RAD 212 Positioning Terminology, Patient Prep & Positioning Devices PDF

RAD 212 Positioning Terminology, Patient Prep & Positioning Devices. + Grids! Learning Outcomes Describe positioning terminology and apply in lab Understand and apply positioning devices for Xray aquisition Demonstrate safety while applying hands free techniques to patients undergoing radi...

RAD 212 Positioning Terminology, Patient Prep & Positioning Devices. + Grids! Learning Outcomes Describe positioning terminology and apply in lab Understand and apply positioning devices for Xray aquisition Demonstrate safety while applying hands free techniques to patients undergoing radiographic acquisition Recall methodology for obtaining radiographs for efficiency, patient care and safely Understand grids and how they play a role in imaging Create quality radiographs of veterinary significance: positioning terminology and aids common radiographic views patient positioning and restraint creating radiographs of cats and dogs record keeping and storage evaluating quality of radiograph  Transfer skills from inanimate objects to animal models Transfer skills from animal models to real animals Reduce retakes Objectives Minimize stress to animals Maximize safety to all persons involved  Simple tools & common sense, most exposures Welfare of both patient & Focus on nonmanual can be completed without youself should be kept in restraint exposing yourself to mind at all times direct or scatter radiation It is essential that you are familiar with normal anatomy of the species and the proper terminology!  First things first… a review (hopefully) of some familiar terminology Dorsal (D) Ventral (V) Cranial (Cr) Introductio Rostral (R) Caudal (Cd) n to Medial (M) Lateral (L) Positioning Palmar (Pa, P) Plantar (Pl, P) Proximal (Pr) Distal (Di) Recumbency (L or R) Oblique (O) Directional Terminology  Derived from American Directional College of Veterinary Terms for Radiology (ACVR) Radiograph ers Is based on orientation of PRIMARY BEAM Directional Terms Directional Left (L/Le) Right (R/Rt) Cranial (Cr) Caudal (Cd) Terms Dorsal (D) Rostral (R) Shorthand Ventral (V) Palmar (Pa) Medial (M) Plantar (Pl) Lateral (L) Oblique (O) Distal (Di) Proximal (Pr)  Cranial & caudal refer to the limb proximal to the carpus/tarsus Dorsal, palmar, plantar used for the limb distal to and including the carpus/tarsus Limb Palmar = forelimbs, plantar = hind limbs Terminolog With limbs, terms dorsal, palmar, plantar, cranial & caudal take y precedence when used in combo e.g. dorsoproximal Oblique is added when central beam passes obliquely (usually limbs) e.g. dorsomedial-oblique palmarolateral oblique (DMPLO) Directional Terms Fore limb ?? ?? ?? ?? ? ? ? ?? Directional Terms Hind limb ?? ?? ?? ?? Primary Beam Orientation Directional terms describe the path of the primary beam The first point of reference is where the beam enters the body The second point of reference is where the beam exits the body For example: Ventrodorsal suggests the beam enters the ventral region and exits the dorsal region.  Named according to beam entry followed by beam exit Combinations – standardize i.e. entry/exit e.g. Rules of ventrodorsal For laterals, label image according to side the patient is Positioni lying on Rt & lt not used in combination terms and should precede ng other terms e.g., right lateral Medial & lateral go second when combined e.g., dorsomedial On the head, neck, trunk & tail, terms rostral, cranial & caudal should go first in a combination e.g., caudoventral  Remember that according to etymological rules, when you combine two terms, the Etymology combination of the root and the combining vowel (usually “o”) is used.  Several factors must be considered when Key creating a quality radiograph: Positioning 1. Welfare of the patient Factors 2. Restraint and immobilization of the patient 3. Minimal trauma to the area of interest 4. Minimize risk of exposure to technician and other personnel  Comfort and welfare of patient are primary Patience is vital, especially with animals who are injured, in pain, or who cannot be sedated The Patient Animals do not understand that x-ray procedure is painless Use all your handling skills to provide calm, quiet, deliberate motions The To minimize anxiety, use a soft voice and gentle stroking Patient - Avoid quick movements, severe restraint Do as much prep work as possible before positioning patient Tips Do not underestimate the value of a muzzle The Patient - Tips Measure patient Set machine settings Position imaging plate Make label or input information in the digital system Document exposures – LOG! Don PPE Last … position patient and expose Common Sense Rules… 1. Based on your understanding of effects of distortion, SID, and anatomy, USUALLY place affected area DOWN 2. Move other things out of the way: collars, leashes, IV tubes, other body parts! 3. Sometimes you need to defy the rules and use COMMON SENSE to achieve image. The Patient Artifacts can be caused by incorrect patient preparation Hair coat - clean and dry Collars, harnesses and leashes, especially metal, must be removed if in the field of interest Bandages, splints and casts should be removed – can cause shadows Measureme nt Use the calipers, never guess! Measure thickest part Measure in final position if possible This will depend on the patient’s condition Required Views Radiography produces a 2-dimensional representation of a 3- dimensional object Therefore, a minimum of two views are necessary for diagnostic purposes Views are usually at right angles to one another  Required Views Lateral Dorsoplantar Guidelines Position area of interest closest to receptor to reduce distortion and magnification With limbs, consider taking image of other leg to compare Use nonslip pad under plate with tabletop views  Primary beam centered directly over area of interest. If there is a known lesion (break) center beam over it, the area of interest. all anatomy fits in view e.g. femur, must include distal & proximal joints Thickest part at cathode end, if possible (consider the heel effect)  Are the settings correct? Is the plate/cassette/machine/grid in position? Is thickest part toward cathode? Before pushing Are markers in proper location? Do you have the correct body part & view? the button- Is patient properly centered? Are borders, correct? exposure Collimated properly Is patient (body part) parallel to receptor & perpendicular to beam Is patient in correct phase of respiration?  Lateral/oblique limbs: proximal part of limb points up and cranial/dorsal aspect of limb is to your left DP/PD/CrCd/CdCr: proximal end of extremity is at top of viewer. Consistency is important! Is it perfect? Is it labeled correctly? Positional lead markers present? Appropriate contrast & density? Properly centered? Appropriate borders included with proper collimation? Body part properly positioned (no rotation)? No human body parts! Not even gloved hands!!! No artifacts IF NO: Is it diagnostic? Should it be recaptured? The Basic Stuff To Remember Long bone views must include both distal and proximal joints Joints include portion of distal and proximal bones Smallest field size possible should be used REMEMBER! Positional terms are related to entrance and exit of primary beam Cats tend to resist too much restraint Dogs respond to calm, authoritative commands Prepare for the unexpected! Restraint, Prep & Positionin g Patient Preparation Abdominal studies GI tract must be free of feces and ingesta – laxative or enema may be necessary Bladder empty or it can displace other organs Restraint Manual Mechanical Chemical  What’s wrong with this rad? What kind of restraint is illustrated? Manual Restraint Least desirable Should be last resort Still very common in practice… ALWAYS wear apron, gloves, glasses, thyroid shield Distance! (6 feet) Mechanical Restraint Some physical means of holding the animal, or convincing the animal that it is being held… Commercial products include sandbags, foam wedges, positioning troughs, ropes, straps, weights, wood blocks, compression bands, Velcro Be creative… make your own! IV bags, tape, rope, boxes, pillows, shipping material, a spare lead glove, etc. are all available to you Positioning Aids Any reusable aids should be water-proof, washable & stain resistant Can wrap some in plastic wrap Sand works better then beads Sand and beads are radiopaque so should not be in field of interest Commercial wedges etc. covered in vinyl (better then homemade) Pawsitioner Aids Make sure entire V-troughs essential Radiolucent – clear field of view is for dorsal plastic or vinyl either on or off the recumbency covered trough Aids Tape, gauze etc. Tape: extend & hold limbs, rotate limbs, secure patellae & femurs for hip view, separate toes etc. Wooden spoon: keep cat’s head out of view or paws Scruffer, clothes pins: mimics scruffing cat  In many cases, dogs will allow you to position them for radiography without using manual restraint. Restraint - Dogs Patience is essential. If you move slowly most dogs will allow you to position them using sandbags and tape. Mechanical Light sedation will be necessary in some dogs. Additionally, a muzzle can be used in canine patients to decrease panting and calm the patient When wearing a muzzle, the dog concentrates on the muzzle rather than the positioning. Mechanical Restraint - Cats Light sedation will be necessary with some cats. Application of non-traumatic forceps to the skin on the back of the cat's neck. This acts to "scruff" and calm the patient during radiography.  Under-utilized option Anxiolytics, Sedation, Anesthesia Low dose often enough Chemical Necessary for some studies Restraint May be contraindicated in some cases (age, trauma etc) Pros: better positioning, fewer re-takes, less stress, safer for technician Cons: efficacy and recovery times, cost to client  Every sedative protocol carries some Chemical degree of risk to the patient and every patient receiving sedative medications These protocols may vary from clinic must have a complete pre-sedative to clinic. Restraint examination to help ensure that the patient is healthy enough to handle the procedure. REMEMBER! Positional terms are related to entrance and exit of primary beam Cats tend to resist too much restraint Dogs respond to calm, authoritative commands Prepare for the unexpected!  Obvious: fractures, fracture reduction, Why X- dislocations, pin/screw/plate positions, arthritis (hip dysplasia etc.), foreign body location etc. Ray? Less Obvious: growth anomalies, abnormal calcification, carcinoma, comparative anatomy, genetic screening for breeding, gestation dating etc. Grids  A device placed between the patient and the film designed to absorb scatter Is composed of alternating strips of lead and spacer Grids material Lead = 0.5 mm, number 500 - 1500 Spacer = aluminum, plastic or fibre Encased in protective cover for durability How Does a Grid Work? Lead strips are aligned Lead strips absorb rays Spacers are inert, and with primary beam not traveling in the permit most primary x- such that desirable x- same direction as rays to reach the film rays reach the film primary beam (scatter) Where’s the Grid? Can be UNDER the tabletop between patient and imaging plate Most are built in and under the tabletop, and was correlated with the bucky tray Concept of Grid Absorbing Scatter Grid Focus Lead strips vary in size and angle, but each grid has a center point, or focal point Focal spot of x-ray tube should align with focal point of grid Ideally grid and machine have been calibrated to work together This is called GRID FOCUS Grid Ratio The more lead in a grid, the more scatter it can absorb, BUT… If lead is too thick, it shows up on radiograph Grid ratio is measure of efficiency Height of lead strip : distance between strips Eg. If height is 6 times greater than spacing distance, ratio is 6:1 Grid Ratio 8:1 very common Types of Grids Linear Crossed Parallel or focused Most effective Most common Linear Grids Parallel Grid lines are consistent with angle of primary beam Absorbs Xrays perpendicular to the primary beam Limited to small x-ray fields Focused Grids  Prominent horizontal lines Grid Cutoff If the SID is beyond the range specified by the manufacturer, grid cutoff can occur Overall lack Cutoff is a progressive decrease of density in density towards edges of grid, caused by unintentional absorption of primary rays Other Causes of Grid Cutoff Improper centering of grid and primary beam Tilting the tube Tilting the grid Focused grid upside down Focused Grid Cutoff Due to Upside Down Placement What’s up Next? Imaging the Abdomen & Thorax!