International Journal of Radiation Research
Volume:18 Issue: 4, Oct 2020

Neutron sources employed in different applications in both medicine and industry. Due to the harmful effects of neutron particles on living organisms, radiation shields have played a vital role in radiation protection against neutrons. In recent decade, numerous investigations conducted on the design and fabrication of nanocomposites as more efficient shielding materials against fast and thermal neutrons. A range of different nanoparticles for a spectrum of neutron energies investigated. However, there is no comprehensive review concerning the shielding properties on these newly proposed shielding materials against neutrons. The current review is an attempt to gather the information provided by the published papers in this regard. The neutron attenuation of nanocomposites and their ordinary counterparts discussed and compared. In addition, the effect of influential parameters, including particle size, neutron energy, particle type, and materials composition analyzed.

The accuracy and the reproducibility of radiotherapy can be provided by using immobilization devices such as thermoplastic masks. In head and neck cancer radiotherapy, the patients are mostly immobilized by using thermoplastic masks. In this study, the effect of the thermoplastic mask to the surface and buildup region doses was investigated by using Markus parallel plate ion chamber, Gafchromic EBT3 film and MOSFET detector for the same field size and different beam angles.

The measurements were made in a water equivalent solid phantom at the surface and in the buildup region of the 6 MV photon beams at 100 cm source-detector distance for 10 × 10 cm2 field size and beam angles of 0°, 30°, 60° and 80° with and without thermoplastic mask.

The surface doses in 0.07 mm depth using 6MV photon beams without a thermoplastic mask for 10 × 10 cm2 field size were found 20.3%, 18.8%, and 41.5% for Markus chamber, EBT3 film, and MOSFET detector, respectively. The surface doses using 6 MV photon beams with a thermoplastic mask for 10 × 10 cm2 field size were found 38.4%, 51.7% and 50.2% for Markus chamber, EBT3 film, and MOSFET detector, respectively.

The thermoplastic masks placed on the surface of the medium affect the surface and buildup region doses. The effect of thermoplastic masks to surface and buildup region doses should be determined before use clinically.

Radiation Pneumonia (RP) is one of the most extensive side effects in Stereotactic Body Radiotherapy (SBRT) of lung cancer. SBRT are performed by means of Intensity Modulated Radiotherapy (IMRT), Intensity Modulated Arc Therapy (IMAT), CyberKnife (CK) or Helical Tomotherapy (HT) treatment methods. In this study, we performed a plan study to determine the plan parameter such as the Mean Lung Dose (MLD), V20Gy Lung Volume and V5Gy Lung Volume in the evaluation of RP risk in the treatment of lung with SBRT.

Fifteen patients with Lung Cancer who had a tumor diameter of less than 5 cm and peripheral located were included to this study. Intensity Modulated Radiotherapy, Intensity Modulated Arc Therapy, CyberKnife and Helical Tomotherapy plans were separately created for each patients. For each plan, a total of 54 Gy dose were given to Planning Target Volume (PTV) in 3 fractions using a dose of 18 Gy per fraction.

In each technique for all parameters of PTV and critical organ doses (OAR) meet the required criteria. Total Lung MLD were found as 3.21 Gy and Total Lung V20Gy Volume were found as 4.05 cc,  Total Lung V5Gy Volume were found as 14.06 cc as the lowest value in IMRT-SBRT plan.

When treatment plans are evaluated in terms of RP risk, Total Lung MLD,  Total Lung V20Gy Volume and Contralateral Lung V5Gy Volume are found the lower in IMRT- SBRT plan than other SBRT techniques. We suggest that IMRT-SBRT irradiation should be preferred in lung radiotherapy in case of high RP risk.

The objective was to explore the value of the CT value difference (△HU) and CT value ratio (CVR) between the hepatic arterial (AP), portal (PP), and delayed phases (DP) to differentiate the small Hepatocellular Carcinoma (SHCC, ≤ 3 cm) from the small Focal nodular hyperplasia (SFNH, ≤ 3 cm).

All the lesions were confirmed by clinically and/or pathologically and all the patients underwent triple-phase enhanced CT scans. The lesions’ CT values (LCV) and the surrounding normal liver parenchyma (NCV) of the enhancement phases were measured separately, the △HU and CVR were calculated.

The median age and the male/female ratios of the SHCC and SFNH have statistically significant, and the size haven’t statistically significant. The △HU and CVR of the AP, PP, and DP of the SHCCs and SFNHs were statistically significant, respectively. The area under curve of △HU and CVR of AP, PP and DP were increased gradually. When the △HU and CVR of the AP, PP and DP were 105.800HU vs. 1.516, -12.600HU vs. 0.949, -19.750 HU vs. 0.951, obtained the maximum You-den indexes. The corresponding sensitivity and specificity were 80.6 % and 90.1 % vs. 88.90% and 72.1%, 100% and 81.1% vs. 100% and 81.1%, 94.4 % and 96.4% vs. 94.4 % and 96.4%, respectively.

The SHCC was highly suggested when △HU and CVR are no greater than 105.800HU and 1.516, -12.600HU and 0.949, -19.750 HU and 0.951 of the AP, PP, and DP in the middle-aged and elderly male patients, especially in the DP.

The grading evaluation of atlas based auto-segmentation (ABAS) of organs at risk (OARs) in thorax was studied.

Forty patients with thoracic cancer were included in this study, and for each thirteen thoracic OARs were delineated by an experienced radiation oncologist. The patients were randomly grouped into the training and the test dataset (20 each). The investigated ABAS strategies included single-atlas (Single), majority voting with 5 atlas matches (MV5) and simultaneous truth and performance level estimation (STAPLE) with 5 atlas matches (ST5). The Dice similarity coefficient (DSC), the difference of the Euclidean distance between centers of mass (ΔCMD), the difference of volume (ΔV), maximum Hausdorff distance (MHD) and average Hausdorff distance (AHD) between auto-segmented and manual contours were calculated.

Most of the index values (33/65) of ST5 were optimal. There were differences in the grading results for the five indexes. With DSC, five, four and four OARs were graded into Level 3, Level 2 and Level 1, respectively. The mean DSC values ranged from 0.88 to 0.96, from 0.73 to 0.79, and from 0.53 to 0.62 for the Level 3, Level 2 and Level 1, respectively.

Grading evaluation of ABAS of thoracic OARs based on the DSC proved to be feasible and relatively more reliable. The thoracic OARs auto-segmentation was divided into three levels based on the DSC. Level 3 OARs can be auto-segmented, Level 2 OARs delineations need to be manually modified after the auto-segmentation, and Level 1 OARs are not recommended for the auto-segmentation.

Radiotherapy is regarded as a standard treatment modality in breast cancer (BC). Radiation causes cellular damage both in cancer and normal cells by inducing DNA-damage and chromosomal aberrations (CA). Different agents were used for ameliorating effects of radiation, mainly antioxidants such as melatonin. Melatonin shows oncostatic properties on human BC. The aim of this study was to evaluate the modulating effect of melatonin on radiation induced CA in cells irradiated at G2 phase of the cell cycle.

G2 assay was applied on whole peripheral blood lymphocytes received from 10 BC patients and 5 normal controls. Blood culture was initiated in complete culture medium. Four h prior to harvesting, cells were irradiated with 1Gy gamma rays. Pretreatment of samples with melatonin was done 3 h before irradiation. After metaphase preparation and slide making, slides were stained in Giemsa. Hundred well spread metaphases were scored for the presence of chromatid type aberrations with a microscope at a magnification of × 1000.

Results indicated a high and significant frequency of CA both in lymphocytes of normal and breast cancer patient after irradiation; however, the frequency was much more in lymphocytes from BC patients. Pretreatment of samples with melatonin led to a considerable increase in the frequency of aberrations especially in lymphocytes of BC patient.

Results showed that despite having antioxidant property, melatonin led to enhanced frequency of radiation induced CA in lymphocytes of BC patients.

Flour is one of the most important food sources, therefore it must be kept healthy and clean. As a potential pest control modality, we aimed to examine whether flour irradiation is a feasible tool to eradicate Tribolium confusum adults from infected flour considering probable health effects of infested flour consumption.

unirradiated and irradiated flour were infested with 70 or 100 T. confusum adults/25g and stored for 6 and 12 weeks, the number of T. confusum progeny, antifeedant activity and biochemical changes (Aspartate Aminotransaminase (AST) and Alanine Aminotransaferase (ALT) activities) in adults were estimated. In addition the effect of feeding rats on bread made from theses infested flour was studied.

the obtained results revealed that flour irradiation caused disturbance in the production and physiology of T. confusum adults feed on it. In addition, the gained data exposed a significant decline in ratschr('39') weight and alterations in some biochemical aspect (glutathione content, glutathione-S-transferase, malondialdehyde, gammagluamyl transferase, AST, ALT) which were more pronounced in those fed on irradiated flour infected with T. confusum. As well as, there was a disturbance in the complete blood picture (white blood cells, the lymphocyte count, red blood corpuscles and hemoglobin). Moreover, rats fed on bread made from irradiated or unirradiated infected flour exhibited pathological damages in their liver sections.

It is concluded that irradiation of flour disturbs the physiological process in T. confusum so it may serve as a good preservation tool and does not significantly affect the rats.

the supplementation of natural antioxidants such plant flavonoids may counteract the deleterious actions of gamma-irradiation and iron overload.

the protective effect of naringin (NIN) against kidney injury induced by γ-irradiation (IRR) (6.5 Gy) and/or iron dextran (ID) (50 mg/kg. b. w) has been studied in rats given 80 mg/kg b.w of NIN for 14 days before, and for 7 days after the exposure to γ-irradiation and/or iron dextran.

a significant elevation in serum urea, creatinine, glucose concentrations, and an increase in kidney lipid peroxidation (LPO), ROS and metallothionein (MTs) were observed in rats treated with γ-radiation and/or ID. In addition, a significant decrease in kidney GSH, SOD content, serum total protein, albumin and A/G ratio were also recorded. Tissue organ displayed some changes in trace element concentrations, which may be due to the radiation and/or ID ability to induce oxidative stress. Treatment with NIN revealed a significant modulation in the biochemical tested parameters and a profound improvement in the activity of antioxidant status; thereby appeared to be effective in minimizing the γ-irradiation and/or ID-induced increase in LPO and ROS as well as changes in essential trace elements in kidney tissue organs. The positive and negative correlation between trace elements and antioxidant markers illuminated antioxidant properties in addition to being an integral part of antioxidant enzymes.

NIN has a role in protecting against oxidative stress and kidney injury produced by iron dextran and/or γ- irradiation.

Alterations of systemic metabolic parameters are always present vitamins in cancer in addition radiotherapy may increases and complicates these disorders. The analysis of each biochemical metabolic alterations may give more understanding to biochemistry of malignancy   and improving the degree of radiotherapy. The current study aimed to follow up the changes of folate, vitamin B12 and homocysteine in normal and malignant mice with and without radiation exposure, as floate and B12 metabolism play a role in hypermethylation of certain genes including tumor suppressor and apoptotic genes of cancer.

The study was conducted through six groups of mice, normal, malignant, normal and malignant exposed gamma radiation with different fractionated doses (0.7 and 1.2 Gy).

Comparisons between the results of all groups revealed that: folate and vitamin B12 were lower and homocysteine was higher in gamma irradiated malignant and gamma irradiated nonmalignant mice in comparison with normal control and malignant mice. Folate and vitamin B12 levels were also lower whereas homocysteine was higher in malignant mice in comparison with normal control   group.

These results denoted that increased homocysteine or/and decreased folate and vitamin B12 in the two malignant exposed groups may have a role in the primary tumor regression leading to the recommendation that preventing up taking of folate and vitamin B12 either as supplements of land nutrients rich with subsequent increase in homocystein may be beneficial through its toxic effect in stopping or minimizing tumor progression. The disturbance of vitamins may be due to the metabolic alterations associated with tumor development.

Hair follicle cycling usually associated with prominent changes in skin vascularization; through follicular dermal papilla production of angiogenic factors. The early response of hair follicles to ionizing irradiation (IR) is induction of early anagen hair and appearance of new hair formation.

Fifty rats were equally divided into 2 groups; control and γ-rays (10Gy) as a single dose, skin biopsy was taken from dorsum of the rat 72 hours after irradiation. Skin biopsy was examined histopathological and with immunohistochemical staining CD31. Blood samples were collected for biochemical analysis of Tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Malondialdehyde (MDA), Catalase (CAT) and Superoxide dismutase (SOD)

γ-rays produced epidermal thinning and dermal inflammatory cells together with dermal endothelial proliferation and new vessels formation around the hair follicle compared with control group as demonstrated by CD31 staining. Furthermore, there was a significant elevation of TNF-α, IL-1β and IL-6 levels compared to control group. Moreover, MDA levels increased significantly in γ-rays group and decreased significantly in control group, whereas CAT and SOD activities decreased in the γ-rays compared with the control group.

The early effects of γ-rays on the skin could be beneficial and stimulatory to hair growth.

In trichinosis, the presence of muscle larvae inside skeletal striated muscle causes loss of identity and function of myotube through the releasing of myogenin and myosin. Considering the dominant role of vaccination, research on gamma radiation-attenuated vaccine has very promising value. The goal of this study was to determine the efficacy of vaccination with radiation-attenuated Trichinella spiralis larvae on the subsequent infectivity. This goal was to be achieved by expression of myogenin, BcL-2 and DNA damages of myocytes in experimental animals.

Mice were randomly assigned to serve as normal control, infected control, vaccinated unchallenged and vaccinated challenged groups. Histopathological and immunohistochemical assessments of skeletal muscle tissues of diaphragm were conducted using different stains. Also, DNA damages of myocytes by comet assay were evaluated.

An improvement of histopathological changes and DNA damages of myocytes with significant decreased expression of myogenin and BcL-2 in vaccinated challenged group was detected.

Vaccination with gamma radiation- attenuated larvae exerted protective effect against challenged infection. This may pave the way to new protective modality in trichinosis control.

Radiotherapy is the gold standard in the treatment of lung cancer. However, the radiosensitization of cancerous cells requires further improvement. Here, we investigated the effect of dihydroartemisinin (DHA) on the radiosensitization of non-small cell lung cancer (NSCLC) cells.

Cell proliferation and cell cycle assays were carried out using A549 cells exposed to DHA. The effect of DHA on the radiosensitization of cells was investigated by clonogenic cell survival assay and apoptosis assay. Polymerase chain reaction and western blotting were used to quantify GSK-3β level. 

DHA significantly inhibited cell proliferation from 24 to 96 h. Cells treated with DHA had a significantly decrease G1 phase but significantly increase S and G2/M phases compared with untreated and vehicle-treated cells. The number of viable DHA-treated cell colonies was significantly lower than that of untreated or vehicle-treated cells. The percentage of early apoptotic and necrotic cells was significantly higher for cells exposed to DHA and irradiation. GSK-3β expression was significantly higher in cells exposed to DHA and irradiation than that in untreated cells, indicating that DHA may enhances the radiosensitization of cells through the activation of GSK-3β.

Our results demonstrate that DHA can increase the radiosensitivity of A549 cells, suggested its potential use to sensitize tumors to radiation therapy in NSCLC. The expressions of GSK-3β were induced by DHA in cells exposed to irradiation, indicating GSK-3β may paly important role in the radiosensitization mechanism of DHA.

Although nuclear technology has various beneficial, it also has a variety of risks. In particular, initial response is very import to respond to risks.
Therefore, the program to increase initial response proficiency can be regarded as very essential. The Republic of Korea annually conducts more than 10 nuclear emergency response training programs, and specialized training courses for initial response are conducted twice several times a year.

The participants of the initial response training program were evaluated by senior professionals who had over 10 years of experience. The DISASTER Paradigm developed by the National Disaster Life Support Program was used as an index for evaluation. The purpose of evaluation was to identify issues in the current training program through evaluation results over a period of three years. The difference-in-differences method was used to quantitatively analyze the evaluation results.

Five indicators of the DISASTER Paradigm demonstrated that personnel skills improved through training. However, three indicators showed that skill levels decreased despite continued training.

According to the results, the treatment of radioactive waste (T), evacuation (E), and triage of radiation exposure (R) indicators showed a decrease in the proficiency level, which were difficult to demonstrate in the real world because of the specificity of radiation. Accordingly, program contents corresponding to T, E, and R indicators must be revised using tools that can accurately portray the specificity of radiation.

One of the main sources of exposure to radiation is terrestrial radionuclides in the environment. These radioisotopes are present in the Earthchr('39')s crust and can be increased by human activity such as mining of coal, oil, and minerals.

In this study, 39 soil samples including virgin and cultivated were collected from around of the Shazand Refinery Complex(SRC) using a template and experimental method. The gamma spectrometry method was used to measure the specific activity of the 226Ra, 232Th, 40K and 137Cs radionuclides.

The average concentrations of 226Ra, 232Th, 40K and 137Cs in the cultivated (virgin) soil samples were 21.95 ± 0.27 (23.99 ± 0.37), 25.37 ± 0.29 (31.74 ± 0. 38), 416.72 ± 1.88 (461.09 ± 2.68) and 5.13 ± 0.08 (5.51 ± 0.14) in Bq kg-1. Excess lifetime cancer risk (ELCR) was obtained for cultivated (virgin) soil as 0.19 × 10-3 (0.22 × 10-3), which is close to the world average (0.29 × 10-3) and lowers than the maximum acceptable value (10-3).

  The specific activities of natural radionuclides were in the global range and are lower than the maximum allowable value. The distribution map of 226Ra and 137Cs indicated some part of 226Ra, distributed as fly ash from a chimney, caused by the incineration of refinery waste. The radiological parameters calculated for both types of soil were lower than the maximum admissible values, and therefore there is no radiological hazard for people living in this area.

The magnetic resonance imaging (MRI)-based radiotherapy planning method have been considered in recent years because of the advantages of MRI and the problems of planning with two images modality. The first step in MRI-based radiotherapy is to evaluate magnetic resonance (MR) images geometric distortion. Therefore, the present study aimed to evaluate system related geometric distortion by a new large field of view phantom.

A homemade phantom with Perspex sheets and plastic pipes containing water was built for evaluating MR images distortion. The phantom size is 48×48×37 cm3 and includes 325 water pipes. The study evaluated four different protocols from a 60 cm bore MAGNETOM® Symphony Syngo 1.5 T (Siemens).

It was found that the amount of distortion for all protocols is under 2 mm for the radial distances less than 10 cm (field of view (FOV) = 20 cm), but distortion increased in radial distances greater than 10 cm, and reached about 5 cm for radial distances greater than 25 cm.

Geometric distortion of each MR scanner has been shown to be dependent on the radio frequency (RF) sequence pulse (Spin echo or Gradient echo) and image parameters (echo time (TE), repetition time (TR), and receiver band-width)). The geometric distortion could be ignored for the FOV<20 cm (for the head region), and must be evaluated and corrected for more FOVs before the MR only radiotherapy.

Acoustic cavitation which occurs at high intensities of ultrasound waves can be fatal for tumor cells; however, it can be used to destroy cancer cells as an efficient therapeutic method. On the other hand, it is known that the existence of nanoparticles in a liquid decreases the acoustic cavitation onset threshold.

In this work, the combined effects of therapeutic ultrasound and gold nanoparticles (GNPs) on a breast carcinoma tumour model in BALB/c mice were studied. The tumour-bearing mice were divided into 4 groups (1) Control, (2) GNPs, (3) Ultrasound alone and (4) Ultrasound in the presence of GNPs. In groups 2 and 4, GNPs were injected into tumours. Therapeutic effects on tumours were evaluated by measuring relative tumour volume (RTV), doubling time (T2) and 5-folding time (T5) for tumours volume.

The T5 showed a significant difference between ultrasound in the presence of GNPs group and the other groups. The maximum T2 and T5 were found in the ultrasound in the presence of GNPs group.

Combined effects of ultrasound and GNPs can be used as a method for increasing the therapeutic efficiency on tumor cells.

The study aims to evaluate the impact of the antioxidant rich pomegranate fruit grown in Taif on the histological and immunohistochemical changes in the cerebral and cerebellar cortex after different levels of mobile exposure.

Thirty adult male rats were divided into group I, II, III; IV, and group V. Group I was control and group II rats were exposed to 900 MHz and in group III the rats are exposed to 1800 MHz for two months. Group IV the rats were exposed to 900 MHz concomitant with pomegranate peel extract (500 mg/kg) and group V rats were exposed to 1800 MHz and pomegranate peel extract (500 mg/kg) orally in aqueous solution once per day for two months. Frontal cortex and cerebellum tissues were dissected out and processed for histopathological and immunohistochemical studies.

The cerebral and cerebellar cortexes of mobile-exposed rats exhibited degenerative changes especially in the nerve cells. These changes were more pronounced with increase in the frequency of radiation. Most of pyramidal and Purkinje cells became irregular in shape, had deeply stained nuclei, and were surrounded with peri-cellular haloes and vacuolated neuropil. However, some of them were surrounded with neuroglial accumulation.

The study concluded that pomegranate peel extract can ameliorate the histopathological changes induced by mobile phone electromagnetic radiations.

This work aimed at studying the protective effect of melatonin (MLT) against cypermethrin or γ-radiation induced testicular damage.

Thirty six Male rats were randomly divided into 6 groups.  Control group, group treated with MLT (10 mg/Kg b. wt.), group administered cypermethrin (25 mg/ kg. b. wt.), group 4 was exposed to fractionated whole body γ-radiation (the sum=8 Gy), group 5 was co-administered with MLT (10 mg/Kg .b. wt.) and cypermethrin (25 mg/kg b. wt.) and finally group 6 rats were supplemented with MLT (10 mg/Kg .b. wt.) and subsequently administered  fractionated γ-radiation(the sum=8 Gy). After treatment for 29 successive days, all animals groups were investigated for hormonal assay, sperm quality, oxidative indices and histological examination of testicular tissues.

Rat’s treatment with g-radiation or Cypermethrin showed a significant decrease in body weight, testis, epididymis, ventral prostate and seminal-vesicles weights. Also, a significant increase was observed in the levels of TBARS and H2O2, while a significant reduction occurred in the activity of SOD, CAT and GSH content in testis tissues, in addition to a significant decrease in testosterone hormone. On the other hand, a significant increase occurred in FSH and prolactin hormones .moreover, a significant decrease in sperm count and motility occured beside a significant increase in abnormal forms. Pretreatment of rats with MLT improved the disturbances induced in the tested parameters of rats either received cypermethrin or γ-irradiation.

According to the present findings, the ameliorative role of MLT is obvious against cypermethrin or γ-irradiation induced testicular damage probably, due to its antioxidative properties.

Radiotherapy (RT) is recommended to all patients undergoing Breast Conserving Surgery (BCS). Two strategies can be applied to irradiation, External Beam RT (EBRT) in addition, Intraoperative Radiation Therapy (IORT). The aim of this study was to introduce a protein biomarker panel related to molecular function of IORT.

Six Breast Cancer (BC) patients as a pilot study were treated by 12 Gy (Boost dose) and 21 Gy (Radical dose). Samples tissue included Margin before IORT (MB), and Margin 24 hours After IORT (MA24 h). High-throughput technology such as Isobaric Tag for Relative and Absolute Quantitation (iTRAQ) was performed to study proteomic of IORT-treated tumor bed.

We classified 110 differentially expressed proteins (DEPs) as a protein biomarker panel by mapping the annotated coding region sequences to the reference canonical pathways in the KEGG database.

The analyses of protein function and signaling pathways of these DEPs reveal a molecular response to the effectiveness of IORT.

Pineal parenchymal tumor (PPT) is extremely rare and histologically heterogeneous, and the optimal treatment strategy is controversial. This study examined clinical outcomes of patients with PPT treated with cyberknife radiosurgery (CKRS) as a primary treatment modality after tumor biopsy.

Between 2009 and 2018, there were six patients diagnosed with PPT who were treated with single or hypofractionated cyberknife radiosurgery (CKRS) after undergoing endoscopic third ventriculostomy (ETV) and tumor biopsy. Two tumors were pineocytoma (PC) and four were pineal parenchymal tumor of intermediate differentiation (PPTID). The marginal dose was 18 Gy, and the median target volume was 3.05 (range 1.4-7.4) cc. The median follow-up period was 55 (range 18 -141) months.

Five patients were alive, and all of their tumors were locally controlled during follow-up periods. Two tumors disappeared completely, two other tumors partially regressed, and another tumor showed no interval change after CKRS. One patient with PPTID showed local progression 14 months after CKRS and died 21 months after CKRS. There were no acute or late complications related to CKRS.

This study suggested that CKRS can be used as a primary treatment modality after ETV and tumor biopsy for PPT with favorable clinical outcomes. However, alternative treatment modalities need to be considered for higher risk groups of patients with PPTID.

The aim of this study was to investigate the protective potency of melatonin, amifostine (WR-2721), and N-acetylcysteine (NAC) when administered intraperitoneally (i.p.) 15 min before 10-Gy single-fraction radiotherapy.

In this study, 35 female Sprague Dawley rats were divided into five groups of seven rats each. The rats in the control group did not receive any treatments. Rats in the radiotherapy, melatonin, amifostine, and NAC groups underwent abdomino-pelvic irradiation with 10-Gy single fraction gamma (γ) irradiation. Melatonin 50 mg/kg, amifostine 200 mg/kg, and NAC 500 mg/kg were i.p. administered to the rats 15 min before irradiation. Animals were sacrificed 48 h after irradiation. Uterus samples were collected and, routine histopathological tissue processing was performed. Sections from tissue samples were stained with H&E and analyzed with the terminal deoxynucleotidyl transferase dUTP nick end labelling method (TUNEL assay).

Severe morphological degenerations and increases in the apoptotic index (AI) were observed in the radiotherapy group. Tissue protection and AI reduction were observed in the amifostine and NAC groups. Melatonin was more effective than amifostine and NAC. Morphological damage was almost completely repaired, and the AI of the melatonin group was quite similar to that of the control group.

This experiment failed to determine a more successful administration technique of amifostine. The protective effects of amifostine and NAC were similar. Melatonin was more successful than these two drugs, and might be an alternative to amifostine when time, dose, or adverse effect constraints are encountered.

the aim of this study was to investigate the prognostic value of 18Fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) parameters in both overall survival and progression-free survival in Stage I-III non-small cell lung cancer (NSCLC).

In this retrospective study, 267 patients who were diagnosed as Stage I-III non-small cell lung cancer and had undergone FDG-PET/CT imaging before treatment were included. PET/CT parameters, maximum and mean standardized uptake values (SUVmax and SUVmean), metabolic tumor volume (MTV), total lesional glycolysis (TLG), and maximum tumor-to-blood standard uptake ratio (SURmax) were calculated. Analyses were performed to evaluate the ability of PET parameters to predict recurrence and death as well as to determine prognostic value.

In predicting both mortality and progression, the area under the ROC curve (AUC) value was highest for TLG (AUC: 0.717, 0.692 respectively). Overall survival was lower in patients with TLG> 214, and progression-free survival was lower in patients with TLG> 194. All PET parameters had a prognostic value in univariate analysis. Age, N1 stage and SUVmean were independent prognostic factors in multivariate analysis.

In predicting death and progression, TLG had the highest predictive value. Age and N1 stage were independent prognostic factors in multivariate analysis, while SUVmean was the most valuable independent prognostic factor.

The total yields of direct Single-Strand Breaks (SSBs) and Double-Strand Breaks (DSBs) in proton energies varying from 0.1 to 40 MeV were calculated. While other studies in this field have not used protons with energy less than 0.5 MeV, our results show interesting and complicated behavior of these protons.

The simulation has been done using the Geant4-DNA toolkit. An atomic model of DNA geometry was simulated. Simulations were performed with a source in the Z-axis direction at the cell nucleus entrance with protons at energies of 0.1-1 MeV in 0.1 MeV steps, 5 MeV, and 10-40 MeV in 10 MeV steps.

The calculated SSB yields decreased from 60.08 (GbpGy)−1 for 0.1 MeV proton energy to 49.52 (GbpGy)−1 for 0.5 MeV proton energy, and then it increased to 54.35 (GbpGy)−1 in 40 MeV. The DSB yields decreased from 4.32 (GbpGy)−1 for 0.1 MeV proton energy to 1.03 (GbpGy)−1 for 40-MeV protons. The DSB yields for energies less than 0.5 MeV was about 56%, and for the other energy levels, it was 44%. As for SSB yields, 35% of the breaks arose from protons with an energy of fewer than 0.5 MeV and 65% from higher energies.

It was found that the proton ranges with an energy less than 0.5 MeV are smaller than the cell size (10 μm), and 100% of the energy is deposited in the cell region. Then protons with these energies are the best choice to increase the number of DSBs.

The basic challenge with computed radiography (CR) systems is the large dynamic range which provides an opportunity for radiographers to gradually increase exposure factors and still produce good image quality, a practice that can lead to dose creep.

The aim of this study was to establish  the entrance skin dose (ESD) values for nine selected examinations in three CR facilities in Ghana (chest PA, abdomen AP, lumbar Pelvis AP, lumbar spine LAT, cervical spine AP, cervical spine LAT, skull PA and skull LAT). ESD was estimated by the indirect method involving the use of a standard equation.  The study involved 150 females and 120 males with the average age of 50 ± 14 years. The average weight of the study population was 69 ± 8 kg, and the average height of 162 ± 9 cm. The CR systems used at all the hospitals were manufactured by Shimadzu medical systems (Kyoto, Japan) and the model number was UD150L-40E.

The average ESDs (mGy) for each examination were; 0.93 ± 0.7, 3.04 ± 0.4 , 4.95 ± 0.9, 0.59 ± 0.3, 0.63 ± 0.4, 1.77 ± 0.3, 1.64 ± 0.3, 2.31 ± 0.4 and 3.15 ± 0.6 for chest PA, lumbar spine AP, lumber spine LAT, cervical spine AP, cervical spine LAT, skull PA, skull LAT, pelvis AP, and abdomen AP respectively. The single factor ANOVA t-test that was performed indicated a significant difference (p-value = 5.73 x 10-15) among the ESDs for chest PA examination.

Over exposure of patients is very possible with CR systems, it is therefore important for patient dose to be audited periodically in order to achieve the principles of As Low As Reasonably Achievable (ALARA).

Monoclonal antibodies have confirmed their merit as biotherapeutics across a wide spectrum of diseases, including cancer, heart disease, infection, and immune disorders.

The dynamics of 89Zr-labelled monoclonal antibodies (MAb) after injection into the human body are modelled. This modified biokinetic model can be used for dose assessment not only for 89Zr-labelled MAb tumour visualization but also for diagnostic and radiation therapy with other MAb-labelled radionuclides. The created modified biokinetic model is based on experimental data from the literature. The cumulative 89Zr activity in organs and tissues per Bq of administered activity is calculated with the WinAct program.

For the organs receiving the highest radiation exposure, the average absorbed doses were estimated with IDAC 2.1 software. The results from the modelled calculations are compared with new published experimental diagnostic results from real patients. The calculations reveal that the organs which received the highest dose were the spleen, liver, kidneys, and red bone marrow (doses of 1.54, 1.33, 0.81 and 0.82 mGy/MBq, respectively). In the modified biokinetic model, the organs exhibiting the highest dose were the liver, gallbladder wall, spleen, pancreas, and kidneys (at 1.07, 0.77, 0.70, 54 and 0.44 mGy/MBq, respectively), when the injection was associated with monoclonal antibodies.

The developed biokinetic model is in good agreement with direct measurements and can be considered a first step for simulating the radiopharmaceutical dosimetry of the 89Zr isotope.

Tumor radioresistance leads to a reduction in the efficiency of radiation therapy. It is very important to explore the cellular mechanisms leading to radioresistance and to find potential therapeutic targets, which might improve the efficacy of radiation therapy. This study was to investigate the role of ataxia-telangiectasia mutated (ATM) and murine double minute X (MDMX) in radioresistance in non-small cell lung cancer A549 cells and their corresponding mechanisms of action.

Non-small cell lung cancer A549 cells were irradiated with X-rays in the presence or absence of ATM inhibitor. Cell survival, cell apoptosis, cell proliferation, mRNA of ATM and MDMX, and protein expression of ATM, MDMX, γ-H2AX, Caspase3, and Beclin1 were measured.

After the inhibitor (KU60019) treatment combined with X irradiation, the A549 cells showed a significant decrease in colony formations compared to the group received irradiation alone. The MDMX knockdown A549 cells showed a significant increase in colony formations compared to the control group. ATM downregulated the expression of MDMX after irradiation treatment in A549 cells. Irradiation led to a significant increase in γ-H2AX expression, but MDMX knockdown decreased the γ-H2AX expression after irradiation. The change of Caspase3 expression was the same as γ-H2AX. Irradiation led to a significant increase of Beclin1 expression and MDMX knockdown increased the Beclin1 expression after irradiation.

This study indicated that ATM induced radioresistance through downregulating the expression of MDMX, which was at least partly associated with the activation of autophagy and the decrease of DNA damage in A549 cells.

This paper aimed to analyze the output constancy of a medical linear accelerator using PTW QUICKCHECKwebline and studied the sensitivity of the PTW QUICKCHECKwebline.

 The paper statistically analyzed the output doses of 6 MV and 10 MV of photons and 6 MeV, 9 MeV, and 12 MeV of electrons from a medical linear accelerator measured before the daily treatment to assess the output stability of a medical linear accelerator. Some modifications were introduced by artificially altering the external irradiation conditions, and the percent variations from baseline values were noted. The gantry angle was changed and some deviations were established in the vertical, longitudinal and lateral directions to study the sensitivity of the PTW QUICKCHECKwebline. The beam flatness, symmetry, radiation quality and output energy of 6 MV of photon energy were statistically analyzed.

Among the measurements, no parameters exceeded the tolerance of ±3%. QUICKCHECKwebline was capable of detecting the variations in the central axis dose, flatness, symmetry and radiation quality under the testing conditions. Similar to the photon energy, electron energy measurements also confirmed that the detector was sensitive to a small variation in output introduced by the testing conditions. An important application of accelerator performance prediction in this study confirms the irreplaceable and important function of morning quality checks of a linear accelerator.

The output dose measured before daily treatment using PTW QUICKCHECKwebline to analyze the linear accelerator output constancy helps to decrease the system error, effectively reduces the errors of the accelerator system, and avoids serious mistakes.

Purpose of the study is to evaluate field-in-field (FIF) and sliding-window intensity modulated radiation therapy (SW-IMRT) treatment plans in terms of homogeneity index (HI), conformity index (CI) and normal tissue doses for organs at risk (OAR) in patients with endometrial carcinoma along with deriving a new expression for CI.

Four different FIF plans with different MLC (multi-leaf collimator) margins and SW-IMRT plan were compared in 20 endometrial cancer patients who underwent adjuvant pelvic radiotherapy with 50.4 Gy in 28 fractions. Normal tissue doses were assessed for OAR from dose volume histograms (DVHs). HI and CI values were calculated according to the reports of International Commission on Radiation Units and Measurements (ICRU)-83, Radiation Therapy Oncology Group (RTOG) 1993 and ICRU-62. A new CI was developed and named CIOPT standing for optimized conformity index.

SW-IMRT provided a significantly better CI in comparison to other FIF plans (p< 0.001). Conventional-FIF (C-FIF) was the most homogeneous plan compared to all other FIF plans and SW-IMRT (p≤0.001). The absolute volume of small intestine that received ≥45 Gy (V45) and doses received by a 30% volume of rectum (D30) were dramatically reduced in SW-IMRT (p < 0.001).

MLC margins had a substantial influence on OAR doses, HI and CI. A close proximity of CIOPT to 1 indicated that this formulation of CI was a useful plan evaluation tool, which was also compatible with the RTOG 1993 and ICRU-62 reports.

There have been growing concerns about environmental pollution and public health issues associated with metal(loid)s and radionuclides. As a baseline for monitorisation, radioactivity and specific metal(loid) levels have been measured to investigate the estimated environmental health risks in Igdir province at the Turkish side of the border, in the vicinity of the Metsamor Nuclear Power Plant, an aging nuclear station without primary containment structures.

Concentrations of radioactivity and accumulation of metal(loid)s in the region were measured and hazard quotient, hazard index, and the excess lifetime cancer risk vaues were calculated according to international methods and standards.

Hazard quotient and index values were determined to be lower than the permissible maximum levels. The average estimated excess cancer risk values for terrestrial and cosmic exposures due to radionuclides were calculated as 1.8±0.9E-04 and 2.4±0.04E-04, respectively. The average estimated excess cancer risk value for the radioactivity in water was determined as 15.2±13.6E-05. The mean excess lifetime cancer risk values due to metal(loid) exposure were as Cr<Ni<As in soil and as Cr<Cd<Pb in water.

The mean concentrations of selected metal(loid)s and radionuclide activities were below the maximum permissible limits. Relatively low hazard indices suggest that the population is currently not at any imminent health risk.

The aim of this study was to estimate the cancer risks and mortalities of different types induced by routine examinations of digital radiography for one year in Mazandaran province, Iran.

Radiation parameters and calculated entrance skin dose (ESD) values of 13 digital radiographic examinations were collected from 2340 patients at 18 high-patient-load radiography centers. Organ mean doses were estimated based on the collected parameters applying PCXMC software. The BEIR VII-Phase 2 model was used to calculate the induced cancer risks and mortalities of various cancer types at different ages.

The average ± standard deviation (SD) lifetime risks (incidence probability in 100,000 people) induced by radiations from radiography examinations for one year was 51.29±4.73 and 99.62±7.36 for new-born males and females, respectively. The lifetime cancer risk decreased with age and reached 3.77±0.62 and 4.88±0.07 for 80-year men and women, respectively. The average lifetime risks of mortality due to cancers induced by annual radiographies were obtained at 14.18±1.62 and 22.83±2.55 for new-born males and females, respectively. This risk reduced with age and was reached 1.97±0.27 and 2.45±0.38 for men and women at the age of 80 years, respectively.

Our results showed that there are low but significant risks of cancer incidence for patients undergoing digital radiography, which included a large percentage of the population in Mazandaran province, especially for children and newborns. Therefore, further efforts like appropriate patient setup and beam geometry should be carried out to decrease patient doses.

This study aimed to estimate and compare the absorbed dose, lifetime cancer risk and mortalities due to cone-beam computed tomography (CBCT) and panoramic examinations on patients.

The exposure factors were applied to 332 patients in two age groups (6-10, and ˃18-year-old). The dose-area product (DAP) values were measured for CBCT and panoramic radiographies. Organ absorbed doses and effective doses were calculated based on the collected parameters applying PCXMC software. The risk of exposure-induced death (REID) and cancer risks were estimated by BEIR VII phase 2 model at different age groups and genders for the two dental radiography modalities.

Salivary glands was the largest contribution of the organ absorbed dose and effective dose in both CBCT and panoramic radiographies. The mean (±SD) REID values (per ten million) in CBCT were obtained at 35.6±5.2 for females and 29.01±1.8 for males, in the pediatric group, and were 31.1±2.2 for females and 25.71±2.02 for males in the adult group for all cancers. In addition, these values for panoramic radiography were 10.2±1.2 and 6.61±1.2 for women and men, respectively, in the pediatric group, and were 5.3±1.06 and 3.01±1.12 in the adult group. The mean REID values were higher significantly in CBCT compared to panoramic, and also in the pediatric than adult groups (p˂0.05).

CBCT had a significantly higher level of radiation risks compared to panoramic radiography. Therefore, clinicians should request CBCT examinations by considering their determents and benefits.

Assessment of activity concentrations of 238U, 232Th, 40K and gamma dose rate (DR) was carried out over a laterite mining field in Ilorin-south, Nigeria.

A well calibrated Super-Spec (RS-125) gamma spectrometer was used to measure the activity concentrations of 40K, 238U, 232Th and gamma doses rate at 1 m above the ground level over the laterite mining field. Fifty (50) measurements of the activity concentration of the radionuclides were obtained at about 1 meter above the topsoil. For each point, measurements were taken four (4) times for better accuracy.

The overall mean of the activity concentrations of 40K, 238U and 232Th are 81.38, 43.89 and 38.79 Bqkg-1 respectively. The mean value for DR was found to be 46.44 nGyhr-1. The mean activity concentrations of 238U and 232Th are higher than the recommended limits provided by UNSCEAR. This is a cause for worry as significant enhancement in the concentration of 238U and 232Th will increase the level of the background radiation and possibly render the soil unfit for use in building and construction. The results of most of the radiological impact parameters (RIP) are above the limits provided by UNSCEAR.

From the results, it implies that the risk of indoor gamma radiation exposure is high for this lateritic soil. So the lateritic soil from this mine field may not be too suitable for building and construction purposes.

Lead glass has a wide variety of applications in radiation protection. This study aims to investigate some characteristics of lead glass such as the γ-ray energy-dependent mass and linear attenuation coefficients, the half-value layer thickness, and the absorbed dose distribution for specific energy.

The attenuation parameters of different lead glass types against high-energy photons (0.2-3 MeV) of gamma rays have been calculated by the Monte Carlo technique and a deterministic method. Besides, the depth dose distribution inside the volume of two cubic lead glass samples was calculated by two Monte Carlo-based computer codes, for gamma rays of 300 keV. In each part of the study, the results of the two methods have been compared.

Increasing the Pb concentration (weight in %) by 1% in the lead glass causes a 1.6%-3% increase in the linear attenuation coefficient, depending on the energy. However, the mass attenuation coefficient does not show significant variation for different types of lead glass, especially for the energies higher than 400 keV. Moreover, almost half of the total dose from 300 keV photons will be absorbed in the first 3.5 mm of the sample’s thickness.

Results indicate that the Monte Carlo technique is as reliable as the deterministic methods for calculating the attenuation characteristics of the lead glass. The provided data in this investigation can be useful for radiation protection purposes, especially in the case of selecting the lead glass type and dimension based on a specific application.

This is a case report on stereotaxic (Stereotactic Body Radiotherapy-SBRT) for lung cancer located in the left lower lobe (Segment 6, S6). There have been no reports on marked displacement of the peripheral lung cancer during radiotherapy. A pulmonary nodule was discovered on computed tomography (CT) conducted for a persistent cough in an 87-year-old male. According to diagnostic imaging, this nodule was clearly delineated and had an irregular margin. The image diagnosis was T1N0M0, stage I primary lung cancer located in the left lower lobe and no pathological type was identified. The patient was treated with SBRT using a Linear accelerator (LINAC) at a total dose of 48 Gray (Gy) in 4 fractions. On performing cone beam CT (CBCT) at the third fraction, the tumor position had moved caudally by about 3 centimeters (cm). For this reason, we canceled further treatment and the case was re-planned. Four days after discontinuing treatment, 4-dimensional CT (4DCT) images were obtained before initiation of the remaining fractions of SBRT. Therefore, the patient completed 4 fractions of SBRT and the tumor location was confirmed before beam delivery. The tumor location differed based on the patient’s position (i.e., standing versus lying in a supine position), and we considered that it moved due to adhesion to the pleura when the patient was standing. If reproducibility of the tumor position cannot be guaranteed, the patient should undergo to CT re-simulation. Oncologists should re-evaluate the movement of the tumor on respiration and adjust the margins accordingly.