Discovery of X-rays

UNIT 1: Discovery of X-rays

Late 19th century:
- Observed the behavior of discharged electrical currents through the air.
- Crooke’s Tube: A partially vacuumed tube where particles stream from the negative to the positive electrode.
- Observed cathode rays and their behavior.

Diagram or representation of Crooke's Tube, indicating its essential parts:
- Anode (P)
- Cathode (C)
- Fluorescent material (B)

Cathode rays emitted from the tube caused certain materials to glow (fluoresce), notably barium platinocyanide.
The Crooke’s tube served as a precursor to modern fluorescent lighting and CRT tubes.
It was noted that particle rays were contained within the evacuated glass tube, enhancing the need for studies in radiology.

Background:
- Roentgen was a Professor of Physics at the University of Wurzburg and became interested in the Crooke’s tube in 1894.
- Hypothesized that 'rays' could penetrate glass, remaining hidden due to the light they generated.
Roentgen's Experiment:
- Date: November 8, 1895
- Procedures:
  - Covered Crooke’s tube with black cardboard and darkened the room.
  - Placed a fluorescent screen adjacent to the tube to check for light leakage.
  - Discharged the tube, leading to the screen glowing despite a thick barrier in place.
- Notable Discoveries:
  - Cathode rays were found to only travel short distances, but the newly discovered rays could pass through solid objects, including:
  - A 1,000-page book
  - A deck of cards
  - Wood
  - Hard rubber
  - Unable to penetrate denser objects, such as lead and bone.
Photographic Plates:
- Roentgen discovered that photographic plates were responsive to the rays, leading him to capture an image of his wife, Bertha's hand.

The first known radiograph was published in 1896, featuring Mrs. Roentgen's hand, stating, "…I have seen my death!!!"
The first documented x-ray exam in America was performed on February 3, 1896, involving patient Eddie McCarthy alongside Prof. E.B. Frost and Dr. G.D. Frost.
Name Origin:
- The term 'X-ray' was adopted due to the unknown properties and characteristics of the rays.

Roentgen was awarded the first Nobel Prize in Physics in 1901 for his groundbreaking work in radiology.

Radiology: A medical specialty that utilizes x-rays, radium, and radioactive substances in the diagnosis and treatment of patients.
Diagnostic Imaging: A medical specialty involving the application of x-rays, radium, radioactive substances, sound waves, and radio frequencies (magnetic fields) for diagnostic and treatment purposes.
Radiologist: A physician skilled in applying various forms of radiation for diagnosis and treatment.
Radiographer: A skilled individual qualified through education to provide patient services using imaging modalities as directed by a qualified physician.

Radiograph: The photographic record produced by x-rays through an object.
Image: A recording of x-rays through an object, often viewed on a computer or display monitor.

Nature of X-rays:
- X-rays are a form of electromagnetic energy, which also includes:
  - White light
  - Ultraviolet
  - Infrared
  - Radio waves
  - Microwaves
Each type of electromagnetic energy has specific electrical and wave-like properties and creates magnetic fields in space due to vibrating electrons.

Definition: A photon is defined as a discrete bundle (or quantum) of electromagnetic energy.
Properties:
- Always in motion with a constant speed of light in a vacuum, represented as:
- c = 2.998 imes 10^8 ext{ m/s} (the speed of light).

The electromagnetic spectrum encompasses various forms of radiation categorized by frequency and wavelength, with gamma-rays, X-rays, ultraviolet, visible light, infrared, microwaves, and radio waves arranged from highest to lowest frequency.
Frequency and Wavelength Relation:
- The wavelength of electromagnetic waves is inversely proportional to their frequency.
Measurement Units:
- Wavelengths can be measured in meters or angstroms; 1 angstrom is equivalent to 1 imes 10^{-10} ext{ meters}.
Example from Various Waves:
- Radio: 1 imes 10^{3} ext{ m}
- Infrared: 1 imes 10^{-5} ext{ m}
- X-ray: 1 imes 10^{-10} ext{ m}

Wavelength: Defined as the distance from one crest to another or from one valley to another on the sine wave.

The shorter the wavelength, the greater the energy level.
Comparative Wavelengths:
- Radio waves: 1 imes 10^{3} ext{ m}
- Infrared: 1 imes 10^{-5} ext{ m}
- X-rays: approximately between 1 ext{ angstrom} (10^{-10} ext{ m}) to 0.1 ext{ angstrom}

Definition: Frequency is defined as the number of cycles per second, measured in Hertz (Hz). Each cycle consists of one positive and one negative alternation.
Inverse Relationship: As the wavelength increases, the frequency decreases, and vice versa.
Energy Levels: Energy levels correlate directly to frequency, with low energy corresponding to long wavelength and low frequency, and high energy related to short wavelength and high frequency.

The velocity (or speed) of all electromagnetic spectrum forms is the same:
- Speed of Light:
  - 186,000 ext{ miles/sec}
  - 3 imes 10^{8} ext{ m/sec}
  - 3 imes 10^{10} ext{ cm/sec}

Essential for grasping the principles of radiology and the properties of X-rays.