Radiology

Question 1

Function of Aluminum filter

Answer 1

blocks low-energy photons to decrease dose to patient

Question 2

function of tungsten filament

Answer 2

creates e- cloud

Question 3

function of molybdenum focusing cup

Answer 3

focuses e- from the tungsten filament to tungsten focal spot

Question 4

tungsten focal spot

Answer 4

smaller focal spot = sharper image

hit with e- to create X-ray beam

Question 5

function of copper stem

Answer 5

dissipates heat

Question 6

step up transformer

Answer 6

high voltage

increases potential

Question 7

step down transformer

Answer 7

filament

decreases voltage

Question 8

Bremsstrahlung

Answer 8

primary source of X-ray production

Question 9

What determines quality of X-ray beam

Answer 9

energy of photons

Question 10

what determines quantity of beam

Answer 10

number of photons

Question 11

what does kilovoltage determine

Answer 11

increasing kVp increases quality and quantity

Question 12

what does miliamperage determine

Answer 12

increase the quantity of photons

Question 13

what does time determine

Answer 13

increase the quantity of photons

Question 14

what does the inverse square law say

Answer 14

the intensity of x–ray beam is inversely proportional to the square of the distance from the source

Question 15

What are deterministic effects of radiation biology

Answer 15

effects that occur once threshold is reached, and after threshold is reached the severity is proportional to dose
oral mucositis

Question 16

what are stochastic effects of radiation biology

Answer 16

effects may occur independent of dose (no threshold)
probability not severity is proportional to dose
radiation induced cancer

Question 17

What cells are most sensitive to radiation

Answer 17

nucleus and DNA are most sensitive parts of the cell

mitotically active and cells with long mitotic futures are most sensitive cells (bone marrow, gonads)

Question 18

Parts and function of parts in X-ray film

Answer 18

emulsion = silver halide grains (sensitive to x-ray)
base = supports emulsion

Question 19

function of intensifying screen

Answer 19

phosphor layer used as screen converts x-ray into light

more light than x-ray = less radiation needed, but decreased resolution

Question 20

How to improve image sharpness

Answer 20

small focal spot
increase distance between focal spot and object
decrease distance between object and receptor

Question 21

what causes forshortening

Answer 21

film is at right angle to xray, but object isn’t

Question 22

what causes elongation

Answer 22

object is at right angle to xray, but film is not

Question 23

steps of x-ray developping

Answer 23

1. developper, converts silver halide into metallic grains
2. rinse, stops developper
3. fixer, dissolves and removes undevelopped silver halide crystals
4. washing, prevents staining from left over fixer

Question 24

charge coupled device, or complementary metal oxdie semiconductors
as Digital imaging detectors

Answer 24

CCD and CMOS = silicon captures x-ray energy as voltage and sends it to computer

Question 25

photostimulable phosphor plates

Answer 25

barium fluorohalide with europium

capture and store x-ray energy, laser used releases fluoresence

Question 26

what is contrast resolution of radiographs

Answer 26

the ability to distinguish shades of gray

Question 27

what is spatial resolution of radiographs

Answer 27

the ability to detect edges or close points

film is better than CCD/CMOS

Question 28

what makes up the Y line of Ennis

Answer 28

superimposition of the floor of the nasal cavity and the border of maxillary sinus

Question 29

what does the Y line of Ennis mark

Answer 29

maxillary canine