A dissection occurs when there is an intimal tear or rupture of the vasa vasorum, leading to an intramural hematoma, which is thought to result from trauma or can occur spontaneously, and is likely multifactorial, involving environmental

and intrinsic factors. The clinical diagnosis of carotid artery dissection can be challenging, with common presentations including pain, partial Horner syndrome, cranial nerve palsies, or cerebral ischemia. With the use of noninvasive imaging, including magnetic resonance and computed tomography AZD4547 purchase angiography, the diagnosis of carotid dissection has increased in frequency. Treatment options include thrombolysis, antiplatelet or anticoagulation therapy, endovascular or surgical interventions. The choice of appropriate therapy remains controversial as most carotid dissections heal on their own and there are no randomized trials to compare treatment options.”
“The purpose of this study was to conduct a measurement and treatment planning study on the dosimetric and delivery advantages of a new 160-leaf multileaf collimator (MLC). Recently, a new 160-leaf multileaf collimator

(Siemens 160 MLC (TM)) was introduced. The 160-MLC ABT-737 in vitro is a single focused design that consists of 160-leafs (80 pairs), each 95 mm thick with a projected leaf width of 5 mm at the machine isocenter. Compared to its double focused predecessors, the 82-leaf MLC (Siemens OPTIVIEW (TM) MLC) and 58-leaf MLC (Siemens 3-D MLC (TM)), the 160-MLC has leaf widths of half the size. The most notable difference is the new slanted leaf design that replaced the tongue and groove system and allows for complete interdigitation. A systematic study that compared the dosimetric and delivery differences among the 160-MLC, 58-MLC, and divergent Cerrobend blocks was performed. Dosimetric conformity for each collimator type was determined by conforming each to circular

targets Protein Tyrosine Kinase inhibitor of various diameters. The effective penumbra for each collimator type was calculated by conforming each, at various collimator angles, to a square stationary target. The quality of 3D conformal radiotherapy treatment (3D-CRT) plans and the quality intensity modulated radiation treatment (IMRT) plans were respectively compared with each collimator type. The 160-MLC was found to have improved dosimetric conformity over the 58-MLC. The divergent Cerrobend block showed marginal dosimetric conformity improvement over the 160-LMC. Overall, the 160-MLC had a 45% and 29% reduction in the 20/80 and 30/90 effective penumbra over the 58-MLC, respectively, while exhibiting only a slightly larger effective penumbra over the divergent Cerrobend block. Comparing 3D-CRT plans generated for small lesions of the head and neck, the V100 for the PTV of the plans generated with the Cerrobend blocks, the 58-MLC, and the 160-MLC were 97.78%, 92.51%, and 99.