Unit 3 (6/24) - patient protection and radiation protection of imaging personnel (copy)

Holistic patient care

• treat the pt as a whole person rather than a. Body part

  • Ex: your pt is Mr. Smith, not the ankle x-ray

Effective Communication & Body Language (10 steps)

1. Introduce self

2. Address pt properly

3. Ease patient stress & anxiety

4. Understanding & dignity

5. Clear & concise instructions

6. Increase their cooperation

7. Give time to ask questions

8. Gain trust

9. Be professional, present, & aware of body language

10. Reduce repeats

Patient motion: involuntary

• caused by muscles, not controllable

  • Heart

  • Digestive

  • Chills

  • Tremors

  • Spasms

  • Pain

  • Withdrawal

Correcting involuntary motion

• decrease exposure time & increase imaging receptor speed

Voluntary motion

• controlled motion

Lack of control caused by:

1. Age

2. Breathing

3. Anxiety

4. Discomfort

5. Fear

6. Mental instability

Correcting voluntary motion:

Gaining patient cooperation & use of proper immobilization

Immobilization

• piggostat

• Papoose/octostop

• Sponges & sandbags

• Mummy wrap/ bunny wrap

  • Tape

  • Velcro straps

  • Radiolucent plexiglass

  • Have non-radiology employee help hold

What immobilization is this

Piggostat

What immobilization is this

Octostop

What immobilization is this

Papoose

Beam limiting devices

• limits primary beam to a smaller area

• Decreases exposure by reducing the amount of tissue that is exposed to radiation

• Reduces scatter

Types of beam limiting devices

• aperture diaphragm

• Cones

• Collimators

Aperture diaphragm

• flat lead w/ a hole cut in it & placed below the windows

  • Most common is RECTANGULAR

    • Square

    • Round

  • Reduces scatter

Cones

• circular metal cylinders that connect to front of the use & limits the size of the beam

• Can be flared or straight

• Can be telescoped 10-12 inches to make field size smaller (extensive cylinder)

Cones have been replaced by ___

Collimators

Cones are mostly used in what

Dental radiography (but can be used for heel, skull, and spine images)

Collimators

• also called light localizing variable aperture rectangular Collimators

  • Most versatile

• Should not be opened larger than body part

• 2 sets of shutters 90 degrees from one another

Collimators can reduce exposure by what percentage?

20-30%

Over collimating (making it too small) can cause what?

Repeat images

Near (upper)

• near x-ray production

  • Reduces exposure from off focus radiation!!!!

Far (lower)

• located close to light source

  • Confines beam to area of interest

Skin sparing

• minimizes the skin exposure by requiring a 15 cm distance from skin to Collimators

  • Spacer bars

Grids clean up__

Scatter

PBL

Positive beam limitation

Positive beam limitation

• electronic sensors in the bucky that senses the size of the IR that is used & opens the Collimators appropriately

  • Slits of pegs

• Reduces human error

Positive beam limitation (PBL) is also known as?

Automatic collimation

PBL/ automatic collimation is regulated to be within ___% accuracy

2%

Filtration

• hardens the beam by cleaning up low energy (longer wavelength)

• Reduces patient exposure to skin & superficial surface

• Reduces absorbed dose

  • Lower energy photons provide no detail to the image!!!

Low energy=

Filtration

High energy=

Lead

Total filtration in the housing is ___ mm Aluminum (Al) equivalent for units that operate above 70 kVp

2.5

2 types of filtration

1. Inherent

2. Added

Inherent filtration

• 0.5 mm Al equivalent

  • Made up of glass envelope, insulating oil, & glass window

Added filtration

• 2.0mm Al equivalent Made up

  • Sheets of Al added outside the glass window above the collimator

  • Can be accessed by service person

  • Can be changed as tube ages

Mobile & fluoro require ___ mm Al filtration

2.5

NCRP report #____ lists minimum requirements for filtration

102

Radiation control for health & safety act of 1981 states___

The x-ray tube must have adequate filtration

HVL (half value layer)

• measures beam quality or effective energy of the beam

• Measured at least once a year by a physicist or if the tube is replaced/ repaired

1 HVL=

50%

2 HVL=

25%

3 HVL=

12.5%

4 HVL=

6.25%

2019 Shielding- AAPM (American association of physicists in medicine)

• statement that shielding of patient gonadal or fetal shielding should be discontinued

What year was shielding discontinued?

2019

CARES committee

Communicating advances in radiation education for shielding

Radiosensitive organs

• lens of eye

• Breasts

• Reproductive organs

2 types of shielding

1. Gonadal

2. Specific area

First step of gonadal protection is proper___

Collimation

Due to location of gonads, females receive__ MORE exposure than males

3x

Appropriate shield placement can reduce exposure by ___% in females, & ___% in males

female= 50%

Male= 90-95%

What type of shielding is this?

Flat contact/ fig leaf

What is the most effective position for flat shields?

• AP/ PA recumbent position

What type of shielding is this?

Shadow shields

Shadow shields are not suitable for what procedures?

Fluoroscopy

What shielding is this?

Shaped shields

Shaped shields

• contoured to enclose the male reproductive organs

• Can be placed by the pt

When can shaped shields not be used?

During PA projections

What kind of shielding is this?

Clear shields (transparent lead-plastic material)

What type of shielding is this?

Lap shields (half)

Half Shield

• used for gonadal protection of patient

• Covers front or back of patient & is attached by Velcro strap or on wheels

What kind of shielding is this?

Specific area shields

Examples of specific area shields

1. Eyes

2. Breast

3. Thyroid

4. Gloves

Compensating filters

1. used when x-raying a part that has varying thickness to reduce dose & provide a uniform density across the image

2. Decreases entrance skin exposure

3. aluminum or lead-acrylic that is attached to the bottom of the collimator

4 types of compensation filters

1. Wedge

2. Through

3. Ferric

4. Boomerang

Wedge compensating filter

• used for foot or spine

Trough compensating filters

• bilateral wedge

• Used for chest

Ferlic compensating filters

• used for hips

Boomerang compensating filters

• used for shoulders

kVp (kilovoltage peak)

• quality of x-ray incr. with thicker body parts

• Unit selected on operating console

• Max possible energy of a photon that exits the x-ray tube

mA/ milliamperage

• quantity of x-rays

• Measurement of x-ray tube current or # of electrons crossing the tube from cathode

• Selected on operating console

• DIRECTLY PROPORTIONAL TO PATIENT EXPOSURE

What is the quality of x-ray that increases w/ thicker body parts

• kVp

What is the quantity of x-rays?

mA

mAs/ milliampere seconds

• controls the amount of radiation produced by the x-ray tube

• DIRECTLY PROPORTIONAL TO PATIENT EXPOSURE

Increase in mAs= increase in

Dose

AEC/ automatic exposure control

• cells that are selected on the operating console that will automatically select the mA, according to cell selection & body part

exposure index (EI)

• the number that is found on the image after processing that measures receptor exposure

Under exposure will cause ____, which needs a repeat

Quantum noise (grainy appearance)

Extreme over exposure will cause ___, and needs to be repeated

Saturation

Use proper exposure factors

1. Makes optimal image w/ minimal dose possible

2. Sufficient penetration

3. When setting manual technique, measure the pt for accuracy

4. Reliable technique charts

Higher kVp= ____ for body parts

Lower mas

Image receptor exposure

• increase in image receptor speed decreases patient exposure but decreases sharpness

  • 200 or 400 speed image receptor

Correct processing

• inadequate processing results in repeats

Rule of thumb is to use a grid when part thickness is over ___ cm @ ___ kVp or higher

over 10 cm @ 60kVp or higher

Grids

• remove scatter

• Improves contrast/ detail of image

• Use lowest grid ratio appropriate for the body part

Grids __ patient dose, but improves the quality of the image which produces a better diagnosis

• increase

Higher grid ratio=

Higher patient dose

Air gap technique

• alternative to using a grid to clean up scatter

Air gap technique distance

4-6 inches (10-15cm) away from image receptor with 10-12 feet SID

Negative of air gap technique

• the increase in magnification & not useful in kVp higher than 90

Repeats are unacceptable if done due to carelessness or poor judgement

1. Positioning

2. Technique

Repeat analysis (7)

1. Problems w/ positioning

2. Incorrect centering

3. Inappropriate technical factors

4. Improper collimation

5. Foreign bodies

6. Processing artifacts

7. Patient motion

Unnecessary exposures For chest x-rays

1. Pre admission

2. Pre employment

3. Routine health check ups

4. Screening for TB

Unnecessary exposure for lumbar x-rays

1. Pre employment

Unnecessary exposure for CT whole body scans

1. Check for disease

Minimal source to skin distance on a mobile fluoroscopy unit is

12 inches (30 cm)

The smaller the source to skin distance, the ___ the entrance exposure

Larger

Portable x-rays

Only perform on patients that cannot be transported to the department

Digital radiography

• do not overexpose pt just because if can be manipulated

• Utilize technique charts & grids

What is the largest exposure to patients in diagnostic radiology

• fluoroscopy