted radiotherapeutic use, due to its nuclear decay and chemical properties. Electrodeposition of rhodium metal on a copper backing was performed in acidic sulphate. The target was bombarded with a current intensity of 120 μA (Ep = 29 → 25 MeV) for 30 min (60 μAh). Radiochemical methods were investigated to optimize the production of no-carrier-added 101Pd/101mRh. The use of a cyclotron target with radiochemical processes (i.e. electrodeposition, electrodissolution and ion-exchange column chromatography) were carried out to produce this radionuclide in high-specific activity and radiochemical form suitable for radiopharmaceutical syntheses.

Concentrations of mercury, lead, chromium, cadmium, arsenic and aluminum in irrigation water wells and wastewaters used for agriculture in Mashhad, northeastern Iran

BACKGROUND

Contamination of water by toxic chemicals has become commonly recognized as an environmental concern. Based on our clinical observation in Mashhad, northeastern Iran, many people might be at risk of exposure to high concentrations of toxic heavy metals in water. Because wastewater effluents as well as water wells have been commonly used for irrigation over the past decades, there has been some concern on the toxic metal exposure of crops and vegetables irrigated with the contaminated water.

OBJECTIVE

To measure the concentrations of mercury, lead, chromium, cadmium, arsenic and aluminium in irrigation water wells and wastewaters used for agriculture in Mashhad, northeastern Iran.

METHODS

36 samples were taken from irrigation water wells and a wastewater refinery in North of Mashhad at four times--May 2008, March 2009, and June and July 2010. Atomic absorption spectrometry was used to measure the concentration of toxic metals. Graphite furnace was used for the measurement of lead, chromium, cadmium and aluminum. Mercury and arsenic concentrations were measured by mercury/hydride system.

RESULTS

Chromium, cadmium, lead and arsenic concentrations in the samples were within the standard range. The mean±SD concentration of mercury in irrigation wells (1.02±0.40 μg/L) exceeded the FAO maximum permissible levels. The aluminum concentration in irrigation water varied significantly from month to month (p=0.03). All wastewater samples contained high mercury concentrations (6.64±2.53 μg/L).

CONCLUSION

For high mercury and aluminum concentrations, the water sources studied should not be used for agricultural use. Regular monitoring of the level of heavy metals in water and employing the necessary environmental interventions in this area are strongly recommended.

Postrhinoplasty acne formation: a case-control study

BACKGROUND

Acne formation is a common dermatological problem which, if left untreated, may lead to severe facial scars, a consideration that may be particularly important for patients who seek cosmetic surgery. Postrhinoplasty acne development has not yet been discussed in the literature. We therefore decided to evaluate the occurrence of acne in nasal plastic surgery in a case-control study.

SUBJECTS & METHODS

One hundred and twenty patients were selected for this case-control study and were then assigned to case and control groups, each consisting of 60 patients. None of the participants was a known case of acne and those with any specific skin condition were excluded from the study. The cases were patients whose external nasal structures had been affected by the procedure; the control group consisted of matched patients who were candidates for closed septoplasty. After the operation, acne formation was evaluated in all participants and a comparison was made between cases and controls looking at the surgical method employed, and at the patients' personal and family backgrounds.

RESULTS

Twelve patients, all from the case group, developed postsurgical acne; all these patients had undergone open rhinoplasty. Age, gender, family history for acne and recent medication use prior to the surgery showed no significant correlation with acne formation.

CONCLUSION

The incidence of acne after nasal plastic surgery was significantly higher than in the control group, especially when the method of surgery was open rhinoplasty.

Impact of metabolic syndrome on ischemic heart disease - a prospective cohort study in an Iranian adult population: Isfahan Cohort Study

BACKGROUND

The impact of the metabolic syndrome among populations in the Middle East region is unknown; we therefore examined the association between the syndrome and the risk of ischemic heart disease (IHD) in an Iranian population.

METHODS AND RESULTS

The Isfahan Cohort Study (ICS) prospectively followed 6146 Iranian people (51.8% women, aged 35-75 years) from three cities and their rural districts who were initially free of ischemic heart disease. During the 5 year follow-up, 209 (56% men) cases of ischemic heart disease were detected. The metabolic syndrome was defined by the modified criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATPIII). End points were defined as fatal and nonfatal myocardial infarction, sudden cardiac death and unstable angina. A clear dose-response relationship was found between the number of metabolic risk factors and the incidence of IHD, with the hazard ratios increasing dose-dependently from 1.72 (95% CI 0.86-3.46) for only one to 1.97 (1.00-3.90), 2.85 (1.45-5.58) and 4.44 (2.25-8.76) for 2, 3 and ≥4 metabolic syndrome component respectively, relative to those with no component. The adjusted hazard ratio (95% CI) associated with the metabolic syndrome was 1.58 (1.06-2.35) in men and 1.72 (1.08-2.74) in women for IHD. The contribution of metabolic syndrome to the IHD risk was particularly strong among smokers although there was no significant interaction.

CONCLUSIONS

The metabolic syndrome by NCEP/ATPIII definition is a major determinant of ischemic heart disease in this middle-aged Iranian population, especially among smokers.

Research priorities in the field of HIV and AIDS in Iran

BACKGROUND

HIV is a multidimensional problem. Therefore, prioritization of research topics in this field is a serious challenge. We decided to prioritize the major areas of research on HIV/AIDS in Iran.

MATERIALS AND METHODS

In a brain-storming session with the main national and provincial stakeholders and experts from different relevant fields, the direct and indirect dimensions of HIV/AIDS and its related research issues were explored. Afterward, using the Delphi method, we sent questionnaires to 20 experts (13 respondents) from different sectors. In this electronic based questioner, we requested experts to evaluate main topics and their subtopics. The ranges of scores were between 0 and 100.

RESULTS

The score of priorities of main themes were preventive activities (43.2), large scale planning (25.4), the estimation of the HIV/AIDS burden (20.9), and basic scientific research (10.5). The most important priority in each main theme was education particularly in high risk groups (52.5), developing the national strategy to address the epidemic (31.8), estimation of the incidence and prevalence among high-risk groups (59.5) and developing new preventive methods (66.7), respectively.

CONCLUSIONS

The most important priorities of researches on HIV/AIDS were preventive activities and developing national strategy. As high risk groups are the most involved people in the epidemic, and they are also the most hard-to-reach sub-populations, a national well designated comprehensive strategy is essential. However, we believe with a very specific and directed scheme, special attention to research in basic sciences is necessary, at least in limited number of institutes.