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Klinisk strålebiologi - normalvev

Klinisk strålebiologi - normalvev. Tidlig reaksjon. Sen reaksjon. teleangiectasi. Basis for dose-respons-kurver. Stigetallet for dose-responskurven. Gaussian distribution of radiation sensitivity. Gaussian distribution of technical and dosimetrical factors.

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Klinisk strålebiologi - normalvev

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  1. Klinisk strålebiologi - normalvev

  2. Tidlig reaksjon

  3. Sen reaksjon teleangiectasi

  4. Basis for dose-respons-kurver

  5. Stigetallet for dose-responskurven

  6. Gaussian distribution of radiation sensitivity Gaussian distribution of technical and dosimetrical factors Uniquely described by two parameters: - gradient at 50% response level D50% - dose to achieve 50% response biolo > clin Dose response curve Clinical dose response curve Pettersen M et al Radiotherapy and Oncology 2008

  7. Uniquely described by two parameters: - gradient at 50% response level D50% - dose to achieve 50% response   is linked to the standard deviation, , of the Gaussian distribution by:  and Pettersen M et al Radiotherapy and Oncology 2008

  8. Steepness of clinical dose-response curve is depending of the dose variation Pettersen M et al Radiotherapy and Oncology 2008 Roué et al 2004 ESTRO-Equal external audit 102 centres, 235 beams in France 3% beams had deviations >  5% 24 centres had deviations >  5%

  9. Design of a randomised clinical study • The null hypothesis is that the two treatment options produce no different outcome • To prove a difference, the null hypothesis has to be rejected • The numberof patients needed is linked to , the difference in response (R), the level of significance () and the power ()  = 0.2  = 0.05 Pettersen M et al Radiotherapy and Oncology 2008

  10. The number of patients required Conclusions: To keep the number of patients required for RCT as low as possible, the standard deviation of the dosimetry should be kept below 5%.

  11. Volumeffet for rektumblødning

  12. Strandqvist plot

  13. a-kill b-kill LQ-formelverket

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