نتایج جستجو برای: stratified shields

تعداد نتایج: 47903  

Journal: :IEEE Transactions on Appiled Superconductivity 1998

2018
Parinaz Mehnati Mehran Arash Parisa Akhlaghi

The article aims at constructing protective composite shields for breasts in chest computed tomography and investigating the effects of applying these new bismuth composites on dose and image quality. Polyurethane and silicon with 5% of bismuth were fabricated as a protective shield. At first, their efficiency in attenuating the X-ray beam was investigated by calculating the total attenuation c...

Journal: :Physics in medicine and biology 2013
Peter K N Yu Martin J Butson

Kilovoltage x-ray beams are used for the treatment of facial cancers when located on the patient's skin or subcutaneous tissue. This is of course due to the sharp depth dose characteristics of these beams delivering much lower doses at depth, than high energy x-ray beams. When treatment is performed, lead shields are often used within the nasal passage, or behind the lips and ears. These shield...

2013
P. Szajerski M. Zaborski H. Bem W. Baryn E. Kusiak

Two commercially available (EP, Z) and eight new elastomeric composites (M1-M4, G1-G4, of thickness ≈1 mm) containing mixtures of differing proportions of heavy metal additives (Bi, W, Gd and Sb) have been synthesised and examined as protective shields. The intensity of the X-ray fluorescence radiation generated in the typical elastomeric shields for CT, containing Bi and other heavy metal addi...

Journal: :Archives of ophthalmology 2006
Frederick W Fraunfelder Jonathan Solomon Thomas J Mehelas

1. Zimmerman LE, Garron LK. Melanocytoma of the optic disc. Int Ophthalmol Clin. 1962;2: 431-440. 2. Joffe L, Shields JA, Osher RH, Gass JD. Clinical and follow-up studies of melanocytomas of the optic disc. Ophthalmology. 1979;86:10671083. 3. Spencer WH. XXXIV Edward Jackson Memorial Lecture: drusen of the optic disc and aberrant axoplasmic transport. Ophthalmology. 1978;85:21-38. 4. Osher RH,...

Ehsan Bakhshandeh Masoomeh Barzegar Ziyarani Mehdi Allahbakhshian-Farsani mohsen bakhshandeh, Nezhat Shakeri

Introduction: Ionizing radiation can cause damage to biologically important DNA molecules. Radiation in nuclear medicine radiation exposes people working in from two main positions; administer in gradiopharmaceuticals (the barn and squeezing a generator, procurement, distribution and drug infusion) and patients that receive radiation treatment (patients that are prescribed a ra...

ژورنال: طب کار 2015

Background: Heat stress as a harmful physical agent in workplace, if is not properly controlled, can cause undesirable effects on the performance and health of personnel. This study aimed to evaluate the heat stress and efficacy of engineering interventions on WBGT index in work station of the workers in a forging industry. Methods: This experimental study evaluated WBGT index in one of the fo...

Ali Tarighatnia Mohammad Yousefi Sooteh Parinaz Mehnati, Reza Malekzadeh Yagub Khalegi Fard

Introduction: Coronary angiography (CA) is an interventional diagnostic procedure to assess cardiovascular disease. CA is performed using dedicated fluoroscopic systems equipped with either flat detector or image intensifier. There is an increase in the number of CA annually. Reducing the radiation exposure in the CA is essential, especially due to high fluoroscopy time. In ord...

Journal: :Nature chemistry 2012
Scott K Silverman

P rotecting groups have a long history in synthetic chemistry 1. A protecting group is covalently attached to one functional group to block its reactivity while a second functional group undergoes a chemical transformation, after which the protecting group is then removed (Fig. 1a). The use of protecting groups requires both protection and deprotection steps, so efficiency considerations dictat...

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