Peaceful Utilization of Nuclear Energy in Iran: Detection of Sentinel Node in Breast Cancer Patients using Technetium Element

Iran has had a peaceful nuclear program for more than 50 years, beginning with a research reactor purchased from the United States in 1959. There were a few suspicions of a nuclear weapons program, but these strongly abated in the decades after Iranian revolution in 1979. One of the most useful applications of nuclear energy in Iran is radionuclide imaging in sentinel lymph detection of breast cancer using Technetium (Tc) element. Sentinel lymph node is the first regional lymph node that drains the lymph from the primary tumor. It is potentially the first node to receive the seeding of lymph-borne metastatic cells. For sentinel node detection, one of the methods most often used in Iran is radionuclide imaging. However, guidelines strongly recommend imaging of the sentinel node combined with identification with a gamma probe before any operative procedure, rather than the use of external probe detection alone. In this regard, guidelines do not provide defined protocols for image acquisition and there is much controversy about the usefulness of dynamic imaging. This study aimed to discuss procedural guidelines for Lymphoscintigraphy for detection of sentinel node using 99mTc-Phytate in Isfahan, Iran. DOI: 10.5901/mjss.2015.v6n1s1p64

Radiation Exposure Aspects during Trans-Radial Angiography and Angioplasty

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Evaluation of the photon dose calculation accuracy in radiation therapy of malignant pleural mesothelioma

Background: Photon dose distribution of malignant pleural mesothelioma (MPM) in matched photon-electron technique is influenced by media inhomogeneity, lateral electronic disequilibrium at interfaces and narrow field. These may influence the dose calculation accuracy, calculated by treatment planning systems (TPS). This study aimed to evaluate the dose calculation accuracy of TiGRT TPS in radiation therapy of MPM. Materials and Methods: 18 MV photon beams of ONCOR Siemens linear accelerator was simulated using EGSnrc Monte Carlo (MC) code. Data of four patients were used to compare TPS and MC results in different regions included: Open and in-field, under shied and out of field regions. Results: Compared to MC results, the TPS overestimated the pleura dose coverage (90% of prescribed dose) about 3-12 mm, and also it overestimated the dose in under the shielded regions of lung (4-74%). While the TPS underestimated the dose profile width about 1-16 mm in low dose region (<50% prescribed dose) as well as the out of field region dose (4-100%). Conclusions: Results showed that TPS underestimated the dose in out of field and overestimated the dose in under the shielded regions. Unlike MC measurements, TPS calculation showed adequate pleural dose coverage. Based on the results, MC calculation can be used in matched photon-electron beam radiation therapy of MPM to modify the TPS photon dose calculations in the presence of heterogeneity, interfaces, and shield in MPM radiotherapy

Estimation of cell response in fractionation radiotherapy using different methods derived from linear quadratic model

BACKGROUND: The aim of this study was to use various theoretical methods derived from the Linear Quadratic (LQ) model to calculate the effects of number of subfractions, time intervals between subfractions, dose per subfraction, and overall fraction time on the cells’ survival. Comparison of the results with experimental outcomes of melanoma and breast adenocarcinoma cells was also performed. Finally, the best matched method with experimental outcomes is introduced as the most accurate method in predicting the cell response. MATERIALS AND METHODS. The most widely used theoretical methods in the literature, presented by Keall et al., Brenner, and Mu et al., were used to calculate the cells’ survival following radiotherapy with different treatment schemes. The overall treatment times were ranged from 15 to 240 minutes. To investigate the effects of number of subfractions and dose per subfraction, the cells’ survival after different treatment delivery scenarios were calculated through fixed overall treatment times of 30, 60 and 240 minutes. The experimental tests were done for dose of 4 Gy. The results were compared with those of the theoretical outcomes. RESULTS: The most affective parameter on the cells’ survival was the overall treatment time. However, the number of subfractions per fractions was another effecting parameter in the theoretical models. This parameter showed no significant effect on the cells’ survival in experimental schemes. The variations in number of subfractions per each fraction showed different results on the cells’ survival, calculated by Keall et al. and Brenner methods (P<0.05). CONCLUSIONS: Mu et al. method can predict the cells’ survival following fractionation radiotherapy more accurately than the other models. Using Mu et al. method, as an accurate and simple method to predict the cell response after fractionation radiotherapy, is suggested for clinical applications

Estimation of cell response in fractionation radiotherapy using different methods derived from linear quadratic model

Background. The aim of this study was to use various theoretical methods derived from the Linear Quadratic (LQ) model to calculate the effects of number of subfractions, time intervals between subfractions, dose per subfraction, and overall fraction time on the cells’ survival. Comparison of the results with experimental outcomes of melanoma and breast adenocarcinoma cells was also performed. Finally, the best matched method with experimental outcomes is introduced as the most accurate method in predicting the cell response

COVID-19 and cancer risk arising from ionizing radiation exposure through CT scans: a cross-sectional study

Abstract Background The surge in the utilization of CT scans for COVID-19 diagnosis and monitoring during the pandemic is undeniable. This increase has brought to the forefront concerns about the potential long-term health consequences, especially radiation-induced cancer risk. This study aimed to quantify the potential cancer risk associated with CT scans performed for COVID-19 detection. Methods In this cross-sectional study data from a total of 561 patients, who were referred to the radiology center at Imam Hossein Hospital in Shahroud, was collected. CT scan reports were categorized into three groups based on the radiologist’s interpretation. The BEIR VII model was employed to estimate the risk of radiation-induced cancer. Results Among the 561 patients, 299 (53.3%) were males and the average age of the patients was 49.61 ± 18.73 years. Of the CT scans, 408 (72.7%) were reported as normal. The average age of patients with normal, abnormal, and potentially abnormal CT scans was 47.57 ± 19.06, 54.80 ± 16.70, and 58.14 ± 16.60 years, respectively (p-value < 0.001). The average effective dose was 1.89 ± 0.21 mSv, with 1.76 ± 0.11 mSv for males and 2.05 ± 0.29 mSv for females (p-value < 0.001). The average risk of lung cancer was 3.84 ± 1.19 and 9.73 ± 3.27 cases per 100,000 patients for males and females, respectively. The average LAR for all cancer types was 10.30 ± 6.03 cases per 100,000 patients. Conclusions This study highlights the critical issue of increased CT scan usage for COVID-19 diagnosis and the potential long-term consequences, especially the risk of cancer incidence. Healthcare policies should be prepared to address this potential rise in cancer incidence and the utilization of CT scans should be restricted to cases where laboratory tests are not readily available or when clinical symptoms are severe

99m Tc-phytate lymphoscintigraphy for detection of sentinel node: Preliminary results of the first year′s clinical experience in Isfahan, Iran

Sentinel lymph node is the first regional lymph node that drains the lymph from the primary tumor. It is potentially the first node to receive the seeding of lymph-borne metastatic cells. This study aimed to discuss lymphoscintigraphy procedural guidelines for detection of sentinel node using 99mTc-Phytate in Isfahan, Iran. Moreover, the preliminary results of the first year′s clinical experience of lymphoscintigraphy in Isfahan, Iran are also presented. A total of 36 consecutive sentinel node procedures were performed following our protocol in March 2013 to March 2014. For all 36 patients, after intradermal injection of 0.5-1 mCi of 99mTc-Phytate, 5, 30 and 120 min with hands up lymphoscintigraphy was performed. All procedures were performed in a 1-day setting with 99mTc-Phytate injection in intradermal volume of about 0.1 cc. At 5, 30 and 120 min after injection, anterior and lateral images (4 min), were acquired using gamma-camera (energy 140 keV, window 15-20% and LEHR collimator). For all patients, at least one axillary sentinel lymph node was detected. For three patients, 2 SNs were seen. The images 5 min after injection showed at least one axillary sentinel node in 18 of 36 patients. However for the remaining patients, more delayed images (after 30 and 120 min) were needed. Although, no changes were seen in 120 min images compared to 30 min images. Considering the used protocol, from the evaluated data it can be concluded that lymphoscintigraphy after 30 min periareolar injection of about 0.5-1 mCi 99mTc-Phytate in an intradermal volume of about 0.1 cc yields an axillary sentinel node in all the patients. Imaging 120 min after injection is of no additional value and can be omitted

A bottom-up approach for demand response aggregators’ participation in electricity markets

This paper proposes a bottom-up model for demand response (DR) aggregators in electricity markets. This model enables a DR aggregator to consider the technical constraints of customers in developing an optimal trading strategy in the wholesale electricity market. In the bottom level, DR options, called load shifting, load curtailment and load recovery are comprehensively modelled in a stochastic programming approach. Each DR program is mathematically formulated in such a way that practically models the constraints of customers. Further, the proposed model considers the customers’ behaviour in participating in the given DR program through a scenario-based participation factor. On the other hand, the upper level proposes trading the DR outcome in day-ahead and balancing markets with uncertain prices, as well as in forward contracts with a predefined price. The overall bottom-up problem is formulated as a stochastic profit maximization model for the DR aggregator, in which the risk is taken into account using the Conditional Value-at-Risk (CVaR) measure. The feasibility of the given strategy is assessed on a case of the Nordic market

ELISA reader does not interfere by mobile phone radiofrequency radiation

Background: The increasing number of mobile phones can physically cause electromagnetic interference (EMI) in medical environments; can also cause errors in immunoassays in laboratories. The ELISA readers are widely used as a useful diagnostic tool for Enzymun colorimetric assay in medicine. The aim of this study was to investigate whether the ELISA reader could be interfered by the exposure to the 900 MHz cell phones in the laboratory. Materials and Methods: Human serum samples were collected from 14 healthy donors (9 women and 5 men) and each sample was divided into four aliquots and was placed into four batches for the in-vitro quantitative determination of human chorionic gonadotropin (hCG). During colorimetric reading of the first, second, and third batches, the ELISA reader (Stat Fax 2100, Awareness Technology, Inc., USA) was exposed to 0.5, 1.0, and 2.0 W exposure of 900 MHz radiation, respectively. For the forth batch (control group), no radiation was applied. All experiments were performed comparing ELISA read out results of the I, II, and III batches with the control batch, using the Wilcoxon test with criterion level of P = 0.050. Results: The final scores in the exposed batches I, II, and III were not statistically significant relative to the control batch (P > 0.05). The results showed that 900 MHz radiation exposure did not alter the ELISA measured levels of hCG hormone in I (P = 0.219), II (P = 0.909), and III (P = 0.056) batches compared to the control batch. Conclusion: This study showed that ELISA reader does not interfere by mobile phone RF radiation at a closed contact (less than 5 cm distance). However, we recommend that medical institutions discuss these issues in the context of their specific use of technologies and frame a policy that is clear and straightforward to guide staff, patients, and visitors