[The new possibilities of digital luminescence radiography (DLR) and digital imaging data processing for the making of field verification images]. / Neue Möglichkeiten von digitaler Lumineszenzradiographie (DLR) und digitaler Bilddatenverarbeitung für die Erstellung von Feldkontrollaufnahmen.

BACKGROUND: Treatment verification for reasons of quality control takes an important place in daily radiotherapeutic work. The quality of conventional, e.g. not digital imaging methods, is often poor. Moreover, portal and verification imaging are commonly used only for photon beam control; even digital portal radiographs were not suitable for verification of electron beams, rotation beams, conformation therapy or dynamic multileaf collimation yet. MATERIALS AND METHODS: We developed a method, using digital luminescence radiography (DLR), not only for portal imaging of photon beams in an excellent quality, but also for verification of electron beams. Further on, DLR was used as basic instrument for image fusion of portal and verification film and simulation film respectively for image processing in "beams-eye-view" verification (BEVV) of rotating beams or conformation therapy. RESULTS: Digital radiographs of an excellent quality are gained for verification of photon and electron beams. In photon beams, quality improvement vs. conventional portal imaging may be dramatic, even more for high energy beams (e.g. 15-MV-photon beams) than for Co-60. In electron beams, excellent results may be easily obtained. By digital image fusion of 1 or more verification films on simulation film or MRI-planning film, more precise judgement even on small differences between simulation and verification films becomes possible. Using BEVV, it is possible to compare computer aided simulation in rotating beams or conformation therapy with the really applied treatment. The basic principle of BEVV is also suitable for dynamic multileaf collimation. CONCLUSIONS: DLR is a multipotent and suitable method for many aspects of imaging treatment verification.

[A simple method of digitizing analog scintigrams for quantification and digital archiving]. / Eine einfache Methode der Digitalisierung von Analogszintigrammen zur Quantifizierung und digitalen Archivierung.

This study was undertaken to evaluate a quick, reliable and cheap method of digitizing analog scintigrams. 40 whole-body bone scintigrams were obtained simultaneously in analog and genuine digital format. The analog scans on x-ray film were then digitized secondarily by three different methods: 300 dpi flat-bed scanning, high-resolution camera scanning and camcorder recording. A simple exposure approach using a light box, a cheap camcorder, a PC and image grabber hard- and software proved to be optimal. Visual interpretation showed no differences in clinical findings when comparing the analog images with their secondarily digitized counterparts. To test the possibility of quantification, 126 equivalent ROIs were drawn both in the genuine digital and the secondarily digitized images. Comparing the ROI count to whole-body count percentage of the corresponding ROIs showed the correlation to be linear. The evaluation of phantom studies showed the linear correlation to be true within a wide activity range. Thus, secondary digitalization of analog scintigrams is an easy, cheap and reliable method of archiving images and allows secondary digital quantification.

[Digital archiving and communication in hospitals]. / Digitale Archivierung und Kommunikation in Krankenhäusern.

Different concepts and already available components of a HIS (Hospital Information System) for archiving all data in a hospital are described. Using the example of the Kiel University Hospital, it is shown that a complete HIS-system can be made from already commercially available components.

[Do strong static magnetic fields in NMR tomography modify tissue perfusion?]. / Beeinflussen starke statische Magnetfelder in der NMR-Tomographie die Gewebedurchblutung?

Findings obtained in humans and test animals raised the question whether strong static magnetic fields as used in NMR-tomography may affect tissue perfusion. In two test series including 20 subjects, each skin blood flow at the thumb was determined by heat clearance, and forearm blood flow was measured by venous occlusion plethysmography. For comparative purposes, measurements were carried out bilaterally at both extremities. The experiments consisted of three sections that lasted 10 min each. During the second section the thumb or the forearm were unilaterally exposed to magnetic fields of 0.9 to 1 T and 0.4 to 0.5 T, respectively. The results of this section were compared with the values obtained during the experimental sections prior to and after the exposure to the magnetic field. The results were also compared with the blood flow measured at the contralateral extremity. Neither at the skin of the thumb nor at the forearm were there changes in local blood flow attributable to the magnetic fields applied.

[Fractionated homogeneous whole body irradiation prior to bone marrow transplantation]. / Fraktionierte homogene Ganzkörperbestrahlung vor Knochenmarktransplantation.

At the University of Kiel, myeloid and acute lymphatic leukemia is treated since 1983 by total-body irradiation applied prior to bone marrow transplantation. Dose deviations in the midplane caused by the irregular surface and tissue inhomogeneities of the patient are reduced down to +/- 3.5% compared to the central ray, with the help of CT-based individual compensators. This method prevents above all an excessive dose to the lungs. The radiobiologic advantages of fractionated irradiation have been employed for all patients treated hitherto (n = 9). At present, a total body dose of 12 Gy in six fractions is applied within three days. There were no undesired acute radiogenic reactions except a mild acute mucositis found in all patients. Chronic side effects, especially in the lungs, were not demonstrated, too. However, the average follow-up time of 149 days has been rather short. One patient died from relapse of leukemia after a total dose of 10 Gy, another patient died because the transplanted bone marrow was rejected, and a third died from catheter sepsis. Six out of nine patients are in complete remission with a maximum index of Karnofsky. The limited experiences gained hitherto show that the homogenous accelerated-fractionated total-body irradiation offers essential advantages compared to non-compensated single dose irradiation with respect to the prevention of undesired radiogenic effects in sound tissues and that its therapeutic efficacy is at least the same.

[Modern requirements of data processing in nuclear medicine (author's transl)]. / Heutige Anforderungen an nuklearmedizinische Datenverarbeitungsanlagen.

Having used a computer system for nuclear medicine for a period of seven years, our experience in its routine use has been evaluated. From this experience, and the present state of computer technique, the demands placed on the computer by scanners, gamma cameras and dynamic measurements have been assessed. Although available hardware meets the demands of present techniques in nuclear medicine, the corresponding software has not yet reached a satisfactory stage of development. There is still a lack of generally recognised, tested and standardised basic principles.

[Practical application of optimization criteria for geometrical distributions of the radiation dose: choice of the irradiation technique in 60Co-teletherapy (author's transl)]. / Praktische Anwendung der Optimierungskriterien für geometrische Strahlendosisverteilungen. Wahl der Bestrahlungstechik bei Co-60.

Fifty-four usual cases of radiation therapy were evaluated, comparing the effective surface doses in sound tissues for different irradiation techniques. Irradiation of the esophagus, mediastinum, lung and bladder was calculated for the cross-fire method, 3-field therapy, and monaxial or biaxial pendulum technique. Pendulum irradiation proved superior to multiple-field techniques in all cases. The number of free parameters in computer-assisted relative optimization of dose distributions can be reduced by means of the determination of the irradiation technique.

[Further considerations on the basis of the Ellis-formula and its application (author's transl)]. / Ergänzungen zu den Grundlagen und Anwendungen der Ellis-Formel.

Computational methods for the determination of normal tissue tolerance under various modes of dose fractionation are applied at many radiation therapy installations. The methods differ in details, but most are based on the Ellis-formula. A survey of the relevant quantities and relations is given in order to facilitate comparison of the various methods. The established equations which are applicable to regular fractionation are related to the generalization of the Ellis-formula which is also applicable to irregular fractionation modes.

[Thermographically visualized cutaneous reactions after irradiation with fast electrons (author's transl)]. / Thermographisch sichtbare Reaktionen der Haut nach Bestrahlung mit schnellen Elektronen.

A comparison was made between thermographically visualized cutaneous reactions of two groups of patients after a therapy with fast electrons. One group underwent one-series irradiation, the other group received two series with an interval of 21 days. The cutaneous reaction after the interval only appeared following considerably higher doses than with one-series therapy. This difference indicates the recuperative capability of normal tissue after the exposition to subtolerance effects. The data were evaluated using a function derived from the Ellis-formula. A "biological dosimeter" can be developed based on thermic reactions of subcutaneous connective tissue.

[Criteria for the optimization of geometrical dose distributions in radiotherapy (author's transl)]. / Optimierungskriterien für geometrische Strahlendosisverteilungen.

The author has deducted biologic criteria for a relative optimization of geometrical dose distributions in radiotherapy. The numerical calculation is based upon, among others, the Ellis formula and the dependence on the volume of tolerance doses in healthy persons. The criteria are suited for being applied in computerized therapy planning. They can be integrated without any problem into existing program systems.

[Importance of the tumor duplication time for the clinical radiotherapy (author's transl)]. / Die Bedeutung der Tumorverdopplungszeit für die klinische Strahlentherapie.

Malignant tumors of man have duplication times ranging between few days and several years. This fact allows to estimate the age of tumor and metastases. The decision whether a curative of a palliative irradiation is to be executed can be taken according to the development and the age of the tumor. The duplication time has an influence on the fractionation of the irradiations and the possible focal dose and also on the time after which check-up examinations are to be made. A method for the determination of the tumor volume by means of radiographs is described in the appendix.

[Consideration of the volume dependence of tolerance doses (author's transl)]. / Berücksichtigung der Volumenabhängigkeit von Toleranzdosen.

A general formula for consideration of the dependence of tolerance doses upon volume is obtained by mathematical evaluation of known skin tolerance doses. The validity for different organs is verified using available data of literature. It is recommended to introduce the volume dependence into the Ellis-formula for tolerance doses.

[Development and utilization of the Nominal Standard Dose for the tolerance dosage to healthy tissue in radiotherapy]. / Die Entwicklun und Anwendung der Nominal Standard Dose für die Toleranzdosis des gesunden Gewebes in der Strahlentherpie

The utilization of the Ellis-formula for the determination of the tolerance of normal connective tissue is described. Beyond this, the formula is adapted to so-called critical organs. The individual suppositions implicated by the Ellis-formula are commented. Because of the verifyable congruency of the Ellis-formula with data obtained in clinical practice also by other authors, this conception is presented for the provisional determination of the limits of tolerance of normal tissue together with a computerized programme elaborated for use in different therapeutic techniques.