Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology
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Comparative Study
The modelled benefits of individualizing radiotherapy patients' dose using cellular radiosensitivity assays with inherent variability.
To model the increases in local tumour control that may be achieved, without increasing normal tissue complications, by prescribing a patient's dose based on cellular radiosensitivity measured using an assay possessing inherent variability. ⋯ Modelling based on measured distributions of fibroblast radiosensitivity shows that improvements in tumour control rates may be achievable through the individualization of radiotherapy dose prescriptions of cancer patients, when assay variability is less than about 50% of the true variability in radiosensitivity, and with greater benefits if tumour and normal tissue radiosensitivity are correlated. Tripartite stratification of the population proved to be less sensitive to assay uncertainty, and can provide most of the benefits of the full individualization.
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Henri Becquerel presented the discovery of radium by Pierre and Marie Curie at the Paris Academy of Science on 26th December 1898. One century later, radium has been abandoned, mainly for radiation protection difficulties. It is, however, likely that modern techniques of brachytherapy have inherited to those designed for radium sources, and that radium has cured thousands and thousands patients all over the world for about eighty years. The history of discovery and medical use of radium is summarised.
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Comparative Study
The effect of independent collimator misalignment on the dosimetry of abutted half-beam blocked fields for the treatment of head and neck cancer.
Independent collimation conveniently allows for the junctioning of abutting fields with non-diverging beam edges. When this technique is used at the junction of multiple fields, e.g. lateral and low anterior fields in three-field head and neck set-ups, there should be a dosimetric match with no overdose or underdose at the matchline. We set out to evaluate the actual dosimetry at the central match plane. ⋯ We recommend that independent jaw alignment be evaluated routinely and provide a simple method to estimate dose inhomogeneity at the match plane. If there is a field gap or overlap resulting in a clinically significant change in dosimetry, jaw misalignment should be corrected. If it cannot be corrected, part of the benefit of asymmetric collimation is lost and other methods of field junctioning may have to be considered. We routinely use a small block over the spinal cord at the mono-isocenter set-up plane for three-field head and neck treatments to prevent an overdose.
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Biography Historical Article
Marie Curie--the founder of the Radium Institute in Warsaw.
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Tumor hypoxia and tumor cell repopulation are known factors determining radiation response. Accelerated radiotherapy as a method to counteract cellular repopulation was combined with carbogen (95% O2 + 5% CO2) breathing and oral administration of nicotinamide as a means to improve tumor perfusion and oxygenation. The feasibility, toxicity and clinical effectiveness of this approach as a voice-preserving treatment for carcinoma of the larynx was assessed in a prospective study. ⋯ These preliminary results indicate that advanced laryngeal cancer can be controlled in a high proportion of patients when treated with accelerated radiotherapy combined with carbogen and nicotinamide. This approach offers excellent possibilities for larynx preservation.