Computer simulation of 57Fe bleomycin auger effects in DNA

Potent candidates for Targeted Auger Therapy: Production and radiochemical considerations

Targeted Auger Therapy represents great potential for the therapy of diseases which require a high degree of selectivity on the cellular level (e.g. for therapy of metastatic cancers). Due to their high Linear Energy Transfer (LET), Auger emitters, combined with selective biological systems which enable delivery of radionuclides close to the DNA of the targeting cell, can be extremely selective and powerful treatment tools. There are two main aspects associated with the development of efficient radiopharmaceuticals based on Auger Emitters: a) the availability of suitable Auger-emitting radionuclides for therapy and b) the design of targeting vectors which can deliver Auger emitters into/close to the nucleus. In the present review, we address the first aspect by defining important parameters for the selection of radionuclides for application to Targeted Auger Therapy and form a categorized list of the most promising radionuclides, their possible production routes, and their use in the synthesis of radiopharmaceuticals.

Doses and risks from uranium are not increased significantly by interactions with natural background photon radiation

The impact of depleted uranium (DU) on human health has been the subject of much conjecture. Both the chemical and radiological aspects of its behaviour in the human body have previously been investigated in detail, with the radiological impact being assumed to be linked to the alpha decay of uranium. More recently, it has been proposed that the accumulation in tissue of high-Z materials, such as DU, may give rise to enhanced local energy deposition in the presence of natural background photon radiation due to the high photoelectric interaction cross sections of high-Z atoms. It is speculated that, in addition to producing short-range photoelectrons, these events will be followed by intense Auger and Coster-Kronig electron emission, thereby causing levels of cell damage that are unaccounted for in conventional models of radiological risk. In this study, the physical and biological bases of these claims are investigated. The potential magnitudes of any effect are evaluated and discussed, and compared with the risks from other radiological or chemical hazards. Monte Carlo calculations are performed to estimate likely energy depositions due to the presence of uranium in human tissues in photon fields: whole body doses, organ doses in anthropomorphic phantoms and nano-/micro-dosimetric scenarios are each considered. The proposal is shown generally to be based on sound physics, but overall the impact on human health is expected to be negligible.