Rad Tech's Guide to Radiation Protection

Euclid Seeram

• Éditeur: Wiley-Blackwell
• Année: 2019
• ISBN:
  9781119640905
• Édition: 2
• Sujet: Medicine
• Sous-sujet: Medical Technology & Supplies

Radiation protection is a core element of radiologic technology programmes and daily practice alike. Rad Tech's Guide to Radiation Protection is a comprehensive yet compact guide designed to illuminate the extensive field of radiation protection for technologists, trainees, and radiology students. Organised into ten digestible chapters, the second edition of this popular book provides new discussions of dose factors in computed tomography, the debate concerning the use of the LNT model, Diagnostic Reference Levels (DRLs), dose optimization, and more.

Written by a recognised expert in medical radiation sciences, this valuable guide:

• Helps students and technologists acquire the skills required to protect patients, personnel, and members of the public in the radiology department
• Reflects the most current standards for radiation protection, with references to relevant organisations and resources
• Covers basic radiobiology, sources of radiation exposure, dose management regulations and optimization, and more
• Presents essential information in a bulleted, easy-to-reference format

Rad Tech's Guide to Radiation Protection is a must-have resource for student radiographers and radiology technologists, particularly those preparing for the American Registry of Radiation Technologist (ARRT) exams.

1
Nature and Scope of Radiation Protection

Chapter at a Glance

• What is Radiation Protection?
• Scope of Radiation Protection
• Diagnostic Radiology Modalities
• Why Protect Patients and Personnel in Diagnostic Radiology?
• Framework for Radiation Protection
  • Radiation Protection Principles
  • Radiation Protection Actions
• Basic Schemes for Patient Exposure in Digital Radiography, Fluoroscopy, and Computed Tomography
  • Digital Radiography
  • Fluoroscopy
  • Computed Tomography
• Factors Affecting Dose in Diagnostic Radiology
  • Radiographic Factors
  • Fluoroscopic Factors
  • Computed Tomography Factors
• Dose Management Techniques
• Pregnancy: Radiation Protection Considerations

Radiation protection is one of the most important subjects in the education and practice of medical imaging technologies using ionizing radiation, because it deals with the safe use of ionizing radiation when imaging patients for the purpose of restoring their health.

The purpose of this chapter is to orient both students and practicing technologists to the nature and scope of radiation protection specifically in diagnostic x‐ray imaging (radiography/radiology) and to provide a brief overview of topics essential to the theory and practice of radiography.

What is Radiation Protection?

Radiation protection is concerned with the protection of persons from the harmful effects of exposure to radiation. In radiography/radiology radiation protection deals with the protection of patients and operators, as well as members of the public. Why?

• Patients are exposed to varying amounts of radiation from the x‐ray tube, depending on the type of examination.
• Personnel may be exposed to radiation scattered from the patient and the equipment.
• Members of the public, in this instance, are individuals who are working or waiting in close proximity to an x‐ray room. These include, for example, radiology support staff and family members of patients.

Scope of Radiation Protection

The scope of radiation protection includes knowledge and understanding of the following:

• Physical factors. These are related to the physics of radiation, including energy dissipation in matter, characteristics of radiation, interaction of radiation with matter, and the physical and chemical factors of radiation.
• Technical factors. These include a range of topics such as technical components of imaging systems that affect dose, standards of radiation protection, dose management techniques, and shielding considerations.
• Procedural factors. These relate to personnel practices during the examination and include such tasks as equipment set‐up, patient communication and positioning, selection of technical factors, gonadal shielding, image processing, and image assessment.
• Biologic factors. The biologic effects of radiation result from the physical and chemical interaction of radiation with matter (tissue). Bioeffects can be somatic (effects that appear in the individual exposed to radiation) or they can be genetic (effects that appear in the offspring of the individual exposed). Bioeffects are now classified as stochastic and deterministic (nonstochastic) effects. These are described further in Chapter 3.

Diagnostic Radiology Modalities

The diagnostic radiology modalities that are described in this book are digital radiography, fluoroscopy, and computed tomography (CT). The basic approaches to exposing a patient to the radiation beam during imaging, depend on the beam geometry. These approaches are described in brief later in the chapter.

Why Protect Patients and Personnel in Diagnostic Radiology?

There are several major reasons for protecting patients undergoing radiographic examination as well as for protecting the personnel conducting the examination. These reasons include:

• Biologic effects data demonstrate beyond question that radiation exposure is harmful to humans.
• Patients receive more radiation exposure from diagnostic radiology compared with any other man‐made radiation sources.
• No dose of radiation is considered safe (there is no risk‐free dose of radiation).
• Various research studies reveal that some diagnostic x‐ray examinations, particularly involving fluoroscopy and CT, deliver high doses of radiation to patients.
• Technologists assume full responsibility for all aspects of the radiographic examination, including radiation exposure of the patient. Protection of patients and operators (technologists and radiologists) depends on the technical expertise of both the technologist and the radiologist.
• Radiation safety is guided by several principles and actions set forth by the International Commission on Radiological Protection (ICRP); these are meant to keep all exposures as low as reasonably achievable (ALARA).

Framework for Radiation Protection

A framework refers to a supporting structure or a basic system. A radiation protection framework includes a number of concepts intended to prevent and minimize the harmful effects of radiation...