Thesis (Ph.D.)--George Mason University, 2008. / Title from PDF t.p. (viewed Oct. 14, 2008). Thesis director: Juan R. Cebral. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Vita: p. 98. Includes bibliographical references (p. 90-97). Also available in print.

Honors Project--Smith College, Northampton, Mass., 2010. / Includes bibliographical references (p. 119-121).

Thesis (M.D.)—Boston University

Ho Siu-ying, Salina. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 51-59). / Abstract and appendix in English and Chinese. / List of Tables --- p.v / List of Figures --- p.vi / Introduction --- p.1 / Method --- p.10 / Results --- p.15 / Discussion --- p.42 / References --- p.51 / Appendices --- p.60

Thesis (MSc (Radiography))--Cape Peninsula University of Technology, 2019 / Introduction: Intracranial aneurysm coil embolization is a fluoroscopically guided interventional procedure that is often preferred over surgical clipping for the treatment of intracranial aneurysms. Fluoroscopically guided procedures are associated with high levels of radiation doses which have the potential to induce skin injuries; and this necessitates adherence to radiation protection measures, especially the optimization of radiation exposure during fluoroscopically guided procedures. Optimization of radiation exposure can be achieved by applying the as low as reasonably achievable (ALARA) principle and by implementing diagnostic reference levels (DRLs). Monitoring and documentation of radiation doses at the end of each procedure is also essential to identify patients that are at risk of developing radiation-induced injuries for possible follow-up. Aim: This research study aimed to determine the average radiation dose to patients' thyroid glands and skin during intracranial aneurysm coil embolization. The objectives were to establish preliminary DRLs for intracranial aneurysm coil embolization; to ascertain whether the anatomical location of the intracranial aneurysm had an effect on the radiation dose and to compare the measured thyroid gland and skin doses to the Monte Carlo calculated doses. Methods: A prospective quantitative research study was conducted on 34 participants who had intracranial aneurysms that required coil embolization during the study period. Radiation doses to the anterior neck of participants, over the thyroid gland region, were measured using lithium fluoride thermoluminescent dosimeters (TLDs). In addition, the air-kerma area product (KAP) values were used to determine the participants' skin dose and the DRLs. Considering that it is not possible to perform direct thyroid measurements on human beings, phantom-based simulation studies were performed to evaluate the difference between the dose measured on the anterior neck and the dose measured directly on the thyroid gland. Three different aneurysm coil embolization scenarios were simulated during the phantom-based simulation studies. TLDs were placed on the anterior neck and in the thyroid hole of the phantom, which represents the anatomical location of the thyroid gland, during each simulation. The thyroid and skin doses were also calculated using a Monte Carlo program. The measured thyroid gland and skin doses were compared to the doses obtained from Monte Carlo calculations. Results: The average percentage difference between the anterior neck doses and thyroid radiation doses was found to be 61%. This value was added to the radiation dose measured on the anterior neck of participants to obtain the thyroid absorbed doses during coil embolization procedures. The thyroid absorbed doses ranged between 3.2 and 20.95 mGy with a mean of 11.25 mGy. The KAP values ranged between 33 and 125 Gy.cm2. The DRL established during this study was 68 Gy.cm2, 616 image frames and 30 minutes of fluoroscopy time. There was no agreement between measured thyroid dose and calculated thyroid doses while there was strong positive correlation between measured and calculated skin doses. The results showed no statistically significant relationship between aneurysm location and the radiation dose. Conclusion: The skin doses in this research study were below the threshold doses suggested in the literature for deterministic effects of radiation. The study results therefore suggest that patients that undergo intracranial aneurysm coil embolization at the research site are not at risk of developing radiation-induced skin injuries. The established DRLs were also lower than internationally published DRLs for intracranial aneurysm coil embolization.

No description available.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 73-84).

Elevated intracranial pressure (ICP) in closed head injury may lead to a vegetative state and even death. Current methods available for measuring ICP may cause infection, haemorrhage or not reliable. A patient-specific correlation between ICP and an external vibration response was used for ICP evaluation, which based on finite element (FE) modeling. In FE modeling, a two dimensional FE model of human head was built in ANSYS. Geometry information was obtained from a magnetic resonance image of the human head, while the material properties were acquired from literatures. Vibration responses, e.g., displacement, velocity, acceleration and equivalent strain, were obtained for applied ICPs in FE analyses. Correlations between ICP and vibration responses were established. Effects of impact magnitude and impact duration were studied. Response sensitivity was defined to find a vibration response that is sensitive to ICP change. A procedure based on response sensitivity was proposed for ICP evaluation.

Elevated intracranial pressure (ICP) in closed head injury may lead to a vegetative state and even death. Current methods available for measuring ICP may cause infection, haemorrhage or not reliable. A patient-specific correlation between ICP and an external vibration response was used for ICP evaluation, which based on finite element (FE) modeling. In FE modeling, a two dimensional FE model of human head was built in ANSYS. Geometry information was obtained from a magnetic resonance image of the human head, while the material properties were acquired from literatures. Vibration responses, e.g., displacement, velocity, acceleration and equivalent strain, were obtained for applied ICPs in FE analyses. Correlations between ICP and vibration responses were established. Effects of impact magnitude and impact duration were studied. Response sensitivity was defined to find a vibration response that is sensitive to ICP change. A procedure based on response sensitivity was proposed for ICP evaluation.

Intrakranijinio spaudimo matavimas yra svarbus apsprendžiant gydymo taktiką daugelio ligų, tokių kaip galvos smegenų traumos, subarachnoidinės kraujosruvos, smegenų insultai bei kitos. Šiuo metu pasaulyje nėra tikslaus bei patvirtinto klinikinei praktikai neinvazinio IKS matavimo metodo. Šio mokslinio tyrimo tikslas nustatyti neinvazinių ultragarsinių intrakranijinio spaudimo matavimo metodų klinikinę vertę. Tyrime atlikti IKS matavimai Lietuvos mokslininkų sukurtu neinvaziniu IKS absoliutinės vertės matavimo įrenginiu, leidžiančiu matuoti IKS mmHg. Toks prietaisas yra unikalus, neturintis analogų, o šia techniškai nauja versija mokslinis tyrimas atliktas pirmą kartą. Tyrime taip pat nagrinėti intrakraniospinalinių pulsinių bangų pokyčiai priklausomai nuo intrakranijinio slėgio kitimo keičiant kūno padėtį. Neinvaziniai IKS absoliučios vertės matavimai, Goslingo pulsacijos indeksai ir kiti kraujotakos parametrai vidurinėse smegenų arterijose (VSA), regos nervo dangalų diametrai bei intimos medijos storis bendrosiose miego arterijose (BMA) buvo palyginti su juosmeninės punkcijos metu išmatuotu smegenų skysčio spaudimu, atspindinčiu IKS. Tyrime nustatėme, kad didžiausią klinikinę vertę bei diagnostinį tikslumą padidėjusiam IKS matuoti parodė neinvazinis IKS absoliutinės vertės matavimo metodas, o Goslingo pulsacijos indeksų VSA, regos nervų dangalų diametrų ir intimos-medijos storio BMA matavimų ultragarsiniai metodai tyrimui atrinktiems pacientams buvo nepakankamai tikslūs. / Measurement of intracranial pressure (ICP) is clinically important in several neurological conditions such as traumatic brain injury, subarachnoid hemorrhage, intracerebral hemorrhage, malignant stroke, idiopathic intracranial hypertension and other. No noninvasive ICP measurement method is clinically approved. In this clinical study we aimed to determine a clinical value of non-invasive ultrasound methods for ICP measurement. In this study we’ve used a unique noninvasive ICP measurement method allowing the measurement of ICP in absolute units- mmHg. This method was invented by Lithuanian scientists. Being technologically new device it was used for the first time in this study. In this study we have analyzed variation of intracraniospinal blood volumetric pulse waves associated with of body posture. Measurements of noninvasive ICP absolute value, Gosling pulsatility index in middle cerebral arteries, ocular nerve sheath diameters and intima-media thickness in common carotid arteries were compared with CSF pressure (reflecting ICP) measurements obtained during lumbar puncture. Noninvasive ICP absolute value measurement method showed best diagnostic accuracy and precision among all noninvasive methods compared in the study. Measurements of Gosling pulsatility index, ocular nerve sheath diameter and intima-media thickness didn’t show sufficient diagnostic accuracy for clinical practice among the patients included.