A short time remote afterloading curietherapy system for treatment of carcinoma of the cervix using one 50 to 150 Ci 192 Ir source in newly constructed kidney shaped applicators in connection with the Gamma-Med is presented. Computer calculated and plotted symmetric and asymmetric isodoses have been drawn by a plotter, adapted to individual cases. Dosage problems and solutions respecting clinical experiences as well as radiobiological information are discussed. Short time irradiations don't offer radiobiological advantages by themselves. On the other hand, flexibility in modelling absorbed dose distributions, excellent reproducibility of applications and therefore possibility of reliable procedures in higher fractionation, and above all the possibility to avoid hospitalisation or the great majority of patients are a decisive argument in favour of the proposed system, not only from a medical and psychological point of view, but also for economic reasons.

Curium↗

PubMed1976

[Surgical and radiotherapeutic problems in the treatment of malignomas of the maxillary-sinus region].

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Humans↗

PubMed1976

[Practice of computer use in radiotherapy planning].

The main problems of radiotherapy planning are discussed with respect to use of computers now being available for a greater number of centers. One of the most essential premises is apart from clear ideas on a modern target volume concept - a sufficiently high speed in producing realistic summarized isodose contours for any radiation therapy arrangement in any individual patient's cross section outline. This problem being solved, those individual summarized isodose figures have to be critically evaluated and therefore the importance of applicable meaningful optimization criteria come into account. The properties of such criteria, which must be quantifiable, generally applicable and really relevant for judgement on quality of a plan, had to be accepted, before automatic optimization procedures could be developed; principles involved are presented. By means of a short series of examples, namely 60Co fixed field combinations with and without use of wedges, combinations of arc therapy for a number of clinical tasks. It has been pointed out, that most experienced estimate by the eye would have been by far insufficient when compared to the automized computer optimization when using such simple criteria as 1. homogeneity of absorbed dose within target volume, 2. numerically limited absorbed dose within areas of risk, 3. as low as possible radiation effects to all "outside areas". It seems to be a real danger, that so called isodose libraries, how high their merits might be estimated, may change into an "isodose bcemetery", unless we'll be successful for each individual clinical case by use of computers, which are now prepared to supply the best possible variant of the standard plan or the primary radiotherapy idea. Regular use of computers in such a way will furthermore give an incomparable documentation material.

Breast Neoplasms↗

PubMed1975

[New experiences in primary radiotherapy for vaginal carcinoma with notes on a multistage refined target volume concept].

Based on an analysis of a small new series of carcinomas of the vagina, observed in St. Georges General Hospital, Hamburg, a five year cure rate of more than 59% as a result of radiotherapy alone in 27 cases has been stated. Compared with former statistical information this effect represents a highly significant improvement. This improvement can be attributed to an individualized use of localised curie therapy. Performed with the flexible application of 127 Cs vaginal cylinders adapted to the individual anatomic extention of tumours. Apart from this individual adaption to the tumour size and site the method of curie therapy includes full utilisation of the space available within the genital tract. It is combined with a telecobalt treatment performed as a 4-axis-180 degrees-rotation directed the lateral parts of the true pelvis. The study gives a chance to discuss the target volume concept for combined radiotherapy of gynecological cancers. It is distinguished between target volumes of 1st, 2nd and 3rd order. The difficulties arising when the different components of combined radiotherapy of gynecological tumours have to be summed up, cannot easily be overcome. Further research with this field seems to be desirable.

Adult↗

PubMed1975

[The concept of target volume of radiotherapy (authors transl)].

It is emphasized to apply the prescribed target dosis not for a single point but in every case for a determined size and volume of the target. This is the target volume, wherein the ordered radiation dose should be applied. The absorbed dose within the target volune should as a rule be given as homogeneously as possible with a standard deviation not greater than +/- 10%. Application of target volume concept is discussed with regard to some special examples (nasopharynx, kidney, gynecological tumours). The target volume is a good basis for optimization of radiotherapy and development of criteria. This is also true for combination of radiotherapeutic methods in gynecological carcinomas. It is mandatory to make full use of the determination of the target volume concept for every single patient, if radiotherapy planning with or without computer has to be performed.

Abdominal Neoplasms↗

PubMed1973