Audrey's PP Quizlet - Equipment Rad Bio

The Image Intensifier has significantly ___ patient does compared to conventional fluoroscopy

Lower

What is the Input Phosphor?

Converts incident x-rays into light

What is the Photocathode?

Turns the light into electrons

What is the Output Phosphor?

Turns electrons back into light

What is the Brightness Gain formula?

Minification gain x flux gain

What is Minification Gain?

Focuses electrons to a smaller area in order to increase brightness (signal)

What is Flux Gain?

Ratio of more light photons going out than x-ray photons going in

What is Magnification Mode?

1. Less area of the input phosphor is used for the signal

2. Creates a larger image

3. Decreased FOV

4. Better visualization of structures

5. Increased patient dose

How does Magnification Mode increase patient dose?

The signal must be increased to maintain brightness

What is Pulsed-Progressive Fluoroscopy?

1. Beam pulsed instead of continuous

2. Controls image acquisition frame rate

3. Higher frame rate = increased dose

What is the biggest benefit of pulsed-progressive fluroscopy?

Decreases patient dose

What is an example of Continuous Fluoroscopy?

30 pulses per second, 33 msec pulse width

What is an example of Grid-Controlled Fluoroscopy?

15 pulses/sec, 10 msec pulse width

Wider pulse width (more msec) = ___ patient dose

Increased

Temporal Resolution = ___

Time

What is last image hold?

Allows review of most recent image before giving patient another pulse of radiation

What is the main benefit of last image hold?

Reduces patient dose

Limiting fluoroscopic field size ___ patient dose

Reduces

Collimation = decreased ___ (intregral) dose

Volumetric

Collimation means there is ___ tissue irradiated and ___ scatter produced

Less; Less

What type of shutters are used for fluoroscopic collimation?

1. Iris

2. Rectangular

How much of a collimated border should be visualized in fluoroscopic collimation?

1"

What does Dose Area Product (DAP) take into account?

Collimation

DAP is a better indicator of ___ risk

Stochastic

What is DAP measured in?

cGy-cm^2

What is the formula for DAP?

Dose x field size (collimation)

DAP ___ with increasing field size

Increases

What is SSD?

Source-skin distance

Increased ___ reduces ESE

Distance

What is the SSD for fluoroscopes?

15"

What is the SSD for mobile?

12"

Filtration ___ patient ESE

Lowers

What is the HVL for fluoroscopy?

3-4mm Al

What is the total filtration above 70 kVp?

2.5 mm Al

What is the Cumulative Timer for fluoro?

Audible alarm reset after 5 minutes

True or False: Beam-on time must be documented

True

Higher occupational dose on the ___ side

Tube

True or False: Never stand in the primary beam

True

Which side should you stand on?

Image-Intensifier side

How far away should you stand from the patient (source)?

6" at 90 degrees

What is the bucky slot shield lead equivalent?

0.25 mm lead equivalent

What is the benefit of the bucky slot shield?

Protects occupational workers at gonadal level

What is the lead equivalent for spot film device protective curtains to protect from scatter?

0.25 mm lead equivalent

Patient position plays a part in ___ rate

Exposure

The image intensifier is the ___ ___ & is considered a ___ barrier

Image receptor; Primary

Bringing the II closer to the patient & raising the table will ___ dose

Reduce

The II is a ___ barrier & must be ___mm lead equivalent

Primary; 2

How do you create decreased SSD?

Place the tube under the table closer to the patient

Decreased SSD = ___ patient ESE

Increased

How do you create increased OID?

The patient table is not raised closer to the II

Increased OID = ___ magnification & patient ESE

Increased

What are the negatives of having the patient table lower closer to the tube?

1. High exposure (increased patient dose)

2. Blurred image (beam divergence reduces spatial resolution)

3. More scatter reaching the IR (reduces contrast resolution)

What is a dead man control switch?

Only continuous pressure applied will allow radiation emission

What does the Eye pedal indicate?

Regular fluoroscopy

What does the Camera pedal indicate?

Cine or High-Level Control (HLC)

What are the regular fluoroscopy ESE guidelines?

1. 10 R/min (88 mGya/min) with 12" SSD

2. If HLC is available, the regular rate is 5 R/min & unlimited HLC

What are the HLC rate (cine) guidelines?

1. 20 R/min (176 mGya/min)

2. Must have continuous audible signal for HLC

True or False: Chart in EMR is ESE reaches 1-2Gy to track reactions

True

True or False: The FDA is trying to limit serious cutaneous skin reactions with long fluoroscopy times and use of HLC

True

In digital, there is constant image contrast ___ of exposure

Regardless

Why is technique much more flexible with digital imaging?

Contrast resolution is CONTRAST

What controls the contrast resolution in digital imaging?

Computer linear response

What manipulates the gray scale in digital imaging?

Window width

In digital, kVp still controls the ___ of the part & ___ production

Penetration; Scatter

Why is kVp less important now in digital?

Digital computer windowing

What is digital very sensitive to?

Scatter

Collimation is ___ in digital

Imperative

What does collimation control in digital?

Controls the production of scatter as well as patient dose

Grids are ___ in digital

Imperative

What do grids control in digital?

Control scatter reaching the IR, but increase patient dose

DR receptors are more sensitive than CR PSP plates so less ___ can be used

Dose

True or False: In general, there are fewer repeat images in digital due to the technique factors

True

What does Linear Response ensure?

Constant image contrast

Wide exposure latitude = more ___ technique

Flexible

What is Windowing?

Computer manipulation of grayscale

True or False: In digital, you can overexpose or underexpose and still get a good image

True

What is Exposure/Dose Creep?

In digital, it is easy to increase patient radiation dose bu using more technique than necessary

What is the Exposure Indicator?

1. Midpoint in histogram VOI (volume of interest)

2. Different ranges for different manufacturers

What is the tube housing made of?

Lead

What is the function of the tube housing?

Protects from off-focus & leakage radiation

What is off-focus and leakage radiation considered?

Secondary, nondiagnostic

How are x-rays emitted?

Isotropically

The tube housing ___ the primary beam

Restricts

What is the restriction rate for the tube housing?

1 mGya (100 mR) per hour @ 1 meter from the source

True or False: Even at the high voltage & current with continuous operation, 1 mGya (100 mR) per hour @ 1 meter from the source should not be exceeded

True

Beam on time must always be ___

Documented

What are 2 notable characteristics of a control panel?

1. Audible tone when the exposure ends

2. Positive indication when the tube is energixed (x-ray on)

What is the protective barrier for the control panel?

1. Lead impregnated glass

2. Still allows for patient visualization

The table has ___ thickness

Uniform

What is the table made of?

1. Carbon fiber (strong)

2. Radiolucent (minimal absorption to reduce patient dose)

What is APR on the control panel?

Anatomically programmed radiography

What is Manual mAs Mode on the control panel?

1. Setting mAs manually

2. No AEC

When needs to be chosen when selecting technique on the control panel?

1. Table bucky

2. Wall bucky

3. Tomography

4. Fluoroscopy

The control panel indicates when the grid is ___

Activated

What is HS on the control panel?

1. High speed (more sensitivity)

2. Used for motion control

What is the HU% on a control panel?

Heat units

What is Load 100% on a control panel?

Heat load to target

What can be changed when setting Manual mAs Mode?

1. kVp

2. mA

3. mAs

4. sec

The control panel has ___ configuration

AEC

What can be selected for the screen on the control panel?

1. High speed

2. Medium

3. Detail