فهرست مطالب

  • Volume:17 Issue:2, 2019
  • تاریخ انتشار: 1398/01/12
  • تعداد عناوین: 20
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  • J. Zhang, Z.R. Bao, X.T. Huang, D.Z. Jiang, C.H. Xie, Y.F. Zhou, H. Liu* Pages 189-202
    Background
    Cone-beam computed tomography (CBCT) scanners for image-guided radiotherapy are in clinical use today, but there has been no consensus on uniform acceptance to verify the CBCT image quality yet. The present work proposed new methods to fully evaluate the performance of CBCT in its three-dimensional (3D) reconstruction space.
    Materials and Methods
    Compared to the traditional methods with only two-dimensional axial slice evaluated, the new methods were designed to evaluate the CBCT image quality not only in the axial slices but also along three dimensions and three sections. Image parameters were evaluated by scanning the corresponding phantom.
    Results
    The new methods demonstrated the high spatial resolution, the image uniformity, the high CT numbers linearity, geometric accuracy and relatively poor performance in low contrast resolution, compared to the results of plan CT. Additionally, the spatial resolution, the CT number linearity and the image uniformity proved to be more superior along the z direction and in the cross-section. Furthermore, the spatial resolution and the CT value linearity decreased gradually when deviating from the center of rotation axis and accelerates the reduction towards the periphery area, suggesting that locating the target within the range of 4 cm around the isocenter during radiotherapy ensure the optimal spatial resolution and the CT value linearity.  
    Conclusion
    Results indicate that the proposed three-dimensional image quality evaluation holds the potential to complement existing standards to provide sufficient information for the CBCT image performance and thereby guiding the clinical applications of CBCT.
    Keywords: Image quality, CBCT, three-dimensional
  • J.Y. Park, J.H. Jung, S. Kim* Pages 203-208
    Background
    The present investigation compared the decrease in the volume of benign tumor before and after High Intensity Focused Ultrasound (HIFU) treatment to evaluate the therapeutic effects of HIFU. in terms of Lifestyle and obstetric characteristics of in patients with Benign Uterine Tumors.
    Materials and Methods
    To collect the data on each patients’ lifestyle and obstetric characteristics, a survey was conducted on 55 patients with benign uterine tumors who had undergone HIFU treatment for three months.
    Results
    Regarding obstetric characteristics, the longer the period of discontinuation of contraceptive pills, the higher the therapeutic effects of HIFU. Regarding lifestyle, the decrease in the benign tumor volume was more when the patient did not exercise during the treatment period, and was a non-smoker (p<0.05).
    Conclusion
    The results of the present investigation may provide valuable basic data for increasing the understanding of the factors that heighten the therapeutic effects of HIFU, thereby contributing to the development of novel therapeutic strategies.
    Keywords: High intensity focused ultrasound, benign uterine tumors, life style, obstetric characteristics
  • G. Gokalp* Pages 209-216
    Background
    To compare image quality and radiation doses of low kilovolt (kV) “prospective ECG-triggering” (PT) and standard “retrospective ECG-gating” (RG) coronary computed tomography (CT) angiography.
    Materials and Methods
    A total of 101 consecutive patients (76 males, 25 females; mean age: 55.44 ± 8.28 years) with low-to-intermediate risk status for coronary artery disease and with a body mass index (BMI) of <30 kg/m² were prospectively included in the study. The images were acquired with a 64-detector (128-slice) CT using the tube current modulation technique. The PT CT technique (100 kV, heart rate [HR]<70) was applied in 59 patients, while the RG CT technique (120 kV, HR≥70-90) was applied in 42 patients. The study was approved by the ethics committee. All patients provided informed written consent. 
    Results
    No significant difference was found between age, sex and BMI of both groups (p > 0.05). The mean image quality score was 2.87 ± 0.25 for the low kV PT CT technique and 2.73 ± 0.31 for the RG CT technique, which was statistically significant (p < 0.05). No statistically significant difference was found between groups for signal-noise and contrast-noise ratios (p > 0.05). The mean effective dose was 1.43 ± 0.3 mSv for low kV PT CT technique and 8.20±2.36 mSv for the RG CT technique (p < 0.001).
    Conclusion
    In the low kV PT CT technique, the radiation dose is significantly reduced without loss of image quality. This technique can reliably be used in patients with BMI<30 kg/m² and HR less than 70 bpm.
    Keywords: Prospective ECG-triggering, kilovolt, coronary CTA
  • R. Shukla, N.P. Patel*, H.P. Yadav, V. Kaushal Pages 217-227
    Background
    The aim of present study was to analyze the effectiveness of electron filters in the Telecobalt radiotherapy treatment by simulation technique. 
    Materials and Methods
    The BEAMnrc Monte Carlo code was used to simulate the electron filters of thickness of 0.5 gm/cm2 below the trimmer bar for 35 × 35 cm2 field size in Theratron Equinox-80 telecobalt unit. The electron filters were made of an aluminum, copper, nickel, tin, PMMA, and lead with single or composite materials. The radiation beams at treatment distance were analyzed by generating profiles for photon and electron along the X-axis of radiation field. 
    Results
    The electron energy fluence for unfiltered beam was 0.32% of the photon energy. The photon energy fluence intensity reduction due to filter was 3.7%. The filters with low atomic number have shown poor electron contamination removal efficiency. The tin, copper and nickel were found effective filters, removing nearly 38% of contaminant electron energy. The lead filter is equally effective as tin, however the high energy electrons emitted from filter due to “photo peaks” adds significant dose at 3.0 to 4.0 mm depth.
    Conclusion
    The tin filter dominates over to other filters on the subject of surface dose reduction and depth of dose maximum (dmax). It reduces the surface dose by 9.6% and 13.9 % of unfiltered beam for 15 × 15 and 20 × 20 cm2 field sizes respectively.
    Keywords: Telecobalt, electron contamination, electron filters, surface dose, Monte Carlo simulation
  • A. Kale*, Ö. Pişkin, Y. Baş, B.G. Aydın, M. Can, Ö. Elmas, Ç. Büyükuysal Pages 229-236
    Background
    Extensive research has been focused on radiation induced brain injury. Animal and human studies have shown that flavonoids have remarkable toxicological profiles. This study aims to investigate the neuroprotective effects of hesperidin in an experimental radiation induced brain injury.
    Materials and Methods
    32 adult male Wistar-Albino rats were randomly divided into 4 groups (control, hesperidin, radiation, and radiation+hesperidin groups; 8 rats in each group). 200 mg/kg  doses of hesperidin were administered to the animals in the hesperidin and radiation+ hesperidin groups, radiation and radiation+ hesperidin groups were exposed to a dose of 20 Gy cranium region. Tissue samples, and biochemical levels of tissue injury markers in four groups were compared.
    Results
    In all measured parameters of oxidative stress, administration of hesperidin significantly demonstrated favorable effects. Both plasma and tissue levels of malondialdehyde and total antioxidant status significantly changed in favor of antioxidant activity. Histopathological evaluation of the tissues also demonstrated significant decrease in cellular degeneration and infiltration parameters after hesperidin administration.
    Conclusion
    This Hesperidin demonstrated significant neuroprotection after radiation induced brain injury. Further studies with different experimental settings including neurological outcome are required to achieve conclusive results.
    Keywords: Radiation, brain injury, hesperidin, neuroprotection
  • B. Goldoost, N. Jabbari*, O. Esnaashari, K. Mostafanezhad Pages 237-244
    Background
    In the radiotherapy of patients with esophagus and breast cancer, the heart receives a significant dose of radiation that might cause heart complications. Thefore, the aim of the current study was to evaluate the effects of esophagus and left breast cancer radiotherapy on the cardiac function and to determine the relationship between the dosimetric parameters and ejection fraction (EF) changes.
    Materials and Methods
    Patients with esophageal (n=13) and left breast cancer (n=21) enrolled at our radiotherapy center from March to October 2017. Echocardiography tests were obtained from patients, before and six months after the radiotherapy. Dosimetric parameters were extracted from treatment planning system. The assessed outcomes included pre- and post-radiation EF ratios and percentage change in the EF following radiation. 
    Results
    The mean ± standard deviations of EFs in patients with breast cancer before and six months after treatment were 55.95%±3.2% and 53.10%±6.30% respectively, which were not statistically significant (P = 0.07). In patients with esophagus cancer, the mean ± standard deviations of pretreatment and post-treatment EFs were 56.76%±3.44% and 52.09%±3.88% respectively, which were statistically significant (P = 0.005).
    Conclusion
    The results of our study showed a significant variation of EFs in esophageal cancer patients following radiotherapy, while breast cancer patients treated with radiotherapy showed no significant change. In patients with esophagus cancer, there was a significant correlation between the variation of EFs and volume of heart receiving radiation doses ≥30 Gy (≥V30). Therefore,  to avoid reduction in EF, the use of V20 as a dose-volume constraint is recommended.
    Keywords: Radiation therapy, cardiac function, breast cancer, esophagus cancer, echocardiography
  • S. Dizman*, R. Keser Pages 245-252
    Background
    The natural radioactivity levels in ceramic tiles produced in Turkey were determined and the related radiological hazards were assessed.
    Materials and Methods
    The natural radioactivity levels (226Ra, 232Th and 40K) in the ceramic tiles were measured using high-purity germanium detector system (HPGe) and the related radiological hazards were assessed by radium equivalent activity (Raeq), external hazard index (Hex), representative level index (Iγ), absorbed dose rate (D) and annual effective dose (AED).
    Results
    The average activity concentrations of 226Ra, 232Th and 40K radionuclides in the ceramic tiles were found to be 36.59 ± 2.64, 51.23 ± 2.81 and 420.81 ± 12.87 Bq/kg, respectively. These values are less than the world average values except the activity values of 232Th. Again, the averages of radiological hazard parameters (Raeq, Hex, D and AED) found for all ceramic tiles were found lower than the world averages.
    Conclusion
    The present results was compared with the literature and the international reference values. This study shows that the investigated ceramic tiles can be used safely in constructions and do not create significant radiological hazard when used in constructions.
    Keywords: Ceramic tile, natural radioactivity, radiological hazard, Turkey
  • A. Cakir*, Z. Akgun, E. Kaytan Saglam Pages 253-263
    Background
    In the treatment of prostate cancer, radiotherapy is the potential to increase second primary cancers such as bladder and rectal cancers. The reasons for this potential are more monitor units (MUs), therefore a larger total body dose because of leakage radiation, a bigger volume of normal tissue is exposed to lower radiation doses. This study was designed to compare the integral dose of using Flattening Filter (FF) and Flattening Filter-Free (FFF) 6 and 10 MV photon beams via volumetric modulated arc therapy (VMAT) for prostate cancer patients.
    Materials and Methods
    Twenty prostate cancer patients were selected retrospectively for this planning study. VMAT plans were developed using the Eclipse (Varian Medical System, Palo Alto, California, USA) Treatment Planning System (TPS) with 6 MV FF, 6 MV FFF, 10 MV FF and 10 MV FFF for each patient. Conformity index (CI), homogeneity index (HI), Integral dose (ID), the volume receiving 5 Gy (V5%) and monitor units (MUs) were compared.
    Results
    The use of 10 MV FF had 206 liter*Gy integral dose to Body-CTV volume. Using 10 MV FFF had 204 liter*Gy integral dose to normal structures. When 10 MV FF or 10 MV FFF were used instead of 6 MV FF and 6 MV FFF integral dose decreased as -7% and -8%, respectively. The dosimetric difference were statistically significant (p<0.05). The use of 10 MV FFF rather than 10 MV FF had limited influence on the integral dose for rectum, bladder, penile bulb and femoral heads.
    Conclusion
    This study showed that high energy photons (10 MV FF, 10 MV FFF) have lower integral dose than low energy photons (6 MV FF, 6 MV FFF). The relationship between low energies, high energies and integral doses is significant, although there is no significant relationship between V5% doses of all energies. In comparison to different treatment plans, we showed that V5% alone did not provide enough information when possible secondary cancer risks were calculated.
    Keywords: Integral radiation dose, secondary cancer, flattening filter free beam, volumetric modulated arc therapy, prostate cancer
  • C. Spatola*, L. Raffaele, A. Tocco, G. Acquaviva, R. Milazzotto, R. Bevilacqua, V. Salamone, P.V. Foti, P. Milone, A. Basile, A. Di Cataldo, G. Privitera Pages 265-273
    Background
    Purpose
    The purpose of our study is to demonstrate that intensified neoadjuvant chemo-radiotherapy (CRT) treatment in locally advanced rectal cancer (LARC), aimed at further enhancing the complete pathological response and local disease control, is feasible and well tolerated. 
    Materials and Methods
    From January 2011 to December 2015, 62 patients (women 21, men 41, mean age 61,5, range 36-84) with LARC (cT2-3 cN0-2) were enrolled in our institution. All patients performed an intensified neo-adjuvant CRT treatment according to the following scheme: FOLFOX4 induction chemotherapy for 3 cycles, followed by a concomitant radio-chemotherapy, with concomitant boost pelvic radiotherapy to a total dose to the primary of 54 Gy and daily continuous infusion of 5-Fluorouracil. After 6-8 weeks pts were re-evaluated by means of colonoscopy, body TC and pelvic MRI.
    Results
    Intensified CRT compliance was 90%. Grade I-II proctitis according to CTCAE v4.0 was 43%, grade III diarrhea was 10%, grade I-II genito-urinary toxicity was 29%. Eleven patients (19%) had a complete pathological response (pCR), 37 patients had a partial response. Sixty patients received surgery, two refused it: sphincter-saving procedure was performed in 85% of patients, Miles’ surgery in 15% of them. Fifty-nine patients are alive, after a median follow-up time of 43 months. Six patients experienced a distant metastatic disease, and two patients a local relapse.
    Conclusion
    This study has shown that the intensification of preoperative systemic therapy, together with intensification of radiotherapy, was feasible, well tolerated and has obtained high rates of local disease control (96,5%), with 19% of pCR rate.
    Keywords: Intensified radio-chemotherapy, locally advanced rectal cancer, concomitant boost radiotherapy
  • J.S. Choi, C.H. Rim, Y.B. Kim*, D.S. Yang Pages 275-281
    Background
    Breast cancer is a common disease in radiation oncology. We evaluated the radiation dose received by breast cancer patients, an often-neglected concern.
    Materials and Methods
    The total effective radiation dose in 101 breast cancer patients was calculated by summing the effective doses of individual diagnostic imaging tests from the first hospital visit to the initiation of radiotherapy. The effective dose from general radiography and computed tomography (CT) was estimated using tissue-weighting factors and dose-length products. The effective dose from isotopes (18F-fluorodeoxyglucose and 99m         Tc-methylene diphosphonate) was estimated from the radioactivity of each isotope using dose coefficients. The patient radiation exposures were analyzed using radiologic records in the Picture Archiving and Communication System.
    Results
    The median duration from initial imaging to the initiation of radiotherapy was 4.5 months (range: 0.7–13.4 months). When comparing the average effective doses associated with each diagnostic modality, CT, positron emission tomography-CT, bone scanning and radiography occupied 64%, 21%, 10% and 5% of the total effective dose, respectively. Comparison of the total effective dose according to clinical factors (age, AJCC stage, T stage, N stage, operation method, and cancer location) by multivariate analysis revealed that only T stage was significantly correlated with the total effective dose (p = 0.004). The median total effective dose was 71.5 mSv (range: 11.9–131.9 mSv).
    Conclusion
    The radiation dose received from diagnostic testing in breast cancer patients is not negligible. We need to systematically collect and manage the doses received by patients from medical procedures.
    Keywords: Effective dose, Radiation exposure, Cumulative dose, Breast cancer
  • J.T. Koizumi, S. Minamiyama, Y. Hayashi, K. Osawa, N. Ohashi, T. Ohya, M. Iida, T. Iwai, S. Oguri, M. Hirota, M. Kioi, K. Mitsudo* Pages 283-291
    Background
    The aim of this retrospective study was to evaluate the therapeutic outcomes and organ preservation in patients with squamous cell carcinoma of the buccal mucosa treated with radiotherapy and retrograde superselective intra-arterial chemotherapy.
    Materials and Methods
    Between April 2006 and March 2016, 28 patients (3 with stage II; 8 with stage III; and 17 with stage IV) with squamous cell carcinoma of the buccal mucosa were treated with definitive intra-arterial chemoradiotherapy. The median follow-up for all patients was 39months (range, 4-123months ). Catheterization of the tumor feeding arteries from the superficial temporal and/or occipital arteries was performed. Treatment consisted of radiotherapy (total 50-70 Gy) and daily concurrent superselective    intra-arterial chemotherapy (docetaxel, 50-70 mg/m2, cisplatin, total 125-175 mg/m2) for 5-7 weeks.
    Results
    After intra-arterial chemoradiotherapy, primary site complete response was achieved in 25 (89.3%) of 28 cases. Three-year local control and overall survival rates were 82.1% and 85.4%, respectively. Grade 3 or 4 toxicities included mucositis in 96.4%, and dermatitis in 28.6% of patients. Grade 3 toxicities included dysphagia in 35.7%, neutropenia in 28.6%, anemia in 10.7%, and fever in 7.1% of patients.
    Conclusion
    Retrograde superselective intra-arterial chemoradiotherapy for squamous cell carcinoma of the buccal mucosa provided good local control and overall survival.
    Keywords: Carcinoma of the buccal mucosa, Chemoradiotherapy, Intra-arterial infusion, Oral cancer, Organ preservation
  • H.J. Kim*, J.S. Lee, W.C. Kim Pages 293-300
    Background
    Based on the radiation biology model of prostate cancer, hypofractionated radiotherapy can improve the treatment outcomes without increasing toxicity. Although hypofractionated radiotherapy is implemented over a short period of time, it is more convenient and cheaper compared with conventional fractionated treatment. The aim of this study was to investigate the early toxicity of moderate hypofractionated schedules with volumetric modulate arc radiotherapy (VMAT) for localized prostate.
    Materials and Methods
    Between 2014-2017, 41 patients were treated using the volumetric modulated arc radiotherapy (VMAT) technique with image guided radiotherapy. The target volume for low risk patient (2.4%) was the prostate alone, and that for intermediate (43.9%) and high risk patients (53.7%) was prostate and two thirds of the seminal vesicles. A prescription dose of 70 Gy in 2.5 Gy daily for 28 treatment was used. Radiotherapy-related toxicity was scored according to the Common Terminology Criteria for Adverse Events 4.0 criteria.
    Results
    Early genitourinary (GU) toxicity was recorded for grades 0, 1, 2 and 3 in 7 (17.1%), 25 (61.0%), 9 (21.9%) and 0 patients, respectively. Most common GU toxicities were urinary frequency and urgency. Early gastrointestinal (GI) toxicity was observed for grade 0, 1 and 2 in 35 (85.4%), 6 (14.6%) and 0 patients, respectively. Most common GI toxicity was rectal discomfort but interventional therapy was not indicated.
    Conclusion
    The moderate hypofractionated VMAT radiation therapy with precise dose delivery technique appeared safe with low early toxicity. Longer follow up is needed to assess late toxicity and tumor control probability.
    Keywords: Prostate cancer, acute toxicity, hypofractionation, volumetric modulated arc therapy, radiotherapy
  • D. Meena, S.K. Gupta*, H.S. Palsania, N. Jakhar, N. Chejara, P. Meena Pages 301-308
    Background
    A 5 Ci 241Am-Be radio isotopic neutron source-based prompt gamma neutron activation analysis (PGNAA) setup was designed for estimation of minimum detectable concentration (MDC) of elements in aqueous solutions.
    Materials and Methods
    Performance variables related to PGNAA setup (source to sample distance, sample to detector distance and volume of water) were optimized experimentally. Characterization of the setup was done by chlorine and boron elements using sodium chloride (NaCl) and boric acid (H3BO3) compounds respectively.
    Results
    PGNAA setup was calibrated for different concentrations of Cl and B in aqueous solution. The chlorine concentration was varied over 1.2 g/L, 2.4 g/L, 3.6 g/L, 4.8 g/L, 6.0 g/L and 7.2 g/L in water samples while boron concentration was varied over 0.1 g/L, 0.2 g/L, 0.3 g/L, 0.4 g/L and 0.5 g/L. The MDC of chlorine and boron were calculated for various characteristic prompt gamma energies. Estimated MDC of chlorine and boron are 175 ± 53 ppm at prompt gamma energy 6110 keV and 3 ± 0.95 ppm at prompt gamma energy 478 keV respectively.
    Conclusion
    In the present work, PGNAA setup was developed and characterized for the in-situ analysis of aqueous solutions using a 5 Ci Am-Be neutron source. The chlorine concentration was varied from 1.2 to 7.2 g/L and boron concentrations were varied from 0.1 to 0.5 g/L. The setup shows linear response for both chlorine and boron for wide energy range. The obtained results were also compared with other previous published work. It shows good agreement with present results.
    Keywords: PGNAA, minimum detection concentration, 241Am-Be neutron source, HPGe detector
  • X.H. Bai, G.L. Zou, Z. Ding, R. Zhao, H. Zhe, Y.Y. Wang Pages 309-315
    Background
    In this study, we explored the relationship between  neutrophil-to-lymphocyte ratio (NLR) and grade 3 or higher treatment related small bowel toxicity and treatment outcome of patients with rectal cancer undergoing capecitabine and concurrent intensity modulated radiotherapy (IMRT).
    Materials and Methods
    From the year of 2012 to 2013, 117 rectal cancer patients who received concurrent chemoradiotherapy in our hospital were enrolled in this study. The association of baseline NLR level with grade 3 or higher treatment related small bowel toxicity and treatment outcome, including overall survival (OS) and progression free survival (PFS) were analyzed. 
    Results
    The optimal cut-off value of the NLR was determined to be 2.2 for the OS according to the receiver operating characteristic (ROC) analysis. A higher level of the baseline NLR was associated with hypoalbuminemia (P= 0.018). No relationship between NLR level and grade 3 or higher acute as well as late treatment related small bowel toxicity was found. A multivariate Cox model revealed that lymph node metastasis (p= 0.013), distant metastasis (p< 0.001), and high NLR level (p = 0.032) were significant predictors for poor OS. Nevertheless, a relationship between NLR level and PFS was not found.
    Conclusion
    This study show that higher baseline NLR level could not predict treatment related small bowel toxicity of rectal cancer patients who received capecitabine and concurrent IMRT. It is very gratifying to see that NLR is a useful predictor for treatment outcome of these patients.
    Keywords: Neutrophil-to-lymphocyte ratio (NLR), rectal cancer, small Bowel toxicity, prognosis
  • H. Saghaei, H. Mozdarani*, A. Mahmoudzadeh Pages 317-323
    Background
    DNA damage in male germ cells due to exposure to environmental and manmade physico-chemical genotoxic agents is considered as the main cause of male infertility. The aim of this study was to evaluate the effects of combined modalities (radiotherapy and chemotherapy) routinely used for cancer treatment on mouse sperm chromatin in vivo.
    Materials and Methods
    Forty-eight mice were divided into 12 groups: 3 irradiation (1, 2, and 4 Gy), 2 drug [Actinomycin-D (ACTD) and Bleomycin (BLM)], 3 ACTD/irradiation, 3 BLM/irradiation, and a control. Mice received intratesticular injection of 7µg/25 g of Actinomycin-D and Bleomycin before irradiation with X-rays. Forty-eight hours after irradiation, mice were sacrificed and epididymis and testes were removed. Sperm DNA damage was assessed with the use of alkaline comet assay. Moreover, morphology, and motility of sperms were investigated microscopically.  
    Results
    Result showed that drug alone had slight but not significant effect on sperm DNA damage, but significantly increased when combined with irradiation. There was a significant difference between the experimental and the control group in DNA sperm damage, but no significant differences were observed in sperm morphology (p>0.05). In the drug+4Gy group, DNA damage increased dramatically compared to the controls (p<0.01), morphology changes increased to about six times that of controls.
    Conclusion
    Results indicate that X-ray induced DNA damage and morphological changes in sperms in a dose dependent manner. Low doses of drugs led to potentiation of radiation effect. This might be indicative of necessity for radiation protection of testes when are in field of radiotherapy.
    Keywords: Ionizing radiation, chemotherapeutics, mouse, sperm DNA damage, comet assay
  • X. Zhang*, Z. Zhou, Y. Miao, Z. Liu, F. Chen, X. Hu, J. Feng, H. Chen, P. Liu, H. Zhang Pages 325-333
    ABSTRACT
    Background
    Tumor cells exhibit an increased requirement for iron to support their rapid proliferation. Deferoxamine (DFO), an iron chelator, has been reported to have anti-proliferative effects on cancer cells through induction of apoptosis and cell cycle arrest. X-rays also induce apoptosis and cell cycle arrest. However, limited information is available regarding the effect of iron depletion on radiotherapy. In this study, the radiosensitizing effect of DFO was investigated in human glioma U251 cells.
    Materials and Methods
    U251 cells were pretreated with DFO before exposure to X-rays. The radiosensitizing effect of DFO on U251 cells was evaluated with a clonogenic formation assay. Apoptosis and autophagy were measured to explore the model of cell death during DFO radiosensitization. Intracellular calcium levels, cell cycle, and ROS levels were examined to study the mechanism of the cell death. 
    Results
    We found that DFO enhanced X-ray-induced growth inhibition of U251 cells. Increased protective autophagy, occurring in U251 cells the first day of being treated with DFO and X-rays, rendered the radiosensitivity enhancement of DFO insignificant. However, the radiosensitizing effect was clear from the fourth day, which was attributed to the increase of apoptosis and decrease of protective autophagy. Further investigation revealed that the high level of apoptosis induced by DFO plus X-rays was dependent on the level of cytoplasmic calcium because the apoptosis was inhibited by [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid], a cytoplasmic calcium chelator.
    Conclusion
    Our results clearly demonstrate that DFO can enhance the radiosensitivity of U251 cells by increased calcium-dependent apoptosis.
    Keywords: Radiosensitivity, Deferoxamine, Apoptosis, Autophagy, Intracellular calcium
  • R.H. Zhang, J. Fleckenstein, Y.L. Gao, M.C. Miao, Z.F. Chi, W.W. Bai* Pages 335-344
    Background
    As the volumetric modulated arc therapy (VMAT) becoming a main role of treatment ways, the effect of couch top becomes more significant. It is imperative to re-evaluate the couches that previously may have been considered of no importance during early treatment techniques. The impact of couch top on radiation delivery was explored and the couch model was tested with the aim of reducing the couch absorption influences. 
    Materials and Methods
    Attenuation measurements were performed in a cylindrical phantom with an ionization chamber positioned at the isocenter. Couch model was obtained by importing its actual CT scan, and the accuracy was evaluated by comparing percentage deviation at 2 and 5 mm voxel grid size. Effects on surface dose were measured using EBT3 film with the constant SSD at different depths and beam energies at the gantry angle 180° and 0°, respectively.
    Results
    Couch top increases surface dose from 45.9 % to 95.8 % , from 35.0 % to 87.9 % and from 29.2% to 73.9 % for 10 cm ×10 cm field at 6 ,10 and 18 MV, respectively. Due to the couch absorption the case of vertebral metastasis VMAT plan D50 of the PTV changed from 30 Gy to 29.3 Gy. Couch model with uniform electron density of 0.18g/cm3 demonstrated an excellent agreement between measured and TPS computed dose.
    Conclusion
    The treatment couch presence between the patient and beam source significantly alters dose in the patient. Modelling the couch in the Monaco TPS can adequately predict the altered dose distribution.
    Keywords: volumetric-modulated arc therapy, treatment planning system, attenuation, buildup, Couchtop
  • J.H. Zhu, Q.C. Hu, K. Gu*, C. Shen, R. Yang, S.J. Ji, Q.Q. Che Pages 345-353
    Background
    Small cell carcinoma of the uterine cervix is a highly malignant form of cancer in women, characterized by its high propensity for rapid extra-pelvic distant metastasis and poor prognosis. The best treatment strategy for this type of cancer is still controversial.
    Case presentation
    We report here a case of small cell carcinoma of the uterine cervix treated by extensive total hysterectomy followed by adjuvant chemoradiotherapy. A 45-year-old Chinese woman was diagnosed with stage IIA small cell carcinoma of the uterine cervix. The patient suffered from head metastasis following a diagnosis made fifteen months prior.
    Conclusion
    We describe the optimal treatment and prognostic factors of this tumour. The stage of the tumour, main treatment, prognostic factors and outcome of this disease are presented with a review of the related literature.
    Keywords: Cerebellar metastasis, small cell carcinoma, uterine cervix, treatment, prognostic factor
  • R. Abedi Firouzjah, A. Nickfarjam*, M. Bakhshandeh, B. Farhood Pages 355-361
    Background
    This study aimed to evaluate the dose calculation accuracy of EclipseTM treatment planning system (TPS) in a heterogeneous chest phantom with the intensity modulated radiotherapy (IMRT) technique using EBT3 film and Delta4.
    Materials and Methods
    Two IMRT plans (A and B) were prepared for radiotherapy of the heterogeneous chest phantom. Plan A was between the left lung and the surrounding soft tissue and plan B was carried out on the soft tissue. EBT3 film and Delta4 were used for dose measurement in the phantom. EclipseTM TPS was also used for dose calculation. Finally, the gamma index values of the TPS with film and TPS with Delta4 were obtained. A 95% passing rate of gamma index with the passing criterion of 3mm/3% and a dose threshold of 20% as the standard criterion was considered in this study. Furthermore, the passing rates of gamma indices of the film and Delta4 were compared with each other via Bland-Altman analysis.
    Results
    The mean passing rate of gamma index with standard passing criterion between the TPS calculations and film measurements was 96.95±0.22%, while it was equal to 97.7±0.56% and 98.45±0.21% between the TPS calculations and 2D and 3D Delta4 measurements, respectively. Additionally, the differences between the passing rates of gamma indices of the film and Delta4 were less than 5%.
    Conclusion
    The findings demonstrate that the accuracy of dose calculations of EclipseTM TPS in a heterogeneous chest phantom with the IMRT technique is within the standard passing criterion. Furthermore, it can be concluded that there is a good agreement between the film and Delta4, as IMRT QA devices.
    Keywords: Delta4, EBT3 film, Heterogeneous phantom, IMRT
  • H.R. Hashemifard, R. Anbiaee, A. Arbabi, S. Bitarafan, D. Soltani, E. Pirayesh* Pages 363-367
    Background
    Breast conserving surgery (BCS) followed by radiotherapy (RT) has been widely accepted as the standard treatment in early stages of invasive breast cancer. The standard technique of RT includes whole breast irradiation (WBI). Additional tumor bed boost irradiation has also an important role in the local tumor control. But there are various controversial delivery methods. The aim of the present study was to compare electron and photon boost techniques in terms of heart and lung volume absorbed dose.
    Materials and Methods
    Thirty patients with breast cancer were selected. All patients had undergone BCS and had been treated by WBI and boost irradiation. After delineation of gross tumor volume (GTV) two CT based 3D conformal boost plans by photon and electron were created for each patient. In each plan coverage index (CI), external volume index (EI), conformity index (COIN) and, lung volume absorbed dose (LVAD) and heart volume absorbed dose (HVAD) of at least 2Gy were measured. Statistical analysis was done using SPSS 17. Data were compared using a nonparametric test (Mann-Whitney) and p values <0.05 were considered significant.
    Results
    Photon boost showed statistically significant superior results in terms of mean CI (P=0.002) and COIN (P=0.005). Results of EI revealed no significant difference between two methods (P=0.171). The heart (p=0.01) and lung (P<0.005) volume received 2Gy was lower in photon therapy in comparison with electron therapy.
    Conclusion
    Our results demonstrated that the heart and lung volume absorbed dose is significantly higher in electron boost technique.
    Keywords: Absorbed dose, breast neoplasm, electron, photon, radiotherapy