نتایج جستجو برای: external dose

تعداد نتایج: 495703  

ژورنال: سنجش و ایمنی پرتو 2020

      Total body irradiation (TBI) is a kind of external beam radiotherapy which is used in conjunction with chemotherapy with the purpose of immunosuppression before bone marrow transplantation. As recommended by AAPM dose distribution uniformity in TBI is very important and dose variation must be within ±10% of prescription dose. Patients treatment geometry for TBI techniques fall into two co...

2018
Lilie Wang Anthony J. Cmelak George X. Ding

Radiation dermatitis during radiotherapy is correlated with skin dose and is a common clinical problem for head and neck and thoracic cancer patients. Therefore, accurate prediction of skin dose during treatment planning is clinically important. The objective of this study is to evaluate the accuracy of skin dose calculated by a commercial treatment planning system (TPS). We evaluated the accur...

Journal: :medical journal of islamic republic of iran 0
m.j. tahmasebi birgani medical physics and radiation therapy departments, jundishapur university of medicalsciences, ahwaz, iranسازمان اصلی تایید شده: دانشگاه علوم پزشکی جندی شاپور اهواز (ahvaz jundishapur university of medical sciences) m. ansari radiation therapy department, jundishapur university of medical sciences, ahwaz, iranسازمان اصلی تایید شده: دانشگاه علوم پزشکی جندی شاپور اهواز (ahvaz jundishapur university of medical sciences) m.a. behrooz medical physics department, jundishapur university of medical sciences, ahwaz, iranسازمان اصلی تایید شده: دانشگاه علوم پزشکی جندی شاپور اهواز (ahvaz jundishapur university of medical sciences)

abstract background: adjacent treatment fields are commonly used in external beam radiation therapy, such as mantle and inverted-y fields for the treatment of hodgkin’s disease and craniospinal fields used in the treatment of medulloblastoma and head and neck tumors when the lateral neck fields are placed adjacent to the anterior supraclavicular field. in each of these situations, there is a po...

Introduction Wedge modifiers are commonly applied in external beam radiotherapy to change the dose distribution corresponding to the body contour and to obtain a uniform dose distribution within the target volume. Since the radiation dose delivered to the target must be within ±5% of the prescribed dose, accurate dose calculation by a treatment planning system (TPS) is important. The objective ...

2014
Haiying Zhang Ling Jiao Songye Cui Liang Wang Jian Tan Guizhi Zhang Yajing He Shuzhou Ruan Saijun Fan Wenyi Zhang

Radiation safety is an integral part of targeted radionuclide therapy. The aim of this work was to study the external dose rate and retained body activity as functions of time in differentiated thyroid carcinoma patients receiving 131I therapy. Seventy patients were stratified into two groups: the ablation group (A) and the follow-up group (FU). The patients' external dose rate was measured, an...

Journal: :Radiation and environmental biophysics 2005
C Thornberg R Vesanen E Wallström I Zvonova T Jesko M Balonov S Mattsson

In 1990, a joint Nordic-Russian project was initiated in order to make independent estimations of the effective dose to selected groups of inhabitants in a highly contaminated area around the city of Novozybkov in the western Bryansk region of Russia. The inhabitants were living in six villages with initial contamination levels of (137)Cs between 0.9 and 2.7 MBq m(-2). Some villages had been de...

A. Pourmoghadas, M. Atarod, P. Shokrani,

Background: In most cancer cases, the treatment choice for a pregnant patient is radiotherapy. In these patients, the abdomen is usually not exposed therefore fetus exposure is due to peripheral dose (PD). The purpose of this study was to estimate the fetal dose (the maximum PD in each pregnancy stage) for modalities available and to fabricate and evaluate a generally applicable fetal ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1392

پایان نامه حاضر در مورد امکان سنجی استفاده از مدلسازی آماری مبـتنی برbmd جهت برآورد حجم بحرانی خونریزی درایجاد مقادیر معینی از خطر مرگ ناشی از خونــریزی مــغزی غیرتروماتیک(خود به خودی) می باشد. روشbmd در رابطه با مقدار دوز یا حجم بحرانی یک وضعیت از پیش تعیین شده برای بدست آوردن بهترین پاسخ جهت ارزیابی خطرات سلامتی و بهداشتی و همچنین برآورد مقدار یا حجم بحرانی دوز می باشد. روشbmd یک روش جایگزین...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی تهران 1379

اسانس گیاه شوید در درمان هیپرلیپیدمی در یک دوره مزمن به بیماران تجویز می شود. در این مطالعه سمیت احتمالی تحت مزمن اسانس این گیاه مورد بررسی قرار گرفت، حال آنکه در مصرف حاد این اسانس سمیتی گزارش نشده است. در این آزمایش 40 رت ماده به 4 گروه 10 تایی تحت گروههای شاهد، ‏‎‏‎a(high dose)، ‏‎(intermeidate dose)b‎‏ و ‏‎(low dose)c‎‏ تقسیم شد و اسانس بصورت خوراکی تحت دوزهای به ترتیب بالا: بدون اسانس، 2 م...

Introduction: Although travertine is now widely used as a building material, the effects of its radiological hazards to public health should be a matter of concern. Therefore, this study aimed to determine its radiological parameters with regard to human health. Material and Methods: In this research 10 travertine samples were collected ...

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