Lakhasly

For some common radiographic examinations, the EU has published guidelines that give diagnostic requirements, criteria for radiation dose and examples of good radiographic technique.The implementation of diagnostic reference levels has led to a reduction in patient absorbed doses and must be considered as a successful radiological protection action and a first step towards achieving optimal imaging conditions Internationally, the concept of diagnostic reference levels (see Chapters 22 and 24) has been implemented in some countries and diagnostic standard doses are periodically measured locally in the hospitals and compared with the reference levels.If the reference level is exceeded in a particular X ray room, the hospital needs to review their imaging conditions and to consider, and possibly implement, corrective action to reduce the dose if the clinical image quality requirements can still be met.For example 'visually sharp reproduction' means that the details are clearly defined, whereas 'visualization' reflects a situation where the details are detected but not fully reproduced.The image criteria relate to important anatomical structures that should be visible in the images.

For some common radiographic examinations, the EU has published
guidelines that give diagnostic requirements, criteria for radiation dose and
examples of good radiographic technique. The requirements include both image
criteria and important image details and apply to ‘standard sized’ patients with
the usual symptoms for that type of examination. The image criteria relate to
important anatomical structures that should be visible in the images. Typically, the
criteria are expressed in several degrees of visibility. For example ‘visually sharp
reproduction’ means that the details are clearly defined, whereas ‘visualization’
reflects a situation where the details are detected but not fully reproduced. The
list of important image details gives the minimum dimensions in the image at
which normal or abnormal anatomical details should be recognizable. The criteria
have been further developed over the years to be more specific to changes in the
imaging condition for use in visual grading evaluation of clinical images (see
Section 23.3.3).
The criteria given in the above guidelines for radiation doses to the patient
are expressed in terms of entrance surface dose. However, the IAEA code of
practice recommends the use of kerma area product, PKA, as the dosimetric
quantity in fluoroscopy. The advantage of PKA over entrance surface dose is that
the radiation beam size is directly included in the measurement and that PKA
values for different projections can be added together with reasonable validity.
Adding entrance surface dose from different projections is not meaningful.
Internationally, the concept of diagnostic reference levels (see Chapters 22
and 24) has been implemented in some countries and diagnostic standard
doses are periodically measured locally in the hospitals and compared with the
reference levels. If the reference level is exceeded in a particular X ray room,
the hospital needs to review their imaging conditions and to consider, and
possibly implement, corrective action to reduce the dose if the clinical image
quality requirements can still be met. The implementation of diagnostic reference
levels has led to a reduction in patient absorbed doses and must be considered
as a successful radiological protection action and a first step towards achieving
optimal imaging conditions