Concepts of radiologic science

CONCEPTS OF RADIOLOGIC SCIENCE

April 10, 2023concepts of radiological science

























Man made radiation---60 mrem.

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Discovery of X rays


During 1870s and 1880s

Conduction of cathode rays through Crookes tube– invented by Sir William Crookes.

Crookes tube—forerunner of modern fluorescent lamps & X rays tubes.



In 1895, Wilhelm Roentgen was working in his lab in Wuzburg Germany.

Completely enclosed his Crookes tube in black photographic paper.

Barium platinocyanide coated plate

The plate glowed.


Intensity of the glow increased as plate was brought closer

Glow—fluorescence

Roentgen named the invisible light-- X light






Development of modern radiology


2 types of X ray examinations

Radiography—uses X ray films

X ray tube is mounted from ceiling on a track

X ray tube can be moved in any direction

Fixed images


Fluoroscopy

X ray tube usually located under examination table.

Moving images are provided to radiologist


X ray voltage is measured in kilovolt peak(kVp)

X ray currents are measured in milliamperes(mA)


OTHER DEVELOPMENTS

Radiographic intensifying screens—by Micheal Pupin in 1896 to reduce the exposure time.

Double emulsion films in 1904—further reduced the exp. Time.

Cellulose nitrate—substitute for glass plate

Fluoroscope—1898 by Thomas A. Edison


In 1907, H.C.Snook—a high voltage power supply—interrupterless transformer.

In 1913,William Coolidge---hot cathode x ray tube. A vacuum tube that allowed x ray intensity & energy to be selected separately & with accuracy.

Further developments…


Reports of radiation injury


The first x ray fatality– in 1904, Edison’s assistant & friend- Clarence Dally.

Suffered severe X ray burns that eventually resulted in amputataions of both arms.


In coming years—the frequency of injuries increased.

Skin damage, loss of hair and anemia.

Blood disorders; aplastic anemia and leukemia—more in radiologists.

By introduction of Coolidge tube and Snook transf. – reduction in frequency of injuries.

Basic Radiation Protection


After 1910, biologic effects of x rays were scientifically investigated & reported.

X ray workers were routinely investigated.

Provided with personnel radiation monitoring devices.

Radiation protection devices


Filtration—Al or Cu filters—low energy x rays are absorbed.

Collimation---restricts useful beam to the part of body to be imaged, reduces scatter radiation, improves image contrast.

Intensifying screens—reduce exposure to x rays by more than 95%

Protective apparel—lead impregnated material used to make aprons & gloves

Gonadal shielding—lead impregnated gonadal shields in persons of child bearing age.

Protective barriers--Radiographic control console should be located behind a protective barrier-often lead-lined & a leaded glass window.


Always practice ALARA; keep radiation exposures

As Low As Reasonably Achievable.


The Ten Commandments of Radiation Protection

1. Understand and apply the cardinal principles of radiation control: time, distance, and shielding.

2. Do not allow familiarity to result in false security.

3. Never stand in the primary beam.

4. Always wear protective apparel when not behind a protective barrier.


5. Always wear a radiation monitor and position it outside the protective apron at the collar.

6. Never hold a patient during radiographic examination. Use mechanical restraining devices when possible. Otherwise, have parents or friends hold the patient.

7. The person holding the patient must always wear a protective apron and, if possible, protective gloves.


8. Use gonadal shields on all people of childbearing age when such use will not interfere with the examination.

9. Examination of the pelvis and lower abdomen of a pregnant patient should be avoided whenever possible, especially during the first trimester.

10. Always collimate to the smallest field size appropriate for the examination.


THANKS


MCQ’s


X-rays voltage is measured in

1.milli ampere2.milli joules3.Electron volt4.Kilo volt peak


Removal of an electron from atom is

1.Radiation2.Ionization3.X-rays4.Amplification


Largest source of natural environmental radiation is

1.Cosmic rays2.Radon3.X-rays4.Potassium 40


Which of these have the longest wavelenght?

X raysMicro wavesInfra redGamma rays


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Concepts of radiologic science