Search Results

You are looking at 11 - 20 of 48 items for :

  • By Author: Xu, Zhiyuan x
Clear All
Restricted access

David J. Salvetti, Tara G. Nagaraja, Ian T. McNeill, Zhiyuan Xu and Jason Sheehan

performed with Elekta's Gamma Plan software. In general, dose selection was based on RTOG 95-08 guidelines. However, additional parameters, such as total number of metastases, tumor volume, and prior or planned WBRT, were also factored into the dose selection process. Data Collection and Follow-Up Patient charts were reviewed for pertinent data including demographic information, KPS score, tumor histology, dates and doses of previous WBRT, prior resection, prior chemotherapy, status of primary tumor, and presence or absence of extracranial tumors. Radiosurgical

Restricted access

Dale Ding, Chun-Po Yen, Robert M. Starke, Zhiyuan Xu and Jason P. Sheehan

with unruptured AVMs, and all patients treated with volume-staged radiosurgery. The remaining 639 patients, classified as Cohort A, had ruptured AVMs and radiological follow-up of any duration. In an attempt to account for the latency of successes and complications typically associated with radiosurgery, another cohort, Cohort B, of patients with a minimum of 2 years of radiological follow-up was defined, and this group of patients had 465 ruptured AVMs and the minimum of 2 years of radiological follow-up. Finally, to optimize the power of statistical analyses used

Restricted access

Jason P. Sheehan, Zhiyuan Xu, David J. Salvetti, Paul J. Schmitt and Mary Lee Vance

difficult to completely excise because of suprasellar extension or invasion of the dura mater, cavernous sinus, or clivus. 31 Incomplete resection or recurrence of the adenoma leads to hypercortisolemia and the accompanying morbidity. Stereotactic radiosurgery has been used to treat sellar and parasellar tumors and has proven particularly valuable for treating Cushing's disease patients with recurrent or residual disease. 8 , 21 , 35 The Gamma Knife is particularly well suited for treating Cushing's disease because these pituitary adenomas tend to have a small volume

Restricted access

Dale Ding, Zhiyuan Xu, Ian T. McNeill, Chun-Po Yen and Jason P. Sheehan

.9)  visual disturbance 9 (13.8)  presyncope 7 (10.8) Tumor Characteristics Of the 90 meningiomas included for imaging analysis, 53 were parasagittal (58.9%) and 37 were parafalcine (41.1%). The median initial tumor volume was 3 cm 3 (range 0.1–15.4 cm 3 ). Preradiosurgery treatment included resection in 72 tumors (80%), embolization in 4 tumors (4.4%), and radiation therapy in 18 tumors (20%). An increase or decrease in tumor size was defined as a 15% increase or decrease in tumor volume. Tumor control was defined as decreased or unchanged tumor volume

Free access

David J. Schlesinger, Håkan Nordström, Anders Lundin, Zhiyuan Xu and Jason P. Sheehan

volume is increased. 48 Embolic Agents and Potential Effects on Delivered Dose Distribution Embolization of AVMs is also playing an increasingly important role, often as an adjuvant treatment to radiosurgery or microsurgery, with the goal to reduce the nidal volume of large AVMs and minimize the risks of any intranidal aneurysms and arteriovenous fistulas. 1 , 11 , 14 , 15 Unfortunately, in a small subset of patients, GKRS fails to result in complete obliteration of the AVM nidus, prolonging the risk of hemorrhage and, in most cases, necessitating retreatment of the

Full access

I. Jonathan Pomeraniec, Robert F. Dallapiazza, Zhiyuan Xu, John A. Jane Jr. and Jason P. Sheehan

deficits. Imaging studies were used to evaluate tumor response to treatment, and endocrine testing was matched to these follow-up time points. All neuroimaging studies were independently reviewed by a neurosurgeon and a neuroradiologist at the University of Virginia Health System. Clinical and radiographic outcomes were determined 2 months postoperatively, just before GKRS, and again by the last available examination. A change in tumor size was defined by 15% or greater increase or decrease in tumor volume. 54 Adenomas with less than 15% change in size were deemed

Full access

Or Cohen-Inbar, Han-Hsun Shih, Zhiyuan Xu, David Schlesinger and Jason P. Sheehan

–08 guidelines, but additional parameters, such as the total number of metastases, the tumor volume, and prior or planned whole-brain radiation therapy, were also factored into the dose selection process. 30 The median tumor margin and maximum doses used in the series were 20 Gy (range 14–22 Gy) and 23.7 Gy (range 16.7–45.1 Gy), respectively. Timing of SRS and Ipilimumab Patients were assigned to one of 2 groups based on the relationship between the timing of SRS and ipilimumab treatment. Twenty-eight patients were treated with SRS before the first dose of ipilimumab; the

Free access

David Schlesinger, Zhiyuan Xu, Frances Taylor, Chun-Po Yen and Jason Sheehan

, the object of this study was to quantify the uncertainty for patient setup and patient immobilization when the Extend system is used. Methods Positioning measurements for 10 consecutively enrolled patients (for a total of 36 fractions) treated at the University of Virginia between January 2010 and August 2011 were used to estimate setup and immobilization uncertainties. Table 1 displays the demographics of the patients, including patient sex and age, diagnosis, tumor volume, and beam time at the time of treatment planning. TABLE 1: Demographics

Restricted access

David Weintraub, Chun-Po Yen, Zhiyuan Xu, Jesse Savage, Brian Williams and Jason Sheehan

history and neurological status consistent with such a lesion. The study was approved by the University of Virginia Health Sciences internal review board. The following baseline clinical variables were recorded: patient age, sex, year of treatment, tumor volume, KPS score, symptoms at presentation, symptom duration at the time of treatment, pathology (if known), tumor location (brainstem, cerebellum, thalamus, or supratentorial cortex), presence of tumor enhancement, method of histopathological diagnosis (none, biopsy, or resection), timing of GKS (primary treatment

Restricted access

I. Jonathan Pomeraniec, Davis G. Taylor, Or Cohen-Inbar, Zhiyuan Xu, Mary Lee Vance and Jason P. Sheehan

lesion (e.g., when cavernous sinus or dural invasion precludes safe complete resection) or in selected patients as primary treatment when surgical risk is deemed excessive. 3 , 13 , 15–17 , 20 , 23–25 , 29 , 31–33 , 36–38 , 48 , 50 Tumor volume control rates following SRS for both functioning and nonfunctioning adenomas are as high as 90%, 29 , 35 , 37 with studies demonstrating actuarial tumor control rates of 98%, 95%, 91%, and 85% at 3, 5, 8, and 10 years after radiosurgery, respectively. 10 , 11 , 25 , 33 , 34 , 38 The incidence of new endocrinopathy following