International Journal of Radiation Research
Volume:17 Issue: 3, Jul 2019

The in vivo radiation-induced bystander effects (RIBE) at the developmental, genetic, and epigenetic levels have been well demonstrated using model plant Arabidopsis thaliana (A. thaliana). However, the mechanisms underlying RIBE in plants are not clear, especially lacking a comprehensive knowledge about the genes and biological pathways involved in the RIBE in plants.

A high-density oligonucleotide probe-based cDNA microarray was used to analyze transcriptomic response in aerial leaf tissues of A. thaliana seedlings at 24 h after root exposure to 10 Gy of α-irradiation.

The root-localized irradiation resulted in up-regulated expressions of 238 genes and down-regulated expressions of 42 genes in bystander aerial tissues with a ≥ 2.0-fold difference and < 0.05 p-values. The high frequency of gene families for up-regulated expressions were glutathione S-transferases, cytochrome P450 enzyme, the ethylene response factor, and the multidrug and toxic compound extrusion efflux, and for down-regulated expressions was the later embryogenesis abundant protein. Moreover, there were 200 up-regulated genes and 183 down-regulated genes with 1.5–2.0-fold expression changes.

In addition to the canonical IR-induced genes, some genes that are not previously linked to radiobiological effects were found to be involved in RIBE in plants.

Ondo city in Ondo State Nigeria includes Ondo East and West could be described as a research city due to antecedent number of research institutes. Dose due to radioactivity content of soil samples from sixteen waste dump sites in Ondo, Southwestern Nigeria was determined using gamma-ray spectrometer in order to evaluate the radiation hazard health profile and excess lifetime cancer risk ELCR. The weighted average value of radon emanation coefficient, mass exhalation rate, concentration in soil gas and surface exhalation rate were 10.5%, 15.2 µBq kg-1 s-1, 2.2 kBq m-3 and 18.8 mBq m-1s-1. The weighted mean concentrations obtained were 354 ± 53, 58±14 and 23 ± 2Bq kg-1 for 40K, 226Ra and 232Th respectively. Radium equivalent activity (119.11Bq kg-1), Outdoor external dose (54.26 nGy h-1), Indoor external dose (107.04 nGy h-1), and total average annual effective dose (0.59 mSv y-1) were obtained. From the measured γ-rays spectra, elemental concentrations were determined for 232Th (mean 5.8ppm), 226Ra (mean 4.8ppm) and 40K (mean 1.1 %). Thorium was lower than world average 7.4ppm by a factor of 1.3; radium was higher than the world average (2.8 ppm) by factor 1.7 while potassium was relatively equal to world average (1.3 %). The total excess lifetime cancer risk ELCR was found to be 1.95 x 10-3 which was slightly higher than the world average. In addition, a good correlation was found between the radium concentration and radon exhalation rate in the area.

The aim of this study is to measure the level of radon gas in the thermal springs of the four seasons in the Black Sea Region and to determine the gamma activity levels in the soils around them. Indoor radon activity concentrations of four spa facilities, namely Ladik, Havza, Ilıcaköy, and Ayder, were measured using CR-39 passive radon dosimeters and active radon monitoring AlphaGUARD for all four seasons. Radon activity concentrations in the soil in the vicinity of these spa facilities were measured using AlphaGUARD. Radionuclides in the soil samples collected from the spa regions were also determined using gamma-ray spectroscopy. The highest radon value in the air environment in the spa facility was measured in swimming pools. Indoor radon levels in the spa’s swimming pool vary within a wide range, (30–2118) Bq·m−3. The average radon gas levels in the soil around the Ayder, Havza, Ladik and Ilıcaköy hot springs were measured as 38±1 kBqm-3, 9±1 kBq m-3, 50±3 kBqm-3, 955±5 kBqm-3, respectively. The annual effective doses due to indoor radon sources changed from 0.6 mSv to 13.4 mSv for workers, and from 1 x10-4 mSv to 3x10-1 mSv for patients. The annual effective dose equivalents from the soils around the spa were calculated to be between 82-558 µSv y-1. The results were compared with those of other measurements performed in different parts of the world.

In prostate radiotherapy, changes in the volume of the bladder and rectum can influence dose delivery. In this study, cone-beam computerised tomography (CBCT) imaging was used to assess volumetric, and corresponding radiation dosimetric changes, for the bladder and rectum in patients with prostate cancer treated using VMAT. Treatment planning computed tomography (simCT) and CBCT images were retrospectively evaluated in 22 patients with prostate cancer. Bladder and rectal volumes were recontoured in 176 CBCT images. CBCT images were used for VMAT treatment plan recalculation and to obtain bladder and rectum radiation doses. Mean rectal volumes measured by CBCT were significantly larger than those estimated by simCT (P=0.001). A 14% increase in rectum volume resulted in a 9% increase in mean rectum doses. The percent volumes (Vx) of the rectum receiving 40, 50, 60 and 70 Gy doses based on CBCT results were significantly larger than those based on simCT results (P=0.002, P=0.001, P=0.001, P 0.003, respectively). Mean bladder volumes measured by CBCT were significantly smaller than those estimated by simCT (P=0.001). A 13% decrease in bladder volume resulted in a 8% increase in mean bladder doses. Mean bladder V65 and V70 values based on CBCT results were significantly higher than those based on simCT results (P<0.001, P=0.002, respectively). Results during prostate radiotherapy, daily changes in bladder and rectal volumes can result in larger actual doses to these organs than the planned dose.

Benign prostatic hyperplasia (BPH) is a common disease among older men and many patients with prostate cancer (PC) also have BPH. External beam radiation therapy (EBRT) is one of the important treatments for PC, nevertheless, few studies have analyzed the effect of BPH on EBRT. We tried to know the risk of bladder toxicity by analyzing the bladder volume variability in patients with BPH. Changes in prostate location with respect to the presence of BPH and bladder volume by bladder zone were analyzed. Dosimetric parameters of prostate and bladder were analyzed using planning computed tomography (CT) scans in 20 patients with PC. Three planning CTs were performed on each patient during RT. Maximum bladder volume variations were calculated using the three planning CT scans and volumes of upper and lower zones were compared. Mean upper and lower bladder volume ratio was 0.85 and 0.15, and mean maximum differences in bladder volumes for the three CTs were 97.33 cc and 10.36 cc for upper and lower bladders, respectively (p < 0.001). Prostate size and location with respect to prostate upper margin showed a moderate linear correlation (r = 0.567, p = 0.009). Prostate superior margins of patients with or without BPH were located at mean distances of 3 mm above and 4.8 mm below the superior border of pubic bones, respectively (p = 0.019). The prostates of patients with BPH were more likely to be located in the upper bladder zone, which exhibited greater bladder volume variability. This implies that the clinical target volume of EBRT is located in an unstable bladder zone, which would decrease treatment accuracy and increase treatment-related bladder toxicity. The further clinical study is required to analyze the relation between BPH and the severity of RT-induced bladder toxicity.

The Diagnostic reference levels (DRLs) play a critical role in the optimization of radiation dose especially, in some conditions like pediatrics. They are useful indicators by which the radiologists can be aware of delivered excess radiation doses to the patients, and take corrective actions if necessary. In order to meet some requirements for establishing the national computed tomography DRLs tables, much studies are needed all around the country. All active computed tomography (CT) scanners in public and private centers in Tehran were identified and checked for quality assurance and control certification. Eleven centers were chosen to be studied according to CT examination frequencies. Weighted CT dose index (CTDIw) and dose length product (DLP) for head, sinus, chest and abdomen/pelvis scans of children were obtained from scanner’s operator consoles and classified into four groups based on their ages (A; <1 year, B; 1-5 years, C; 5-10 years and D; 10-15 years).  The 3rd quartiles of CTDIw were considered as DRLs and compared with the reported European :::union::: (EU) and United Kingdom (UK) ones. DRLs for head, sinus, chest and abdomen/pelvis scans were found to be 86.76, 31.33, 6.33, 7.65 mGy; 43.38, 31.33, 6.33, 7.65 mGy; 43, 31.33, 6.33, 7.65 mGy and 44.53, 31.33, 6.33, 7.65 mGy in the four groups (A-D) respectively. They are lower than the reported DRLs in EU and UK. There are variations in the radiation dose between the CT centers and identical scanners indicating the necessity for dose optimization. The data reported in this study can be remarkably useful in this concern.

The success of radiation therapy depends on accurate dose delivery to the target. Diode in vivo measurement of entrance and exit dose is a valuable quality assurance (QA) tool to ensure accurate dose delivery. 

This study was performed at BINO Cancer Hospital, Bahawalpur. Entrance and exit dose measurements were done with p-type diode for various types of cancer patients treated on Co-60 teletherapy unit. These measurements were compared with calculated (planned) dose values. A total of 3285 radiation fields of 723 cancer patients of various sites were included in current investigation.

The action level was ± 3 % for current measurements. The average percentage variation between the expected and measured dose was 0.37 with standard deviation 2.08. It was observed that 87.49 % of measurements were within tolerance level. It was also noticed that all dose deliveries fell within ± 5 %. This study showed that exit/wedged/oblique dose measurements were harder than entrance/non wedged/normal incidence dose measurements and more standard deviation were observed for these measurements.

The Quantitative entrance and exit absorbed dose verification for cancer patients is beneficial for quality improvement in radiation therapy. A great majority of measurements were found within the acceptable limit. Execution of entrance and exit dose measurement procedure had demonstrated to be very helpful for detecting potential mistakes and avoiding errors due to accurate positioning of patients.

The annual effective dose equivalent (AEDE) due to ionizing radiation in a coaster area in Nigerian has been determined using Geiger-Muller counter. isolevels in the study area were represented by using the kriging interpolation technique on ArcGIS 10.1 software. Duncan multiple range test was performed using Statistical Package for Social Sciences (SPSS). The results obtained show that the AEDE ranged from 0.19±0.01 to 0.35±0.02 mSv y-1 with a mean of 0.27±0.03 mSv y-1. The excess lifetime cancer risk (ELCR) ranged from 0.0007 to 0.0012, with a mean of 0.0010. The total annual collective effective dose equivalent is 4839.49 person-Sv.  The AEDE in the study area is lower than the maximum permissible limit of 1 mSv y-1 recommended by ICRP. The AEDE was higher in areas of high elevations than those of low elevations. It was estimated that about twenty-eight (28) of every one hundred thousand (100,000) persons are at risk of developing radiation-induced diseases per annum in the study area.

External beam radiation therapy is often administered to patients implanted with silicone gel breast prosthesis. The aim of this study was to investigate the influence of silicone gel breast prosthesis on photon dose distributions. In the event of recurrence, the oncologist may be forced to irradiate through the prosthetic device. To quantify the dose enhancement or reduction below the silicone gel breast prosthesis, depth dose enhancement factors (DEFs) were calculated. The study was based on Varian linear accelerator (LINAC) operated at 6 and 15 MV photon energies. Monte Carlo package Electron Gamma Shower (EGSnrc) was employed to simulate the depth dose distribution in a three dimensional scanning water phantom with various field sizes. The polydimethyl silicone gel breast prosthesis with density of 0.97 g/cm3 was used. The measured and calculated DEFs were verified by using the thermoluminescent dosimeter (TLD). The results indicate that the percentage difference between the calculated and measured dose distributions on depth dose curves for 6 and 15 photon energies was less the 2% for all locations. DEFs at 0.5 cm below the 3.5 cm prosthesis were 0.99 and 1.02 for 6 and 15 MV photon beams, respectively. The interface region receives enhanced dose of about 2.4% with 15 MV photon beam while the 6 MV photon beam delivered a dose reduction of about 2.0%. It was observed that DEFs increase with photon beam energy. The 6 MV photon beam reduces dose enhancement factor compared to that of the 15 MV photon beam.

Several potential challenges with radiation protection (RP) and safety culture in radiology departments need to be addressed. This study assesses radiographers’ adherence to radiation protection practices in radiology departments. A cross-sectional study was conducted among radiographers; 210 self-administrated questionnaires were sent to the participants. An analysis was conducted to determine participants’ adherence to radiation protection practices, including the implementation of personal protection, patient and environmental protection. The educational level of the radiographers, their years of experience and sociodemographic characteristics were assessed and compared. The percentage of radiographers’ adherence to practices related to environmental protection, patient protection and self-protection were 75.1%, 60.4% and 45.7%, respectively. The overall adherence to radiation protection practices score was 75.2%±18.5, where 57.4% of the radiographers exhibited good adherence, 26.9% exhibited moderate adherence and 15.7% had poor adherence. The adherence score was significantly higher among elder radiographers (P<0.0001) and more experienced ones (P=0.001). However, no significant difference in adherence score was found in relation to the radiographers’ educational qualifications. Forty percent of the radiographers’ practices proved relatively unsatisfactory in implementing radiation protection. Thus, proactive steps and corrective actions are necessary to improve radiographers’ knowledge of international standards of proper radiation protection practices.

This study is conducted with the aim of determining the knowledge, attitude and behaviors of the personnel on radiation safety, who are exposed to radiation and working in a university hospital in Istanbul.  In this research, which is descriptive, a questionnaire that consists of 20 questions conducted to 101 healthcare personnel who are working with radiation source in operating room, endoscopy, radiology units. The obtained data is analyzed with Statistical Package for the Social Sciences (SPSS) 22.0 program and chi-square test is applied. 58.4% of the participants are women and 41.6% of them are men. 32.7% of the participants stated that they got fluoroscopy education and 50.5% of them stated that they got dosimeter education. 64.4% of the participants stated that they use in fluoroscopic environment at least two times a day and 78.2% of them stated that they did not use legal ray permission. 2% of the participants stated that they do not know about the protective equipment that should be used during fluoroscopy. 74.3% of the participants stated that they do not feel qualified enough about radiation measuring and dosage units. Findings indicate that the healthcare personnel, who participated in this research and working with ionizing radiation sources, do not have the adequate knowledge about radiation safety. For this reason, the most important subject is that the managements of the institutions which are practicing radiation should take precautions with providing either personnel or necessary substructure in terms of equipment and necessary trainings.

Thirteen (13) types of building tiles and Sharp sand commonly used for building purposes were collected for their radionuclide contents analysis. Both imported and locally produced building tiles were examined.   The samples of tiles and sand were crushed to powder and they were prepared such that their content could be examined by the use of gamma-ray spectrometry. The average activity concentration of 238U (60.61 Bq/kg), 232Th (76.55 Bq/kg) and 40K (528.40 Bq/kg) for all the samples were observed to be higher than the world recommended standard of 35, 30 and 400 Bq/kg respectively. The external and internal hazard indexes were estimated for all the building materials, the average results were found to be below the recommended limits. However, samples 3 and 6 reported internal hazard indices of 1.08 and 1.06 respectively, which are higher than the world standard. Furthermore, the estimated absorbed dose rates were observed to be within the recommended safe limits. Moreover, a comparative study of the products revealed that the results of the measured parameters from both India and China products are far higher than Nigeria products by a factor of about 1.34. The results obtained showed the following trend of activity concentration for the analyzed samples, India > China > Nigeria, which implies that a long exposure to both India and China products poses higher risk to the inhabitants.

Due to the current trends towards replacing axillary dissection with radiotherapy, the need for more precise definition for different nodal stations becomes a must to ensure safe and adequate dose coverage. So, our study aimed to evaluate the coverage of axillary nodal volumes based on Project on Cancer of the Breast (PROCAB) guidelines, for cases previously treated with our standard tangential approach.

Ten cases of previously treated patients diagnosed with breast cancer were included in this study. All patients were treated with three dimensional (3D) conformal radiotherapy. For each patient, a new contouring based on PROCAB guidelines were done for each lymph node (LN) station. An adequate dose coverage was assessed for all volumes using our Eclipse version 11 planning system.

From Jan. 2016 and March. 2016, ten patients who were pathologically confirmed to have breast cancer and treated at Kasr Alaini Centre of Clinical Oncology and Nuclear Medicine, Cairo University, Egypt were included. The mean volumes of axillary levels I, II, and III were 33.29 cm3 (range 18.6 – 54.8cm3), 13.27 cm3 (range 9.4–16.8 cm3), and 12.84 cm3 (range 7.9—18.2 cm3), respectively. Level I, II and III lymph nodes received a median D98% of 7.82 Gy, 9.54 Gy, and 22.54 Gy, respectively. The mean dose was 34.94 Gy, 33.64 Gy, and 39.79 Gy, respectively.

PROCAB guidelines present a method for standardization of axillary LN delineation. More advanced radiotherapy planning is needed to improve coverage of axilla in post-operative treatment of breast cancer.

This study assessed the application value of 64-slice spiral computed tomography angiography (CTA) in a follow-up evaluation of patients receiving coronary stent implantation. A total of 468 patients who underwent percutaneous coronary intervention (PCI) at our hospital between January 2013 and October 2016 were selected for this study. Coronary angiography and 64-slice spiral coronary CTA were performed. The differences between CTA and coronary angiography regarding the diagnosis of in-stent restenosis (ISR) were compared. The sensitivity, specificity, false positive rate, false negative rate, positive predictive value, negative predictive value, and accuracy of 64-slice spiral coronary CTA in evaluating ISR were 77.9%, 96.4%, 3.6%, 22.1%, 69.1%, 97.7%, and 94.71%, respectively. The results of the CTA and coronary angiography in diagnosing ISR in different locations of the coronary artery were not significantly different (P>0.05). CTA imaging quality was significantly better for stents with diameters >3 mm than that for stents with diameters ≤3 mm (P<0.05). Overall, 64-slice spiral coronary CTA has very high accuracy and was not significantly different compared with coronary angiography when assessing the patency of stents. CTA is advantageous because it is inexpensive, simple and convenient, and it can be used for follow-up examinations.

Presence of artifacts, caused by dental filling high-Z materials (DFM), on intensity-modulated radiation therapy (IMRT) treatment plan CT images may lead to uncertainty in head and neck calculated dose distributions. Hence, the purpose of this study was to investigate the effects of DFM on the IMRT calculated dose distribution and consequent radiobiological derived outcomes for nasopharyngeal cancer patients. IMRT optimization of two groups (15 patients in each) of nasopharyngeal cancer (NPC) patients with (group I) and without (group II) dental amalgam was performed by using the Prowess Panther treatment planning system (TPS). For all the patients, target prescribed dose was 70 Gy to planning target volume. We used 3 sets of treatment plans including; nine fields arrangement (F9E) and two plans of seven fields (namely: F7 and F7E) at different angles. The dose volume histograms (DVHs), monitor units (MUs), Homogeneity index (HI), conformity index (CI), Tumor control probability (TCP) and normal tissue complication probability (NTCP) of main organs at risk (OARs) were analyzed. According to the results, the TCP of PTV70 due to presence of dental filling material was significantly decreased (p=0.031). On the other hand received dose by mandible, left cochlea, both eyes and right optic nerve were considerably different between patients with and without artifacts (p<0.05), whereas mandible showed the maximum differences (up to 315.65 cGy) compared to the other studied OARs. Results Presence of dental artifact in patients with nasopharyngeal carcinoma leads to uncertainty in calculated dose of IMRT treatment plans, especially for mandible as an OAR.

Due to the small size of the beamlets in IMRT (intensity modulated radiotherapy), physical penumbra is one of the important dosimetric parameters and small changes in the penumbra have a notable impact on the results. The physical penumbra width is defined as the lateral distance between two specified isodose curves at a specified depth of phantom. In this study, after demonstrating the inconsistency of conventional physical penumbra definition for non-uniform MLC (multileaf collimator) fields, two new dosimetric parameters proposed that are suitable for MLC fields. Physical penumbra evaluation was obtained using IAEA (international atomic energy agency) phase space data for a Varian IX and EGS (electron gamma shower)nrc Monte Carlo code package.  These measurements have been performed in water phantom at an SSD of 100 cm and a depth of 5 cm. With conventional definition, physical penumbra width for all MLC setups on right and left sides of isodose curves (parallel to X and Y axes) are not equal.  With a novel beam penumbra parametrization, the effect of MLC setup is taken into consideration. The conventional definition of physical penumbra for non-uniform MLC setups is not comprehensive. For such cases, surface penumbra and uniformity index parameters are demonstrated to be more suitable and indicative of the field non-uniformity. It is also shown that for an idle treatment planning system, the uniformity index approaches unity.

Bismuth composites are new and non-lead shields that are capable of breast dose reduction while preserving image quality. In this study, different percentages of Bismuth were used in designing and constructing polymer composites as breast shields in chest CT.  Micro particles of Bismuth with a ratio of 1% to 15% in Silicone matrix with two thicknesses were used as Bismuth Silicone composite (BSC) shield. The female chest phantom and standard chest CT exposure factors were used. Dosimetry was performed by thermo luminescent dosimeters. The image quality was evaluated with two methods. Statistical analyses were performed by Kruskal-Wallis and Mann-Whitney tests using SPSS 16. The application of 1% and 15% BSC shields reduced the breast dose to 14.9% and 62.2%, respectively. Increases in image noise in BSC was observed 2.33% (P=0.439) for breast and from 7.13% (p=0.513) for mediastinum areas, depending on the type of shields. The Application of Bismuth shields with Silicone composite and changing of the Bismuth percentages in composite and thickness are effective factors on the breast dose reduction significantly that can reduce the risk of breast cancer when engaged in Chest CT.

The article was first report a case of a 32-year-old female with NPC that is G6PD-deficient. The patient completed induction chemotherapy and concomitant chemoradiotherapy successfully. The patient experienced grade 1 neutropenia , grade 1 diarrhea, and grade 2 acne-like skin reactions during the three cycles of  induction chemotherapy. Grade 1 neutropenia, grade 1 diarrhea, grade 2 oral mucositis  and grade 1  skin reactions were observed during the concomitant chemoradiotherapy. No hemolytic events were observed. We conclude that it is safe for G6PD-deficient patients with NPC to received chemotherapy and targeted therapy.

Neurofibroma of the prostate is an extremely rare benign tumor, particularly when it is not associated with neurofibromatosis-I (NF-1). This study aimed to report the case of a 44-year-old man who presented with dysuria for about 4 years. Magnetic resonance imaging (MRI) showed a mass in the prostate with “target sign” on T2-weighted imaging. The mass was surgically excised, and histopathological findings revealed a neurofibroma. No clinical or laboratorial manifestations of NF-1 were identified. Also, no local recurrence occurred after the 3-month follow-up. This was the first case of prostate solitary neurofibroma without NF-1, and the “target sign” on MRI could supply some significant implications in the diagnosis.

Radon as a potential risk of radiation exposure is a natural radioactive element that can emit from rocks and soils. Due to solubility in water, it can be inhaled or consumed by the public. The purpose of this study was carrying out measurement and evaluation of radon concentration in samples of drinking water which are collected from water supplies of Borujerd. Dose This research was performed to estimate the annual average effective dose (mSva-1) to the public from dissolved 222Rn of 16 drinking water supplies of Borujerd, western part of Iran. The methodology of the study includes utilizing radon monitoring apparatus, RTM 1688-2, to meter the concentrations of 222Rn and 220Rn dissolved in samples. The measured average of radon concentration was 3.451 Bq.l-1 which was lower than 11 Bq.l-1 (the EPA level recommended for drinking water). Total radon annual effective dose, ranged from 5.4×10-3 to 72.1×10-3 mSv.a-1 with an average of 34.9×10-3 mSv.a-1 which was insignificant compared to all natural sources, 2.4 mSv. The effective received doses for all age groups were less than the standard limit (0.1 mSv/y) therefore there is no need for treatment of water for removal of 222Rn in Borujerd County.

Melorheostosis has been discussed infrequently in the nuclear medicine literature. A 25-year-old female patient presented with a one-year history of b:union: pain, sclerotic change and skin pigmentation on the left big toe interphalangeal joint. Ulceration, poor healing and hyperkeratoses of the wound were noted post debridement. The plain film of the left foot incidentally showed melorheostosis. Radiographs revealed cortical hyperostosis of big toe. After further evaluation by X-ray and bone scan of the left foot, the radiologic findings still indicated melorheostosis. A further Tc-99m MDP bone scan revealed extensive bone involvement in the left side of the pelvis and entire left lower extremity. Moreover, plain film whole body bone scan and MRI also revealed melorheostosis. The clinical symptoms of her left big toe included interphalangeal joint callus formation, debridement, ulcer and hyperkeratoses. X-rays often reveal a pattern of thickened bone that resembles dripping candle wax, with periosteal cortical thickening, confined to sclerotomes; and can be seen apparently flowing across joints to the next bone. In the nuclear medicine image, an increase in radiotracer uptake is usually present on late phase bone scans. There was excellent correlation between the scintigraphic and radiographic distribution of these lesions in the following radiographs of pelvis, left femur, lower leg and MRI of the left foot. This study reported a rare case of melorheostosis affecting the big toe and reviewed the role of various imaging diagnosis of this rare bone dysplasia.