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Radiation Sources in medicine
diagnostic Radiology
Diagnostic and interventional
radiology x-ray systems INTRODUCTION
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International Atomic Energy Agency
Day 6 – Lecture 8(1)
Objective
To achieve an understanding of the uses of x-ray systems
in diagnostic and interventional radiology.
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Contents
• The clinical objectives of diagnostic and interventional
radiology.
• An overview of some of the terminology used in
diagnostic and interventional radiology.
• An overview of the various types of equipment used.
• Introduction to radiation doses in diagnostic and
interventional radiology.
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Clinical Objectives of Radiology
• The purpose of diagnostic radiology is to provide clinical
images of human body structures using the information
given by the attenuation of an x-ray beam through the
examined region.
• All radiological equipment comprises an x-ray source
(x-ray tube and generator) and an image receptor
(e.g. x-ray film / intensifying screens, electronic image
intensifiers, digital image receptors, etc).
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Clinical Objectives of Radiology (cont)
•
Continuing advances in technology have led to the
development and routine use of extensive and elaborate
x-ray procedures particularly for interventional therapies.
•
Medical x-ray exposures constitute the greatest source of
human exposures to artificial sources of ionizing radiation.
•
With the large (and apparently increasing) number of people
undergoing medical x-ray procedures, it is essential that
high standards of safety are maintained to minimize
unnecessary radiation exposure to patients.
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Background
Diagnostic x-rays have been used in medicine since
the late 19th century with steady and continual
advances:
1895 : Discovery of x-rays (Röntgen), first clinical
images
1920s : Barium contrast studies
1930s : Intravenous contrast media
1940s : Angiography
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Background (cont)
1950s : Fluoroscopic image intensifiers / catheterization
techniques.
1960s : Early work on rare-earth intensifying screens.
1970s : Computed Tomography (CT).
1990s : Interventional radiological techniques; helical and
multi-slice scanners.
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Diagnostic Radiology
Diagnostic Radiology involves the exposure of:
• patients as part of their own medical diagnosis or
treatment;
• individuals as part of occupational health
surveillance;
• individuals as part of health screening programs;
• voluntary participants in research programs;
• individuals as part of medico-legal procedures;
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Common Diagnostic Radiology procedures
The most common radiological procedures comprise
diagnostic and therapeutic (interventional) procedures
performed on symptomatic patients with specific clinical
indications.
•
Where practicable, procedures should be performed in
radiology departments by specialized and trained
practitioners using equipment appropriate to the procedure
undertaken.
•
The use of x-ray equipment by medical practitioners or
other persons without relevant radiographic (or radiological)
and radiation safety training should not be permitted.
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Types of Procedures
Medical imaging can involve a range of specialties depending on
the part of the body to be examined and the pathology under
investigation (e.g. cardiologists, vascular surgeons,
gynaecologists, urologists, etc):
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Thoracic imaging.
Breast imaging.
Musculo-skeletal radiology.
Gastrointestinal radiology.
Genitourinary radiology.
Head and neck radiology.
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Neuroradiology.
Cardiovascular and
endovascular radiology and
therapy.
Pediatric radiology.
Dental radiology.
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Equipment used in diagnostic radiology
X-ray equipment may be designed and intended for a single purpose
or for special purposes e.g.
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General purpose radiography.
General purpose fluoroscopy.
Dedicated fluoroscopy equipment for interventional radiology
procedures.
Computed tomography (CT).
Mammography .
Pediatrics.
Dental radiography.
(Note: These types of radiology x-ray systems will be discussed
one by one in detail in the following presentations)
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Radiation doses in diagnostic and
interventional radiology
•
Medical practitioners should justify the benefits an x-ray procedure
will produce against the radiation detriment.
•
All patient doses from radiological purposes (other than
radiotherapy) shall be kept as low as reasonably achievable
consistent with obtaining the required diagnostic information, taking
into account economic and social factors.
•
Doses should be compared to acceptable guidance levels and
optimized by ensuring proper performance of the x-ray equipment
and film processors, by using the fastest practicable imaging
systems (commensurate with the required image quality) and by
restricting use only to properly trained persons.
•
Dose limits do not apply to the radiation exposure of patients
because the decision to use radiation is meant to be justified
according to each patient’s situation.
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