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P Sneed

Publications and source records attributed to P Sneed.

10 recordsLinked to original sources
PubMed2001

Multidisciplinary management of adult anaplastic astrocytomas.

The management of patients with anaplastic astrocytoma (AA) requires multidisciplinary involvement. In this article, the literature on the treatment of patients with AA is reviewed, emphasizing randomized trials and key retrospective studies. The role of surgery, radiation therapy, and chemotherapy in newly diagnosed patients and those with recurrent disease is described. Basic science insights, advances in neuroimaging and neuropathology, and novel therapies targeting invasion, angiogenesis, and growth modulation will hopefully lead to improved outcome in this subset of patients with malignant glioma.

Adult↗
PubMed1999

A multi-institutional analysis of complication outcomes after arteriovenous malformation radiosurgery.

PURPOSE: To better understand radiation complications of arteriovenous malformation (AVM) radiosurgery and factors affecting their resolution. METHODS AND MATERIALS: AVM patients (102/1255) who developed neurological sequelae after radiosurgery were studied. The median AVM marginal dose (Dmin) was 19 Gy (range: 10-35). The median volume was 5.7 cc (range: 0.26-143). Median follow-up was 34 months (range: 9-140). RESULTS: Complications consisted of 80/102 patients with evidence of radiation injury to the brain parenchyma (7 also with cranial nerve deficits, 12 also with seizures, 5 with cyst formation), 12/102 patients with isolated cranial neuropathies, and 10/102 patients with only new or worsened seizures. Severity was classified as minimal in 39 patients, mild in 40, disabling in 21, and fatal in 2 patients. Symptoms resolved completely in 42 patients for an actuarial resolution rate of 54% +/- 7% at 3 years post-onset. Multivariate analysis identified significantly greater symptom resolution in patients with no prior history of hemorrhage (p = 0.01, 66% vs. 41%), and in patients with symptoms of minimal severity: headache or seizure as the only sequelae of radiosurgery (p < 0.0001, 88% vs. 34%). CONCLUSION: Late sequelae of radiosurgery manifest in varied ways. Further long-term studies of these problems are needed that take into account symptom severity and prior hemorrhage history.

Adrenal Cortex Hormones↗
PubMed1995

Stereotactic radiosurgery in children.

The role of stereotactic radiosurgery in the treatment of pediatric patients is still being explored. We report the Gamma Knife treatment of 33 patients under the age of 21, at the University of California, San Francisco, between the years 1991 and 1993. Treatment-related toxicity has been low. 10/14 patients treated for arteriovenous malformation (AVM) with follow-up > 1 month have shown partial or complete AVM obliteration. No patient has had a new hemorrhage after AVM treatment. In children with malignant tumors, treatment was well tolerated, although most patients, ultimately, had progressive disease. Stereotactic radiosurgery is logistically possible in the pediatric population. Its use in selected patients with AVMs seems appropriate, although its role in the treatment of malignant brain tumors remains to be defined.

Adolescent↗
PubMed1983

Extralymphatic involvement in diffuse non-Hodgkin's lymphoma.

Between 1961 and 1982, 543 patients with diffuse histiocytic, mixed, or undifferentiated lymphoma were treated at Stanford University, Stanford, Calif. Of this group, 281 (52%) had extralymphatic lesions and the 111 patients with stage IE and IIE disease were subjected to analysis. Most patients (94) had diffuse histiocytic lymphoma. Lymphangiography was performed in 77%, bone marrow biopsy in 91%, and diagnostic or staging laparotomy in 52% of the patients. All but five patients were treated with megavoltage irradiation and 35 patients received combination chemotherapy. Median follow-up was 4.0 years. Kaplan-Meier actuarial survival at five and 10 years was 46% and 36%, respectively. Freedom from relapse (FFR) at five years was 49% with no relapses beyond that point. The most common extralymphatic sites were the gastrointestinal tract, the head and neck region, and the lung. Prognosis could not be correlated with the specific sites of involvement. Patients with bulky disease (greater than 10 cm) or more than three sites of involvement had a significantly lower survival and FFR. There was no significant difference in outcome for patients treated with irradiation or combined modality therapy. Most patients (62%) relapsed in distant extralymphatic sites.

Actuarial Analysis↗
PubMedDate not supplied

A thresholding for radionuclide angiocardiography.

A thresholding algorithm for nuclear angiocardiographic studies is presented. The algorithm is free of operator intervention. The threshold is defined on the basis of the distribution of picture elements with decreasing count rates during systole. The application is valid for first-pass and equilibrium ECG gated studies. Reproducibility by different operators with various degrees of experience is high; concordance of the results with those of contrast studies is within the published ranges. The method provides a reliable step in full automation and standardization of scintigraphic angiocardiographies.

Heart↗
PubMedDate not supplied

Heating patterns of the Helios ultrasound hyperthermia system.

Thermal dosimetry studies of the Helios ultrasound system were performed in a tissue-equivalent phantom and in porcine tissues in vivo. SAR distributions in the phantom demonstrate the adjustability of the power deposition pattern from the 50 cm diameter annular array of 30 transducers. Examples are given of well-localized SAR patterns (< 3 cm diameter) in the phantom, and of peripherally enhanced (doughnut-shaped) SAR patterns up to 10 cm in diameter at the focal plane. In vivo trials in porcine thigh muscle demonstrate the ability of the Helios system to produce regions of therapeutic heating (42-45 degrees C) as small as 20 cm3 and as large as 200 cm3 at depths of greater than 10 cm at a frequency of 0.5 MHz.

Animals↗