AlphaGlue: A Novel Conceptual Delivery Method for α Therapy

Extensive research is being carried out on the application of α particles for cancer treatment. A key challenge in α therapy is how to deliver the α emitters to the tumour. In AlphaGlue, a novel treatment delivery concept, the α emitters are suspended in a thin layer of glue that is put on top of the tumour. In principle, this should be an easy and safe way to apply α therapy. In this study, the effectiveness of AlphaGlue is evaluated using GEANT4 and GEANT4-DNA simulations to calculate the DNA damage as a function of depth. Two radionuclides are considered in this work, 211At and 224Ra. The results indicate that, as a concept, the method offers a promising hypothesis for treating superficial tumours, such as skin cancer, when 224Ra is applied directly on the tissue and stabilized with a glue layer. This results in 2×10−5 complex double strand breaks and 5×10−5 double strand breaks at 5 mm depth per applied 224Ra atom. When applying a 224Ra atom concentration of (4.35±0.2)×1011/cm2 corresponding to an activity of (21.8±1)μCi/cm2 on the skin surface, the RBE weighted dose exceeds 20 Gy at 5 mm depth. Hence, there is significant cell death at 5 mm into the tissue; a depth matching clinical requirements for skin cancer treatment. Given the rapidly falling weighted dose versus depth curve, the treatment depth can be tuned with good precision. The results of this study show that AlphaGlue is a promosing treatment and open the pathway towards the next stage of the research, which includes in-vitro studies.