Although patients has significantly decreased since the introduction of

Although
X-rays provide important clinical information, they increase the risk of
harmful radiation exposure. Radiography services have grown rapidly over the
last few years and diagnostic radiography contributes a large share of public
dose from man-made sources (ref). Radiographers have a legal duty of care under
the Ionising Radiation (Medical Exposure) Regulations (IR(ME)R) 2000 to keep
radiation doses ‘as low as reasonably practicable’ (ALARP). Therefore, they
must use as little radiation as possible to obtain an image of diagnostic
quality (ref).

Due
to the increasing awareness of stochastic effects of radiation exposure, there
has been a lot of research into the effective dose that patients receive from
having diagnostic examinations. Effective dose to the patient can be calculated
using theoretically derived conversion factors to convert the dose-area product
(DAP). Dose-area product is the absorbed dose to the patient multiplied by the
area irradiated, and so is particularly valuable as biological effects induced
by radiation exposure are directly affected by the magnitude of the radiation
dose and the total amount of tissue that is irradiated (ref).

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

The
information collected on population dose levels from medical exposures has been
used to develop National Diagnostic Reference Levels (NDRLs) which give
advisory values for the radiation exposure of patients for all radiographic
examinations; for example, the DAP for a postero-anterior chest radiograph is
0.1 Gycm2 (ref).  DRLs were
first introduced in 1996 by the International Commission on Radiological
Protection (ICRP) due to research which showed huge variation in radiation dose
received by patients undergoing the same radiological examination. DRLs are an important
tool in the process of justification and optimizing radiation dose to patients (ref).
Under IR(ME)R 2000 legislation, hospitals have an obligation to establish local
diagnostic reference levels to develop quality assurance and to set a benchmark
so that investigations can be made when exposures are abnormally high. The implementation
of DRLs has significantly reduced radiation dose received by patients and therefore
highlights how important evidence-based practice is to healthcare.  Evidence-based practice allows newly found knowledge
to be turned into processes and decisions that improve patient care and outcomes,
a process that is particularly important in radiation protection (ref).

Although
effective radiation dose to patients has significantly decreased since the
introduction of DRLs, research has also shown variance in dose between
different imaging departments for the same radiographic examination (ref, 00). This
raises concerns as it suggests that the same diagnostic image could be achieved
at a lower dose and with less detriment to the patient.  A possible reason for this is differences
between using computed radiography (CR) X-ray systems and digital radiography
(DR) systems.  Research has shown that CR
dose tends to be higher than DR dose for the same X-ray examination, and DR
dose is usually much lower than the recommended DRLs. This could be because DR
is more efficient at converting dose to signal and so can obtain the same image
quality as CR at a lower dose, without changing the signal-to-noise ratio.  DR can also produce higher contrast resolution
images than CR using the same dose (ref). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Methodology

 

The
data collection will take place in the imaging departments of three different
hospitals. An introductory letter will be given to the radiographers to explain
the reason for the data collection and to confirm that all data and
radiographer details will be kept confidential and anonymous. The make and
model of the equipment in each hospital will be noted and will stay the same
for the duration of the data collection period, which will be for four weeks
beginning on the 16th April 2018. Keeping the data collection in the
same X-ray room in each hospital will keep consistency in the type of equipment
used.  Whether the X-ray equipment is CR
or DR will also be noted along with the unit of measurement that it uses to
calculate the effective radiation dose to the patient. This will be
particularly important for the analysis of the data as different models of
X-ray equipment vary in the unit of measurement that is used to calculate the
radiation dose to the patient, therefore, all of the doses collected will need
to be converted to the same unit for analysis.    A
sample of 50 patients from each hospital will be used in the study.  They will all be undergoing plain film chest
imaging and will be over the age of 16. The radiographer will note down in the
data collection table the date of birth, gender and body type
(small/medium/large) of each individual patient. The projections that each
patient had will also be recorded; for example, anterior-posterior, posterior-anterior,
lateral or lordotic. The radiographer will also note in the data collection
table if there were any repeat X-rays taken, the projection of the repeat image
and how many times it was repeated. Finally, there will be space in the table
to note down the total effective radiation dose that each patient received.