Ultra-high dose rate radiotherapy with electrons and protons has shown potential for cancer treatment by effectively targeting tumors while sparing healthy tissues (FLASH effect). This study aimed to investigate the potential FLASH sparing effect of ultra-high-dose rate helium ion irradiation, focusing on acute brain injury and subcutaneous tumor response in a preclinical in vivo setting. Raster-scanned helium ion beams were used to compare the effects of standard dose rate (SDR at 0.
View Article and Find Full Text PDFBackground And Purpose: In carbon ion radiotherapy (CIRT), different relative biological effectiveness (RBE) models have been used for calculating RBE-weighted dose (D). Conversion between current RBE predictions and introduction of novel approaches remains a challenging task. Our aim is to introduce a framework considering multiple RBE models simultaneously during CIRT plan optimization, easing the translation between D prescriptions.
View Article and Find Full Text PDFBackground: Clinical carbon ion beams offer the potential to overcome hypoxia-induced radioresistance in pancreatic tumors, due to their high dose-averaged Linear Energy Transfer (LETd), as previous studies have linked a minimum LETd within the tumor to improved local control. Current clinical practices at the Heidelberg Ion-Beam Therapy Center (HIT), which use two posterior beams, do not fully exploit the LETd advantage of carbon ions, as the high LETd is primarily focused on the beams' distal edges. Different LETd-boosting strategies, such as Spot-scanning Hadron Arc (SHArc), could enhance LETd distribution by concentrating high-LETd values in potential hypoxic tumor cores while sparing organs at risk.
View Article and Find Full Text PDFBackground: The role of radiolytic oxygen consumption for the in-vitro "Ultra-High Dose Rate" (UHDR) sparing and in-vivo FLASH effect is subject to active debate, but data on key dependencies such as the radiation quality are lacking.
Purpose: The influence of "dose-averaged Linear Energy Transfer" (LETd) and dose rate on radiolytic oxygen consumption was investigated by monitoring the oxygen concentration during irradiation with electrons, protons, helium, carbon, and oxygen ions at UHDR and "Standard Dose Rates" (SDR).
Methods: Sealed "Bovine Serum Albumin" (BSA) 5% samples were exposed to 15 Gy of electrons and protons, and for the first time helium, carbon, and oxygen ions with LETd values of 1, 5.