Advanced Radiographic Imaging Mod 1

_______________ is a filtration added to the tube prior to install

_______________ is a filtration added to the tube prior to install

added filtration

_______________ is a filter designed to even out the exposure due to uneven part density

compensating filter

_______________ is removal of low energy x-rays from the useful beam with Al or other

filtration

_______________ is an x-ray beam with many different energized photons

heterogeneous beam (polyenergetic)

_______________ is the filtration from permanently installed components of the tube housing

inherent filtration

_______________ is the x-ray beam coming directly form the tube

primary beam

_______________ is inherent filtration plus added filtration

total filtration

_______________ is a filter with a "trough" in the middle

trough filter

_______________ is a compensating filter added in order to image parts of uneven density

wedge filter

Why do we filtrate?

to absorb soft/low energy photons that would otherwise only stay in the patient

filtration creates _______________ beam which can also be described as increasing the beam quality (beam with higher energy photons)

hard

_______________'s primary purpose is the reduction in patient radiation dose

filtration's

What is Al atomic number (Z number)?

13

what is the #1 used diagnostic filter material?

Al

there is one piece of Al between the x-ray tube and collimator box to stop photons under _______________ kV

10

since low energy photons do not leave the patient, it causes what to the image quality if we filter?

the image quality doesn't change, only patient dose does (becomes less if filtered)

filters made out of different _______________ will filter out differ energy photons

elements

_______________ is the element used in mammo filters

molybdenum (Mo)

_______________ is the stuff in the tube, but there for another purpose than filtering but does do some filtering. Is equivalent to about _______________ mm of Al

inherent filtration, .5

,,__ and ________ are the components of the tube that cause inherent filtering

glass envelope of tube, insulating oil, carbon fiber window of tube housing

_______________ is meant to dissipate heat in tube but also causes inherent filtering

insulating oil

_______________ is the average total filtration of diagnostic x-ray tube

2.5mm Al

_______________ is using a filter (Al) to make an image look better (get rid of edge burnout)

beam shaping

if you need to add a lot of Al to reach half-value layer, it means the beam is already _______________

heavily filtered

_______________ is aluminum added by the manufacturer for filtration only

added filtration

a type of added filtration is _______________ which is 1 mm

aluminum sheet

NCRP stands for _______________

National Committee on Radiation Protection

_______________ mm Al is required by NCRP for rooms shooting below 50 kV

.5

_______________ mm Al is required by NCRP for rooms shooting between 50-70 kV

1.5

_______________ mm Al is required by NCRP for rooms shooting above 80 kV

2.5

if a little amount of Al reduces beam a lot, it means a lot of _______________ energy photons are present

low

mammos uses _______________ window instead of glass to bring the inherent filtration down to .1 mm Al eq. ----- mammo uses this instead of glass to allow more photons through easier, so it isn't filtering out as much

beryllium

measuring _______________ is used to check filtration

half-value layer

_______________ is the amount of Al added that will reduce the beam exposure level to half its initial value

half value layer

if half-value layer is 3+, the beam is already _______________ (or no more weak photons left to filter out)

strong

for rooms that shoot over 70 kV, the HVL must be greater than _______________ mm Al per federal regulation

2.3-2.5

In kVp ranges from 60 to 100, if adding to existing filtration how much should you in theory increase mAs?

adding .5 mm Al = add _______________ mAs

adding 1 mm Al = add _______________ mAs

adding 3 mm Al = add _______________ mAs

14%, 17%, 50%

why do we in theory add mAs if we use added filtration? Why is it "in theory"

to compensate for lost photons, because a noticeable difference requires 25-30% change in mAs, so if you went up the 14% or 17% it wouldn't make a different for image quality

_______________ are filters made of 2-3 different elements

compound filters

what are the elements used in compound filters?

.25 mm Cu and 1 mm Al, or .1 mm Er (erbium) and .5 mm Al

Why is Al always under Cu or Er in compensating filters?

copper will sometimes create secondary radiation, so Al will absorb the secondary radiation created from copper

_______________ either happens in Photoelectric effect or comptom interactions

secondary radiation

_______________ is a useful filter for when needing high kV for thick areas where penetration is needed, but we need to avoid soft tissue burnout in the thin areas

compound filters

_______________ filters are used in mammography. This is because these filters create photons in the tube that are in a 20 kV range or window (all photons are one energy) This type of beam is called _______________ beam

molybdenum/rhodium, monenergetic

_______________ are externally used filters that weed out photons on the thinner parts of the image (prevent soft tissue burnout) without compromising the penetrating power for the thicker parts of the image

compensating filters

what are some examples of compensating filters and what exams are they used for?

wedges (used for foot and lateral decub abdomen), trough/bilateral wedge, clear Pb plastic filter (protects breast in females for scoli studies), silicone boomerang (shoulder, patella)

_______________ part of compensating filter goes over the thinnest part of the body. _______________ part of compensating filter goes over the thickest part of body.

thickest, thinest

_______________ is the amount of shielding that will reduce the beam to 1/10 its original intensity. Used for _______________ not _______________

tenth-value layer, shielding, filtration

The higher the atomic #, the __ __energy photons you will filter out, and ______ parts

higher, thicker

Molybdenum filters are used for __ __and filter up to about ______

mammo, 20 kV

Copper absorbs ____ than aluminum

more

Beryllium window is a _____ to the thin area of glass

additive

We should filter more for things like soft tissue _____

neck

Compound filters are good for ______ _____ ______

soft tissue neck

monoenergetic beam filter everything below __ , it is set at. _______ shell binding energy

K shell binding energy, K

heavy metal filters are

copper, tin, erbium, holmium (higher atomic numbers)

heavy metal filters ___ patient skin dose

reduce

intensity in the tenth value layer is measured in___ or _______

MR or R

at a 100 kV setting ___ inches of concrete will reduce the beam intensity to ___ of its original value

2.5, 1/10

___ mm of wood equals the shielding power of ___ mm of lead

19, .1

OSL use a _____ ___ ___ to collect radiation from _______

photo-stimulated phosphor, scatter

-sensitive down to 1 miliRem

What are the 3 filters of the OSL badge and what do they measure?

-plastic window

shows the skin dose

-aluminum filter

shows the medium dose or what is called the lens dose (dose of the eyes)

-copper filter

shows the deep dose

There are two types of equipment filtration, they are ____ and _____

inherent, added

Inherent filtration is ____ and ____

oil, glass

added filtration is *__ and*__ ________

Al, mirror

a hardened beam consists of what type of x-ray photons?

higher energy

what does HVL stand for

half value layer

define compound filter

a filter having two kinds of elements