Discovery of x-rays
Wilhelm Conrad Roentgen in 1895
Properties of X-rays
Clinical Use of X-rays
ALARA- 1994: As Low As Reasonably Acheivable
No such thing as a SAFE dose
When to Take X-rays
New patient or existing patient with a new complaint or an Existiing patient with **no or poor response **to treatment then:
Clinical History and Examination and Evaulation
What is the working clinical differential diagnosis or assessment?
Will radiographs help clarify or impact the Diagnosis and/or Prognosis and/or treatment?
If NO-there is no clinical need for diagnostic imaging then: NO DIAGNOSTIC IMAGING PERFORMED.
If YES-There is clinical justification for diagnostic imaging then: Do the benefits of imaging outweigh the risks to the patient? Then:
** If NO- **Then: NO DIAGNOSTIC IMAGING PERFORMED.
If YES- Then: Determine imaging modality most appropriate depending on patient presentation and differential diagnosis. Then:** DIAGNOSIS IMAGING PERFORMED**
Advanced Imaging
Producing Radiographs
Minimal equipment:
X-ray source
Image recorder (film)
Subject/patientX-ray beam travels from the source, through the subject, to the film.
Image Formation
X-ray Photons
Produced when electrons hit the target
X-ray photon interaction
X-ray photons penetrate object and are absorbed or passed through an object and strike the film
X-ray Beam
Radiographic Image
Differential Absorption
Tissue Density
Anatomic Densties
Photons in= the same amount of photons hit the tissues but only some continue through the tissues.
Bone- the least photons pass through the tissue therefore, shows up as the whitest image on the film.
Muscle- moderate amount of photons pass through the tissue therefore shows up as a gray image on the film
Air- the most photons pass through unobstructed by tissue therefore shows as the blackest image on the film.
Differential Absorption 2
Black→ Air (Lungs/ Trachea/ Outside the body)
Dark Gray→Fat ( Perirenal fat/ Fascial plane)
Gray→ Water ( Muscle/ Organs)
White/Light Gray→ Bone (Bone/ Atherosclerotic plaquing)
White→ Metal ( Filings/ Markers? Ortho devices)
X-ray Photons Passed Through
X-ray Photons Absorbed
Radiographic Densities
Image Terminology
RADIOLUCENT- Readily allowing x-rays to pass through the object to strike the film.
RADIOPAQUE- Not permitting the transmission of x-rays though the object to the film.
Positonal Terminology
PROJECTION- Most common
Projection - AP/PA
Anteroposterior / Posteroanterior (AP/PA)
-The central ray enters the patient in a:
Projection - Lateral
-Lateral
Left Lateral = Beam→Rightside →Leftside →Film
Right Lateral = Beam→Leftside→Rightside→Film
Projection-Oblique
Oblique
Left or Right
and
Anterior or Posterior
Body Postion
**Upright- **AP or PA or Lateral
**Recumbent- **Supine or Prone or Lateral
**Oblique- **Right or Left and Anterior or Posterior
**Decubitus- **Any positon in the lying posiiton