[en] A high standard of radiotherapeutic practice must be sought in all phases of management of a patient with malignant disease. Radiation therapy must be appropriately chosen and integrated with surgery, cytotoxic chemotherapy and all other modes of treatment. The most suitable technique with a dose, fractionation and time regime must devised and executed with technical and personal care. Follow-up to truly assess tumor control and morbidity is essential so as to guide the management of future patients. To achieve this in Europe great reliance is placed upon the training and qualification of the therapist and staff. High standards are applied to the professional qualifications for radiation physicists, nurses and technical staff. In the countries belonging to the European economic union, a new Diploma in Radiation Therapy has been established to be a standard for consultant practice through all the countries included. The European Organization for Research and Treatment of Cancer has recently initiated a quality control study in some of the centers included in the Radiotherapy Group. A preliminary report has just appeared on the results of the clinical and dosimetric studies in 8 centers placed in 5 European countries

[en] The goal of radiation therapy is to yield the greatest possible uncomplicated local and regional tumor control. Inasmuch as higher doses of irradiation and adequacy of treatment portals (volume irradiated) appear to correlate with greater probability of tumor control and major complications, there is a critical need to optimize treatment planning and quality assurance in radiation therapy. Along with this, techniques must be developed for reliable patient reposition and immobilization so that the optimized treatment plan can be translated into precise delivery of the irradiation. It is obvious that in clinical trials, the basic parameters of therapy need to be optimally observed, in order to make comparison of experimental arms more reliable. Stringent criteria must be incorporated into the protocol describing the requirements and techniques for planning and delivery of the radiation therapy. Furthermore, the dosimetry checks carried out by the Radiological Physics Center should be an integral part of this program. In some studies it is necessary to do an initial review of dosimetry factors and portal films. Since an increasing number of reports point out that the doses of irradiation delivered and the volume treated may affect therapeutic results, a completed case review should always be carried out. Costs of these programs in clinical trials should be justified since, for a small inveestment, the evaluability rate in a protocol can be incresed by 10%

[en] Radiocolloid internal mammary lymphoscintigraphy (ILM) was evaluated in 364 patients with ovarian carcinoma to determine the frequency of abnormalities in post-operative patients, the association between the results of the lymphoscintigram and known clinical prognostic variables, and to establish whether IML yielded predictive information independent of these variables. Results of IML showed a correlation with established clinical prognostic features and yielded independent prognostic information. The sensitivity and specificity of IML in predicting relapse are 51% and 71% respectively, indicating that a single post-operative IML does not predict relapse or freedom from relapse with sufficient accuracy to make it a clinically useful test even though it provides an independent prediction of relapse

[en] A short history of the International Commission on Radiation Units and Measurements (ICRU) and its main objectives are presented. They now include the development of internationally acceptable recommendations regarding: (1) quantities and units; (2) procedures suitable for the measurement and application of these quantities (as well as the associated uncertainties); (3) physical data needed in the application of these procedures; and (4) definition of terms and concepts used in radiation therapy. One of the most important actions of the ICRU during the last two decades was its recommendation in favor of the introduction of the SI units (International System of Units) in the field of ionizing radiation. Recently published ICRU reports in the field of radiation therapy are reviewed. Reports 23 and 24 provide recommendations for determining the absorbed dose in a patient irradiated with X or gamma ray beams. High energy electron and neutron beams have been considered in Reports 21 and 26 respectively. Report 31 provides a survey of the available anti W values and Report 29 makes recommendations on dose specification for reporting therapeutic irradiation in external beam therapy

[en] Future efforts in physics will have to address the new developments in each component of the whole radiation treatment process. Certain new developments, using both computer and imaging technologies, show promise in providing tools to verify the accuracy of the delivered radiation treatment. Areas receiving careful attention are: integration and registration of information from multiple sources of diagnostic studies; validation of the accuracy of treatment planning systems; assessment of relative merits of alternate dose distributions; improvement of portal and verification film image quality; real time monitoring using light emitting screens and coupled with TV systems; monitoring of treatment and machine parameters using ''record and verify'' computer systems. The medical physics community, primarily through the American Association of Physicists in Medicine (AAPM), will continue the development of methodologies for techology transfer in the area of quality assurance. By necessity, the national Radiological Physics Center (RPC) and the regional Centers for Radiological Physics (CRP) will have to take a major role in the development of new quality assurance programs

[en] A survey was conducted in Latin America to evaluate the clinical aspects of quality assurance in radiotherapy. A questionnaire was prepared and sent to 46 institutions. Twenty-seven centers (58.5%), from nine countries, answered the questionnaire. The study was divided into three topics: a) patient-related statistics; b) staffing and education; and c) equipment and facilities. Radiotherapy training programs are available in only 37% of the centers studied. A large number of megavoltage units are old, operating at a shorter than optimum distance with sources of very low activity. The number of high energy linear accelerators is unsatisfactory. Problems in treatment planning facilities were also identified. Regionalization of radiation therapy services is recommended as a possible way to improve quality at a reasonable cost

[en] Consensus of best current management developed by a rational and deliberative process can provide the basis for clinical quality assessment. When it is possible to arrive at consensus in a specific disease, this consensus should detail appropriate pretreatment evaluation and the details of the treatment. Committees of experts for each specific disease site can formulate the consensus and must document their decision based on information from the current world literature. The authors have observed that individuals formulating consensus of best current management do not strictly follow their own criteria, and that compliance in various strata of practice throughout the United States shows a greater deviation from consensus than anticipated and indeed this deviation crosses all types of practice. The authors have observed quite different outcomes for two groups of patients with Hodgkin's disease treated with the same processes (i.e., mantle field technology and adequate radiation dose, etc.). They were unable to identify the reason for an increased failure rate in one group of these patients until they looked at each individual mantle port film from the two groups of patients. They identified that one facility was not including the Hodgkin's disease in the treatment portal due to poor technical performance. This program of process verification may be important in evaluating quality for any disease site

[en] The present study shows that a prolonged exposure of V-79 cells to a variety of nitroimidazoles (misonidazole, Ro-05-9963, Sr-2508, and MRT1-80) results in an enhanced cytotoxicity when these cells are subsequently exposed to melphalan. This process of enhanced malphalan toxicity occurred only when cells were pretreated with misonidazole under hypoxic conditions, suggesting that nitroreduction is necessary for chemosensitization as it is for increased radiosensitization. Different nitroimidazoles tested vary in the extent to which they sensitize cells to the subsequent action of melphalan. Repair from a misonidazole pretreatment is essentially complete by six hours. This study demonstrated that cysteamine could reduce the cytotoxicity of misonidazole and the enhancement of melphalan toxicity. This was an effect reversible with time and one implying similar mechanisms for the preincubation effect observed in vitro for radiation and chemotherapy agents

[en] Trials of neutrons as an alternative to x-rays for the radiotherapy of human cancer are underway in Great Britain, the United States, Continental Europe and Japan. A major obstacle to the pooling of clinical data and to the comparison of results is the fact that the various machines used for neutron therapy include a wide range of different neutron energies with consequent variations in biological effectiveness. Various efforts have been made to make biological intercomparisons between the various neutron beams with a variety of biological systems. The present report summarize the results of a new series of biological intercomparisons based on measurements at facilities around the world using an established line of cells cultured in vitro

[en] Results of the first nationwide evaluation of radiation therapy in the United States with respect to its quality and accessibility are presented. The Patterns of Care Study (PCS) is financially supported by the National Cancer Institute and has served as a model for other oncology-related disciplines. The PCS has determined criteria by which to evaluate radiation therapy care in 10 disease sites in which curative radiation therapy plays a major role. The sampling design identified the institution to be surveyed and included all types of practice in the U.S. This paper examines results related to carcinomas of the cervix, larynx and prostate