Range and Energy Straggling in Ion Beam Transport


Book Description

A first-order approximation to the range and energy straggling of ion beams is given as a normal distribution for which the standard deviation is estimated from the fluctuations in energy loss events. The standard deviation is calculated by assuming scattering from free electrons with a long range cutoff parameter that depends on the mean excitation energy of the medium. The present formalism is derived by extrapolating Payne's formalism to low energy by systematic energy scaling and to greater depths of penetration by a second-order perturbation. Limited comparisons are made with experimental data.




HZETRN


Book Description




Technical Evaluation of the NASA Model for Cancer Risk to Astronauts Due to Space Radiation


Book Description

NASA's current missions to the International Space Station (ISS) and potential future exploration missions involving extended stays by astronauts on the lunar surface, as well as the possibility of near- Earth object (NEO) or Mars missions, present challenges in protecting astronauts from radiation risks. These risks arise from a number of sources, including solar particle events (SPEs), galactic cosmic rays (GCRs), secondary radiation from surface impacts, and even the nuclear isotope power sources transported with the astronauts. The serious early and late radiation health effects potentially posed by these exposures are equally varied, ranging from early signs of radiation sickness to cancer induction. Other possible effects include central nervous system damage, cataracts, cardiovascular damage, heritable effects, impaired wound healing, and infertility. Recent research, much of which has been sponsored by NASA, has focused on understanding and quantifying the radiation health risks posed by space radiation environments. Although many aspects of the space radiation environments are now relatively well characterized, important uncertainties still exist regarding biological effects and thus regarding the level and types of risks faced by astronauts. This report presents an evaluation of NASA's proposed space radiation cancer risk assessment model, which is described in the 2011 NASA report, Space Radiation Cancer Risk Projections and Uncertainties-2010. The evaluation in Technical Evaluation of the NASA Model for Cancer Risk to Astronauts Due to Space Radiation considers the model components, input data (for the radiation types, estimated doses, and epidemiology), and the associated uncertainties. This report also identifies gaps in NASA's current research strategy for reducing the uncertainties in cancer induction risks.




Charged Particles in Oncology


Book Description

High-energy charged particles represent a cutting-edge technique in radiation oncology. Protons and carbon ions are used in several centers all over the world for the treatment of different solid tumors. Typical indications are ocular malignancies, tumors of the base of the skull, hepatocellular carcinomas and various sarcomas. The physical characteristics of the charged particles (Bragg peak) allow sparing of much more normal tissues than it is possible using conventional X-rays, and for this reason all pediatric tumors are considered eligible for protontherapy. Ions heavier than protons also display special radiobiological characteristics, which make them effective against radioresistant and hypoxic tumors. On the other hand, protons and ions with high charge (Z) and energy (HZE particles) represent a major risk for human space exploration. The main late effect of radiation exposure is cancer induction, and at the moment the dose limits for astronauts are based on cancer mortality risk. The Mars Science Laboratory (MSL) measured the dose on the route to Mars and on the planet’s surface, suggesting that a human exploration missions will exceed the radiation risk limits. Notwithstanding many studies on carcinogenesis induced by protons and heavy ions, the risk uncertainty remains very high. In this research topic we aim at gathering the experiences and opinions of scientists dealing with high-energy charged particles either for cancer treatment or for space radiation protection. Clinical results with protons and heavy ions, as well as research in medical physics and pre-clinical radiobiology are reported. In addition, ground-based and spaceflight studies on the effects of space radiation are included in this book. Particularly relevant for space studies are the clinical results on normal tissue complications and second cancers. The eBook nicely demonstrates that particle therapy in oncology and protection of astronauts from space radiation share many common topics, and can learn from each other.