Radiotherapy treatment plan evaluation relies on an implicit estimation of the tumor control probability (TCP) and normal tissue complication probability (NTCP) arising from a given dose distribution. A potential application of radiobiological modeling to radiotherapy is the ranking of treatment plans via a more explicit determination of TCP and NTCP values. Although the limited predictive capa...

The presence of oxygen in tumours has substantial impact on treatment outcome; relative to anoxic regions, well-oxygenated cells respond better to radiotherapy by a factor 2.5–3. This increased radioresponse is known as the oxygen enhancement ratio. The oxygen effect ismost commonly explained by the oxygen fixation hypothesis, which postulates that radical-inducedDNAdamage can be permanently ‘f...

The presence of oxygen in tumours has substantial impact on treatment outcome; relative to anoxic regions, well-oxygenated cells respond better to radiotherapy by a factor 2.5–3. This increased radioresponse is known as the oxygen enhancement ratio. The oxygen effect ismost commonly explained by the oxygen fixation hypothesis, which postulates that radical-inducedDNAdamage can be permanently ‘f...

The presence of oxygen in tumours has substantial impact on treatment outcome; relative to anoxic regions, well-oxygenated cells respond better to radiotherapy by a factor 2.5–3. This increased radioresponse is known as the oxygen enhancement ratio. The oxygen effect ismost commonly explained by the oxygen fixation hypothesis, which postulates that radical-inducedDNAdamage can be permanently ‘f...

The presence of oxygen in tumours has substantial impact on treatment outcome; relative to anoxic regions, well-oxygenated cells respond better to radiotherapy by a factor 2.5–3. This increased radioresponse is known as the oxygen enhancement ratio. The oxygen effect ismost commonly explained by the oxygen fixation hypothesis, which postulates that radical-inducedDNAdamage can be permanently ‘f...

The synthesis of methotrexate (MTX) polyglutamates has been investigated in a human leukemia cell line, CCRF-CEM. An increase in either the extracellular MTX concentration (0.1-10 microM) or exposure time (4-24 h) allowed a greater accumulation of polyglutamate derivatives. The species which predominated (di-, tri-, or tetraglutamate) was also time and concentration dependent. Derivatives up to...

The presence of oxygen in tumours has substantial impact on treatment outcome; relative to anoxic regions, well-oxygenated cells respond better to radiotherapy by a factor 2.5–3. This increased radioresponse is known as the oxygen enhancement ratio. The oxygen effect ismost commonly explained by the oxygen fixation hypothesis, which postulates that radical-inducedDNAdamage can be permanently ‘f...

Microbeams are ideally suited to the study of so-called ‘non-targeted’ phenomena that are now known to occur when living cells and tissues are irradiated. Non-targeted effects are those where cells are seen to respond to ionising radiation through pathways other than direct damage to the DNA. One such phenomenon is the ‘bystander effect’; the observation that unirradiated cells can be damaged t...

The presence of oxygen in tumours has substantial impact on treatment outcome; relative to anoxic regions, well-oxygenated cells respond better to radiotherapy by a factor 2.5–3. This increased radioresponse is known as the oxygen enhancement ratio. The oxygen effect ismost commonly explained by the oxygen fixation hypothesis, which postulates that radical-inducedDNAdamage can be permanently ‘f...

The presence of oxygen in tumours has substantial impact on treatment outcome; relative to anoxic regions, well-oxygenated cells respond better to radiotherapy by a factor 2.5–3. This increased radioresponse is known as the oxygen enhancement ratio. The oxygen effect ismost commonly explained by the oxygen fixation hypothesis, which postulates that radical-inducedDNAdamage can be permanently ‘f...