International Journal of Radiation Research
Volume:15 Issue: 3, Jul 2017

Quercen has been reported to modulate cell proliferaon and apoptosis. The present study aimed at idenfying whether treatment of ionizing radiaon (IR) combined with quercen induces apoptosis in HepG2 cells.
HepG2 cells were plated at an appropriate density according to each experimental scale and irradiated with 1, 5 and 10 Gy gamma-rays from a 60Co source at room temperature. Cell viability, SOD and CAT were assessed by using commercial assay kits. Western blot analyses were done on apoptosis related proteins. The cells were treated with various concentraons of quercen alone or in combinaon with IR.
The cell viability was decreased in a concentraon-dependent manner 24 h a3er treatment of quercen. It was significantly lowered a3er the combined treatment of quercen with IR than that of the cells treated with quercen alone. Moreover, quercen increased the expression of p53 levels in a dosedependent manner. Combined treatment of quercen with IR significantly increased the levels of pro-apoptoc proteins, cleaved caspase-3 and caspase -7, and Bax. Cell cycle analyses indicated a drasc increase in the Sub G1 populaon a3er quercen treatment combined with IR. The acvity of caspase-3 increased coincidently with apoptosis. The combined treatment of quercen with IR decreased catalase and superoxide dismutase acvies, as well.
Quercen made the radio-resistant HepG2 cells undergo apoptosis by acvang p53. These results suggest that the combined treatment of quercen with IR may provide an effecve therapeuc strategy to improve the radiotherapy efficacy.

This study aims to calculate the air-kerma strength (SK), the dose rate constant (∧) and the dose rate profiles of a Gammamed 12i Ir-192 source by using the Monte Carlo technique and to compare the dose rate values with those calculated by the Abacus HDR treatment planning system (TPS).
Air-kerma strength (in units of U; 1 U= μGy m2 h-1) and the dose rate constant (∧) of a Gammamed 12i Ir-192 source were computed with the Monte Carlo-based code MCNP. For a single dwell posi4on, profiles of dose rate per air kerma rate strength (in unit of U) along the x axis were obtained with MCNP and compared with data from the Abacus TPS at y=0, 1, and 2 cm.
The air-kerma strength and the dose rate constant of the source were calculated to 9.98×10-8 U and 1.106 cGy h-1 U-1, respec4vely. The maximum dose differences between MCNP and TPS along the x axis were found to be 1.3, 3.7 and 5.4% at distances more than 1 cm away from the source center for y= 0, 1 and 2 cm planes, respec4vely.
The dose rate profiles calculated with MCNP and by the TPS show good agreement except for points located beyond the 4p of the source.

To evaluate computed tomography (CT) and magnec resonance imaging (MRI) fusion images for delineang gross tumor volume (GTV) in three-dimensional conformal radiotherapy (3D-CRT) of nasophanrygeal carcinoma (NPC), and compare treatment outcomes between CT- and CTㄒbased targets.
A total of 120 NPC paents treated with 3D-CRT were included, in which, 60 each were treated with CT-based and 60 with CTㄒ fusion targets. We explored the clinical applicaon of CTㄒ fusion targets and compared the 1-, 3-, and 5-year survival and relapse rates between both targets.
The clinical characteriscs and treatment factors were well balanced. The differences in public volume using CT alone in the CTㄒ (Group A) and the CT arm (Group B) were not significant (33.6±2.18 vs. 34.3±2.98, P > 0.05). The public volumes of GTV in the two arms were 49.48±2.46 cm3 and 33.6±2.18 cm3 respecvely (P The variability in GTV delineaon in NPC was ascribed to intermodality and not interobserver variability. CT fusion images likely reduced the 3-year out-of-field relapse rate.

The purpose of this study was to evaluate the characteriscs of TomoDirect (TD) plans compared to convenonal TomoHelical (TH) plans in chest wall irradiaon in paents with breast cancer.
TD and TH plans for only chest wall were retrospecvely created for 30 paents previously treated with TH technique in our clinic. The beam angles were arranged to cover PTV chest wall and to minimize doses to OARs, ipsilateral lung and contralateral breast in TD plan. The prescribed dose was 50 Gy in 25 fracons.
The mean treatment mes were similar in TH and TD (310.8 and 309 s, respecvely, p> 0.05). There was no difference between the values of CI and HI of both plans (p>0.05). The values of Dmean, V5 and V20 of the ipsilateral lung in TD plan was significantly lower than that in TH plan for all 30 paents (p0.05).
Both of TH and TD plans produce acceptable target dose coverage in chest wall RT. Considering the risk of low-dose radiaon to the crical organs; TD mode improve dose distribuon.

The purpose of this study was to assess the dose distribuon and coverage of level I-II axillary lymph nodes during whole breast tangenal field radiotherapy (RT) aer breast-conserving surgery in paents with breast cancer.
The level I-II axillary lymph node volumes were retrospecvely contoured by a single radiaon oncologist based on computed tomography simulaon data from 44 paents who underwent breast-conserving surgery without axillary dissecon and who received postoperave whole breast RT between January and December 2014. The dose distribuons of the whole breast tangenal RT fields were reassessed in relaon to the axillary level I and II lymph node volumes.
: The average doses delivered to level I and I axillary lymph nodes were 49.4% (range, 14.2–94.6) and 30.8% (range, 2.6–71.5) of the prescribed radiaon dose, respecvely. The volumes receiving at least 95% of the prescribed radiaon dose were 12.7% (range, 0–67.4%) for level I and 1.4% (range, 0– 7.7%) for level II nodes. Compared to thin paents, the average doses delivered to axillary lymph node levels I and II were significantly higher in overweight paents.
The radiaon dose coverage of axillary lymph nodes by whole breast tangenal RT varies greatly among paents. To safely omit axillary lymph node dissecon from the treatment of clinically axillary lymph node negave T1-2 breast cancer paents with 1–2 posive sennel lymph nodes, standardizaon and individualizaon of whole breast RT are necessary.

The lack of lateral electronic disequilibrium (LED) becomes a main problem in small field. This factor affects the dose in target volume cannot predict correctly. In addi"on, u"liza"on of high-energy linear accelerator (10 MV) can emit some unwanted par"cles (electron contamina"on). Therefore, the aim of this study was to characterize head linear accelerator (linac) Varian Clinac iX 10 MV photon beam for square small field size (1×1, 2×2, 3×3, 4×4 and 5×5 cm2) using Monte Carlo (MC) simula"on.
The commissioning process for this linac, has been conducted for field size 6×6, 10×10 and 20×20 cm2 by comparing the measurement and MC simula"on data. Head linac simula"on was performed with BEAMnrc and dose calcula"on with DOSXYZnrc. The phase space (phsp) data from BEAMnrc was analyzed using BEAMDP to get the par"cles informa"on in scoring plane.
The sca6er angle of par"cles depends on the field size. This factor affects the penumbra width in water phantom. On the other hand, PDD data show that the depth of maximum dose and penumbra width in small field shi:ed correspond with the number of sca6er par"cle. The difference of rela"ve output factor between measurement and MC results were found less than 2%. However, the 2% difference was s"ll acceptable in photon beam dosimetry.
From this simula"on, the electron contamina"on give contribu"on in surface dose of water phantom about 13.0581% and less than 1% for field size 10×10 cm2 and small field size, respec"vely.

This study evaluated whether IMRT using fewer beams and segments could reduce delivery me without compromising plan quality in gastric cancer adjuvant radiotherapy.
Fi een paents with advanced gastric cancer who underwent D2, R0 surgery were included in this study. IMRT plans for each paent were designed as 7 equal beams with 40 segments, 5 beams with 25 segments and 4 beams with 20 segments. The dosimetric parameters were compared for the planned target volume (PTV). The dose of normal organs at risk (OARs) was also assessed. The monitor units and treatment mes of the different IMRT plans were calculated.
The 20-segment IMRT plan significantly reduced the PTV maximum dose compared to the 40-segment IMRT plan. The 20-segment IMRT plan improved le kidney and liver dose sparing in V20 and V30 as well as the 40-segment IMRT plan did and provided be4er protecon for the V20 (13.86±7.78) of the right kidney, the V30 (9.25±4.04) of the le kidney, the D mean (19.68±2.47) of liver and D max (38.79±3.57) of the spinal cord. Irradiaon mes in the 20-segment and 25-segment plans decreased by 2.5 and 1.9 min, respecvely, compared to the 40-segment IMRT plan.
IMRT using fewer beams and segments reduced delivery me without compromising plan quality in gastric cancer adjuvant radiotherapy. Fewer segments IMRT plans lowered the monitor units and the treatment me.

The aim of this study was to develop and implement a Monte Carlo framework for evaluaon of paent specific out-of-field organ equivalent dose (OED).
Dose calculaons were performed using a Monte Carlo-based model of Oncor linac and tomographic phantoms. Monte Carlo simulaons were performed using EGSnrc user codes. Dose measurements were performed using radiochromic films. Furthermore, the applicability of this framework was examined for a 3D conformal radiotherapy of breast.
Commissioning of the beam model was done by comparing the measured and calculated out-of-field dose values of several points in the physical and tomographic phantoms, respecvely. The maximum percentage difference was 17%, which was smaller than 30% acceptance criteria for Monte Carlo modeling. The maximum stascal uncertainty in out -of-field dose calculaon was 23%. Organ equivalent doses for out of field organs in 3D conformal radiotherapy of le1 breast varied from 2.4 cGy for right kidney to 134.6 cGy for the le1 humeral head.
The framework developed in this research is a valuable tool for calculang peripheral dose and out-of field paent specific OEDs, the quanes needed for calculang risk of secondary cancer inducon as a result of radiotherapy. This code can be used as a paent specific treatment plan opmizaon tool in order to select a treatment plan with the lowest risk of secondary cancer inducon.

The radiaon dose received by contralateral breast (CLB) is one of the concerns of breast radiotherapy, because it may lead to the inducon of secondary breast cancer. The aim of this study was to evaluate the CLB surface dose in the breast treatment in Yazd radiotherapy center.
The surface dose of CLB was measured using TLD dosimetry in 50 cancer breast paents. The TLD chips were placed at four points on the each of CLBs. The paents were treated by 6MV photon beams of Oncor (physical wedge) and Compact (motorized wedge) LINAC. The TLD chips were placed on the surfaces of CLB during the medial and lateral tangent radiaon fields in one of radiotherapy fracons.
The mean percent of prescripon dose of the CLB surface doses on the point 1 in the two Linac (Oncor & Compact) were significantly different. The mean of CLB surface doses of point 1 in the physical and the motorized wedge techniques were 5.78 and 7.84 percent of prescripon dose of breast cancer, respecvely. The medial and lateral field's contribuon from 7.4% surface dose of CLB were 5.8% and 1.6%, respecvely.
In Shahid Ramezanzadeh radiotherapy center, the CLB surface dose due to breast cancer radiotherapy by the Compact machine (7.84 %) was significantly more than the allowable value (6% prescripon dose). The CLB does due to the medial field beam was more than the lateral field.

: Due to the difficules of locally obtaining ZnS(Ag), preliminary invesgaon of the radioluminescence characterizaon of Zinc oxide (ZnO) for alpha parcle detecon was performed.
The scinllaon properes of ZnO films were tested using alpha sources (Am-241). The correlaons between ZnO scinllaon responses and irradiaon me and source acvity were also verified and compared with the response of a ZnS(Ag) detector.
The obtained results showed that the response of ZnO was linear with the exposure me, and the uncertainty of the repeatability was less than 1%. In addion, ZnO was found to have good radiaon resistance over a wide range of doses.
The preliminary results may be indicave that the proposed ZnO detector could be considered as a promising detector for alpha parcles.

In this study, the health risk associated with three types of drinking waters (fissure, underground treated and surrounding waters) from two mines in South Africa were assessed.
The measurement of the radionuclides concentraon was carried out by liquid scinllaon counter and alpha spectrometer. The esmated radiological risk pose to the people consuming the water types were evaluated based on the calculated radionuclide concentraons.
The value of the gross alpha was 1.08 ± 0.02 Bq/L and gross beta acvity was 0.65 ± 0.04 Bq/L in the treated underground water. These values were several fold above the limit value of 1.0 Bq/L for gross alpha and 0.1 Bq/L for gross beta. For the fissure water, the gross alpha acvity value was 0.59 ± 0.07 Bq/L which is less than the limit of 1.0 Bq/L and the gross beta acvity was high with a value of 0.54 ± 0.05 Bq/L compared to the limit value of 0.1 Bq/L. The results around the Princess gold mine showed very high gross alpha and beta acvity in the collected water samples studied. In general, the concentraons of the natural radionuclides were high especially 238U, 226Ra, 230Th, 235U, 234U and 210Po in all the water samples.
The calculated chemical toxicity, cancer mortality/morbidity and hazards quoent with respect to 238U were very high. Hence, the waters within these vicinies are polluted with radionuclides and may posed serious health effect to the inhabitant.

The Ural region is highlighted among other Russian regions for its unfavorable radiaon situaon and complexity of the overall environmental situaon. The source of man-made radioacve contaminaon is the work of the "Mayak" Producon Associaon. A significant radioacve contaminaon has happened as a result of several radiaon incidents in the early period of the company acvity and it has affected a territory total area of over 23,000 km2 in the Chelyabinsk, Kurgan and Sverdlovsk regions. Our primary aim is to compare the characteriscs of Heart Rate Variability among residents of the Ural region, living in the territories with different levels of radioacve contaminaon.
The segment of the populaon exposed to increased radiaon exposure amounted to approximately 500 thousand people. We have disnguished three territories in the Urals region to perform a comparave study of environmental factors (the radioacve contaminaon) on human health. Two of these territories are case territories, which are exposed to environmental hazards, and one of them is the control. Data were collected from 1992 to 1995.
To assess the dependence of the state of adaptaon abilies of the organism exposed to radiaon contaminaon of the territory, we used the stress index. We determined the stascally significant influence of man-made radioacve contaminaon of the environment on the funconal adaptaon of the body.
Our study showed the predominance of sympathec regulaon of heart rate, which indicates the tension of adaptaon capabilies of the organism for the populaon living in radioacve contaminated areas.

The acvity concentraons of natural radionuclides in soil around a coal-fired thermal power plant of northwest China were invesgated for assessing the radioacvity level.
Soil samples were collected around the coal-fired thermal power plant and their radioacvity levels were determined using gamma ray spectrometry. Radiaon hazards were assessed by radium equivalent acvity (Raeq), air absorbed dose rate (D) and annual effecve dose equivalent (AEDE).
The acvity concentraons of 226Ra, 232Th and 40K ranged from 24.7 to 89.8, 38.4 to 122.3 and 206.7 to 573.8 Bq kg-1 with an average of 49.7, 63.5 and 396.3 Bq kg-1, respecvely. The mean Raeq value was less than the recommended limit, while the mean values of D and AEDE were slightly higher than the corresponding world average.
The coal-fired thermal power plant enhanced the natural radiaon of surrounding soil environment.