Overt hepatic encephalopathy: development of a novel clinician reported outcome tool and electronic caregiver diary.

Clinical management and clinical trials of patients with overt hepatic encephalopathy (OHE) are compromised by lack of standardized and reproducible tools for its clinical diagnosis or for caregiver (CG) identification of OHE manifestations which merit medical evaluation. Using an iterative Delphi method, Steering Committee and international hepatologist panel, the West Haven (WH) scale was modified to develop and operationalize a clinician tool for OHE identification and grading (HE Grading Instrument, HEGI™). Major diagnostic criteria included disorientation to time, place, and person, asterixis, lethargy, and coma.

Prospective Multicenter Observational Study of Overt Hepatic Encephalopathy.

Background: Overt hepatic encephalopathy (OHE) is a frequent complication of decompensated cirrhosis.

Aims: A multicenter prospective observational study was performed to assess the most commonly recorded presenting manifestations of OHE and its associated health-care burden.

Methods: Qualifying patients must have experienced ≥1 OHE episode within 30 days of enrollment (qualifying OHE) and were followed for recurrence (on-study OHE).

Multiple local minima in IMRT optimization based on dose-volume criteria.

Multiple local minima traps are known to exist in dose-volume and dose-response objective functions. Nevertheless, their presence and consequences are not considered impediments in finding satisfactory solutions in routine optimization of IMRT plans using gradient methods. However, there is often a concern that a significantly superior solution may exist unbeknownst to the planner and that the optimization process may not be able to reach it.

A method for determining multileaf collimator transmission and scatter for dynamic intensity modulated radiotherapy.

The main purpose of this work is to demonstrate a practical means of determining the leaf transmission and scatter characteristics of a multileaf collimator (MLC) pertinent to the commissioning of dynamic intensity modulated radiotherapy, especially for the sweeping window technique. The data are necessary for the conversion of intensity distributions produced by intensity-modulated radiotherapy optimization systems into trajectories of MLC leaves for dynamic delivery. Measurements are described for two, tungsten alloy MLCs: a Mark II 80-leaf MLC on a Varian 2100C accelerator and a Millenium 120-leaf MLC on a Varian 2100EX accelerator.

Dynamic splitting of large intensity-modulated fields.

The aims of this paper are to describe a method of splitting large intensity-modulated fields that cannot be delivered as a single field and to verify the accuracy of our method. Some multi-leaf collimators may be operated in the dynamic mode to deliver intensity-modulated radiation treatments (IMRT) using the 'sliding window' technique. In this technique each pair of leaves sweeps over the treatment field while the beam is on.

Algorithms and functionality of an intensity modulated radiotherapy optimization system.

The main purpose of this paper is to describe formalisms, algorithms, and certain unique features of a system for optimization of intensity modulated radiotherapy (IMRT). The system is coupled to a commercial treatment planning system with an accurate dose calculation engine based on the kernel superposition algorithm. The system was designed for use for research as well as for routine clinical practice.

Radiobiological considerations in the design of fractionation strategies for intensity-modulated radiation therapy of head and neck cancers.

Purpose: The dose distributions of intensity-modulated radiotherapy (IMRT) treatment plans can be shown to be significantly superior in terms of higher conformality if designed to simultaneously deliver high dose to the primary disease and lower dose to the subclinical disease or electively treated regions. We use the term "simultaneous integrated boost" (SIB) to define such a treatment. The purpose of this paper is to develop suitable fractionation strategies based on radiobiological principles for clinical trials and routine use of IMRT of head and neck (HN) cancers.