Different effectiveness of hyperthermia with regard to fast electrons and X-rays with different energy spectra
Creators
- 1. Goettingen Univ. (Germany, F.R.). Abt. fuer Strahlenphysik und Strahlenbiologie
Description
The synergistic enhancement of the irradiation effect by mild (40.50C) and strong (430C) hyperthermia (TER = temperature enhancement ratio) was examined for different sparsely ionizing radiation qualities (15 MeV electrons in two irradiation depths corresponding to a relative depth dose of 100% and 30%, 200-kV and 29-kV-X-rays). Hypotetraploid ( 4n ) and diploid (2n), asynchronous, exponentially growing CHO fibroblasts were used as experimental subjects. The survival in the colony test was used as criterion to assess the effect. The experiments carried out with 4n cells showed that, for the two temperatures, the TER decreases with increasing ionization density and, when applying fast electrons producing an extremely sparse ionization in an irradiation depth of 100%, the TER shows a maximum increase as compared to the more densely ionizing radiation qualities. Already when mild hyperthermia is employed, fast electrons show a TER of 1.25 which rises to about 2.25 at 430C. In case of 29-kV-X-rays, these values amount to 1 and 1.66 respectively. As to the 2n cells, the TER reaches here the double value and seems to be similarly dependent on the ionization density. (orig.)
Abstract (German)
Die synergistische Verstaerkung der Strahlenwirkung durch milde (40,50C) und starke (430C) Hyperthermie (TVF = Temperatur-Verstaerkungs-Faktor) wurde fuer verschiedene duenn ionisierende Strahlenqualitaeten untersucht (15-MeV-Elektronen in zwei Bestrahlungstiefen, entsprechend 100% und 30% relativer Tiefendosis, 200-kV- und 29-kV-Roentgenstrahlen). Als Versuchsobjekte dienten hypotetraploide ( 4n ) und diploide (2n), asynchrone, exponentiell wachsende CHO-Fibroblasten, als Wirkungskriterium das Ueberleben im Kolonietest. An den 4n-Zellen konnte gezeigt werden, dass der TVF bei beiden Temperaturen mit zunehmender Ionisationsdichte abnimmt und bei den extrem duenn ionisierenden schnellen Elektronen in der 100-%-Tiefe gegenueber den dichter ionisierenden Strahlenqualitaeten maximal erhoeht ist. Schon bei milder Hyperthermie zeigen schnelle Elektronen einen TVF von 1,25, bis 430C auf etwa 2,25 steigend, waehrend er bei 29-kV-Roentgenstrahlen 1 bzw. 1,66 betraegt. Fuer die 2n-Zellen erreicht der TVF den doppelten Wert, und es deutet sich eine vergleichbare Abhaengigkeit des TVF von der Ionisationsdichte an. (orig.)Additional details
Additional titles
- Original title (German)
- Unterschiedliche Wirksamkeit von Hyperthermie bei schnellen Elektronen und Roentgenstrahlen mit verschiedenen Energiespektren
Publishing Information
- Journal Title
- Strahlentherapie
- Journal Volume
- 157
- Journal Issue
- 8
- Series
- Strahlentherapie.
- Journal Page Range
- 544-552
- ISSN
- 0039-2073
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 13664464
- Subject category
- S63: RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; S62: RADIOLOGY AND NUCLEAR MEDICINE;
- Descriptors DEI
- BETATRONS; CELL CULTURES; DOSIMETRY; ELECTRIC POTENTIAL; ELECTRON BEAMS; FIBROBLASTS; HARD X RADIATION; HEAT TREATMENTS; LET; MEV RANGE 10-100; PHANTOMS; RADIATION INJURIES; RADIATION QUALITY; RADIOSENSITIZERS; SOFT X RADIATION; SURVIVAL CURVES; WATER
- Descriptors DEC
- ACCELERATORS; ANIMAL CELLS; BEAMS; BIOLOGICAL EFFECTS; BIOLOGICAL RADIATION EFFECTS; CONNECTIVE TISSUE CELLS; CYCLIC ACCELERATORS; DISEASES; DRUGS; ELECTROMAGNETIC RADIATION; ENERGY RANGE; ENERGY TRANSFER; HYDROGEN COMPOUNDS; INJURIES; IONIZING RADIATIONS; LEPTON BEAMS; MEV RANGE; MOCKUP; OXYGEN COMPOUNDS; PARTICLE BEAMS; RADIATION EFFECTS; RADIATIONS; RESPONSE MODIFYING FACTORS; SOMATIC CELLS; STRUCTURAL MODELS; X RADIATION