Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Author(s): 

ZHU J. | REN Z. | CHEN Y. | HU BURONG

Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    1-7
Measures: 
  • Citations: 

    0
  • Views: 

    30
  • Downloads: 

    161
Abstract: 

The radiobiological effects of high atomic number and energy (HZE parcles) ion beams are of interest for radioprotecon in space and tumor radiotherapy. Space radiaon mainly consists of heavy charged parcles from protons to iron ions, which is disnct from common terrestrial forms of radiaon. HZE parcles pose a significant cancer risk to astronauts on prolonged space missions. With high delivered energies and intense ionizaon, HZE parcles can damage not only the biological systems but also the shielding materials. HZE parcles are more effecve than low-LET radiaon likeg- or X-rays to induce genec mutaon and cancer. On Earth, similar ions are being used for targeted cancer therapy due to the advantage of the inverse dose profile, with delivering higher doses to the tumor while keeping lower doses to the surrounding ssues. In this review, we focus on the recent insights into the biological effects caused by HZE parcles and the corresponding mechanism. We also discuss the current applicaon of HZE parcle in cancer therapy. Understanding the mechanisms underlying the repair of DNA damage induced by HZE parcles contribute to accurately esmate the risks to human health associated with HZE parcle exposure and to improve the effecveness of tumor radiotherapy.

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    9-16
Measures: 
  • Citations: 

    1
  • Views: 

    47
  • Downloads: 

    133
Abstract: 

Background: DNA damage is one of the major consequences of radiaon exposure onto the biological systems. A series of compounds including flavanoids were found to render DNA protecon against radiaon damage. In this study we elucidated the potenal of run and run hydrate to protect plasmid DNA against damage induced by irradiaon.Materials and Methods: DPPH and hydroxyl radical scavenging assays were performed to assess the anradical potenal of run and run hydrate. Absorpon measurements were performed to assess binding parameters of run and run hydrate with calf thymus (CT) -DNA. Plasmid relaxaon assay was performed to compare the radio protecve potenal of run and run hydrate against gamma irradiaon mediated oxidave damage of pET28 plasmid DNA.Results: DPPH・assay indicated fast reacon kinecs for run and run hydrate. However anradical parameter in terms of EC50 suggested be/er scavenging capacity for run hydrate as compared to run. Hydroxyl radical scavenging assay further suggested that both the compounds displayed significant reducon in hydroxyl radicals. Absorpon binding study with CT-DNA suggested that run hydrate has be/er binding constant value (Ka=8.257 x 104 M-1) compared to Ka=1.834 x 104 M-1 for run. Plasmid relaxaon study demonstrated that plasmid DNA remains predominantly in super-coiled form in the presence of both run and run hydrate a8er exposure to 100 Gy of g-radiaon.Conclusion: The mechanisc studies suggested that binding and scavenging capacity of run hydrate and run contributes towards DNA radioprotecon.This study may be helpful in devising potent radioprotector molecules helpful for the radiotherapy treatment.

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Author(s): 

ACAR HILAL | YAVAS G. | YAVAS C.

Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    17-24
Measures: 
  • Citations: 

    0
  • Views: 

    36
  • Downloads: 

    133
Abstract: 

Background: In radiaon therapy, the peripheral dose is important when anatomical structures with very low dose tolerances are involved. In this study, the two available calculaon algorithms of the Varian Eclipse 8.6 treatment planning system (TPS), the anisotropic analyc algorithm (AAA) and pencil-beam convoluon (PBC) was used to compare measured and calculated peripheral dose distribuon of physical wedged (PW) and enhanced dynamic wedged fields (EDW).Materials and Methods: Peripheral dose measurements were carried out for 6 and 18 MV photons using a 0.6cc Farmer-type ionizaon chamber in the slab phantom. Measurements were performed using 15o, 30o, 45o and 60o PW and EDW for three different field sizes at dmax and up to a maximum distance of 50 cm beyond the field edges.peripheral dose was further computed using two different algorithms of a TPS. The measured and calculated datas were then compared to find which algorithm calculates peripheral dose distribuon more accurately.Results: Both algorithms from the TPS adequately model the peripheral dose distribuon up to 45 degrees. For large field sizes with 600 EDW, the largest deviaon between calculated and measured dose distribuon is less than 3.5% using the AAA, but can increase up to 9.7% of the distribuon using PBC.Conclusion: The AAA models wedged peripheral dose distribuons more accurately than the PBC does for all studied condions; the difference between the algorithms are more significant for large wedge angles and large field sizes. It must be emphasized that the use of PBC for planning large-field treatments with 600 EDW could lead to inaccuracies of clinical significance.

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    25-30
Measures: 
  • Citations: 

    0
  • Views: 

    28
  • Downloads: 

    205
Abstract: 

Background: Use of contrast agents (CAs) during CT simulaon for treatment planing system leads to changes in electron density. In this study we aimed to invesgate the effect on calculated dose of various concentraons of CAs on treatment planing systems in different dose calculaon algorithms.Materials and Methods: Contrast agent (0.769 mg/ml Iopromid) - water mixtures at concentraons of 0%, 1%, 2%, 5% and 10% in total volume of 500 ml for each were made by using five idencal balloons. Calculaons were performed by Cobalt-60 and 10 MV linear accelerator devices in CMS XIO treatment planning system. The prescribed dose of 100cGy was given to the center of balloon that is isocenter of SAD technique at 10cm from the surface.The doses at maximum dose depth (dmax) and at 5 cm were calculated according to the separate algorithms by either making or not making a correcon for CA, and the results were recorded.Results: In all algorithms, as contrast rao increases, the dose values at dmax and 5 cm-depth increase accordingly. When the doses at dmax and 5 cm-depth were compared for Linac and Co-60 in all algorithms, it has been shown that the dmax value of Co-60 was higher and the difference was greater in parallel with increasing contrast rao in comparing with Linac.Conclusion: When required during the planning, the treatment plan should be calculated via providing an electron density correcon by contouring the volume retaining CAs along the beam line.

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Author(s): 

CHOI K. | HAN T.J. | CHO JUNG KEUN

Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    31-37
Measures: 
  • Citations: 

    0
  • Views: 

    37
  • Downloads: 

    285
Abstract: 

Background: Recently, there have been many studies on the harmful effects of radiaon and the regulaons on radiaon safety have been toughened both at the in naon and abroad. This study aims to idenfy the percepons and acons taken as to radiaon safety, and the degree of knowledge related to radiaon held by the radiologists working in large hospitals.Materials and Methods: The research tool used in this study is a structured quesonnaire. It is consisted of three parts. The first part was about demographic characteriscs with 10 quesons. The second part was about basic knowledge with 15 quesons. The third part was about the percepons and acons with 10 quesons each. The data was stascally analyzed byt-test, ANOVA and I-P analysis.Results: First, the more educaon the study subjects received, their knowledge of radiaon increased even though the result was not stascally significant. Second, there was a stascally significant difference in relaon to the gender and the age group in safety management pracces. The degree of safety management pracce was higher among the men than the women.Third, there was a stascally significant difference at the significant level of 5 percent in all 10 quesons on the radiaon safety management and the degree of pracce.Conclusion: Since there is a growing importance on the radiaon safety management, it is imperave to tailor educaonal programs to trainees’ gender, age, educaonal level and duty in order to make the educaon program for radiaon professionals more teleological.

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    39-46
Measures: 
  • Citations: 

    2
  • Views: 

    41
  • Downloads: 

    158
Abstract: 

Background: Radioacve substances are water chemical contaminants. In this study, the concentraon of radon was measured in drinking water supplies of Ta- villages (part of Dehshir-Ba- fault located in central part of Iran) and also Shirkooh area with granite rocks (containing uranium).Materials and Methods: This cross seconal research was conducted in fall 2013 and winter 2014 on the sources of drinking water and also drinking water network of Ta-city of Yazd province. According to the measured radon levels; the annual effecve absorbed dose was also calculated.Results: Minimum and maximum levels of radon gas were related to sample number 54 (0.88 BqL-1) and number 31 (43.01BqL-1). Range of radon concentraons was 1.88-43.01 BqL-1 in samples of wells in private homes, 0.88- 20.36 BqL-1 in supplier wells of public network of drinking water, 1.23-10.29 BqL-1 in aqueducts, 1.23-11.49 BqL-1 in water tap connected to the public network and 12.89 BqL-1 in one measured spring. The annual effecve absorbed dose through drinking and breathing in an environment that this water is used ranged from 0.00 msv/y (sample No.54) to 0.11 mSv/y (sample No.31).Conclusion: Radon concentraon was lower than the limit set by the Environmental Protecon Agency of United States of America, in 82% of samples. Samples with high radon concentraons were located around Shirkooh area due to the presence of granic rocks. Dehshir and Garizat villages located through Dehshir - Ba-fault and the Radon concentraon of these samples was less than the permissible limit, probably due to the inacve Fault.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    47-51
Measures: 
  • Citations: 

    0
  • Views: 

    329
  • Downloads: 

    315
Abstract: 

Background: Ionizing radia on irradiated from iodine-131 can induce DNA damage and cell death. The cellular DNA damage is the cause of muta on and cancer. The micronucleus assay in polychroma c erythrocytes was applied to assess the radio-protec ve effect ofTurmeric extract on genotoxic poten al of iodine therapy.Materials and Methods: Thirty six male albino rats were randomly divided in six groups. A single dose (200 or 500 mg/kg) ofTurmeric extract was injected to the rats 30 min before iodine therapy. Iodine-131 (5.55 MBq) was administrated intra peritoneal to the experimental animals.The percentage of micronuclei in PCE, NCE and ra o of PCE / (PCE+NCE) was determined 48 h a6er iodine injec on for each experimental group to assess iodine-131 radia on effects with or withoutTurmeric extract. Results: Iodine therapy showed a significant increase in the number of micronucleus forma on. The animals treated with different doses ofTurmeric extract+ iodine showed a significant reduc on in the frequency of micronucleus compared to the animals treated with iodine-131 alone. Both doses of Turmericextract had the same effect when injected 30 min prior to iodine therapy.Conclusion: Our results indicate protec ve effect of Turmeric extract against gene c damages induced by iodine-131 administra on.

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    53-57
Measures: 
  • Citations: 

    1136
  • Views: 

    340
  • Downloads: 

    300
Abstract: 

Background: Ewing Sarcoma Family of Tumors (ESFTs) is the second most common primary tumors of bone in childhood. The decision regarding the op mal modality for achieving local tumor control remains uncertain. The aim of this study was to report the clinical features and outcome as well as reviewing risk factors in pa ents.Materials and Methods: This retrospec ve study included 75 ESFTs pa ents who were treated at cancer ins tute between 2004 and 2009. Files of all pa ents with ESFTs were reviewed retrospec vely and we called them for follow up. Specific data were collected with regard to the age at diagnosis, gender, tumor site and size, clinical stage, surgical procedure, plan of radiotherapy and treatment outcome (5-year and median survival).Results: The mean age at diagnosis was 21 that ranged from 1 to 52 years (SD=9.6). The mean tumor size at diagnosis was 4.8±4.48 cm. The percent of biopsy only, par al and complete resec on was 54.7% (41 pa ents), 6.7% (5 pa ents) and 37.3% (28 pa ents) respec vely.Radiotherapy was done as defini ve treatment or postopera vely (adjuvant) in 46 (61.3%) and 16 (21.4%) pa ents respec vely. Overall 5 year survival was 24% and median survival for pa ents with and without metastases was 21±17 and 75±10 months.Conclusion: Presence of metastases, age at diagnosis, posi ve surgical margin and tumor size were the prognos c factors that influenced outcome of pa ents. This study suggests that radia on therapy is an acceptable local treatment modality in pa ents with Ewing sarcoma family.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    59-65
Measures: 
  • Citations: 

    0
  • Views: 

    52
  • Downloads: 

    196
Abstract: 

Background: Accurate small radiaon field dosimetry is essenal in modern radiotherapy techniques such as stereotacc radiosurgery (SRS) and intensity modulated radiotherapy (IMRT). Precise measurement of dosimetric parameters such as beam profile, percentage depth doses and output factor of these beams are complicated due to the electron disequilibrium and the steep dose gradients. In the present work the MAGIC polymer gel was used for dosimetry of small circular photon beams. The results of MAGIC were compared with EBT2 measurements and Monte Carlo (MC) calculaons.Materials and Methods: Experimental measurements were made by menoned dosimeters in four small field sizes 5, 10, 20 and 30 mm. The BEAMnrc code based on EGSnrc was used for simulaon to calculate dosimetric parameters at these small fields. The phantoms were irradiated in a 6 MV photon beam Varian 2100C linear accelerator at SSD=100 cm. gel readout performed by 3 Tesla MRI scanner.Results: The results showed that the Percent depth dose (PDD) values measured and calculated by EBT2 film and MC had maximum local differences 4% and 5% with PDD values measured by MAGIC for field size of 5mm respecvely. These differences decreased for larger field sizes. The measurements of output factor and penumbra (80%-20%) and (90%-10%) showed good agreement between the measurements and MC calculaon.Conclusion: This study showed that the MAGIC polymer gel based on high resoluon MRI images is useful detector for small field dosimetry but its agreement with MC is less than agreement of EBT2 film with MC.

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    67-71
Measures: 
  • Citations: 

    0
  • Views: 

    46
  • Downloads: 

    131
Abstract: 

Background: One major challenge in brachytherapy is to verify the accuracy of dose distribuons calculated by the treatment planning system. In this project, a new phantom design has been introduced for quality assurance of dose distribuons in gynocological (GYN) brachytherapy implants using EBT GafChromic film.Materials and Methods: This phantom has been designed and fabricated from 90 slabs of 18×16×0.2 cm3 Perspex to accommodate a tandem and ovoids assembly, which is normally used for GYN brachytherapy treatment. In addion, this phantom design is allowing the use EBT GafChromic films for dosimetric verificaon of GYN implants with Cs-137 Selectron LDR system. With this assembly, GafChromic films were exposed using a plan designed to deliver 2.5 Gy dose to point"A" in Manchester system for tandem and ovoids configuraons and to deliver 1.5 Gy of dose to 0.5 cm distance from the lateral surface of ovoids for using ovoid-pair. The measured dose distribuons with GafChromic films were compared with the TPS isodose lines both numerically and spaally. For a quantave analysis of the results, the measured doses values at several points of interest were evaluated with the treatment planning data and values obtained following the TG-43 dose calculaon formalism.Results: The results of these invesgaons have indicated that the new phantom design enables us to measure differences of greater than ±6% for LDR brachytherapy GYN treatments.Conclusion: The new phantom design could be ulized for the QA procedure of the brachytherapy remote aCer loading systems to confirm the accuracy of dose distribuon in GYN implants.

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    73-76
Measures: 
  • Citations: 

    0
  • Views: 

    35
  • Downloads: 

    166
Abstract: 

Background: Different kinds and models of personal dosimeters are used in individual monitoring by workers. Performance tesng as part of approval procedures is carried out to demonstrate that the essenal performance specificaons are rounely maintained. There are four service providers in Iran which use different luminescence techniques (i. e. TLD and RPL) with various kinds of dosimeter materials/reader instruments in personal dosimetry services.Materials and Methods: A naonal performance approval tests program was performed for the dosimeters of the service providers in energy range of so', 660 keV and 1.25 MeV, at the doses values around the recoding, invesgaon and annual dose limits, and different angle of incidents (e. g.0, 20, 40 and 60 degree).Results: The results of this tesng sasfies the overall accuracy criteria with 95% confidence levels specified by the ICRP, except that of RPL technique in low energy which overesmates the dose out of the acceptable accuracy band defined as the ICRP trumpet curves.Conclusion: The inter-comparison has proved that the personal dose equivalent quanty, Hp (10), defined by the ICRU and recommended by the IAEA are becoming widely accepted and implemented in most parcipated laboratories.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    14
  • Issue: 

    1
  • Pages: 

    77-79
Measures: 
  • Citations: 

    0
  • Views: 

    42
  • Downloads: 

    131
Abstract: 

A discrete MIBI avid lung lesion was found in cinemac views of myocardial perfusion imaging (MPI) of a 59 year-old woman. Interesngly, the abnormal uptake in the lung was detectable only in the rest phase images and not in the images acquired in the stress phase. MPI was performed for pre-operaon cardiac risk assessment before correcon surgery for spinal canal stenosis.She had no past medical history or symptoms concerning pulmonary problems. The clinical examinaon of the pulmonary system was normal. MPI was reported normal but for the lung lesion she was sent for consultaon with pulmonologist. The pulmonologist diagnosed the lesion was an old inflammatory/infecve lesion probably secondary to tuberculosis. No histopathological examinaon was done. By reporng this case we intended to highlight the possibility of the effect of stress on uptake of MIBI in tumoral lesions as a tumor agent in nuclear medicine.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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