فهرست مطالب

Radiation Research - Volume:17 Issue:4, 2019
  • Volume:17 Issue:4, 2019
  • تاریخ انتشار: 1398/07/09
  • تعداد عناوین: 20
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  • Y. Mori*, H. Nakazawa, C. Hashizume, T. Tsugawa, T. Murai Pages 519-530
    Background

    As the optic pathways are thought to be the structures most vulnerable to irradiation, skull base tumors involving them are especially challenging to treat. Stereotactic radiosurgery (SRS) / stereotactic radiotherapy (SRT) is an effective and safe option for the treatment of them. Characteristics of dosimetry of SRT for skull base tumors by Gamma Knife were evaluated in comparison with those by other modalities.

    Materials and Methods

    Original Novalis (NV) multi-beam-intensity-modulated-SRT(MB-IM-SRT) plan and additional simulation plans of Gamma Knife (GK) and TomoTherapy (TT) were compared in 20 cases. For target covering, 95% dose was assigned for 95% of the planning target volume (PTV) (D[95%]=28.5 Gy / 5 fractions).  Conformity index (CI), homogeneity index (HI=D95% / maximum dose of PTV)), gradient index (GI=V[47.5% dose] / V[95% dose] of body), and the doses to organs at risk (OARs) were evaluated.

    Results

    CI and GI were significantly better with GK than NV or TT. HI was significantly smaller (less homogeneous) with GK. D[1 ml] and V[20 Gy] of brainstem were significantly smaller with GK than NV or TT. V[20Gy] of whole brain was also significantly smaller with GK. D[0.1 ml] and V[20 Gy] of optic pathways were smaller with GK than NV or TT, though the differences did not reach statistical significance.  

    Conclusion

    If a higher internal dose gradient is interpreted as an advantage for tumor ablation, GK SRT might be expected to be a more effective and safer treatment for skull base benign tumors adjacent to the optic pathways and brainstem when they are not large.

    Keywords: Skull base, benign tumor, radiosurgery, IMRT, optic nerve
  • R. Bechchar, N. Senhou, J. Ghassoun* Pages 531-540
    Background

    In this study, a fast dose kernel method (DKM) taking into account an appropriate buildup factor to calculate dose rate distributions around brachytherapy sources was presented. In addition, the dose distribution in various tissue-equivalent materials was investigated using this method.

    Materials and Methods

    To validate the accuracy of the proposed method, the dose rates in water was calculated by dose kernel method and those obtained by Monte Carlo simulation, thermoluminescent dosimetry (TLD) measurements and AAPM Task Group 43 (TG-43) formalism were compared. The validated dose kernel method (DKM) and the MCNP5 code were then applied to evaluate the effect of tissue composition on dose distribution around a Low Dose Rate (LDR) Ir-192 source located in phantoms simulating water, bone and lung tissue.

    Results

    The calculated dose rates were in good agreement with published data for water phantom. Statistical analysis showed that there is no significant difference in terms of dose distribution between the method used in this study and other established methods. Also, the results indicated that the tissue composition affects the dose distribution significantly. Based on the results of this study, the assumption of a homogeneous water phantom in dosimetry of radioactive sources used in brachytherapy may lead to either overestimation of up to 45% or underestimation of up to 19% in bone and lung tissues, respectively. Photon isodose distributions in water, bone and lung were also presented. 

    Conclusion

    Results provides an alternative calculating method for quality assurance purposes using a fast and accurate dose kernel method.

    Keywords: Brachytherapy, Buildup factor, Point kernel, Phantom, Dose, TLD, MCNP
  • S. Yassin, M. Al Sersawi, S. Abuzerr*, M. Darwish Pages 541-548
    Background

    Worldwide, indoor radon exposure is considered to be the second leading cause of lung cancer, particularly among people who stay indoors for a long time as the children and the elderly. The goal of this study is to get a better understanding of indoor radon levels in the houses of the Gaza governorate.

    Materials and Methods

    One hundred eighty passive diffusion radon dosimeters containing CR-39 solid state nuclear track detectors (SSNTD) were distributed in the rooms of the Gaza governorates houses following a cluster random sampling. Only 154 dosimeters were found in the places and collected, while the remaining 26 dosimeters were lost. The detectors were left for two months during the period from March to June of 2006. Variability between dwellings neighborhoods, floors, rooms at the same floor, ventilation status, smoking, dwelling age were assessed.

    Results

    The indoor radon concentrations in the houses of Gaza governorate were lower than the EPA and ICRP recommended limits (150 Bq/m3), with a mean indoor radon concentration (mean±SD) of 40±14 Bq/m3 and a range from 3 to 105 Bq/m3. The house ventilation status was the key variable which affects the indoor radon level, since badly ventilated houses had higher indoor radon concentrations, particularly in the basement floors rather than the higher floors.

    Conclusion

    Despite fulfilling the international limits, we strongly recommend conducting a wider national survey for natural radiation measurements and mapping radon-borne areas throughout the country. Moreover, well ventilation of the house indoor environment is highly recommended.

    Keywords: CR-39, dosimeters, detectors, Gaza governorate, buildings, indoor radon
  • H. Wang, H. Chen, Y. Shao, H. Gu, Y. Duan, A. Feng, Z. Xu* Pages 549-557
    Background

    During upper and middle esophageal cancer patients' radiation therapy, dose hot spots located in the normal portion of the esophagus (NPE) may increase radiation esophagitis, so NPE may also needs sparing. Automatic planning may have an advantage on sparing NPE over conventional trial-and-error type planning. We compared radiation esophagitis predicted by two esophageal NTCP models between different optimization strategies.

    Materials and Methods

    20 upper and middle esophagus cancer patients were reviewed and re-optimized by three strategies: autoplan in which NPE was not spared called A1 plan; trial-and-error type plan in which NPE was spared called T plan; autoplan in which NPE was spared called A2 plan.Dose volume parameters of four different esophagus structures were compared between three types of plans. Predicted radiation esophagitis between different optimization strategies were compared.

    Results

    Target dose coverage of three types of plans all met clinical desires. Dose hot spots of ESOwhole-PGTV and ESOinfield-PGTV from A2 plans are lowest in 3 types of plans. While Dose hot spots of ESOwhole and ESOin field from T plans are highest.V60 and Dmax of four types of esophagus structures in A2 plans are lower than T plans. AET =2 probabilities predicted by Kwint modle for A2 plans are slightly lower than T plans, respectively 70.1±2.5%,76.9±3.2%,54.8±1.7% and 72.7±2.8%.AET=3 probabilities were also lowest for A2 plans. Standard deviation of dose volume parameters and AETs of four types of esophagus structures in automatic plans are significant less than T plans.

    Conclusion

    Upper and middle esophagus cancer patients who received SIB-IMRT could benefited by a new NPE sparing technique by automatic planning. It may decrease patients’ radiation esophagitis.

    Keywords: NPE sparing technique, NTCP model, SIB-IMRT, automatic planning
  • X. Liu, C. Shen* Pages 559-567
    Background

    The aim of this present study was to evaluate the relationship between perfusion characteristics of ovarian tumors and tumor angiogenesis using contrast-enhanced ultrasound imaging.

    Materials and Methods

    Dose 116 patients with ovarian tumors were preoperatively subjected to contrast-enhanced perfusion imaging. Immunohistochemistry was performed to detect the expression of vascular endothelial growth factor (VEGF) and CD34 in ovarian tumors. The correlation between the VEGF positive index, microvessel density (MVD) of ovarian tumors and ultrasound perfusion parameters was investigated. We also established a nude mouse ovarian cancer SKOV3 xenograft model; the expression of VEGF and MVD in the transplanted tumor was observed, and their correlation with the ultrasound perfusion parameters was studied.

    Results

    The MVD and VEGF positive indexes of ovarian tumors were positively correlated with the peak intensity (PI), area under the curve (AUC) and time from peak to one half (TTH) of the ultrasound perfusion parameters. The correlation coefficients between MVD and the PI, AUC and TTH were 0.69, 0.71 and 0.59, respectively, while the correlation coefficients between the VEGF positive index and the PI, AUC and TTH were 0.71, 0.65 and 0.68, respectively. Moreover, there were significant differences in the PI, AUC and TTH between the high-MVD and low-MVD groups (P<0.05). Furthermore, the same trend was found in the xenograft model.

    Conclusion

    the ultrasound perfusion parameters PI, AUC and TTH of ovarian tumors were positively correlated with the tumor MVD and VEGF positive index, which reflects the angiogenesis status of ovarian tumors and provides important information for the diagnosis and treatment of ovarian tumors.

    Keywords: Ovarian tumors, Ultrasound perfusion imaging, Angiogenesis, Perfusion parameters
  • V.V. Kojić, I. Djan, V.V. Bogdanović, I. Borišev, A.N. Djordjević, T.V. Ivković, Kapicl, D.S. Jakimov* Pages 569-578
    Background

    Cancer cells may develop resistance to radiation which results in decreasing effects of radiation therapy. The effectiveness of high dose radiation can be increased with previously delivered low dose. Also, the approach that has been used to enhance the efficacy of radiation is to increase the radiosensitization. The focus of interest is on usage of gold-based nanoparticles as radiosensitizers. Modification of gold nanoparticle surface may increase its effectiveness in cells. The aim of the study was to prepare and characterize nanogold/β-cyclodextrin formulation (nAu/β-CD) and to investigate cytotoxicity and differences in radio-adaptive response of irradiated normal and malignant cell lines.

    Materials and Methods

    Nanoparticles distribution and zeta-potential of nAu/β-CD were obtained by dynamic light scattering (DLS). Cell lines MRC-5 and A549 were pretreated with 0.05 µM nAu/β-CD formulation and irradiated in single and double regimes. The MTT test was performed after 24 h and 72 h of recovery. 

    Results

    Nanogold particles didn’t express cytotoxic effect on MRC-5 and A549 cells. Tested nanoformulations with nAu/β-CD ratio 1:1 achieved the best cytotoxic effect against A549 cell line. Pre-treatment with low dose (0.05 Gy) prior to therapeutic dose (2 Gy) and application of nAu/β-CD nanoformulation decreased the cell survival in all investigated samples, showing diverse effects on normal and tumor cells.

    Conclusion

    Results indicate potential selectivity and increased efficiency of both applied radiation and pre-treatment with nAu/β-CD regarding the malignant cells, while sparing the normal tissue from radiation damage, which could be beneficial for the radiotherapy.

    Keywords: gold nanoparticles, β–cyclodextrin, cytotoxicity, human cell lines, radioadaptive irradiation
  • E.N. Hafez*, M.M. Amin Pages 579-586
    Background

    Gamma radiation-attenuated vaccine has a very promising value in controlling schistosomiasis. The objective of this study is to investigate the effects of vaccination with gamma radiation-attenuated schistosomules regarding histopathological and immunohistochemical changes in mice model of human Schistosoma mansoni infection.

    Materials and Methods

    The study is conducted upon 40 mice, divided into four groups of 10 each: uninfected control group A (normal control), Schistosoma mansoni infected group B (infected control), Group C subcutaneously injected with 200 Gy gamma radiation–attenuated schistosomules (vaccine control) and group D injected with the same dose of gamma radiation-attenuated schistosomules then challenged after 4 weeks by S. mansoni cercariae (vaccinated-challenged). Parts of liver tissues stained with Masson's trichrome (MT) stain for classifying the granulomas into cellular, fibrocellular or fibrous according to the amount of collagens; stained bluish green. Immunohistochemistry assay was then done on the other portion through expression of Smad2/3 protein and CD8+ in the extracellular matrix (ECM).

    Results

    Compared to control infected group, mild histopathological changes with decrease of egg granulomas mainly cellular is detected in vaccinated-challenged group. This is accompanied with moderate immunohistochemical expression of Smad2/3 and CD8+ proteins in vaccine-control group and mild expression in vaccinated-challenged group.

    Conclusion

    The The results indicate that vaccination with 200 Gy gamma-irradiated schistosomules could reduce histopathological and immunohistochemical changes induced due to infection which represents an effective strategy in disease control.

    Keywords: Schistosoma mansoni, vaccination, immunohistochemistry, histochemistry
  • S.T. Kim, J. Kim, J.M. Park Pages 587-593
    Background

    Hot cells are used in the production of radiopharmaceuticals to provide radiation workers with a safe environment in which to work. This study was conducted to measure the radiation dose that leaks through the walls of a hot cell. 

    Materials and Methods

    For this study, hot cells of five big hospitals (≥ 1000 beds) in South Korea were selected. To calculate the radiation exposure outside the walls of the hot cell (i.e., the external dose) during fluorine-18 fluorodeoxyglucose (18F-FDG) synthesis and dispensing activities, exposure rates were measured with a Geiger Muller counter (GM counter) at five locations around the hot cells (10 measurements per each measurement point). Based on the measurements, operating conditions of the hot cells of the five hospitals were conservatively considered to calculate the effective dose. The radiation exposure inside the hot cell (i.e., the internal dose) was estimated considering the operating conditions of the hot cells of five large hospitals as well as international guidelines.

    Results

    The Based on the experimental results, the impact of the internal dose was found to be negligibly low during 18F-FDG synthesis and dispensing activities (less than 0.21 mSv/y); however, the radiation leakage exhibited levels requiring caution in all directions, with a radiation leakage of up to 19.5 µSv/h measured on the lead glass windows of the hot cells in some hospitals.

    Conclusion

    The conclusion is that radioisotope manufacturers operating radiopharmaceutical synthesis and dispensing hot cells should implement various improvements. Strengthening the shielding of the lead glass windows on the front and sides of cells, implementing real-time dosimetric monitoring, setting dose limits for radiopharmaceutical production processes, and regular worker rotations are needed.

    Keywords: 18F-FDG, hot cell, radiation worker, external dose, internal dose
  • X.S. Hu*, S.M. Wen, J. Bie, F. Xian, W.W. He, D. Li Pages 595-603
    Background

    To compare radical surgery with definitive radiotherapy for upper third esophageal squamous cell carcinoma.

    Materials and Methods

    A total of 191 patients were included in the study. Patients’ clinicopathologic features, and survival time were recorded. Kaplan-Meier (K-M) analysis was adopted to analyze Overall survival (OS), Disease-free survival(DFS), Progression-free survival(PFS), and a Cox multivariate model was used to adjust potential confound factors.

    Results

    The K-M survival analysis showed that treatments, location of lesion, and length of lesion were all associated with the OS (P<0.005). In the surgery group, K-M survival  showed that T stage (T1 vs T2, P=0.012, T1 vs T3, P=0.002), location (upper vs upper merged middle, P<0.001), and length lesion (<5 cm vs >5 cm, P=0.015), affected the OS,T stage (T1 vs T2, P=0.018, T1 vs T3, P=0.020) and location of lesion (upper vs upper merged middle, P=0.007) was associated with DFS. The Cox model showed that none of these parameters independently influenced the OS and DFS. In the radiotherapy group, K-M survival showed that supraclavicular lymph node metastasis (P=0.007), concurrent chemo-radiotherapy (P=0.012), and sex (P=0.047) influenced the OS,adjuvant chemotherapy (P=0.013) and age (P=0.013) influenced PFS, The Cox model showed that supraclavicular lymph node metastasis (P=0.018) independently influenced OS and adjuvant chemotherapy (P=0.046) independently influenced PFS.

    Conclusion

    Surgery has better therapeutic effect than radiotherapy. Patients with an upper merged middle lesion and advanced T stage for surgery, male, local advanced and without concurrent chemo-radiotherapy for radiotherapy have a poor prognosis.

    Keywords: Esophageal upper squamous cell carcinoma, surgery, radiotherapy
  • B. Rawaa, S. Al Tarabichi Pages 605-615
    Background

    Ondo Estimating the health effect of 222Rn progeny deposited on inner surfaces of airways regions is of great interest because 222Rn progeny are considered the major contributors in imparted energy to lung structures.

    Materials and Methods

    In this study, (CT) scan of a healthy, non-smoking Syrian volunteer male, 3D-Slicer 4.7.0 medical image processing software, Solidworks mechanical design software and MCNPX 2.5.B code were used to create the geometry and to evaluate the absorbed fraction and specific energy due to alpha particles emitted by inhaled radon progeny in nuclei and layers of sensitive cells in the epithelium of human trachea-bronchial tree. Absorbed fraction (AF) and specific energy were determined using Micro-dosimetry approach and airway tube wall as proposed by ICRP (1994), and NRC (1991).

    Results

    Absorbed fractions (AFs) and specific energy of alpha particles were calculated for each generation from 1st to 15th. Comparison of average AFs values in sensitive layers was carried out with ICRP66 airway model where some significant differences were found due to dimensions differences between both models. Furthermore, AFs of cell nuclei had the same trend of those for layers, where the highest values were for 7.69 MeV alpha particles in BB region and the opposite in bb region. 

    Conclusion

    Interactions of alpha particles with secretory and basal cells show significant differences which can influence dose weightings. Comparisons with ICRP66 data reveal the influence of geometry and target cells distribution on absorbed fraction and specific energy values.

    Keywords: Absorbed fraction, specific energy, Radon progeny, micro-dosimetry, Monte Carlo method
  • D.H. Kim, Y.M. Choi, Y.K. Ki, K.S. Cho, Y.J. Choi, W.T. Kim* Pages 617-624
    Background

    We investigated whether topical administration of melatonin ameliorates radiation-induced skin fibrosis (RISF) and inhibits the expression of profibrogenic genes in mice.

    Materials and Methods

    Forty-eight female BALB/c mice were randomly divided into three groups: topically applied 5% ethanol (Control), topically applied 5% ethanol plus irradiation (IR), and topically applied melatonin plus irradiation (Mel+IR). The right hind legs of the IR and Mel+IR group mice were exposed to two fractions of electron beam radiation (20 Gy × 2). For 4 weeks, melatonin solution (10 mg/day) was topically applied to Mel+IR group mice. Fourteen days after IR, the relative levels of transforming growth factor (TGF)-β1 mRNA expression and TGF-β1 protein in skin specimens were analyzed by real-time quantitative PCR and immunohistochemical staining. Dermal thickness and tissue collagen accumulation were measured at 100 days post irradiation.

    Results

    The Radiation caused a 2.2-fold increase in TGF-β1 mRNA expression relative to that in control group, which was decreased by 37% following melatonin treatment (P = 0.024). We also observed substantial reduction of TGF-β1 expression in immunohistochemical studies. The mean values of dermal thickness were 105 ± 11 μm (Control), 195 ± 21 μm (IR), and 148 ± 19 μm (Mel+IR). Dermal thickness and collagen accumulation, which increased in the IR group, was significantly reduced by topically applied melatonin. 

    Conclusion

    Topical administration of melatonin successfully attenuated RISF.

    Keywords: Melatonin, Radiation, Fibrosis, Transforming growth factor-β, Topical application
  • G. Turkkan*, M. Caloglu, V. Yurut, Caloglu, A.R. Karasalihoglu, M. Dogan, C. Uzal Pages 625-632
    Background

    This study aimed to evaluate the relationship between late dysphagia and dosimetric–clinical parameters in patients receiving radiotherapy for head and neck cancer (HNC).

    Materials and Methods

    Twenty-six HNC patients treated with three-dimensional conformal radiotherapy were evaluated. A total dose of 66–70 Gy in 33–35 fractions was administered for curative purposes. Six swallowing organs at risk were contoured for each patient: the superior, middle and inferior pharyngeal constrictor muscles (SPCM, MPCM and IPCM); the cervical oesophagus (CE); the base of tongue (BOT); and the larynx. The mean dose in Gray [Dmean(Gy)], maximum dose in Gray [Dmax(Gy)] and percentages of organ volumes receiving ≥ 50 Gy, ≥ 60 Gy and ≥ 70 Gy [V50 (%), V60 (%) and V70 (%), respectively] were calculated from the dose–volume histograms for each structure. Dysphagia was evaluated using video laryngoscopy, the European Organization for Research and Treatment of Cancer quality of life module for HNC and the Leipzig scale.

    Results

    Dmean, V60 and V70 for the BOT; Dmean and V60 for the SPCM; Dmean, Dmax, V60 and V70 for the IPCM; Dmean, Dmax, V60 and V70 for the larynx; and Dmean, Dmax, V50 and V70 for the CE were correlated with the presence of pharyngeal secretion. Only V50 for the CE was correlated with abnormal glottic closure. Dmean, Dmax, V60 and V70 for the BOT and the SPCM were correlated with liquid swallowing problems. Dmax for the MPCM; Dmean, Dmax, V60 and V70 for the IPCM; and Dmax, V60 and V70 for the CE were correlated with the Leipzig score.

    Conclusion

    The dose–volume parameters of swallowing organs were found to be associated with different rates of late dysphagia in HNC patients receiving radiotherapy. The identification of dosimetric parameters that predict late dysphagia is not adequate yet. Well-designed multi-institutional studies are necessary to clarify the dose–volume constraints.

    Keywords: dysphagia, head, neck cancer, radiotherapy
  • A.H. Rezaeyan, H. Ghaffari, S.R. Mahdavi, A.R. Nikoofar, M. Najafi, F. Koosha, S. Cheraghi Cheraghi* Pages 633-641
    Background

    Hearing loss is a major concern in the patient with head and neck cancer (HNC) undergoing radiotherapy (RT) and/or chemotherapy (CHT). The present study aimed to assess the incidence of sensorineural hearing loss (SNHL) at 6 months follow-up after RT and/or concurrent Cisplatin-based CHT. 

    Materials and Methods

    In this prospective study, 60 patients with histopathologically proven HNC underwent three-dimensional conformal radiotherapy (3DCRT) (35 patients) and concurrent Cisplatin-based CHT and RT (25 patients). The status of the hearing was assessed pre-treatment (baseline), one day, 1, 3 and 6 months after treatment by pure tone audiometry (PTA) and other audiometric tests such as tympanometry (TM), acoustic reflex (AR), and speech audiometry (SA).

    Results

    In the RT group, SNHL was observed in 18 patients and hearing loss occurred in 47 % (33 of 70 ears) of ears. In the chemo-radiotherapy (CRT) group, SNHL was discerned in 20 patients and hearing loss appeared in 88 % (44 of 50 ears) of ears. Perforation of the tympanic membrane occurred in 2/35 patients in the RT group and 1/25 patients in the CRT group. The AR threshold (ART) of patients with CRT significantly increased compared to the RT group at the end of 6 months after treatment (P <0.05). Meanwhile, there was a significant difference in the speech discrimination score (SDS) and speech recognition threshold (SRT) between the CRT group and RT group at the 6 months after treatment (P <0.05).

    Conclusion

    The incidence of hearing loss in patients that underwent CRT was higher. The auditory system should be considered as a critical organ at risk (OAR) in treatment planning.

    Keywords: Sensorineural hearing loss, head, neck cancer, radiotherapy, cisplatin-based chemotherapy
  • A.A. Elkady*, R.M. Ebrahim, S.S. Tawfik Pages 643-649
    Background

    Gamma-rays-induced cellular damages in the vital organs of rats. The study investigates the protective impacts of Terminalia (T. arjuna) against γ-rays induced cardiac injuries in rats.

    Materials and Methods

    Dose A dose of 400 mg/kg body weight of T. arjuna was administered to male rats via gastric intubation for 30 days before whole body γ-irradiation (8 Gy).

    Results

    The animals exposed to γ-rays showed a significant rise in levels of lipid-peroxidation (MDA), cardiac injury markers; Aspartate transaminase (AST) and lactate dehydrogenase (LDH), inflammatory markers; tumor necrosis factor-alfa (TNF-α) and interleukin-6 (IL-6), and finally, reduced oxidative enzyme markers; superoxide dismutase (SOD) and glutathione peroxidase (GPx) as compared to control group. The histopathological sections from irradiated rat group showed myocardium necrosis, loss of striations in myofibrils and leuckocytic infiltration. Pre-treatment with T. arjuna reduced the altered levels of these markers, which was further confirmed by histopathological observations. A tendency towards normal architectures of the myocardium was distinguished and a decrease in the degree of damages and inflammations in the myocytes was demonstrated.

    Conclusion

    T. arjuna modifies antioxidants and inflammatory markers in rat heart and also prevents the myocardium from γ-rays-induced myocardial damages and should have prophylactic value in the prevention of heart toxicity.

    Keywords: Terminalia, radioprotector, γ-rays, heart, rats
  • N. Ahmadi, A. Karimian, M.N. Nasrabadi*, A. Rahmim Pages 651-657
    Background

    Clinical application of PET imaging for diagnosis, staging,                    re-staging treatment planning and treatment response assessment have become a major focus of studies in the past decades. Fetus is more sensitive to ionizing radiation, consequently, radiation absorption risks need to be assessed carefully. The objective of this article is to accurately estimate the absorbed dose during pregnancy in PET examinations. The method adopted in this article is simulative-analytic.

    Materials and Methods

    The absorbed dose from administrating 18F-FDG during pregnancy is estimated through the BodyBuilder anthropomorphic mathematical phantom (inexpensive) together with Monte Carlo simulations in order to obtain a reliable and feasible methodology. In this simulation, the Specific Absorbed Fractions (SAF) is estimated for organs of 3, 6 and 9-months fetal.

    Results

    The obtained results indicate that the absorbed dose of 18F-FDG PET imaging the fetal is 2.50×10-2 mGy/MBq early; 2.04×10-2 mGy/MBq first three months of pregnancy, 1.80 ×10-2 mGy/MBq second three months, and 1.50 ×10-2 mGy/MBq in the third three months of pregnancy. Maternal absorbed dose estimation here is (R2=0.965) which perfectly corresponds to ICRP publication.

    Conclusion

    The results from Monte Carlo code with BodyBuilder anthropomorphic phantoms and ICRP recommendation are of acceptable correlation. Applying the pure BodyBuilder anthropomorphic phantoms in this simulation, which yields agreeable results in addition to its low time consumption, corresponds to the available finding by other researchers while reducing calculation times. Moreover, the fetal & maternal absorbed doses remain however well below the threshold for any deterministic effects.

    Keywords: Fetal dose, maternal dose, GATE, GEANT4, PET, CT, 18F-FDG
  • H. Hassanvand, M. Birjandi, A. Amiri, M.S. Hassanvand, B. Kamarehie* Pages 659-666
    Background

    One of the most important natural sources of human exposure is inhalation of radon radioactive gas and its decay products in homes and at workplaces. According to the World Health Organization, radon is the second leading cause of lung cancer. This study is the first survey of indoor radon concentration in dwellings of the Aleshtar city (west of Iran).

    Materials and methods

    In this work, radon concentrations were measured in 24 dwellings by using a passive method known as Alpha Track Detectors (ATDs) with CR-39 polycarbonate film for three months during the year 2016. In addition, the annual effective dose due to radon exposure was estimated for residents.

    Results

    The indoor radon concentration ranged from 1.01 to 206.53 Bq/m3 with an average value of 55.19 Bq/m3 (CI (Confidence Interval) 95%: 31.46 - 78.92), and the average annual effective dose to the population in Aleshtar was estimated to be 1.39 mSv/y. According to the result of this study, there was a significant difference between apartment buildings and villas as well as between different floors in terms of the average radon concentration.

    Conclusion

    It was found that radon concentration in 20.8% of dwellings was higher than the reference levels recommended by the World Health Organization (100 Bq/m3).

    Keywords: Radon, Indoor Air, CR-39, Iran-Lorestan
  • D.Z. Jiang, Z.T. Dai, Z.R. Bao, H. Liu, H.L. Zhao, C.H. Xie, C. Chen, Y.F. Zhou, J. Zhang* Pages 667-674
    Objective

    By dividing the CT value into different intervals, the authors aimed to investigate the effect of CT value variation on dosimetric results and propose a method to combine MRI with assigned CT values.

    Materials and Methods

     Imaging data were analyzed from thirty patients in three different regions by a treatment planning system. The average CT value of each tissue or organ, standard deviation and 95% confidence interval were obtained by the Eclipse treatment planning system. Fifteen patients were included in this study by IMRT. Eclipse was used for all delineations, registrations, and dose calculations. In the synthetic CT image, the CT values of the target and OAR were assigned according to the sampled CT value above. The homogeneous assigned method divides the human tissue CT image into another synthetic CT image that only assigns bones and water. Dosimetric differences and dose homogeneity were compared under the same dose and field conditions.

    Results

    By dividing the CT value with the interval method and verifying it with dose calculation, different CT value intervals can reflect different human tissues or organs. The effect of CT value variation between -100 HU and 100 HU on dose calculation is within 2%. Compared with the same treatment plan on different CT images, there is little deviation between the synthetic CT image and the original CT image. The Dmax, Dmean, Dmean, D98%, D95%, D5%, and D2% of PTV are all below 1.61%, and the dose percentage and volume percentage of OAR are below 1.86%.

    Conclusion

    The combination of MRI with assigned CT values is feasible for the performance of MR alone in pelvis tumor treatment plans.

    Keywords: CT value interval, organ assigned, homogeneous assigned, cervical carcinoma, dose calculation, TPS
  • M. Kong, J.W. Lee, M. Yun, S.H. Lee* Pages 675-682
    Background

    No study has reported radiosensitizing effect of triptolide in lung cancer cell lines. We explored the effect and underlying molecular mechanisms of combined triptolide and irradiation treatment in lung cancer cell lines.

    Materials and Methods

    Colony formation assays were conducted to test the radiosensitizing effect of triptolide in A549 and H460 lung cancer cell lines. Survival fractions and sensitizing enhancement ratios were calculated. To determine the underlying mechanism of triptolide and irradiation combination, immunofluorescence cytometric analysis of apoptosis was conducted after treatment with triptolide and/or 4 Gy irradiation. To explore the molecular mechanisms of apoptosis induced by triptolide and irradiation combined treatment, western blot analysis was conducted after treatment with triptolide and/or irradiation (1, 2, 3, or 4 Gy). The antibodies used for Western blotting were PARP, JNK, p53, HSP70, and Akt.

    Results

    Combined triptolide and irradiation treatment significantly decreased the surviving fractions than irradiation alone in both cell lines. Triptolide and irradiation combination treatment also resulted in significant increase in apoptosis rates than irradiation alone in both cell lines. The expression of PARP cleavage, JNK, and p53 were prominent in the groups treated with triptolide and irradiation combination. The expression of HSP70 and Akt were suppressed in groups treated with the triptolide and irradiation combination.

    Conclusion

    This study showed that triptolide in combination with irradiation enhanced antitumor effects in lung cancer cell lines.

    Keywords: Radiotherapy, lung cancer, triptolide, radiation sensitizing agent
  • G. Liu*, R. Zhang, L. Niu, Y. Li, X. Wu, Y. Liu Pages 683-688
    Background

    To explore the carcinogenic effect about the veterans of taking atmospheric nuclear weapons testing troops in Gansu, China.

    Materials and Methods

    During 2005-2014, all the veterans of taking atmospheric nuclear weapons testing troops were required to have a medical examination in Gansu, 3721 veterans were requested to make an occupational health examination. They were exposed the radioactive fallout particles from atmospheric nuclear burst (the total β radioactive substances and the        radio-nuclides: 3H, 90Sr, 137Cs, 239Pu, 99Mo 95Zr,97Zr,131I,133I,and 132Te etc.), they were away from testing sites 10-30 Km. Cancer patients were required to provide the in-patient case history and check pathologically report. For part of the veterans, the level of radiation dose was 100-150mSv. 

    Results

    There were 40 primary tumor and 25 malignant tumors, incidence rate was 1075 /105 and 672/105; The cancer incidence of the transportation corps was 1253 /105, average age was 48.08 years, average service life was 6.08 years; The cancer incidence of the engineering corps is 762 /105,average age is 55.56 years, average service life was 5.48 years; The comparison of the cancer incidence was shown that the trend of escalation about the cancer incidence along with the servicing year increase; In order of the cancer incidence: gastric cancer, lung cancer, carcinoma of colon, esophagus cancer, rectum cancer and skin cancer, the incidence rate was remarkably increasing (p<0.01).

    Conclusion

    It was shown that the trend of escalation about the cancer incidence along with the servicing year increase, the first was neoplasms of digestive system; it may be due to the contaminated radioactive materials transferred through the digestive tract, hence leading to in vivo irradiation.

    Keywords: Radioactive fallout, carcinogenic effect, cancer incidence, the veterans, late effect of radiation
  • M. Li, F.L. Shan, L. Li, Y.F. HU, L.N. Jiang, S.H. Jiang* Pages 689-694

    Multiple primary cancers of the esophagus and lung were mostly reported in individual cases. Most patients visited a doctor because of dysphagia or respiratory symptoms. Chest CT can determine the location of lesions but cannot clearly determine the nature of lesions. Definite diagnosis needs bronchoscopy combined with gastroscopy, lung biopsy combined with gastroscopy or surgical operation to obtain pathological tissue. Recently, we confirmed a case of multiple primary cancer of the esophagus and lung by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and shared the diagnosis and treatment process. The advantages of this technique are that endobronchial ultrasound can determine the nature of mediastinal and hilar lesions, and needle aspiration biopsy is characterized by minimal invasion and repeatable biopsy, thus providing pathological diagnosis, especially for multiple primary cancers, that avoids misdiagnosis or missed diagnosis.

    Keywords: Synchronous primary cancer, endobronchial ultrasound-guided transbronchial needle aspiration