The Fundamental Tenets of Radiographic TechniqueThis is a featured page

The Ten CommandmentsThere are a number of practices in radiography that are so widely accepted that they can be considered to be fundamental tenets of the technique of radiography. These rules no doubt arose from radiographer experiences and observations as to where radiography can fail or result in undesirable or harmful outcomes. This page is dedicated to consideration of these rules, traditions and common understandings.

These are "a" set of rules rather than "the" set of rules- the level of acceptance and importance/emphasis will vary from institution to institution.

At least one Joint Demonstrated on Every Longbone Image
FEMURThe radiographic demonstration of a longbone without the demonstration of either joint is a disturbing sight. Is this a matter of doctrinaire thinking or are there well founded reasons for including at least one joint when undertaking longbone radiography?

One of the reasons for including at least one joint on a longbone image is to allow the identification of the bone. In extreme cases, where a relatively short section of a longbone has been imaged, it can be very difficult to establish which bone has been imaged. Long bone joints are sufficiently characteristic to be able to identify any longbone from the joint(s) demonstrated.

There are other arguably less important reasons for including at least one joint on a longbone image including
  • a joint provides a reference point
  • joint closest to the pathology is usually of interest in surgical treatment.
  • consistency of serial imaging
An extension of this concept is the practice of including the joints both above and below any longbone pathology. I would suggest that this should not be practiced as a matter of routine. Whilst there may be good reasons to image both joints in particular circumstances (e.g. to demonstrate rotational displacement of a fracture), the routine imaging of both joints is not consistent with one of those other fundamental tenets of radiography- the ALARA principle. You will find individuals, departments and institutions that advocate routine radiography of the joint above and below the symptomatic longbone. If this is your departmental protocol, you may have little scope for avoiding this routine.

The Exceptions
There may be grounds for not including either joint when performing longbone radiography. These circumstances could occur when performing supplementary views. The anatomy has been established on the routine views. Coned or tangential views can be performed without inclusion of a joint- the lesion or foreign body provides the reference point.

The desire to avoid parallax error may also provide grounds for not including a joint on along bone image, particularly when performing supplementary views.

Two Views at Right Angles (90 degrees)

Two views at 90 degrees is one of the mantras of plain film radiographic imaging. These can be referred to as orthogonal views.

In geometry, orthogonal means "involving right angles" (from Greek ortho, meaning right, and gon meaning angled). [,,sid5_gci283993,00.html]

ankle trauma 2 apThe single view in radiography is rarely adequate. In the words of John Harris "... one view is no view". Or as another author suggested ...

This AP ankle view demonstrates no displaced fracture (see lateral view of same ankle below)
ankle trauma 2 lat1The lateral view clearly demonstrates a fractured fibula.

An extension to this "two view thesis" is the 3 or even 4 view requirement in particular cases. There are numerous examples in this wiki of cases where radiographers 'chased' suspected fractures with multiple supplementary views.

The Routine Comparison View
AP pelvisThe notion of a routine comparison view might appear, prima facie, to be overkill and unjustifiable in terms of the ALARA principle. In general, radiographic anatomy has meaning without the need for imaging of the contralateral side. There are some notable exceptions and the AP pelvis is a case in point. In some institutions, the AP pelvis is a routine view for hip radiography in both acute and follow-up situations. This must surely be a case of a routine comparison view in patients with unilateral symptoms or unilateral known pathology. Another routine comparison view practiced in some centres is the skyline view of the knee- it is not unusual to see imaging of both sides for comparison.

Routine comparison views in appendicular skeleton radiography are generally not justified.

The aim with comparison views is develop a balanced workpractice. Comparison views should neither be forbidden nor routinely practiced (exceptions noted). A comparison view can provide additional confidence to a diagnosis, but should only be practiced where the potential benefits are greater than the potential harm.

The ALARA Principle
radiation symbol
ALARA is an acronym for As Low As Reasonably Achievable. This is a radiation safety principle for minimizing radiation doses by employing all reasonable methods.

Current radiation safety philosophy is based on the conservative assumption that radiation dose and its biological effects on living tissues are modelled by a relationship known as the “Linear Hypothesis”. The assertion is that every radiation dose of any magnitude can produce some level of detrimental effects which may be manifested as an increased risk of genetic mutations and cancer.

An important application of the ALARA principle is to establish the pregnancy status of all women of childbearing age prior to commencement of an examination.

The 3 c'S
Patient Identification
The 3 C's refers to the practice of patient safety based on
  1. Correct Patient
  2. Correct site
  3. Correct procedure
It matters little how well you practice radiography if you have the wrong patient, or you are imaging the wrong limb, or you are performing the wrong examination

Side Markers

Notes on Chest Radiography - wikiRadiographyClosely related to the concept of the 3 C's (correct patient, correct side, correct anatomy imaged) is the requirement to mark the image with the correct patient's name and annotate with the correct side marker.

This chest X-ray image (left) arrived with a patient who was transferred from a regional hospital. The radiograph did not have a patient name or side marker. When the chest X-ray was repeated in the resus room, it was revealed that the patient had dextracardia (below left). Failure to use a side marker (or correctly annotate) an image can have serious adverse consequences for the patient. Some centres will not accept plain film images that have not been imaged with a lead/brass side marker.
Notes on Chest Radiography - wikiRadiographyFailure to use a side marker can prove very costly for the patient in the resus room.

Review Old Imaging
Femur TraumaPrevious relevant imaging should be viewed prior to commencement of any plain film radiographic examination where possible. This requirement is based on the premise that you should fully understand what you are trying to achieve before you start a radiographic examination. It is often the case that viewing old imaging will influence the radiographic examination- sometimes in subtle ways...sometimes in profound ways.

Viewing old imaging is most important in an orthopaedic clinic follow-up situation. Even if you think you know the correct imaging required for a particular patient, if the previous imaging was consistent (and different to what you intended to perform), you will probably want to provide the same imaging for reasons of consistency of follow-up. For example, if a patient has a long tibial intramedullary nail, and you intended to perform separate knee-down and ankle-up views, it would be worthwhile checking the approach used previously. If all of the previous post-op imaging involved placing the limb diagonally across the IR and providing a single image knee-to-ankle, that might be a better approach for reasons of consistency alone.

One of the common reasons for checking old imaging is to establish the type of orthopaedic hardware used- in particular, the length of intramedullary nails and plates.

Clinically Focused
clinical examination
I advocate a patient-focused approach to radiography rather than a picture-focused approach. That is to say, the focus of your radiographic pursuits should be based around achieving a benefit to the patient rather than simply the production of images that were requested by the referring clinician. This approach may appear to have little practical utility, but I would argue that it should have a profound effect on everyday practice.

A clinical approach to radiography will affect your decision to repeat a view- the question to be asked is not simply whether the image you have produced is up to your standards (or your department's standards), it should be based on a balanced consideration of whether the repeat view is likely to be of benefit to the patient. For example, repeating an abdominal plain film because you have not included the symphysis pubis is probably unjustified when the patient has presented with RUQ pain.

A clinical approach to radiography involves a good measure of communication with the patient- the basis of this approach is to understand why the patient has presented for imaging. You can't rely on the clinical information supplied with the request form; it can variably range from comprehensive and accurate to just plain wrong.

Understanding the patient's reason for presentation can have an affect on the imaging you produce. If the referring doctor has asked for an abdominal plain film to assess possible pneumoperitoneum, you know that he/she has requested the wrong examination. There are similar issues for ?pneumothorax, ?aspirated foreign body, ?pulled elbow ?constipation ?abdominal hernia etc etc

If I was to provide radiographic imaging of this patient, I would want to know why the referring doctor requested a hand X-ray examination rather than a finger X-ray examination (there may be legitimate reasons). If the finger only is of interest, I would ensure that the position of the finger was such that the joint of interest was demonstrated to maximum advantage. I would also check old relevant imaging before I start and ask the patient what she knew about this lesion.

Clinical Peer Review

chest radiography
Clinical peer review is a hallmark of professional practice rather than a fundamental radiographic practice. Clinical peer review for radiography refers to the practice of reviewing your clinical work by your peers (your professional colleagues). This process has several advantages
  • good practices can be shared with colleagues (e.g. my modified technique was successful)
  • colleagues can be warned of failed practices (e.g. my modified technique failed)
  • questionable practices can be debated (was the high-dose imaging warranted)
  • followup of patient outcomes can be considered in the context of radiography performed (in retrospect, was the radiography unnecessary?)
  • allows discussion of new practices, techniques, and technology (the new II can do this)
  • cross-modality discussions can occur regarding imaging of specific patients (were the modalities complementary for specific pathologies or did they duplicate findings)
  • cost-benefit can be discussed (radiation dose vs clinical benefit)
  • radiography can be discussed in light of diagnosis (gold standard)
  • 3 C's failures can be shared/discussed
  • Image interpretation skills can be developed
  • facilitates discussion of appropriate supplementary views for specific pathologies
  • Allows discussion of technique approaches for specific patients
  • Red Dot system can undergo continuous audit
This process is relatively straightforward in a PACS environment. You could use a folder system where radiographers enter cases for discussion in a radiographers meeting folder. Radiographers can share the role of meeting facilitator. It is very useful to have a meeting room with a projector and screen linked to a PACS computer. The meeting facilitator simply opens the meeting folder and progresses through the cases. It is important to include cases that went badly as well as those that went well.

This is a radiographer clinical peer-review meeting- there are good reasons for not having other professional groups present- this is peer review not Radiologist review.

Providing lunch is a big drawcard!

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Latest page update: made by M.J.Fuller , Apr 3 2012, 12:54 PM EDT (about this update About This Update M.J.Fuller Edited by M.J.Fuller

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