Radiation Dosimetry Instrumentation and Methods (2001)

Gad Shani

• Publisher: CRC Press
• Year: 2017
• Print ISBN: 9781138105591
• eBook ISBN: 9781351358613
• Topic: Medicine
• Subtopic: Forensic Science

Radiation dosimetry has made great progress in the last decade, mainly because radiation therapy is much more widely used. Since the first edition, many new developments have been made in the basic methods for dosimetry, i.e. ionization chambers, TLD, chemical dosimeters, and photographic films. Radiation Dosimetry: Instrumentation and Methods, Second Edition brings to the reader these latest developments. Written at a high level for medical physicists, engineers, and advanced dosimetrists, it concentrates only on evolvement during the last decade, relying on the first edition to provide the basics.

1 Introduction

CONTENTS

I. Units and Definitions

II. Absorbed Dose in Terms of Exposure and Stopping Power

III. Linear Energy Transfer

A. Dose-Equivalent Quantities

,B. Dose Equivalent

C. Ambient Dose Equivalent

D. Directional Dose Equivalent

IV. Dosimetry Methods

A. Ionization Method

B. Chemical Methods

C. Calorimetric Methods

D. Thermoluminescence Methods

V. Gamma Dosimetry

A. Point Source Dose

B. First Collision Dose

VI. Beta Dosimetry

VII. Neutron and Heavy Particles Dosimetry

A. Neutron Dosimetry

B. Heavy Particles

VIII. Biological Dosimetry

IX. Cavity Theory

References

I. Units And Definitions

The energy imparted by ionizing radiation to matter of a given mass is the fundamental quantity of radiation dosimetry. Radiation field can be described by the average number of rays (or particles) per unit area, per unit time at each point. The rays can be in a parallel beam at angle θ to the plane or moving at all directions. In the second case the examined surface should be a sphere. If the examined area is a circle with area Δα (or one quarter of the sphere area) and the number of rays crossing it at time Δt is ΔΝ, then the flux density is given by

Φ=ΔNΔaΔt⁢(1.1)

and integration over time gives the fluence

Φ=ΔNΔa⁢(1.2)

Another way to deal with a radiation field is by summing the kinetic energy of all the particles entering the sphere:

ΔE=ΣiTi⁢(1.3)

where T_i is the kinetic energy of the ith ray or particle. The intensity is given by

I=ΔEΔaΔt⁢(1.4)

If there is more than one kind of ray or particle, the flux density and the energy fluence can be calculated for each separately. If the particles (or rays) have different energies within a range, the flux density will be the integration of the distribution (or spectrum) over the energy range. When a beam of radiation encounters matter, it will be attenuated by the interaction with the matter. The attenuation can be measured by the reduction in number of rays or panicles, or by the reduction of the total beam energy.

The official units used in health physics and dosimetry are those agreed upon by the International Commission on Radiological Units and Measurements (ICRU). [1] In radiation protection the term for the linear energy transfer dependent factor is the quality factor (QF) by which absorbed doses are multiplied to obtain a quantity expression of the irradiation incurred on a common scale. The distribution factor (DF) expresses the nonuniformity effect of the irradiation. The produ...

Table of contents

• Cover Page
• Half Title
• Title Page
• Copyright Page
• Preface
• The Author
• Contents
• Chapter 1 Introduction
• Chapter 2 Theoretical Aspects of Radiation Dosimetry
• Chapter 3 Ionization Chamber Dosimetry
• Chapter 4 Thermoluminescent Dosimetry
• Chapter 5 Film Dosimetry
• Chapter 6 Calorimetry
• Chapter 7 Chemical Dosimetry
• Chapter 8 Solid-State Dosimeters
• Chapter 9 Gel Dosimetry
• Chapter 10 Neutron Dosimetry
• Index