Maharashtra HSC Radiology Technician (Vocational) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Bremsstrahlung radiation

Continuous X-ray spectrum produced when electrons decelerate in the anode target; maximum photon energy equals the applied kVp, and intensity rises with kVp squared.

Line-focus principle

The anode is bevelled so the effective focal spot is smaller than the actual focal spot, improving spatial resolution while spreading heat over a larger target area.

Total filtration

Sum of inherent and added filtration in the X-ray tube assembly; it removes low-energy photons, hardens the beam, and reduces patient skin dose.

Inverse square law

Radiation intensity is inversely proportional to the square of the distance from a point source; doubling the distance reduces the dose rate to one quarter.

PA chest projection

Posteroanterior projection of the chest at about 180 cm focus-to-receptor distance; it reduces cardiac magnification and scapular overlap compared with AP.

Frog-leg lateral hip

Lateral projection of the hip with the patient supine, knees flexed, and hips abducted about 45 degrees; it demonstrates the femoral neck and head.

Open-mouth odontoid view

AP projection of the upper cervical spine taken through the open mouth to show C1 and C2, including the dens and lateral masses of the atlas.

Two-view rule

At least two orthogonal projections at 90 degrees are required for suspected fractures, because a single view can miss displacement or a fracture line.

Hurter-Driffield curve

Characteristic curve plotting optical density against log relative exposure; the straight-line portion indicates contrast, and toe and shoulder indicate under- and overexposure.

Optical density

Logarithm of the ratio of incident to transmitted light; a density of 1.0 transmits 10 percent of light, and 2.0 transmits 1 percent.

Photostimulable phosphor plate

Computed radiography receptor that stores X-ray energy in metastable electron traps; a scanning laser releases blue light read by a photomultiplier tube.

Window width and level

Display settings in digital radiography; window width controls contrast and window level controls brightness of the image on the monitor.

Safelight test

Quality control test using a coin on a pre-exposed film; a visible coin shadow after development indicates unsafe safelight or excessive darkroom fog.

Developer temperature

Manual processing standard of about 20 to 22 degrees Celsius; each 1 degree rise requires roughly a 10 percent reduction in development time.

Sensitometer and densitometer

Sensitometer exposes a step wedge on film; densitometer measures optical density of each step to produce a processor control chart for quality assurance.

Pi-line artifact

Black line on a radiograph caused by a crack or scratch in the intensifying screen or cassette; it indicates the screen must be replaced.

ALARA principle

As Low As Reasonably Achievable; all exposures must be optimized so patient and staff doses are kept below dose limits and as low as practical.

Occupational dose limit

Effective dose of 20 mSv per year averaged over five years, with no single year exceeding 50 mSv; the eye lens limit is 20 mSv per year.

Thermoluminescent dosimeter

Personal monitor using lithium fluoride; absorbed radiation is stored and released as light when heated, giving a measure of cumulative dose.

Lead apron equivalence

A 0.25 mm lead-equivalent apron attenuates about 90 percent of diagnostic X-rays; 0.35 mm gives greater protection and aprons are checked annually for cracks.

Femoral neck-shaft angle

In adults the angle between the femoral neck and shaft is about 125 degrees; a reduced angle indicates coxa vara and an increased angle coxa valga.

Radiographic densities

Standard scale from black to white: air, fat, soft tissue and fluid, bone and calcification, and metal; each step is progressively more attenuating.

Carina level

The tracheal bifurcation lies at about the T4-T5 vertebral level; it is a key landmark on the PA chest radiograph for assessing lung position.

Pneumothorax sign

Absent lung markings peripheral to a visible pleural line on the chest radiograph, with possible mediastinal shift in a tension pneumothorax.

Barium sulphate

Insoluble inert positive contrast agent for the gastrointestinal tract; contraindicated if perforation is suspected because it causes peritonitis.

Intravenous urogram

Examination using intravenous iodinated contrast with films at about 1, 5, 15, and 25 minutes to show the nephrogram and collecting system.

Digital subtraction angiography

Technique that subtracts a pre-contrast mask image from the contrast image to show vessels; patient movement causes misregistration artifact.

Double-contrast barium enema

Study of the colon using barium sulphate plus air insufflation to coat the mucosa and distend the lumen, improving detection of small polyps.

Anaphylaxis first-line drug

Adrenaline 0.5 mg intramuscularly as 1:1000 solution into the anterolateral thigh, repeated as needed, for contrast-induced anaphylaxis with hypotension or bronchospasm.

Adult BLS compression ratio

Chest compressions at 100 to 120 per minute with a depth of 5 to 6 cm, given in a ratio of 30 compressions to 2 rescue breaths.

Four ethical principles

Autonomy, beneficence, non-maleficence, and justice; these guide consent, confidentiality, and decisions in radiological practice.

10-day rule

Abdominal and pelvic radiography in women of reproductive age should be performed within 10 days of the onset of menstruation to avoid irradiating an early pregnancy.