Intro Lectures Flashcards
What is an X-ray?
a photon of electromagnetic radiation
What was the first clinical use of X-rays?
John Hall-Edwards in Jan. 1896 to visualize a needle in an associates hand
Who discovered X-rays?
Wilhelm Conrad Röntgen, called the unknown radiation x
What is your role as a medical radiation tech?
- operate x-ray equipment
- Deal with patients
- Perform radiographic procedures
What responsibilities fall under operating x-ray equipment?
- understand how it works
- set proper exposure factors for the procedure (kVp, mA, time)
- be able to troubleshoot/perform QA
What responsibilities fall under deal with patients?
- have patient change into hospital attire
- obtain patient history prior to exam
What responsibilities fall under perform radiographic procedures?
- verify that the order is correct
- direct and manipulate patient into proper positions
- ensure that only the anatomy of interest is being radiated
- be able to respond to changing patient conditions
- follow proper radiation safety protocols
- ensure that resulting image is of diagnostic quality
What is a bucky?
it has the tray for the IR, and a grid to reduce scatter radiation
need to ensure tray is lined up with tube when in use
ensure it is actually inside
What are the four types of image receptors?
solid state digital detectors: used in digital radiography
CR cassette: used in computed radiography
Fluoroscopic IR: used in fluoroscopy
Film cassette: not commonly encountered anymore
How are CR cassettes read?
must be inserted into reader after exposure
must wait for image to be created on viewer
patient may have moved during processing
What are the benefits solid state detectors?
Image available for viewing immediately, shorter processing, much easier to adjust for repeats
What is a radiograph?
An image of a patient’s anatomy created by exposing it and an image receptor to X-rays
What is fluoroscopy?
Dynamic images, the colour is inverted, allows us to view movement, demonstrates the function as well as structure
What are the causes of motion that can affect X-rays?
- heart pulsation
- chills
- peristalsis
- tremors
- spasms
- pain
- nervousness
- discomfort
- excitability
- fear
- age
- breathing
How do you control motion for X-rays?
- give the patient clear instructions
- make the patients comfortable
- use support devices
- reduce exposure time
- immobilize if necessary
What is the central ray?
the principal beam of x-rays, entered to the anatomy of interest
What is SID?
Source to image receptor distance - distance from where the x-rays are produced to the image receptor
What does the SID affect?
Magnification, detail of the image and patient dose
What are the common SID’s?
For most tabletop imaging and some Bucky - 40in or 102cm
For some Bucky - 44-48in or 112-122cm
For Bucky with a large OID or field size - 72in or 180cm
What is collimation?
restricting the beam to reduce the amount of radiation hitting the patient
Why use collimation?
safer for patient and better looking image
What are standard precautions in the lab?
- Follow proper hand hygiene IN FRONT OF THE PATIENT
- Clean equipment with alcohol after use
- Wipe down any surface that patient’s face may come into contact with
What is the NOD approach?
A way to introduce yourself to the patient by sharing your name, occupation and duty
What should you do before imagining?
- ensure proper patient ID
- obtain clinical history
- verify order
- obtain consent
- rule out pregnancy
When ruling out pregnancy what are the rules to follow?
- always ask patients of reproductive age (10-55)
- 10 day rule (within 10 days of the start of their last period is okay
- Risk vs benefit (doesn’t mean you don’t image if pregnant, ask if absolutely necessary)
What is the ALARA principle?
As low as reasonably possible
3 core concepts of this are time, distance and shielding
How to achieve ALARA?
- minimize repeats
- proper filtration
- proper collimation
- optimal IR’s
- higher kVp, lower mAs techniques when possible
- SHIELDING
When is gonadal shielding advised?
- gonads lie within or close to X-ray beam
- the patient is of reproductive age
- image will not be compromised
What should your annual dose of radiation not exceed?
<20mSv to whole-body
What is the oblique plane?
Any angle between corneal and sagittal plane
What is the cronal plane?
a vertical plane running side to side that divides the body or any of its parts into anterior and posterior
What is the sagittal plane?
a vertical plane the passes through the body dividing it or any of its parts into right and left
What is the midsagittal plane?
A plane the goes through the midline of the body dividing it equally into left and right
What is the axial or transverse plane?
horizontal plane that splits the body into top and bottom
What is the intertiliac plane?
Runs horizontally across the top of hip bones
What is the occlusal plane?
along the bottom of the top teeth
What is the anatomic position?
face-forward, with palms forward
patient facing you
anterior of the hand would be the palm and of foot is top of foot
What is anterior?
front part of the anatomy
What is ventral?
also refers to the front
- the anterior part of the hand and posterior part of the foot
What is posterior?
back part of the anatomy
What is dorsal?
also refers to the back
- the posterior part of the hand and anterior part of the foot