It has been shown from an evaluation of the inverse reading of the dosemeter (1/M) against the inverse of the polarizing voltage (1/V), obtained with a number of commercially available ionization chambers, using dose per pulse values between 0.16 and 5 mGy, that a linear relationship between the recombination correction factor kS and dose per pulse (DPP) can be found. At dose per pulse values above 1 mGy the method of a general equation with coefficients dependent on the chamber type gives more accurate results than the Boag method. This method was already proposed by Burns and McEwen (1998, Phys. Med. Biol. 43 2033) and avoids comprehensive and time-consuming measurements of Jaffé plots which are a prerequisite for the application of the multi-voltage analysis (MVA) or the two-voltage analysis (TVA). We evaluated and verified the response of ionization chambers on the recombination effect in pulsed accelerator beams for both photons and electrons. Our main conclusions are: (1) The correction factor k(S) depends only on the DPP and the chamber type. There is no influence of radiation type and energy. (2) For all the chambers investigated there is a linear relationship between kS and DPP up to 5 mGy/pulse, and for two chambers we could show linearity up to 40 mGy/pulse. (3) A general formalism, such as that of Boag, characterizes chambers exclusively by the distance of the electrodes and gives a trend for the correction factor, and therefore (4) a general formalism has to reflect the influence of the chamber construction on the recombination by the introduction of chamber-type dependent coefficients.

The hyperthermia effect is based on its thermal influence on tumours. Therefore a controlled heating of the tumours must be achieved. In order to guarantee this, two points must be fulfilled at least: First, the hyperthermia equipment must have the necessary power and steering capability. Second, the distribution of the ‘hyperthermic drug’, the heat, has to be measured and controlled over the whole treatment time. To reach this aim both a sophisticated technique and a staff trained in hyperthermia are required. In treating patients such as those with cervical cancer, the volume to be exposed and the dosage must be clarified. This means that very special technical and medical conditions must be fulfilled in hyperthermia. To reach and maintain a certain level of quality, hyperthermia is embedded in a framework of procedures. These procedures are defined in the modules of quality management. Therefore quality management must contain specific guidelines for each application, i.e. coordinated standards have to be defined. When adapting these standards in hyperthermia, comparable and comprehensible results of the treatment are guaranteed. Furthermore, an analysis of the treatments under a scientific point of view will be possible and finally result in improvements of this method.

Every day a large amount of data is produced within a radiotherapy department. Although this data is available in one form or other within the centralised systems, it is often not in the form which is of interest to the departmental staff. This work presents a flexible browser based reporting and visualization system for clinical and scientific use, not currently found in commercially available software such as MOSAIQTM or ARIATM. Moreover, the majority of user merely wish to retrieve data and not record and/or modify data. Thus the idea was conceived, to present the user with all relevant information in a simple and effective manner in the form of web-services. Due to the widespread availability of the internet, most people can master the use of a web-browser. Ultimately the aim is to optimize clinical procedures, enhance transparency and improve revenue. Our working group (BAS) examined many internal procedures, to find out whether relevant information suitable for our purposes lay therein. After the results were collated, it was necessary to select an effective software platform. After a more detailed analysis of all data, it became clear that the implementation of web-services was appropriate. In our institute several such web-based information services had already been developed over the last few years, with which we gained invaluable experience. Moreover, we strived for high acceptance amongst staff members. By employing web-services, we attained high effectiveness, transparency and efficient information processing for the user. Furthermore, we achieved an almost maintenance-free and low support system. The aim of the project, making web-based information available to the user from the departmental system MOSAIQ, physician letter system MEDATECR and the central finding server MiraPlus (laboratory, pathology and radiology) were implemented without restrictions. Due to widespread use of web-based technology the training effort was effectively nil, since practically every member of staff can master the use of a web-browser. Moreover, we have achieved high acceptance amongst staff members and have improved our effectiveness resulting in a considerable time saving. The many MOSAIQ-specific parts of the system can be readily used by departments which use MOSAIQ as the departmental system.