Study of myocardial cell inhomogeneity of the human heart: Simulation and validation using polarized light imaging.

Purpose: The arrangement or architecture of myocardial cells plays a fundamental role in the heart's function and its change was shown to be directly linked to heart diseases. Inhomogeneity level is an important index of myocardial cell arrangements in the human heart. The authors propose to investigate the inhomogeneity level of myocardial cells using polarized light imaging simulations and experiments.

Treatment delays using an automated afterloading low-dose-rate brachytherapy system.

Purpose: Low-dose-rate (LDR) brachytherapy is an integral treatment modality in radiation oncology. Clinical efficacy is based on experience with manual source loading and continuous dose delivery. With remote afterloading technology, sources may be loaded and unloaded during the treatment course to prevent radiation exposure to nursing staff members and visitors.

Update from the GHMonitorSM observational registry in children treated with recombinant human growth hormone (Saizen).

Since 2003, the GH MonitorSM, an observational registry, has collected data on pediatric subjects treated with Saizen (recombinant human growth hormone (r-hGH)) in the United States and Canada. This article provides an update on the demographic characteristics of subjects enrolled in the GHMonitorSM Registry. As of August 2007, 1733 subjects were enrolled (68.

Issues and trends in pediatric growth hormone therapy--an update from the GHMonitor observational registry.

The GHMonitor observational registry collates data on pediatric subjects receiving Saizen (recombinant human growth hormone (GH)) therapy. From January 2003 through August 2006, 1335 subjects were enrolled in the registry, approximately two-thirds of whom are male. The most common diagnosis in the registry is idiopathic growth hormone deficiency (58%).

Anastrozole increases predicted adult height of short adolescent males treated with growth hormone: a randomized, placebo-controlled, multicenter trial for one to three years.

Context: The process of epiphyseal fusion during puberty is regulated by estrogen, even in males.

Objective: Our objective was to investigate whether anastrozole, a potent aromatase inhibitor, could delay bone age acceleration and increase predicted adult height in adolescent boys with GH deficiency.

Methods: Fifty-two adolescent males with GH deficiency treated with GH were randomized to cotreatment with anastrozole or placebo daily for up to 36 months.

The role of Gamma Knife Radiosurgery in the management of unresectable gross disease or gross residual disease after surgery in ependymoma.

Purpose/objective: To evaluate the efficacy and the toxicity of Gamma Knife (GK)-based stereotactic radiosurgery (SRS) in the management of gross disease in ependymoma.

Materials And Methods: Eight patients with 13 ependymomas were treated with GK-based SRS in our institution for gross disease. Five patients were treated for recurrent disease that developed after surgery and external beam radiotherapy (EBRT), two received SRS to the gross disease after surgery and EBRT, and one received SRS alone (in a 1.

Patient outcomes in the GHMonitor: the effect of delivery device on compliance and growth.

To determine the effect of method of growth hormone (GH) administration on patient outcomes, we studied data from the GHMonitor, an electronic database registry of North American children treated with Saizen GH (somatropin [rDNA origin] for injection). Data from 631 children, 305 treated with needle and syringe and 326 treated with cool.click needle-free device, were analyzed.

Evaluation of underdosage in the external photon beam radiotherapy of glottic carcinoma: Monte Carlo study.

Purpose: Underdosage in the human larynx may be the true factor behind the decrease in local control rates.

Patients And Methods: To evaluate underdosage with Monte Carlo a CT-based geometrical model of the patient's neck (mathematical neck) was created. Dose was calculated for a pair of 6 Me V parallel-opposed photon beams modulated with 15 degree steel wedges.

Monte carlo simulation of the Leksell Gamma Knife: II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery.

The absence of electronic equilibrium in the vicinity of bone-tissue or air-tissue heterogeneity in the head can misrepresent deposited dose with treatment planning algorithms that assume all treatment volume as homogeneous media. In this paper, Monte Carlo simulation (PENELOPE) and measurements with a specially designed heterogeneous phantom were applied to investigate the effect of air-tissue and bone-tissue heterogeneity on dose perturbation with the Leksell Gamma Knife. The dose fall-off near the air-tissue interface caused by secondary electron disequilibrium leads to overestimation of dose by the vendor supplied treatment planning software (GammaPlan) at up to 4 mm from an interface.

Lung cancer radiation therapy: Monte Carlo investigation of "under dose" by high energy photons.

Loss of electronic equilibrium in lung tissue causes a build-up region in the tumor. Increasing the photon energy increases the depth at which electronic equilibrium is reestablished within the lung tumor. This study uses the Monte Carlo code PENELOPE for simulations of radiation treatment of tumor surrounded by lung.

Monte Carlo simulation of the Leksell Gamma Knife: I. Source modelling and calculations in homogeneous media.

The Monte Carlo code PENELOPE has been used to simulate photon flux from the Leksell Gamma Knife, a precision method for treating intracranial lesions. Radiation from a single 6OCo assembly traversing the collimator system was simulated, and phase space distributions at the output surface of the helmet for photons and electrons were calculated. The characteristics describing the emitted final beam were used to build a two-stage Monte Carlo simulation of irradiation of a target.