rad positoning lesson 2

1. Radiographic Table

a. Floating tabletop

• To freely move table in same horizontal plane: depress one of the 2 outside pedals at the base of the table front

• To raise/lower table: depress one of the 2 inside pedals at the base of the table front 

b. Bucky tray

• Pull bucky tray out

• Place cassette in bucky tray, put back of cassette against back plate and gently push locking mechanism in until front clamps grab front of cassette

• When cassette is gripped front and back, push down on the locking mechanism

• Bucky tray can be moved toward head-end/foot-end of table by depressing black button on right-hand side of the bucky tray

c. Wall Unit

• Vertical wall unit moves up & down when hand lock is depressed

• Place cassette holder in appropriate spot for the cassette size/orientation that you will be using

• IR locks in wall bucky tray the same as the table bucky

• Button on bottom of the wall bucky turns on the collimator light

2. X-ray tube/Collimator

a. X-ray tube

• Enclosed in lead housing

• Generates x-rays to pass through part of interest

b. Collimator

• The collimator is a box-like device attached to the x-ray tube that allows for adjustment of the size of the light field (before exposure) and therefore, the x-ray field (during exposure)

• Lead shutters inside the collimator work in pairs to limit the size of the x-ray field

• The round dial on the left side of the collimator controls the 2 lead shutters that limit the x-ray field from the head-end to foot-end of the table: or longitudinal direction

• The round dial on the right side of the collimator controls the 2 lead shutters that limit the x-ray field from the front to the back of the table: or the transverse direction

• The size of the collimation is displayed on the front of the tube 

• Coning in:  refers to bringing the collimator shutters in toward the borders of the part being imaged

• Since there isn’t a preset for 45”, use the 40” preset when using 45” SID; use the 72” preset when using 72” SID

• If you are going to use the same size collimation for multiple images, you can set your collimation by using the memory button

• Push the memory button in the upper right of the collimator; set your transverse size first, then set your longitudinal size; push either M1, M2 or M3

• Once you have your memory button programmed, anytime your collimation opens up, and you want to revert back to that size, just push your memory button 

• c. Light source

  • The round button on the front of the collimator allows for activation of the collimator light source and the centering laser light

  • If you push and hold the button on the front of the collimator in, it will activate the centering laser light only

  • The collimator light source determines the area that the x-rays will strike when the x-ray exposure is activated; light will stay on 30-60 seconds

  • You should only activate the light when you are ready to center the patient

  • Once the centering light and collimator light have been turned on, you can turn them off by pushing the button 

  3. Central ray 

  • Refers to the exact center of the x‑ray field as the beam leaves the x‑ray tube and passes through the patient to reach the cassette (image receptor/IR)

  • All patient positions described in textbook refers to the placement of the CR

  • CR placement allows for the inclusion of all essential anatomy while excluding anatomy not important for proper diagnosis

. Locks (on front of tube)

•  – green - depress to angle tube toward head-end or foot-end of table; degree of angulation (0^o to 180^o) is displayed on front of x-ray tube just above collimator

•  – orange - depress to move tube transversely, release to lock

•  – blue - depress to move tube vertically, release to lock

•  – pink - depress to move tube longitudinally, release to lock

•  - white – depress to move tube in any & all directions at once. Same as the gray button on the front handle, release to lock

•  - purple – depress to swivel tube in front-to-back direction, release to lock

• DETENTS – there are certain detents built into the system where the tube will automatically lock in. Bucky Center – centers the tube transversely to the table & wall bucky. 45” & 72” SID detents to wall bucky

5. Source‑image receptor distance (SID) 

• The specific distance (in inches or centimeters) from the source of radiation in the x‑ray tube to the IR

• With IR in bucky tray & table raised to working height, use numerical measurements on tube face

• With IR tabletop, use tape measure that pulls down from the front underside of collimator

• With erect radiography using the wall bucky tray, use ceiling numerical measurements or use tape measure to the cassette

6. Accessory Devices

• lead aprons & lead blockers

• sponges; calipers

7. Control Panel

• kVp: controls penetration of x-rays

• mA: controls current & number of x-rays that are produced per second

• seconds: controls length of exposure & how long current passes through tube

• rotor: turns anode part of tube

• exposure switch: activates x-ray production

• technique charts: guidelines for technique selection

• EXP HOLD: Sometimes the system will detect an issue and will not let you take an exposure. Generally, there will be a message on the control panel that will tell you what the issue is. Correct the problem and try again 

RADIOGRAPHIC CONTROL PANEL

1 On (right) and Off (left) buttons

2 X-ray exposure light indicator

3 X-ray Exposure controls and display

4 Image receptor buttons

5 Anatomical programming controls and display

6 Prep and x-ray exposure button

X-RAY EXPOSURE CONTROLS & DISPLAY

1 Press button to select: AEC (on or off), If AEC is off, you will be setting mAs or mA 

2 (for AEC only) Press one or more buttons to select photocells

3 Press button to select small focal spot (SM) or large focal spot (LG)

4 Press button to decrease/increase kVp; hold to decrease/increase quickly

5 Press button to decrease/increase mA/mAs

6 Press button to decrease/increase density (for AEC)

7 mA or mAs readout

8 AEC on indicator 

IMAGE RECEPTOR BUTTONS

Select the Image Receptor Button prior to setting technical factors!

1. Press this button to indicate the IR is placed in the wall bucky

2. Press this button to indicate the IR is placed in the table bucky

3. Press this button to indicate the IR is placed tabletop

SUGGESTED PROCEDURE FOR RADIOGRAPHIC EXAMINATIONS

1. Review Requisition

• Note exam requested; check for appropriate clinical data 

• Note patient condition listed (ie. Patient blind, confused, diabetic, etc.)

• Note patient age

• Get extra help if necessary (babies, children, older patients, critically ill patients)

• Use moving tools if needed (smooth-mover, draw sheet)

2. Assemble necessary equipment & set up radiographic room

• LOOK PROFESSIONAL – BE PREPARED

• Obtain proper cassettes for exam

• Obtain lead dividers if needed

• Make sure RT & LT lead markers are available

• Clean table; make sure equipment is clean

• Change linens

• Have sandbags, lead aprons in room if needed (remember: sandbags, metal, lead are radiopaque; sponges, sheets, cotton clothing are radiolucent)

• Bring up patient exam and check technique chart

3. Bring patient into room

• Introduce yourself to patient

• Check patient identification (inpatient: verify patient has an ID bracelet on wrist; outpatient: have patient repeat full name and DOB)

• Females patients of child-bearing age: ask LMP date (first day of last menstrual period) – if greater than 10 days, ask about the possibility of pregnancy 

• Remove all radiopaque items that will interfere with procedure (jewelry, hair apparel, metallic or dense clothing; remove shoes & glasses only after patient is sitting on table)

• Do not remove splints, braces, slings prior to physician approval

• Explain procedure to patient in terms they can understand

4. Begin Exam Procedure

• Set control panel with technique

• Direct patient’s trunk to proper position (sitting on stool, lying down, erect)

• Align IR with anatomy

• Position part of interest, align CR to part, immobilize part if necessary

• Use proper protective lead shielding

• Instruct patient on breathing procedure (practice if necessary)

• Make exposure; watch for patient movement

• Instruct patient to breathe after holding breath

• Move tube and assist patient off table; OR ask patient to wait while images are processed

5. Identify & Process Images – if in CR room

6. Check Images

• Make sure that positioning is appropriate and acceptable

• Make sure that technique is acceptable

• Make sure that there are no artifacts in image that may hinder a diagnosis

• Make sure that all anatomy of interest is included

SUGGESTED SCRIPT FOR START OF RADIOGRAPHIC EXAMINATIONS

1. Retrieve patient from waiting room or hallway by using their first name only

2. Once in the exam room: 

   • Introduce yourself – “Hi, Mary, my name is Heather, I will be taking your x-rays today” (You can do this on the way to the room)

   • Confirm their identity and wash your hands – “Mary, while I wash my hands, can you tell me your full name and date of birth?”

   • Check LMP (last menstrual period) on female patients of childbearing age – “Mary, because we are using radiation today, I need to make sure that you are not pregnant, can you give me the first day of your last menstrual period?” If the date is more than 10 days ago, you need to ask a follow-up question “Is there any chance that you might be pregnant?” Be prepared for a myriad of answers to this one! If the patient feels that there may be a chance that she is pregnant, follow the imaging pregnant patients policy. 

3. Confirm their exam – you can either ask them what brings them in today, or say something like “I have that you are here today for an x-ray of your right hand, is that correct?” 

4. Confirm the reason for their exam – “It says here that you fell on the ice last night and hit your right hand, is that correct?”

5. If all the information is correct, then you may proceed with doing the exam. Explain what you are going to be doing and roughly how long it is going to take to do it. Also, ask if they have any questions before you get started – “Mary, we are going to be doing 4 pictures of your right hand today. It should take me no more than 10 minutes to do the exam. Do you have any questions for me before we begin?”

6. Once the images have been completed, let the patient know that you are all finished. If they ask about results, tell them that the referring physician will be in touch with them after the images have been read by a radiologist. They should hear something within 5-7 days.  AT NO TIME are we allowed to tell a patient what we saw on their images, even if it is extremely obvious!!!

7. As you are walking them out, thank the patient for coming in. You can also ask them if they need any help getting to where they are headed next.