International Journal of Radiation Research
Year:2017 | Volume:15 | Issue:4|Papers Count:13

About 10% of apparently normal individuals are sensi ve to clastogenic effects of physico-chemical agents. More than 45% of breast cancer pa ents’ exhibit elevated radiosensi vity. Although the nature of inherent radiosensi vity is not fully understood, but insufficiency and impaired DNA repair mechanism might be prime cause of radiosensi vity. This is evident from gene cally affected individuals such as ataxia telangiectasia, severe combined immunodeficiency, Xeroderma pigmentasum, Fanconi anemia who show sensi vity to ionizing radia on, ultraviolet light and alkyla ng agents. All these gene c diseases are caused due to impaired DNA damage repair mechanism. Radia on therapy (RT) is a common and effec ve way of treatment in several types of malignant tumors. Some cancer pa ents suffer from side effects of RT such as radia on induced early or late adverse responses in normal  ssues within weeks, months, or even years post irradia on, due to intrinsic radiosensi vity. The RT efficiency limita on raises from ionizing radia on toxicity reac ons in normal  ssues. An appropriate protocol to prevent or treat these side effects, has not been developed yet. Molecular pathways involved in adverse responses to cancer treatment agents have not been well defined. Iden fica on of molecular mechanisms may be promising to enhance the output of treatment technologies and overall survival of cancer pa ents. Several techniques such as microarray technology has been used to clarify molecular mechanisms involved in radiosensi vity by finding genes related to RT normal  ssue responses. DNA repair, apoptosis, cell cycle, and growth factor associated genes are the most important candidates in this field.

Background: The dose-related effects of pa ent setup errors on bio-physical indices were evaluated for the conven onal wedge (CW) and field-in-field (FIF) whole breast irradia on techniques (WBI). Materials and Methods: The treatment plans of 10 pa ents receiving le' WBI were retrospec vely selected for evalua on. The bio-physical effects of dose varia ons were evaluated by shi'ing the isocenters and gantry-angles of the treatment plans. Dose-volume histograms of the planning target volume (PTV), heart, and lungs were generated, and the conformity index (CI), homogeneity index (HI), tumor control probability (TCP), and normal  ssue complica on probability (NTCP) were determined. Results: The D95 of the PTV for an “ isocenter shi' plan” with a posterior direc on decreased by approximately 15%, and the TCP of the PTV decreased by approximately 50% for the FIF technique and by 40% for the CW; however, the NTCPs of the lungs and heart increased for both techniques. Increasing the gantry-angle decreased the TCPs of the PTV by 24. 4% (CW) and by 34% (FIF). The NTCPs of the lungs and heart for the two techniques differed by only 3%. The CIs and HIs for the CW case were higher than the corresponding values obtained for the FIF case. Significant differences were observed between the two techniques (p<0. 01). Conclusion: Our results revealed that the biophysical proper es of the FIF case were more sensi ve to setup errors than those in the CW case. The radiobiological-based analysis could be detected significant dosimetric errors and provided a prac cal pa ent quality assurance method for guiding the bio-physical effects.

Background: The aim of this study was to compare the differences of the dosimetric parameters between three-dimensional conformal radiotherapy (3D-CRT) and simultaneous-integrated boost intensity-modulated radiotherapy (SIB-IMRT) techniques in the prone and supine posi$ons for breast irradia$on. Materials and Methods: Ten pa$ents underwent a computed tomography simula$on in both the prone and supine posi$ons. For each set-up posi$on, the treatment plans were created with 3D-CRT and SIBIMRT. The dosimetric parameters were obtained from dose-volume histograms. Results: High-dose regions in the whole breast were decreased in IMRT with a simultaneous integrated boost technique. The lung doses were significantly reduced for all pa$ents, and the heart doses were lower in le+-sided breast cancer pa$ents in the prone posi$on. The heart doses except mean dose were not significantly lower with SIB-IMRT in the prone posi$on. Conclusion: SIB-IMRT allowed a more conformal dose distribu$on regardless of posi$on. The prone posi$on is superior to the supine treatment regarding doses in the ipsilateral, contralateral lung, and heart. The contralateral breast doses were increased in the prone posi$on. Prone IMRT can be chosen for simultaneous integrated boost treatment in women with pendulous breasts.

Background: This study aims to inves gate the metabolic characteris cs of radiotherapy-induced temporal lobe injury in elderly pa ents with nasopharyngeal carcinoma using 1H-magne c resonance spectroscopy (MRS). Materials and Methods: Data were collected from 21 elderly pa ents and 33 young pa ents before and during therapy with different radia on dosages (20, 40, and 60 Gy). The Student’ s t-test was used to compare the 1H-MRS-based N-acetyl aspartate /Crea ne (NAA/Cr), Choline/Crea ne (Cho/ Cr), and NAA/Cho ra os in the temporal lobes. Results: Sta s cally significant differences in the NAA/Cr and NAA/Cho ra os was found between the two groups (P < 0. 05) at 20, 40, and 60 Gy. The Cho/Cr ra os (20/40/60 Gy) were 1. 82 ± 0. 16/1. 61 ± 0. 29/1. 37 ± 0. 13 and 1. 77 ± 0. 19/1. 48 ± 0. 17/1. 06 ± 0. 14 in the elderly and young pa ents, respec vely. We found significant differences between the two groups at the dosages of 40 and 60 Gy (P<0. 05). The decrease in the NAA/Cr and NAA/Cho ra os in the elderly group was significantly higher than that in the young pa ents with dosages of 20, 40, and 60 Gy. The decrease in the Cho/Cr ra o in the elderly group (2. 15%/11. 29%/12. 90%) was significantly lower than that in the young pa ents (3. 30%/15. 93%/17. 58%). Conclusion: Under the same radiotherapy pa

Background: External beam radiotherapy and brachytherapy plays a vital role in the management of cancer cervix. High dose rate brachytherapy is being presently used worldwide for the brachytherapy applica ons. At present, 2-Dimensional linear array detectors are the most common QA tool used for pretreatment pa ent specific quality assurance in external beam radiotherapy alone and  ll date no dedicated brachytherapy tool is available. An a$empt has been made to explore the feasibility of using 2 dimensional linear array, Imatrixx as a QA tool for brachytherapy. Materials and Methods: Reference treatment plans are generated by Plato treatment planning system using the images of Imatrix acquired with Siemens CT simulator. The efficacy of Imatrixx as a QA tool for intracavitary treatment plan verifica on, dwell posi on and dwell  me accuracy verifica on are studied. Results: The length and the widths along with the area of the reference isodose curves of the intracavitary treatment plans generated by Plato Planning system and measured with Imatrixx is compared. The difference in area of the reference isodose curve is found to vary from-0. 59 cm2 to 4. 59 cm2. The es mated user correc on factor for Iridium-192 energy, 0. 38 MeV is 1. 090 with a standard devia on of ± 0. 0211. Machine related QA such as dwell posi on and dwell  me were measured with Imatrixx with an accuracy of 0. 5 mm and 0. 02 s respec vely. Conclusion: Results shows that the 2-Dimensional linear array, Imatrixx can be used with accepted accuracy for both machine and pa ent specific quality assurance in brachytherapy treatments.

Background: This study evaluates dosimetric and spa al varia ons in inter– frac on applicator posi oning in high dose rate (HDR) brachytherapy. Materials and Methods: This study includes 25 retrospec ve pa ents of carcinoma of the cervix. Each pa ent received 5 frac ons of HDR intracavitary brachytherapy. High Risk-Clinical Target Volume (HR-CTV) were drawn on CT images. First implant was considered as a reference, and all subsequent CT data sets were rigidly registered on first implant’ s CT data set. Another point A, called point Aabs, was defined on first plan and all subsequent plans. Registra on proper es were recorded for all 125 plans that include X, Y, Z DICOM offset, rota onal, transla onal values and normalized D90 (ND90) doses were also recorded. Results: The mean angle of rota on on X, Y and Z axis are 0. 63 ± 1. 85 deg,-0. 86 ± 1. 30 deg,-1. 14 ± 2. 44 deg, respec vely. While mean transla onal mo on on X, Y and Z axes are – 2. 77 ± 10. 32 mm,-6. 12 ± 9. 71 mm and 14. 62 ± 23. 83 mm, respec vely. Mean ND90, and mean HR-CTV were found to be 1. 18 ± 0. 26 and 26. 91 ± 17. 70 cc, respec vely. Conclusion: Results of the study reveals that transla onal mo on is higher than the rota onal mo ons, and inter – frac on applicator varia on does not produce any significant change in Point A doses. The change in volume coverage is observed only due to applicator mo on. HR-CTV coverage decreases with increasing HR-CTV volume. Hence, dose prescrip on should be based on 3D HR-CTV volume.

Background: In CT systems, the machine u lizes a bow e filter to shape the X-ray beam and remove lower energy photons. The shape of this bow e filter is complicated and its geometry is o! en not available in detail. These renders the CT dose index (CTDI) to have different values in measurement versus Monte Carlo simula on studies and other analy cal calcula ons especially in dosimetry of internal organs. In exis ng literature, the bow e filter shape is extracted by using expensive sensors Materials and Methods: In the present work, the shape of the bow e filter of the Biograph 6 PET/CT was derived by using Thermolumenecence dosimeters (TLDs). Subsequently, to evaluate the accuracy of the body bow e filter shape as generated by TLDs, Monte Carlo simula on of CT was performed. 16 X-ray sources in various angles were used within the Monte Carlo code (MCNP-4C) to simulate the CT sec on of the PET-CT Biograph 6 system and to calculate dose. Results: The rela ve difference between simulated and measured CTDI value for the PET/CT Siemens Biograph 6 at 80, 110 and 130 kVp were 4. 2, 2. 9 and 2. 3%, respec vely. Conclusion: In this study, we demonstrate that it is possible to calculate the bow e filter shape by using an inexpensive TLD method. The results showed that it is possible to determine the shape of the bow e filter in PET/CT using TLDs with acceptable accuracy.

Background: Natural radionuclides in rock samples, primarily 238U (uranium), 232Th (thorium) and 40K (potassium), are the main source of radia on exposure to workers and general public and their measurement is of paramount importance from radia on protec on point of view. Materials and Methods: Gamma spectrometry using HPGe detector was used to measure the radioac vity and assess the radiological hazards and annual effec ve dose. The data is sta s cally significant. Results: In the studied rock samples, the mean ac vity of 238U, 232Th, 40K is 12. 15 ± 1. 68 Bq/kg, 45. 17 ± 6. 92 Bq/kg and 639. 24 ± 115. 86 Bq/kg, respec vely. The mean values of radium equivalent ac vity, radiological hazards external hazard index (Hex), Internal hazard index (Hin), Gamma index (Iγ ) and Alpha index (Iα ) are 125. 96 ± 14. 94 Bq/kg, 0. 34 ± 0. 04, 0. 37 ± 0. 04, 0. 48 ± 0. 06 and 0. 06 ± 0. 00 respec vely. The mean values of absorbed dose rate, indoor and outdoor annual effec ve dose of gamma radia on are 59. 55 ± 7. 16 nGy/h, 0. 29 ± 0. 04 mSv and 0. 07 ± 0. 00 respec vely. A strong posi ve correla on was observed between the radium equivalent ac vity and the absorbed dose (correla on coefficient R2 = 0. 99). Conclusion: The present inves ga ons showed that the inborn radioac vity is within the world and Indian average value. And the findings indicate that the studied samples do not pose any significant radia on hazard to the public in large and the workers in par cular and when used as construc on material also.

Background: The natural radioac vity levels in soil samples of Karadağ Mountain in central Anatolia region have been determined. Materials and Methods: Analyses on the collected samples were performed to determine gross alpha and beta radioac vity concentra ons by using a gas-flow propor onal counter and the concentra ons of 238U, 232Th and 40K by using a NaI(Tl) scin lla on detector. Results: The es mated ac vi es of gross alpha and beta ranged between 305. 155± 46. 830 and 1305. 437± 77. 23 Bq. kg-1, 479. 743± 22. 658 and 1177. 373± 30. 908 Bq. kg-1, respec vely. The mean ac vity values of U, Th and K radionuclides were found to be 71. 6, 83. 9 and 451. 1 Bq. kg-1, respec vely. Also, known radia on health hazard indices were calculated using radioac vity concentra ons of soil samples. Conclusion: The present results have been compared with the obtained values from other regions in Turkey and the interna onally reported values as well as the reference values. The soil samples in the studied area are safe and can be used as a construc on material without posing any significant radiological threat to public. This inves ga on reveals a baseline of levels of natural radioac vity in Karadağ Mountain, Turkey.

Background: Radioactive contamination in soil arises due to various activities of human being, such as nuclear energy generation, use of radioisotopes in industrial applications, science, technology, medicine and release of radiation in nuclear weapon tests. Materials and Methods: The two districts (Peshawar and Nowshera) of Khyber Pakhtunkhwa, Pakistan were selected for the study of anthropogenic Cs-137 assessment. A total of 102 soil samples were collected from different locations of these two districts of Khyber Pakhtunkhwa. Results: The activity concentration of Cs-137 was determined by gamma ray spectrometry using a high purity germanium detector coupled with a PC. The highest values for Peshawar and Nowshera found were 44. 1 ± 4. 6 Bq/kg and 27. 9 ± 4. 3 Bq/kg, respectively. Conclusion: The presence of Cs-137 shows that the areas under study have gained some fallout, however, the activity concentrations of Cs-137 found in the surveyed area were nominal and do not pose any potential health hazard to human beings.

Background: Environmental ionizing radia on has been associated with increased cancer risk by several studies. The Brazilian city of Poç os de Caldas, MG, seats on a huge deposit of uranium, which was un l recently mined. We performed a retrospec ve analysis of 310 cases of pa ents with breast cancer, who were exposed for at least ten years to different levels of ionizing radia on around their homes, to verify whether a correla on existed between disease incidence, prevalence, and exposure. Materials and Methods: Gamma radia on was measured on the roads and the urban street grid. We retrieved the clinical files of 310 pa ents from the Popula on-Based Cancer Registry of Poç os de Caldas city, MG, Brazil and compared the local prevalence and incidence of breast cancer per city district to the local effec ve doses. Results: Effec ve doses of radia on around pa ents’ homes varied from 0. 72 and 1. 30 mSv/year, with 70% of the homes exposed to doses > 1. 0 mSv/year. When considered the number of cases in the study in rela on to the adult female popula on of the city, the incidence of female breast cancer was 25. 9% higher than the na onal average incidence for the same period, 2003-2011 (68. 32/100, 000 versus 50. 61/100, 000 respec vely). Conclusion: The higher incidence of breast cancer among the adult female popula on of Poç os de Caldas may be associated with chronic exposure for ten or more years to effec ve doses equal or slightly above the interna onal reference dose of 1. 0 mSv/year. Other known risk factors for breast cancer in our pa ents were not different from those found na onwide.

Background: Ultraviolet radia on is present in sunlight. If ultraviolet radia on exceeds the limit, it can cause detrimental effects on human health such as skin cancer and cataract. Materials and Methods: In this descrip ve cross-sec onal study, the level of solar ultraviolet radia on type A (UVA) were measured using UV LOG HAND HELD in Kermanshah city. The intensity of ultraviolet radia on was measured three  mes a day including two hours before noon, noon and two o'clock in the a. ernoon. The results were analyzed using ANOVA sta s cal tests with a confidence interval of 95%. Results: The lowest and highest average intensity levels of solar UVA in Kermanshah were in December (14. 21± 0. 94 w/m2) and August (32. 87 ± 2. 3 w/m2), respec vely. Also, winter and summer seasons (with average intensi es of 16. 37± 1. 12 w/m2 and 30. 12± 1. 7 w/m2) had the lowest and highest intensity of this radia on, respec vely. Conclusion: Regarding that UVA radia on exceeds the safe exposure level, even in the winter in Kermanshah, it is recommended for people to avoid from long-term staying in open spaces at noon and use proper protec ve wears especially in summer.

Background: CdWO4 is a scin llator with some unique proper es. For example, high density, thermal and chemical stability and so on. Different applica ons of this scin llator such as X-ray scin llator has been inves gated thoroughly so far. However, there is limited number of studies repor ng the characteris cs of CdWO4 as an alpha counter. Materials and Methods: The CdWO4 powder was synthesized by a simple co-precipita on method. Then, the CdWO4 films with different thicknesses were prepared by spin coa ng method on glass substrates. The CdWO4 powder and films were characterized by X-ray diffrac on, photoluminescence, scanning electron microscopy, Fourier transformed-infrared spectroscopy, and ion beam induced luminescence. Finally, the response of samples with different thicknesses was measured using a 241Am alpha source with 1860 Bq ac vity. Results: The analyses revealed that the nanocrystalline CdWO4 with about 30 nm size was successfully synthesized without any impurity. Besides, the CdWO4 films had the same luminescence emission peak characteris cs as CdWO4 powder had. Conclusion: It was observed that the sample with 2. 9 mg/cm2 thickness had the best coun ng efficiency (over 2π geometry) among the others.