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متن کامل


اطلاعات دوره: 
  • سال: 

    2019
  • دوره: 

    16
  • شماره: 

    1
  • صفحات: 

    91-97
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    219
  • دانلود: 

    0
چکیده: 

Introduction: Long-term teletherapy program is not suitable for old and working patients and those living in areas where little access to primary health care is available. Accelerated partial breast irradiation (APBI) using high dose rate (HDR) brachytherapy is an appropriate alternative for these patients due to its limited number of fractions. The AccuBoost is a system for delivering APBI. The brachytherapy dose is delivered from parallel-opposed beams from 192Ir sources in circle applicators. This study was conducted to investigate the effects of breast phantom material on the dose distribution in AccuBoost brachytherapy using Monte Carlo N-Particle method. Material and Methods: In this study, different inhomogeneous breast phantoms composed of various materials were simulated. Dosimetric evaluations including a comparison of dose distribution between different breast phantom materials and water phantom was performed. Results: There was no significant difference between the breast and water phantoms in terms of mean dose values in different positions of each phantom. The most significant differences between the doses of different compositions and water were found to be about 6% near the skin. Conclusion: No significant differences were observed between the breast phantoms composed of diverse materials and water phantoms considering the dose distributions. Therefore, it is not necessary to replace the current treatment planning systems using Task Group No. 43 formalism with combined model-based and patient-specific dosimetry methods.

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بازدید 219

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اطلاعات دوره: 
  • سال: 

    2017
  • دوره: 

    8
  • شماره: 

    4
  • صفحات: 

    274-280
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    220
  • دانلود: 

    0
چکیده: 

Phantom materials are important tools for quality control and dosimetry works in medical physics. The tannin-bonded Rhizophora spp. particleboards in were fabricated as phantom and the dosimetric properties at high energy photons and electrons were evaluated. The particleboards were fabricated at dimensions of 30 x 30 x 1 cm3 and target density of 1. 0 g/cm3 based on the commonly used solid water phantoms in radiotherapy. The effective atomic number of the particleboard was determined based on the elemental compositions measured using energy dispersive x-ray analysis (EDXA). The mass attenuation coefficients at high energy photon were measured at 16. 59-25. 26 keV photons and 60Co and 137Cs gamma energies. The percentage depth dose and beam parameters of the particleboards were measured at 6 MV photons and 6 MeV electrons using Gafchromic EBT2 film and treatment planning system (TPS) software. The results showed that the effective atomic number and electron density of the particleboards were close to the value of water. The mass attenuation coefficient at high energy photons were close to the XCOM value of water. The percentage depth dose at high energy photons and electrons showed an agreement to the value in water and solid water phantom within 10% at all measured depths. The overall results indicated the suitability of tanninbonded Rhizophora spp. as phantom material for high energy photons and electrons.

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نویسندگان: 

POORZAMANY NEJAT KERMANY MAHTAB | MODIRIAN EHSAN | SOROUSH MOHAMMADREZA | MASOUMI MEHDI | HOSSEINI MARYAM

اطلاعات دوره: 
  • سال: 

    2016
  • دوره: 

    10
  • شماره: 

    3
  • صفحات: 

    42-47
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    370
  • دانلود: 

    0
چکیده: 

Objective To determine the frequency of phantom limb sensation (PLS) and phantom limb pain (PLP) in children and young adults suffering landmine-related amputation.Materials & Methods All youths with amputation due to landmine explosions participated in this study. The proportions of patients with phantom limb sensation/pain, intensity and frequency of pain were reported. Chi square test was used to examine the relationship between variables. Comparison of PLP and PLS between upper and lower amputation was done by unpaired t-test.Results There were 38 male and 3 female with the mean age of 15.8±2.4yr. The mean interval between injury and follow-up was 90.7±39.6 months. Twelve (44.4%) upper limb amputees and 11 (26.8%) lower limb amputees had PLS. Nine (33.3%) upper limb amputees and 7 (17.1%) lower limb amputees experienced PLP. Of 27 upper limb amputees, 6 (14.6%) and among 15 lower limb amputees, 6 (14.6%) had both PLS and PLP. One case suffered amputation of upper and lower limbs and was experiencing PLS and PLP in both parts. PLS had a significant difference between the upper and lower amputated groups.Significant relationship was observed between age of casualty and duration of injury with PLP.Conclusion Phantom limb sensation and pain in young survivors of landmine explosions appear to be common, even years after amputation.

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اطلاعات دوره: 
  • سال: 

    2018
  • دوره: 

    15
  • شماره: 

    2
  • صفحات: 

    71-77
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    288
  • دانلود: 

    0
چکیده: 

Introduction: The determination of accurate dose distribution is an issue of fundamental importance in radiotherapy, especially with regard to the fact that the human body is a heterogeneous medium. Therefore, the present study aimed to analyze the density and isodose depth profiles of 6 MV beam in a SP34 slab‐wooden dust (pine) ‐SP34 slab (SWS) heterogeneous phantom.Materials and Methods: The density of SP34 slab, wooden dust of pine, and thoracic region of 10 patients were calculated using computed tomography (CT) images. The depths of isodose lines were measured for 6 MV beam on the CT images of the chest, SP34 slab phantom, and SWS phantom. Dose calculation was performed at the depths of 2, 13, and 21 cm in both phantoms. Furthermore, patient-specific quality assurance (QA) was implemented using both phantoms.Results: The mean densities of the lung, SP34 slabs, and wooden dust were 0.29, 0.99, and 0.27 gm/cc respectively. The mean depths of different isodose lines in the SWS phantom were found to be equivalent to those in actual patients. Furthermore, the percentage variation between the planned and measured doses was higher in the SWS phantom as compared to that in the SP34 phantom. Furthermore, the percentage variation between the planned and measured doses in patient‐specific QA was higher in the SWS phantom as compared to that in the SP34 phantom.Conclusion: As the findings indicated, the density and isodose depth profiles of the SWS phantom were equivalent to those of the actual thoracic region of human.

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اطلاعات دوره: 
  • سال: 

    2012
  • دوره: 

    19
تعامل: 
  • بازدید: 

    149
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

PRODUCING THE PHANTOM MATERIALS FOR MODELING THE MECHANICAL PROPERTIES OF SOFT TISSUE IS THE PURPOSE OF THIS STUDY. THIS TISSUE IS COMBINED OF TWO DIFFERENT TYPES OF TISSUE, TUMOR AND BACK GROUND TISSUE. FINALLY GELATIN MATERIALS USED TO CONSTRUCT PHANTOM AND WEIGHT RATIO OF THE DRY GELATIN AND DEIONIZED WATER FOR 21 K PA AND 102 K PA YOUNG'S MODULUS ARE OBTAINED. THIS PHANTOM IS USED IN ULTRASOUND ELASTOGRAPHY WITH EXTERNAL EXCITATION LESS THAN 5%

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نویسندگان: 

نشریه: 

HEALTHCARE

اطلاعات دوره: 
  • سال: 

    2021
  • دوره: 

    9
  • شماره: 

    2
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    35
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 35

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اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    8
  • شماره: 

    1
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    102
  • دانلود: 

    0
چکیده: 

Percutaneous renal biopsy is the most common method for obtaining renal tissue. In this article, the authors first explained how to make a cheap model of phantom easily by sheep’, s kidney in a bowl filled with jelly. Then in the attached video, they showed how to find the ideal site (lower pole of kidney) and in real time, traced biopsy needle from jelly surface to kidney concomitant with ultrasound screen.

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اطلاعات دوره: 
  • سال: 

    2012
  • دوره: 

    2
  • شماره: 

    1
  • صفحات: 

    37-41
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    316
  • دانلود: 

    0
چکیده: 

Annually, many people are irradiated for diagnostic and therapeutic purposes. As-sessment of radiation dose and its related risks to patients are important issues in radiation protection dosimetry. The complex mathematical calculations of the absorbed and effective doses are now done with computers. The calculations are performed with the help of anthropomorphic computational models of human body called phantoms and Monte Carlo codes (MCNP). There are various types of phantoms, yet the latest type is hybrid phantom which has been introduced to the scientific community in recent years. Hybrid phantom is the connection between mathematical and voxel phantoms. They retain both the anatomic realism of voxel phantoms and the flexibility of mathematical phantoms. Using hybrid phantoms, the absorbed doses can be determined for any patients before they are exposed to radiation. Then, the energy of the emitted particles and irradiation geometry can be determined for any special purposes. A hybrid phantom is under construction for Iranian patients to be used in different applications such as testing new radiopharmaceuticals or cancer treatments with high LET radiation. Herein, we report on our findings.

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اطلاعات دوره: 
  • سال: 

    1394
  • دوره: 

    22
تعامل: 
  • بازدید: 

    256
  • دانلود: 

    103
چکیده: 

لطفا برای مشاهده چکیده به متن کامل (PDF) مراجعه فرمایید.

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اطلاعات دوره: 
  • سال: 

    1398
  • دوره: 

    7
  • شماره: 

    2
  • صفحات: 

    43-48
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    477
  • دانلود: 

    177
چکیده: 

فانتوم ها ی معادل انسان، به طور گسترده ای در پزشکی مورد استفاده قرار می گیرند. از فانتوم ها برای مقاصد دزیمتری، کالیبراسیون و کنترل کیفی دستگاه های پرتودرمانی استفاده می شود. با توجه به توسعه روز افزون تکنیک های پرتودرمانی و نیز گسترش علوم آن در درمان بیماران سرطانی و افزایش سطح کیفی درمان و همچنین با توجه به توسعه مراکز آموزشی و بخش های پرتودرمانی در سراسر کشور، استفاده از فانتوم های معادل انسان مورد نیاز می باشد. در طول سال ها فانتوم های متعددی در سراسر دنیا طراحی و ساخته شده اند که از جمله آن ها می توان به فانتوم راندو اشاره کرد. از آن جایی که تهیه فانتوم راندو پر هزینه می باشد، فانتوم مشابهی توسط شرکت تابش پرداز پگاه طراحی و ساخته شده است. به منظورمقایسه فانتوم ساخته شده با فانتوم راندو، هر دو فانتوم در میدان یکسان گاما پرتودهی شدند. نتایج نشان می دهد که میانگین درصد اختلاف نسبی دز گاما در فانتوم ساخته شده نسبت به فانتوم راندو، تقریبا 21% می باشد که با اعمال اصلاحاتی در فانتوم ساخته شده، نتایج دز گاما همخوانی بیشتری با فانتوم راندو خواهد داشت.

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