부산대학교 도서관

• We investigated the impact of organ motion on the effectiveness of hypoxia-guided proton therapy in lung cancer patients. • Large motion amplitude, especially together with increased dose escalation, was associated with a reduction of target coverage and dose homogeneity. • TCP benefits from dose escalation outweigh motion-induced TCP losses. • Large NTCP benefits for lungs, heart and oesophagus were found for escalated proton plans, even compared to photon plans. • Respiratory gating in combination with rescanning is the recommended strategy should motion mitigation be necessary. To investigate the impact of organ motion on hypoxia-guided proton therapy treatments for non-small cell lung cancer (NSCLC) patients. Hypoxia PET and 4D imaging data of six NSCLC patients were used to simulate hypoxia-guided proton therapy with different motion mitigation strategies including rescanning, breath-hold, respiratory gating and tumour tracking. Motion-induced dose degradation was estimated for treatment plans with dose painting of hypoxic tumour sub-volumes at escalated dose levels. Tumour control probability (TCP) and dosimetry indices were assessed to weigh the clinical benefit of dose escalation and motion mitigation. In addition, the difference in normal tissue complication probability (NTCP) between escalated proton and photon VMAT treatments has been assessed. Motion-induced dose degradation was found for target coverage (CTV V 95% up to −4%) and quality of the dose-escalation-by-contour (Q RMS up to 6%) as a function of motion amplitude and amount of dose escalation. The TCP benefit coming from dose escalation (+4–13%) outweighs the motion-induced losses (<2%). Significant average NTCP reductions of dose-escalated proton plans were found for lungs (−14%), oesophagus (−10%) and heart (−16%) compared to conventional VMAT plans. The best plan dosimetry was obtained with breath hold and respiratory gating with rescanning. NSCLC affected by hypoxia appears to be a prime target for proton therapy which, by dose-escalation, allows to mitigate hypoxia-induced radio-resistance despite the sensitivity to organ motion. Furthermore, substantial reduction in normal tissue toxicity can be expected compared to conventional VMAT. Accessibility and standardization of hypoxia imaging and clinical trials are necessary to confirm these findings in a clinical setting. [ABSTRACT FROM AUTHOR]