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J Swyngedauw

Publications and source records attributed to J Swyngedauw.

At least 19 recordsLinked to original sources
PubMed1976

[Radiotherapy for carcinoma of the cervix by intermittent sessions with deferred loading using Cobalt 60 or Caesium 137 (author's transl)].

Fractioning in gynaecological radiotherapy is a tolerance factor which may usefully be exploited in after loading. The advantage of fractioning is that it makes it possible to considerably increase the output of the projection apparatus (Curietron) and to avoid protection of the rooms : the patient retains the applicator in situ during the hospital stay and her bed is simply taken into the protected application room. With a source of 1 to 1.5 curie of cobalt, the author proposes twice-daily sessions of around ten minutes for ten days. Treatment may easily be given in the cobaltotherapy chamber. Using Caesium, it is necessary to protect only one room with a virtually two-fold increase in output since 10 to 12 hour treatments, either by day or by night, may be given. This very supple schedule makes it possible to modify dose and tolerance in relation to clinical conditions and the method of treatment (combined radiotherapy and surgery or radiotherapy alone). As far as axial vaginal source introducer is concerned, it is of prove, effectiveness as well as being easy to use. After describing the applicator, the source-carrier and the isodoses, the authors reviews the different methods of application, relying upon two previous studies of the influence of fractioning and protraction on tolerance (J. SWYNGEDAUW, 1975 and 1976).

Cesium Radioisotopes↗
PubMed1976

[T.D.F. (time-dose-fractioned irradiation) and tolerance to low flow and low fractioned irradiation (author's transl)].

1. The factor (T.D.F.) defined by ORTON and ELLIS for regularly distributed discontinuous irrdiation may be dissociated from Ellis' equation. The essential fact is that, in principle, the T.D.F. is given as 100 for all techniques which are associated with full tolerance or, if desired, exact saturation of the normal supporting tissue. 2. From this standpoint, all techniques in which T.D.F. = 100 have the same effectiveness as the N.S.D., i.e. 1,800 Rads given at a flow of approximately 10 Rads per minute. A TD.F. greater or less than 100 should be considered as evaluating the effective dose as a percentage of the N.S.D. The total dose administered effectively as a percentage of N.S.D., Dt/18 represents by contrast the actual dose. 3. With discontinuous treatment of 50 or 100 Rads/minute, the ratio effective dose over actual dose = T.D.F. 18/Dt represents the coefficient of reduction in effectiveness due to fractioning. Crf (the T.D.F. of which is given in the tables of Orton and Ellis). In the case of continuous uninterrupted treatment, the coefficient of reduction of effectiveness by protraction Crp is calculated using Orton's equation. With treatment given on an interrupted basis (split) the reduction in effectiveness Crs is calculated on the basis of the appendix ratio of Orton and Ellis. 4. In low flow rate, low fractioned treatment, in interrupted sections, the overall coefficient of reduction of effectiveness equals the product of the three mentioned above: Crg = Crf-Crp-Crs. 5. Dissociation of the T.D.F. factors from Ellis' equation makes it possible to generalise its principle and to extend it to all normal tissue (kidney, lung, intestine, marrow), the T.D.F. of which represents that state in which radiolesions are maximally compatible with reversibility, in the immediate or in the shortest possible time. It would be theoretically possible, using a suitable experimental technique, to develop, for each of these particularly senstive organs, tables analogous to those provided by ORTON and ELLIS for supporting tissue in conditions which seem acceptable to many.

Cobalt Radioisotopes↗
PubMed1975

[Dose of tissue tolerance, dose of tumour sterilisation in continuous and discontinuous irradiation (author's transl)].

In the radiotherapy of cancer, two conditions are necessary:-- 1 degree sterilisation of the tumor; 2 degrees safeguard of surrounding tissues. In discontinuous irradiation, sterilisation depends on the administration of a certain tumour-dose within a suitable period or number of sessions. At the rate of 5 sessions weekly, the following dose-number law may be formulated (ELLIS): DT = 2,500.N0,22. Perfect tolerance of the connective tissue is in fact obtained if the total dose is equal or less than: N.S.D..N0,24.T0,11. The nominal standard dose of ELLIS, is a limiting dose of about 1,800 rads. ORTON and ELLIS have published tables which permit one to obtain, without an index of saturation of the supporting tissue by means of a series of double entry tables corresponding each to a frequency of 1, 2, 3, 4, 5 sessions per week. Each table provides the T.D.F. factor in relation to the number of sessions and the elementary dose. The T.D.F. factor is about 100 whatever the periodicity, and whatever the subdivisions of the dose when ELLIS' equation is satisfied, i.e. when one is at the limit of tolerance. Furthermore, the T.D.F. factor of two parts, of treatment under various regimens may be added together. It is sufficient for the sum to be equal to 100 to ensure full tolerance, which eliminates all difficulty of manipulation of a fractionated formula. The conditions of obtention of continuous irradiation do not permit one to separate the doses of sterilisation and tolerance, as was the case with discontinuous irradiation but, generally speaking, both in continuous and discontinuous administration the shorter the period of treatment the more the sterilising dose exceeds the tolerance dose, whereas with very small tumours, one may obtain tumour sterilisation within the limits of tolerance of the supporting tissues. For very large or radio-resistant tumours, one may have to, in order to obtain sterilisation, exceed more or less the perfect tolerance defined by T.D.F. 100 or its equivalent using ELLIS' equation. The latter is, moreover, only an approximation : the effective tolerance, if one takes into consideration late fibrosis, is very much less than that defined by T.D.F. 100, in particular for high partial dose irradiations. The author insists, after others, on the absolute necessity of taking into consideration the time factor as defined by ELLIS' relationship recalled above. There is no sense in obtaining strict physical dose measurement if one does not also take into consideration the time factor, the biological importance of which is considerable.

Animals↗
PubMed1972

[Toxic adenomas].

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Goiter, Nodular↗