1. Radiation Sources in medicine diagnostic Radiology
Diagnostic and interventional radiology x-ray systems -
INTRODUCTION
Day 6 – Lecture 8(1)

2. Objective
To achieve an understanding of the uses of x-ray systems in diagnostic and interventional radiology.

3. 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.

4. 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).

5. 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.

6. Background 1895 : Discovery of x-rays (Röntgen), first clinical images
Diagnostic x-rays have been used in medicine since the late 19th century with steady and continual advances:
: Discovery of x-rays (Röntgen), first clinical images
1920s : Barium contrast studies
1930s : Intravenous contrast media
1940s : Angiography

7. 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.

8. 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;

9. 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.

10. 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):
Thoracic imaging.
Breast imaging.
Musculo-skeletal radiology.
Gastrointestinal radiology.
Genitourinary radiology.
Head and neck radiology.
Neuroradiology.
Cardiovascular and endovascular radiology and therapy.
Pediatric radiology.
Dental radiology.

11. Equipment used in diagnostic radiology
X-ray equipment may be designed and intended for a single purpose or for special purposes e.g.
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)

12. 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.