Radiologic Technology Basic Cervical Radiography

transcript

Pharos universityfaculty of Allied medical sciences

Clinical Practice I (RSCP-201) Department of Radiological Sciences and Medical Imaging Technology

Prof. Dr. Hesham Badawy

Dr.Mohamed El Safwany

Radiologic TechnologyBasic Cervical Radiography

Tube Angulation

• Erect Radiography requires adding or subtracting the required angle from 90 degrees.

• Cephalad angles: Add required angle to 90 degrees.

• Caudal angles: Subtract required angle from 90 degrees.

Elements of Technique Chart

• mAs: Product of mA and time. Determines the number or quantity of photons. Establishes the density of the film.

• kVp: Quality of beam. Controls the contrast of the image.

• Patient size in centimeters: Determines the mAs and added filters used to equalize exposure.

• Focal spot size: Controls geometric resolution

Fixed kVp Technique Charts

• Consistent image contrast

• Proper penetration of body part.

• More image latitude: less retakes.• Use of higher kVp will reduce the

ionization in body tissue. Reduction in patient exposure.

Complete Technique Charts

• Chart should be located in the control booth and easy to read.

• This will help avoid technique errors.

• They will work fine for 85% of the patients.

Technique Adjustment for Contrast

• Rule of “Tens or 15%”• Increase kVp by 10 or 15% and reduce mAs

50%• Decrease kVp by 10 or 15% and double mAs• Change kVp by 8% and adjust mAs by 25%• If the film is underexposed increase the kVp

15% and leave the mAs alone if patient is unstable.

• If the film is overexposed, reduce kVp 15% if it lacks contrast and patient is stable.

• The 15% rule can be used to adjust the technical factors for different patient body habitus or disease processes.

• Elderly patients often have osteoporosis and muscle loss making them easier to penetrate. This calls for a reduction in kVp to avoid over penetration.

• Extremely muscular patient need an increase in kVp to avoid under penetration and a light film.

• Osteopenic patient require a reduction in kVp by 4 to 10 kVp.

• Frail and osteopenic patient require a reduction in both mAs and kVp.

• Children require a 30% reduction in mAs.

Technique Adjustment for Density

• The 30 – 50 Rule is most commonly used to adjust the technical factors for over or under exposure.

• If the film is very light or underexposed, double the mAs if the patient is stable.

• If it is dark or overexposed, cut the mAs in half.

• If it is slightly under or over exposed adjust the mAs 30%.

Collimation

• A key factor in patient exposure.

• Reduces radiation to the area of interest.

• Reduces scatter radiation that improves contrast.

Collimation Rules

• Collimation must be at a minimum slightly less than film size.

Or• To the area of clinical

interest. Whichever is smaller.

• Need three borders.

Dark room

• Painted a light color.• Should have good

safe light.• Sink with eye wash.• Space to store fresh

processing chemicals.• Work counter with I.D.

Camera.

Darkroom: Film Bin

• Light tight container for storage of unexposed film.

• Small film in front..• Larger film in back.• Never opened in light

or with darkroom door open.

Darkroom: I.D. Camera

• Used to print patient information from flash card on film.

• Card goes under clip to hold it in place.

• Film goes next to clip to align information in I.D. Block of film.

Darkroom: Film Processor

• Kodak M-35 processor

• Fresh Chemical storage

• Hazardous Waste storage

• Film fed into processor on feed tray.

• Developer is not considered hazardous waste.

• Fresh Fixer is not considered hazardous waste.

• Used fixer is hazardous waste due to silver.

• Chemicals in secondary containment.

• Air tight containers to keep fresh and reduce fumes.

• Always wear eye protection and gloves when handling chemicals.

• With automatic processing you should not need to become in contact with the processing chemicals.

• Only when a film is lost or jammed in the processor will we open the processor.

Processing Chemicals

• Chemical Safety• Developer contains

Hydroquinone and Sodium Bisulfate. Both are hazardous.

• Hydroquinone can be absorbed through the skin.

• Gloves must be used when in contact with developer.

• Chemical Safety• Fixer contains

Ammonium Thiosulfate and Sodium Thiosulfate.

• Since it removes the unexposed silver from the film, it becomes hazardous waste when used.

• Fresh Fixer is not hazardous waste.

• Chemical Safety• Eye Protection and

gloves must be used when working on the processor.

• Eye Wash facilities should be provided in case of accidental exposure to the chemicals.

Sequence of Steps for Taking Radiographs

• Introduce yourself to patient. Explain what your are going to do.

• Determine that a female patient of child bearing age is not pregnant. Have the patient the sign the release from liability. Give the gowning instructions consistent for the views being taken.

Gowning Instructions

• Cervical Region :

• Remove everything from the waist up and put gown on with opening to the back.

• Remove any necklaces, ear rings or dentures and any other items that contain metal in the skull or neck area.

• Watch & rings may be left on.

• Thorax & Chest

• Remove everything from the waist up and shoes.

• Remove bra.

• Put gown on with the opening towards the back.

Lumbar spine or Full spine

•Remove all clothing except for underpants.

•Remove shoes but leave socks on

•Remove any removable jewelry.

•Put gown on with the opening towards the back.

Asking about Pregnancy

• “It has been reported that the safest time to take x-rays of females of childbearing age is within ten to fourteen days of the onset of menses. Are we within that time frame? If not is there any change that you could be pregnant? Please sign this form that states that to the best of your knowledge, you are not pregnant and the start of the last menses.”

• Take all measurements needed for the study being taken. Record measurements on the request form.

• Locate the radiation protection being used for the first film.

• Using the technique chart, determine and set the technique for the first film.

• Position tube, film and patient. • Set the SID and tube angle for first film.• Place film in Bucky or Non-Bucky film

holder. Set I.D. Blocker and anatomical

marker in the correct location for the

view. Position patient in correct position

for the view.

Anatomical Markers

• Identify the side of patient closest to film. Lateral & Oblique Views.

• Faces the same way as patient. Easy to read for A-P views. Pronated for P-

A views.

• Identify the right or left side of patient on A-P or P-A views.

• Center horizontal central ray to patient and film to the central ray. Or Set film to patient and center central ray to film.

• Push film into Bucky.

• Fine tune positioning of vertical central ray. Check all planes and object to film distance.

• Collimation to area of clinical interest or slightly less than film size. Which ever is smaller.

• Step into the control booth. Ask patient to remain still and give the breathing instructions required for the view.

• Watch the patient while preparing the rotor and make the exposure.

Breathing Instructions

• Suspended respiration:” Don’t breathe move or swallow.” Cervical spine A-P and Obliques

• Inspiration:”Hold very still. Take a very deep breath and hold your breath in.” Thoracic spine, upper ribs & chest views

• Expiration:” Hold very still. Take a small breath in and blow it all the way out and hold it out. Lateral c-spine and all views below diaphragms.

• Tell the patient to breathe and relax. Set the technical factors for the next view.

• Proceed with the positioning for the next view until the exam is completed.

• Carefully process all films.

Landmarks for Cervical Spine and Skull Radiography.

Cervical Spine Radiography

• All cervical spine views are routinely taken on 8” x 10” Regular Speed Cassettes.

– The lateral can be taken on a 10 X 12 for anterior weight bearing patients.

– The I.D. is placed down .

Acanthameatal Line

• This is the most important base line for cervical positioning.

– It runs from the base of the nose to the EAM. – It is parallel to the floor and perpendicular to

the film for all views.

Cervical Spine Variations

• Different schools will perform cervical spine exams differently.

• Some places will take the lateral in the Bucky instead of Non-Bucky.

• The Oblique and Lateral Views can be taken at 40” though 72” SIDs with changes to the technical factors.

A-P Open Mouth

• Used to visualize the top two cervical vertebra.

• Common view of all cervical spine series.

• Most challenging of all routine cervical spine views.

A-P Open Mouth View

• Measure: A-P at C-4• Film: 8” X 10” I.D.

down• Requires very precise

positioning.• Routine: No tube

angle• Protection: Full or half

apron.

APOM positioning

• Acanthiomeatal line perpendicular to film.

• Mastoid tips and upper incisors perpendicular to film.

• HR: 1” below upper incisors.

• VR: mid sagittal with no head rotation.

APOM positioning

• Center film to horizontal central ray

• Collimate to 5” x 5”• Breathing Instructions:

Don’t breathe move or swallow or phonate “AH”

• Make exposure.• Have patient breathe

and relax.

The A-P Open Mouth Film

• The should be no rotation.

• The Mastoid tips and upper incisors aligned.

• Dental caps are blocking view of dens.

A-P Cervical Spine

• One of the required views of all cervical spine series.

• Tube must be angled cephalad to open the disc spaces.

A-P Cervical spine

• Measure: A-P at C-4• Protection: Half or

Full Coat Apron• SID: 40” Bucky• Tube angle: 15 ° to

20 °cephalad• Film: 8” x 10” I.D.

A-P Cervical spine

• Head extended until acanthiomeatal line is perpendicular to film. Horizontal Central Ray: at level of C-4

• Vertical Central Ray: mid sagittal with no rotation

A-P Cervical spine

• Center film to Horizontal Central Ray and push Bucky tray in.

• Collimation side to side: Skin of neck

• Collimation top to bottom: EAM to T-2

A-P Cervical spine

• Breathing instructions: “Don’t breathe, move or swallow.” Suspended respiration.

• Make exposure• After exposure:

“Breathe and relax.”

A-P Cervical Spine Image

• Mandible and base of skull should be superimposed.

• Sternoclavicular joints should be equal distance from T-spine. No evidence of rotation.

Posterior Oblique Cervical Spine

• Part of the complete cervical spine series.

• Always done in pairs

• Marks must note the side closest to the film.

• Markers in front of the body of the vertebra.

Posterior Cervical Oblique

• Measure: A-P at C-4• Protection: Half

apron• SID: 40”• Tube Angle: 15 °to

20° cephalad• Film: 8” x 10”

Regular speed I.D. down

• Patient turned 40 to 45° from A-P.

• Marker to side closest to film.

• Acanthiomeatal line perpendicular to film.

• Head turned to true lateral.

• Horizontal central ray: At level of C-4

• Vertical central ray: through EAM with skull lateral. One inch anterior with head not turned.

• Center film to horizontal central ray.

• Push film into Bucky.• Collimation Top to

Bottom: EAM to T-1• Collimation Side to

Side: Skin of neck.• Breathing Instructions:

Suspended respiration ”Don’t breath move or swallow”

• Make exposure.• Tell patient to relax

Posterior Oblique Cervical Films

• Disc spaces should be open.

• Mandible should be clear of spine.

• RPO shows left foramina (furthest away from film)

• LPO show right foramina

Anterior Cervical Oblique

• Measure: A-P at C-4• Protection: Half

Apron• SID: 40”• Tube angle: 15°to

20° caudal• Film: 8” x 10” regular

cassette I.D. down

• Patient faces Bucky.• Turn patient 40 to 45°

from P-A.• Tall patient is seated.• Skull turned lateral with

acanthiomeatal line perpendicular to film.

• Marker pronated and to the side closest to the Bucky.

• Horizontal central ray: level of C-4

• Vertical central ray: through EAM.

• Film centered to horizontal central ray.

• Collimation Side to side: skin of neck

• Collimation Top to Bottom: EAM to T-2

• Breathing Instructions:

• “Don’t breathe, move or swallow” Suspended respiration

• Make exposure• Have patient

breathe and relax.

Anterior Cervical Oblique Film

• The IVF’s must be open.

• Disc spaces must be open.

• RAO will demonstrate the right foramina (side closest to film)

• LAO will demonstrate the left foramina

C-spine Problems

• The angles of the mandible should be superimposed.

• The I.D. is in the wrong location.

Poor Gowning: Ear Ring

• A single ear ring on a lateral cervical spine view.

Poor Gowning: Pins in Hair

• Bobby pins can ruin cervical or skull radiographs.

Poor Gowning: Hair in Pony Tail

• Most bands used for pigtails or ponytails have have metal clips.

• There appears to be an ear ring also.

Poor Gowning: Wet Hair

• The patient’s hair is wet. Combined with the ponytail resulted in significant artifacts.

Poor Gowning: Mousse

• This patient had dreadlocks with lots of mousse in the hair.

Poor Gowning: Mousse

• The A-P c-spine was repeated with the hair in pigtails.

Poor Gowning: Bra

• The complete study of a brassiere.

• P-A & Lateral Views

Cervical Spine Positioning Errors

• Horizontal CR too low so the EAM and part of upper c-spine missed.

• EAM must be in collimation and film properly centered to avoid missing anatomy.

Cervical Spine Positioning Errors

• I.D. in wrong location so it blocks part of C-1.

• Note that the oblique view provides a good look at C-7 & T-1.

Assignment

• One student will be selected for assignment.

Radiologic Technology Basic Cervical Radiography

Documents