Technology evolution: is it survival of the fittest?

New technologies are constantly being developed and introduced into medical practice. Their potential or actual use raises questions of efficacy and cost. All too often financial considerations of profit primarily determine whether a technology will be adopted.

Trials and tribulations in charged particle radiotherapy.

A number of aspects of radiotherapy using protons and ions such as carbon and neon are discussed, focusing less on the oft-enumerated advantages or potential advantages of these particles as on those aspects which are, or may be, problematic. First, for protons and so-called heavy ions separately, the potential advantages and disadvantages of the particles, on physical and radiobiological grounds, are reviewed and some outstanding problems, both technical and scientific, are enumerated. Then, mention is made of the danger that financial pressures can lead to suboptimal medical care of patients.

Spread-out antiproton beams deliver poor physical dose distributions for radiation therapy.

Background And Purpose: Antiprotons have been suggested as a possibly superior modality for radiotherapy, due to the energy released when they annihilate, which enhances the Bragg peak and introduces a high-LET component to the dose. Previous studies have focused on small-diameter near-monoenergetic antiproton beams. The goal of this work was to study more clinically relevant beams.

Secondary carcinogenesis in patients treated with radiation: a review of data on radiation-induced cancers in human, non-human primate, canine and rodent subjects.

Concern for risk of radiation-induced cancer is growing with the increasing number of cancer patients surviving long term. This study examined data on radiation transformation of mammalian cells in vitro and on the risk of an increased cancer incidence after irradiation of mice, dogs, monkeys, atomic bomb survivors, occupationally exposed persons, and patients treated with radiation. Transformation of cells lines in vitro increased linearly with dose from approximately 1 to approximately 4-5 Gy.

Proton beam irradiation for neovascular age-related macular degeneration.

Objective: To evaluate safety and visual outcomes after proton therapy for subfoveal neovascular age-related macular degeneration (AMD).

Design: Randomized dose-ranging clinical trial.

Participants: One hundred sixty-six patients with angiographic evidence of classic choroidal neovascularization resulting from AMD and best-corrected visual acuity of 20/320 or better.

Organ and tumor motion: an overview.

An overview is presented of some of the issues that arise when considering how to manage motion of the patient (including setup errors), the tumor within the patient, and normal tissues that are sufficiently close to the tumor as to be likely to be at least partially irradiated. Problems arise in 3 areas: (1) at the tumor periphery where the question of just where the tumor surface is must be decided, (2) within the tumor proper where interplay effects between tumor motion and the radiation application (eg, in intensity-modulated radiation therapy) may result in dose inhomogeneity within the tumor, and (3) just outside the target volume where the extent to which organs at risk are to be irradiated (which needs to be based on an estimate of the consequences to them) must be decided. In the context of these problems, one must decide how to deal with potential motion.

Intensity modulation in radiotherapy: photons versus protons in the paranasal sinus.

Purpose: The purpose of this study is to investigate whether successive tightening of normal tissue constraints on an intensity modulated X-ray therapy plan might be able to improve it to the point of clinical comparability with the corresponding intensity modulated proton therapy plan.

Materials And Methods: Photon and proton intensity modulated plans were calculated for a paranasal sinus case using nominal dose constraints. Additional photon plans were then calculated in an effort to match the dose-volume histograms of the critical structures to those of the proton plan.

Evidence-based estimates of outcome in patients irradiated for intraocular melanoma.

Background: Melanoma of the eye is the only potentially fatal ocular malignancy in adults. Until radiation therapy gained wide acceptance in the 1980s, enucleation was the standard treatment for the tumor. Long-term results after proton beam irradiation are now available.

Effects of intra-fraction motion on IMRT dose delivery: statistical analysis and simulation.

There has been some concern that organ motion, especially intra-fraction organ motion due to breathing, can negate the potential merit of intensity-modulated radiotherapy (IMRT). We wanted to find out whether this concern is justified. Specifically, we wanted to investigate whether IMRT delivery techniques with moving parts, e.

Relative biological effectiveness (RBE) values for proton beam therapy.

Purpose: Clinical proton beam therapy has been based on the use of a generic relative biological effectiveness (RBE) of 1.0 or 1.1, since the available evidence has been interpreted as indicating that the magnitude of RBE variation with treatment parameters is small relative to our abilities to determine RBEs.