Comparison of range of α (red) and β− (white) particles
The primary advantage ofalpha particle (α) emitters over other types of radioactive sources is their very highlinear energy transfer (LET) andrelative biological effectiveness (RBE).[5]Beta particle (β) emitters such asyttrium-90 can travel considerable distances beyond the immediate tissue before depositing their energy, while alpha particles deposit their energy in 70–100 μm long tracks.[6]
Alpha particles are more likely than other types of radiation to causedouble-strand breaks to DNA molecules, which is one of several effective causes ofcell death.[7][8]
Some α emitting isotopes such as225Ac and213Bi are only available in limited quantities from229Th decay, althoughcyclotron production is feasible.[9][10][11] Among alpha-emitting radiometals according to availability, chelation chemistry, and half-life,212Pb is also a promising candidate for targeted alpha-therapy.[12][13]
The ARRONAX cyclotron can produce211At by irradiation of209Bi.[14][9]
Though many α-emitters exist, useful isotopes would have a sufficient energy to cause damage to cancer cells, and ahalf-life that is long enough to provide a therapeuticdose without remaining long enough to damage healthy tissue.
Several radionuclides have been studied for use inimmunotherapy. Though β-emitters are more popular, in part due to their availability, trials have taken place involving225Ac,211At,212Pb and213Bi.[9]
The shortpath length of alpha particles in tissue, which makes them well suited to treatment of the above types of disease, is a negative when it comes to treatment of larger bodies ofsolid tumour by intravenous injection.[20][21] Potential methods to solve this problem of delivery exist, such as direct intratumoral injection[22] andanti-angiogenic drugs.[23][3] Limited treatment experience of low grade malignantgliomas has shown possible efficacy.[24]
^abSeidl, Christof; Senekowitsch-Schmidtke, Reingard (2011). "Targeted Alpha Particle Therapy of Peritoneal Carcinomas". In Baum, Richard P. (ed.).Therapeutic nuclear medicine. Berlin: Springer. pp. 557–567.doi:10.1007/174_2012_678.ISBN978-3-540-36718-5.
^Kane, Suzanne Amador (2003).Introduction to physics in modern medicine (Repr. ed.). London: Taylor & Francis. p. 243.ISBN9780415299633.
^Baum, Richard P (2014).Therapeutic Nuclear Medicine. Heidelberg: Springer. p. 98.ISBN9783540367192.
^Hodgkins, Paul S.; O'Neill, Peter; Stevens, David; Fairman, Micaela P. (December 1996). "The Severity of Alpha-Particle-Induced DNA Damage Is Revealed by Exposure to Cell-Free Extracts".Radiation Research.146 (6):660–7.Bibcode:1996RadR..146..660H.doi:10.2307/3579382.JSTOR3579382.PMID8955716.
^abcSeidl, Christof (April 2014). "Radioimmunotherapy with α-particle-emitting radionuclides".Immunotherapy.6 (4):431–458.doi:10.2217/imt.14.16.PMID24815783.
^Huang, Chen-Yu; Pourgholami, Mohammad H.; Allen, Barry J. (November 2012). "Optimizing radioimmunoconjugate delivery in the treatment of solid tumor".Cancer Treatment Reviews.38 (7):854–860.doi:10.1016/j.ctrv.2011.12.005.PMID22226242.
^Cordier, Dominik; Krolicki, Leszek; Morgenstern, Alfred; Merlo, Adrian (May 2016). "Targeted Radiolabeled Compounds in Glioma Therapy".Seminars in Nuclear Medicine.46 (3):243–249.doi:10.1053/j.semnuclmed.2016.01.009.PMID27067505.
