42 Result(s)
within
Chapter
Indra J Das
-
Chapter
Interactions of Electromagnetic Radiation with Matter
Photons are a type of boson that carries electromagnetic energy. They have no charge and are therefore an indirectly ionizing particle. At lower energies, they predominantly interact with matter through cohere...
-
Chapter
Oxygen Effect, Relative Biological Effectiveness, and Linear Energy Transfer
Oxygen is one of the most effective dose-modifying agents. Oxygen causes “fixation” of radiation-induced DNA damage. The oxygen enhancement ratio (OER) is equal to the ratio of doses of radiation (hypoxic over...
-
Chapter
Quantification and Measurement of Dose
Radiation dosimetry is based on exposure defined as C/kg (Roentgen). The energy transferred by photons to a medium is called KERMA, and the subsequent absorption of energy in a medium is quantified as dose, me...
-
Chapter
Tumor Microenvironment
Tumor growth is frequently limited by oxygen supply. Tumor cells may be chronically hypoxic if they are too far away from blood vessels or transiently hypoxic if a blood vessel is temporarily blocked. Tumors s...
-
Chapter
Therapeutic Ratio
The objective of radiation therapy is to control tumors without causing excessive normal tissue toxicity. Predictive models may be used to compute tumor control probabilities (TCP) as well as normal tissue com...
-
Chapter
Dosimetry of Photon Beams in Water
The purpose of dose calculations is to determine how many monitor units are required to deliver a desired dose. The formulae and techniques in this chapter provide several methods for calculating monitor units...
-
Chapter
Acute Effects of Total Body Irradiation (TBI)
Total body irradiation (TBI) effects depend on the dose and the time that elapses between the irradiation and when one observes the effects in various organ and tissue systems which in turn depends on the life...
-
Chapter
Biology of Brachytherapy, Particle Therapy, and Alternative Radiation Modalities
Most radiation therapy is delivered by linear accelerators capable of photon and electron irradiation. However, alternative modalities may have advantages in some clinical situations. Brachytherapy is radiatio...
-
Chapter
Stochastic, Deterministic, and Heritable Effects (and Some Radiation Protection Basics)
Radiation carcinogenesis is considered a stochastic effect, and is modeled by the linear no-threshold (LNT) model. The excess risk of dying from a radiation-related cancer (above the natural baseline) is based...
-
Chapter
Physics and Dosimetry of Brachytherapy
Radium brachytherapy is the oldest form of radiation therapy. In the modern era, many different nuclides and devices are used for brachytherapy. The properties of a sealed source vary with encapsulation. Sourc...
-
Chapter
Linac Quality Assurance
Quality assurance is designed to ensure that radiation is delivered correctly. AAPM TG-40 and TG-142 recommendations set a standard of practice for radiation oncology practices. Machine characteristics are mea...
-
Chapter
Quality Management Program
The Nuclear Regulatory Commission (NRC) is responsible for regulating nuclear material, including any nuclides used in brachytherapy. All medical sources are classified as nuclear byproduct material. The use o...
-
Chapter
Atomic and Nuclear Structure
The nucleus is the core of the atom and is made up of several nucleons called protons and neutrons that are held together by strong force but also have tension to fall apart by coulombic forces exerted by the ...
-
Chapter
MRI-Linear Accelerator (MRL)
MRI-Linac is a new device that combines an MRI unit and a 6 MV linear accelerator (on a single circular gantry) very similar to a tomotherapy unit for image-guided and adaptive therapy. It uses MRI for plannin...
-
Chapter
Molecular Mechanisms of DNA Damage and Repair
There are many types of lesions that may be induced in DNA by ionizing radiation. Radiation creates ion pairs in water. If clusters of ionization are formed near DNA, they can potentially damage the DNA. Norma...
-
Chapter
Production and Properties of Radiation
Electromagnetic radiation is used in radiation therapy for its unique properties and relative ease of production compared to other forms of particle radiation. Particles are directly ionizing while electromagn...
-
Chapter
Molecular Biology and Signaling
The target of radiation for the purpose of therapy is the DNA. DNA is made up of sugars, phosphates, and bases and will form superstructures with other proteins to form chromosomes, which can be viewed under a...
-
Chapter
Radiation Survival Models, SLD, PLD, and Dose Rate
Post-irradiation cell survival as a function of radiation dose can be biophysically modeled in several different ways, using Poisson statistics as the basis for survival equations. The single-hit, multitarget ...
-
Chapter
Interactions of Particulate Radiation with Matter
Particle radiation includes electrons, protons, neutrons, heavy nuclei (including alpha particles), and mesons but does NOT include photons for the purpose of describing particle radiotherapy. Particles can be...
-
Chapter and Conference Paper
Factors Affecting Accuracy in Proton Therapy
Introduction: To examine the various processes involved and to assess their effects on the accuracy of proton therapy. Materials and methods: Proton therapy involves several processes: (1) Beam commissioning. ...
