Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1) 5
Review article
OPTIMISATION OF RADIOGRAPHIC PROCEDURES – LUMBAR 
SPINE IMAGING IN GENERAL RADIOGRAPHY
OPTIMIZACIJA POSEGOV V RADIOLOŠKI TEHNOLOGIJI – SLIKANJE LEDVENE HRBTENICE 
V SPLOŠNI RADIOLOGIJI
Erna ALUKIĆ 1,*, Nika ZALOKAR 2, Nejc MEKIŠ 1
1 University of Ljubljana, Faculty of health sciences, Medical imaging and radiotherapy department, Zdravstvena pot 5, 1000 
Ljubljana, Slovenia
2 University Medical Centre Ljubljana, Clinical Institute of Radiology, Zaloška 7, 1000 Ljubljana, Slovenia
* Corresponding author: erna.alukic@zf.uni-lj.si
Received: 29. 7. 2021
Accepted: 31. 8. 2021
https://doi.org/10.47724/MIRTJ.2021.i01.a001
Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1)
ABSTRACT
Purpose: Any use of ionizing radiation must be justifi ed and 
the benefi t must be greater than the harm it causes. Imaging 
must be performed with the lowest possible dose received by 
the patient, while maintaining optimal radiographic image 
quality. Imaging of the lumbar spine is a relatively high dose 
imaging procedure. This systematic review aims to explore 
optimisation options to reduce patient exposure, while 
maintaining radiographic quality during plain lumbar spine 
imaging. 
Methods: A systematic review of the literature from the 
databases Pub Med Central, EBSCOhost including CINAHL, 
Cochrane Library, Web of Science, Science Direct, DiKUL and 
Springer Link was conducted. The documents were fully 
accessible and in the English language. 
Results: 26 experimental studies were included in the analysis. 
There are many optimisation methods: changing the tube 
potential, comparison of diff erent projections, use of shielding, 
primary beam collimation, increasing the source-to-image 
receptor distance, compression of the imaged area, using 
the air gap technique, evaluation of the need for additional 
projections, and rotating the patient depending on the tube 
side. On average, the dose is reduced by 44%. Studies that also 
evaluated the quality of radiographs found all radiographs to 
be diagnostically acceptable. 
Conclusion: The results confi rm a reasonable use of methods 
to optimize radiation exposure and to maintain an optimal 
image quality of radiographs. A systematic review for each 
specifi c area in general radiography should be conducted in 
the future.
Keywords: lumbar spine imaging, optimisation, dose 
reduction, low dose, image quality
IZVLEČEK
Namen: Vsaka raba virov sevanja mora biti upravičena, korist, 
ki jo dosežemo z uporabo ionizirajočih virov pa mora biti večja 
od škode, ki jo povzroči. Postopke slikanja moramo izvajati tako, 
da pacient pri slikanju prejme najnižjo dozo, ki je še razumno 
dosegljiva ob optimalni kakovosti rentgenograma. Slikanje 
ledvene hrbtenice spada med preiskave z relativno visoko 
dozo ionizirajočega sevanja. Namen sistematičnega pregleda 
je raziskati možnosti optimizacije v smislu zniževanja doze na 
paciente in hkratni ohranitvi kakovosti rentgenogramov na 
področju slikanja ledvene hrbtenice v splošni radiologiji. 
Metode: Narejen je bil sistematični pregled literature s 
pregledom podatkovnih baz Pub Med Central, EBSCOhost 
preko CINAHL, Cochrane Library, Web of Science, Science 
Direct, DiKUL in Springer Link. Dokumenti so bili iskani v 
polnem besedilu in v angleškem jeziku. 
Rezultati: V analizo je bilo vključenih 26 eksperimentalnih 
raziskav. Kot možnosti za optimizacijo so bile uporabljene 
različne metode spreminjanja napetosti, primerjava različnih 
projekcij, uporaba svinčenih zaščit, zaslanjanje primarnega 
polja, povečanje razdalje od izvora do slikovnega sprejemnika, 
kompresija slikanega področja, ocenjevanje potrebe po 
dodatni projekciji slikanja ter obračanje pacienta glede na 
postavitev rentgenske cevi. Povprečna doza ionizirajočega 
sevanja se zmanjša za 44 %. Raziskave, v katerih so poleg doze 
ocenjevali še kakovost rengenogramov, med ocenami niso 
opazili statistično značilnih razlik oz. rentgenogrami so bili 
diagnostično sprejemljivi. 
Zaključek: Rezultati potrjujejo smiselno uporabo metod 
za optimizacijo tako na področju zniževanja doze kot tudi 
ohranjanja optimalne kakovosti rentgenogramov. V prihodnje 
bi bilo smiselno narediti sistematični pregled za vsako 
posamezno področje v splošni radiologiji.
Ključne besede: slikanje ledvene hrbtenice, optimizacija, 
zniževanje doze, kakovost rengenograma
6 Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1)
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
INTRODUCTION
In the last century, population exposure has increased with 
the use of man-made radioactive sources. Despite the harmful 
eff ects of ionising radiation, its use in medicine has signifi cant 
diagnostic and therapeutic benefi ts, increasing the frequency 
of X-ray examinations. Any use of radiation sources must be 
justifi ed, and the benefi t of the use must be greater than the 
harm it causes (1,2). 
Radiation protection results in avoiding unnecessary or 
unproductive irradiation, which is achieved by general 
principles of radiation protection. The fi rst principle is the 
justifi cation principle. The procedure may be performed if it 
is clinically indicated and if a greater benefi t can be expected 
than the harm caused by the radiation. The referring physician 
and the radiologist are responsible for the procedure, and 
they must be familiar with the radiation exposures involved 
in certain radiologic procedures. The goal is to assess 
whether the radiological procedure will improve diagnosis or 
treatment and provide the necessary information. The second 
principle is the principle of optimisation. Radiation doses 
and the frequency of patients irradiated must be as low as 
possible, considering the purpose of the radiation application. 
Quality and safety are essential characteristics for eff ective 
and successful medical treatment of patients. Radiation dose 
and radiographic image quality must be optimised for proper 
radiological procedures. Optimising means fi nding the lowest 
possible dose at which the purpose of the radiologic procedure 
is still achieved. By justifying the indication for the radiological 
procedure and optimising the equipment, techniques, 
and proper use of radiation sources, the procedure can be 
optimised. The third principle is the principle of applying dose 
limits. Departments and facilities may vary in their radiation 
doses. The causes of these diff erences must be identifi ed and 
prevented (3). Radiographic procedures are used only when 
the diagnosis cannot be made by other methods that are not 
as risky for the patient (4). We must follow the ALARA principle 
(As Low As Reasonably Achievable), which means that the 
procedure must be performed at the lowest possible dose 
that still gives the optimal quality of the images or procedure 
(4,5). By reducing the radiation dose, patients are protected 
from genetic damage (2). According to the 2007 data 
from International Commission on Radiological Protection 
(ICRP) 103, the most radiosensitive organs with the highest 
weighting factor (0.12) are the breasts, lungs, stomach, colon, 
and bone marrow. The weighting factor of the specifi c organ 
represents the average of both sexes and all age groups (3).
Several optimisation studies have been conducted. They 
are all based on reducing patient exposure whilst still 
obtaining images of high diagnostic quality. There are no 
strict guidelines in the European guidelines for performing 
imaging, but they are supposed to present the basic criteria 
that have proved appropriate in the past (4). Dose limits do 
not exist for radiological procedures (6). However, reference 
values are established for each examination to aid and 
provide basic guidance in the optimisation of protocols 
(4). The establishment of reference values is one of the 
mechanisms by means of which patient overexposure is 
detected. Diagnostic reference levels (DRLs) represent dose 
values in diagnostic radiological procedures. They represent 
a dividing line between optimized and non-optimized 
radiological practice. DRLs are not expected to be exceeded 
during optimized procedures. The health authorities set the 
values in collaboration with the national health and radiation 
protection authorities (3). 
Among the most common reasons for visiting a primary care 
physician is low back pain leading to imaging of the lumbar 
spine (7,8). Lumbar spine imaging is one of the examinations 
with the highest radiation exposure in plain radiography with 
a relatively high radiation dose (4,9–12). According to the 
European Commission (13), Slovenia is among the countries 
where patients receive the lowest dose area product (DAP) 
values for lumbar spine imaging. Many radiosensitive organs 
located near the lumbar spine (breasts, lungs, stomach, colon, 
gonads) must be protected (14). 
General principles in accordance with the optimisation of the 
protocol (4):
• quality control of the radiographic equipment,
• correct positioning of the patient (the proper technique of 
patient positioning – as the lowest dose with the highest 
radiogram quality),
• imaging fi eld collimation that leads to a better quality of 
the radiogram with lower doses,
• use of shielding (protective aprons for radiosensitive organ 
protection),
• proper exposition parameters (tube current, tube voltage 
and other parameters that infl uence the dose and quality 
of the radiograms) and
• proper image annotation;
Regular checks of the doses received and comparison with 
diagnostic reference values represent excellent radiological 
practice as the use of these methods has led to progressively 
lower exposure doses in many countries (15). 
The aim of this systematic review was to investigate 
optimisation options to reduce the dose to patients while 
maintaining the quality of radiographic images in plain 
lumbar spine radiography. The focus was on the lumbar spine 
imaging, where the patient receives the highest dose in plain 
radiography. The aim was to investigate all optimisation 
possibilities in this area for easy transfer to clinical practice.
METHODS
We performed a systematic review and quantitative analysis. 
All studies that were included addressed lumbar spine 
radiography and optimisation, and were fully accessible. The 
literature search was conducted in English. Since radiography 
is a relatively new fi eld in which new opportunities for protocol 
optimisation in terms of the ALARA principle are constantly 
emerging and new ways of performing examinations are 
being discovered as technology evolves, no additional 
restrictions were placed on the selection of studies.
Document references
Based on the research title, we selected key words that apply 
to the topic under study. First, we conducted the search in the 
Pub Med Central, EBSCOhost including CINAHL and Cochrane 
Library. Since few documents were found, the scope of the 
study was expanded to include sources found in Web of 
Science, Science Direct, DiKUL and Springer Link.
Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1) 7
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
Methods of document identifi cation 
All documents were searched using the following keywords: 
radiography, lumbar spine and dose reduction. The keywords 
were selected based on the aim and objectives of this 
systematic review. The keyword for image quality assessment 
was not used. Nevertheless, this area was considered. 
The following exclusion criteria were also used: Magnetic 
Resonance, Computed Tomography, CT and MRI, as a large 
number of documents related to MR and CT appeared in the 
fi rst search. 
The retrieved documents were reviewed based on the title 
and the abstract. All documents that were not suitable for 
the research were excluded. All documents that did not relate 
to plain radiography of the lumbar spine and those that did 
not relate to the process of optimisation or dose reduction 
were also excluded. Then, all duplicate documents were 
eliminated. Finally, all articles were read and two documents 
were excluded because they were not fully accessible and one 
document did not refer to the study area. 
The criteria for including the documents in the analysis were 
studies covering the topic of plain radiography, lumbar 
spine imaging, documents that examined dose reduction, 
documents with full accessibility and in English, as well as 
quantitative, qualitative, and experimental studies.
Exclusion criteria were all the documents that did not relate 
to plain radiography imaging, documents that covered other 
areas of general radiography and did not involve optimisation 
or dose reduction, and all documents in duplicate or without 
full accessibility.
Methods for quality evaluation of research 
When evaluating the quality of research works included in 
this systematic review, a few main features were checked. The 
following features were taken into consideration:
• a country in which the study was performed,
• research design,
• subjects under investigation (participants),
• inspected area,
• inspected results,
• measurement tools,
• results.
Studies identifi ed from:
Database PubMed Central (n=4509)
Cochrane Library (n=22)
Web of Science (n=38)
Science Direct (n=1878)
DiKUL (n=5738)
Springer Link (n=2635)
Studies screened (n=5706)
Use of all listed exclusion factors
Title / abstract review
Duplicate studies removed
Assessing the adequacy of the full text
Studies sought for retrieval (n=44)
Studies for more accurate analysis (n=30)
Studies included in review (n=26)
Id
en
tifi
 c
at
io
n
Sc
re
en
in
g
In
cl
ud
ed
Figure 1: Flow chart of the included studies
8 Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1)
RESULTS
The literature search in all seven previously mentioned 
databases yielded 14,832 results (articles). Based on this, 
exclusion factors were used for several search results. After 
using exclusion factors, all the articles were screened by title 
and abstract and all the articles that did not describe lumbar 
spine radiography or did not describe dose optimisation were 
excluded. Afterwards, duplicate documents were encountered. 
After all of the above exclusions had been made, all of the 
remaining articles were read and four of them were excluded; 
three were excluded because they were not consistent with 
the aim of the study and the fourth was excluded because 
it was not within the scope of general radiography. Figure 1 
presents a fl ow chart of the studies selected.
Main characteristics of investigated papers
Twenty-six papers were included in our systematic literature 
review. All key data from our review are presented in Table 1. 
The data are ordered by year of publication, from the oldest 
to the most recent. The presented data include  the country of 
research, the research methodology and the reviewed subjects 
on whom the research was conducted, the reviewed research 
area, which measurement devices were used, keywords, and 
fi nally, the results and conclusions of the research reviewed.
Result analysis
Papers describing optimisation techniques in lumbar spine 
radiography have been studied in several countries around the 
world. Those countries are Finland (16), Australia (17,34,39,41), 
Ireland (18,19,21,22,25), China (20), Sweden (24,26,33), Kuwait 
(23), United Kingdom (27,30,36), Slovenia (28,35,37), Iran 
(29,32), Israel (31), Croatia (38) and Malta (40). 
The research methodology was experimental in almost 
all studies, except for three studies (16,32,39) in which the 
research methodology was a retrospective study of lumbar 
spine images. In most cases, the research was performed on 
an anthropomorphic phantom (17,20,34,41,22–25,29–31,33), 
in a few studies the research was performed on patients only 
(27,36–38), and some of them performed a combined study 
fi rst on a phantom and then on patients (18,19,21,26,28,35,40). 
The sample size of the examined patient studies varied from 
study to study. The smallest sample size of patients studied 
was three (26), and the largest sample size was 110 (38). The 
investigators studied the radiation dose to the patient and/
or phantom in all papers, but the measurement tool for the 
dose measurements varied from study to study. The dose was 
measured using TLDs (16,18–22,25,28,33), ionization chambers 
(17,26,30), with some mathematical formulas and using 
conversion factors (21,23,32), DAP meters (27,35,36,38,40), 
based on calculations with the PCXMC program and Monte 
Carlo simulation (24,29–31,35–38,41) and other ways 
(24,29,34). Image quality was not checked in a large number 
of the papers examined (17,20,34,37,25–29,31–33).
There were several ways to achieve dose optimisation in 
lumbar spine radiography. In 7 papers, the researchers used 
diff erent tube potentials (kV) (21–24,34,39,41), diff erent 
mAs (41), in 5 papers they used alternative positioning of 
the patient, in which the patient or phantom was rotated 
to diff erent positions (19,27,29–31,35–37), and 2 studies 
used lead shielding as a method of radiation dose reduction 
(25,28). Four papers investigated increasing the distance 
(focus-fi lm distance and source-to-image distance) on the 
radiation dose to the patient during lumbar spine radiography 
(17,18,22,41), and some of the papers evaluate the eff ect of 
proper collimation (32,33,38). Other methods described 
to reduce radiation dose include the need for additional 
image projection (16), changing the patient position on the 
cathode and anode sides of the X-ray tube (20), using a carbon 
fi bre cassette and a faster fi lm/screen combination (22), 
compression of the body part being examined (26), the eff ect 
of an additional copper fi lter (41), and replacing an antiscatter 
grid with an air-gap technique (40). 
On average, the ESD decreased the most by 65% (18), dose to 
gonads by 42% (25), eff ective dose by 58% (29), DAP by 59% 
(27) and the dose to other inspected organs decreased the 
most by 80%, where they evaluate the use of lead shielding to 
reduce the radiation dose to breasts (28).
Of the 26 reviewed papers, 14 (16,18,38–41,19,21–24,30,35,36) 
examined the eff ect of the optimisation procedure on image 
quality. In eleven papers, the researchers found no statistically 
signifi cant diff erence between image quality before and after 
optimisation (16,18,41,19,22,30,35,36,38–40). In three others 
(21,23,24), the researchers concluded that the optimisation 
procedure decreased image quality but the images were still 
diagnostically acceptable.
DISCUSSION 
The aim of this systematic literature review was to investigate 
the options for radiation dose optimisation in lumbar 
spine radiography. This was selected because lumbar 
spine radiography is a procedure that delivers the highest 
radiation dose to the patient in general radiography. There 
are many ways to achieve dose optimisation in lumbar 
spine radiography, but all the inspected methods have their 
limitations. We did not limit our literature review according to 
the year of publication of the articles as we were interested in 
the trends of changing measuring equipment, the transition 
from the fi lm/screen system, and CR and DR detectors.
All the 20 inspected papers off er a large variety of achieved 
dose reduction in lumbar spine radiography. The method 
used was mainly experimental. An experimental research 
method off ers the researcher an inspection and testing of new 
methods for dose reduction and its comparison with previously 
established methods. In this way, the effi  ciency and safety of 
the new protocol can be evaluated. The disadvantage of the 
experimental method is mainly its ethical concerns; therefore, 
several researchers investigated their newly established 
methods on an anthropomorphic phantom (17,20,34,41,22–
25,29–31,33) before carrying on with the study on the patients. 
The use of ionising radiation may negatively aff ect patients 
(1,2). However, the ethical concern can be avoided if the 
newly established research methodology is fi rst performed 
on a phantom and results of the optimisation procedures are 
in that manner primarily investigated (18,19,21,26,28,35,40). 
Some of the investigated papers describe that the research 
was performed on patients, but many of them performed the 
primary analysis on a phantom before carrying on with the 
study on patients. 
All the reviewed studies have proven that radiation dose in 
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1) 9
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
Table 1: Main features of the studies included in the analysis.
RESEARCH COUNTRY
RESEARCH 
METHOD & 
SUBJECT
INSPECTED 
AREA
AIM OF THE 
STUDY
MEASURING 
EQUIPMENT KEYNOTES
RESULTS AND 
COCNLUSION
Moilanen 
et al.,
1983 (16)
Finland Retrospective 
study -  image 
evaluation 
n=250
Lumbar 
spine in 
AP, LAT 
projection 
and lumbo-
sacral joint 
(LS) view 
in LAT 
projection
Evaluation of 
the necessity 
of LS joint 
imaging and 
the infl uence 
on gonadal 
dose.
Termoluminiscent 
dosimeters (TLD) 
were used to 
measure the dose. 
The images were  
retrospectively 
evaluated by 
radiologists.
Film/screen 
combination was 
used.
In 91% of the cases the 
third image (LS joint) 
does not contribute any 
diagnostic information.
The dose was doubled, 
when three projections 
are used compared of 
two projections.
Dilger 
et al., 
1997 (17)
Australia Experimental 
research 
-  Phantom 
study
Lumbar 
spine
(AP and LAT 
projection)
Comparison of 
radiation dose 
to patient at 
diff erent focus 
fi lm distance 
(FFD was 
100cm and 
200cm).
A chamber 
dosimeter to 
measure entrance 
testicular dose.
Film/screen 
combination was 
used.
The increase of FFD 
decreases radiation 
dose for AP projection 
by approximately 30% 
and for LAT projection 
by 70%.
Brennan 
and Nash, 
1998 (18)
Ireland Experimental 
research - 
Phantom 
and patient 
study (n=21; 
females 
between 55 
and 65 kg)
Lumbar 
spine in LAT 
projection
Comparison of 
radiation dose 
to patient at 
diff erent focus 
fi lm distance 
(FFD was 
100cm, 130cm 
and 200cm) 
and infl uence 
on image 
quality.
Entrance surface 
dose (ESD) was 
measured using 
TLDs.
Image quality 
assessment was 
performed by two 
radiographers and 
one radiologist 
based on quality 
criteria by 
the European 
Commission.
Film/screen 
combination was 
used.
entrance surface 
dose and dose 
to ovaries were 
measured.
The larger FFD 
resulted in 65.5% of 
ESD reduction in the 
phantom and 44.1% 
reduction in the patient 
study.
63-69% dose reduction 
to ovaries when a larger 
FFD was used.
There were no 
statistically signifi cant 
diff erence in image 
quality.
Brennan in 
Madigan, 
2000 (19)
Ireland Experimental 
research – 
Phantom and 
patient study
(n=30; 70 ± 
5kg, 1,55-
1,75m)
Lumbar 
spine in 
AP and PA 
projection
The infl uence 
of PA projection 
on ESD and 
image quality.
ESD was measured 
with TLDs.
The diameter of 
the investigated 
part was measured 
to determine the 
compression in PA 
projection.
Image quality 
assessment was 
performed by three 
clinicians based 
on quality criteria 
by the European 
Commission.
In PA projection 
the diameter of 
the investigated 
part was 
decreased by 
9.6%. That has 
infl uenced the 
AEC to terminate 
the exposure 
sooner than in 
AP projection.
Decrease of ESD in PA 
projection by 38.9% in 
phantom study and by 
38.6% in patient study.
There was no 
statistically signifi cant 
diff erence in image 
quality.
Fung in 
Gilboy, 
2000 (20)
China Experimental 
research 
-  Phantom 
study
Lumbar 
spine in AP 
and LAT 
projection
Radiation dose 
to selected 
radiosensitive 
organs (ovaries, 
testicles, 
breasts, 
thyroid and 
eyes) based 
on position 
of the patient 
regarding 
the tube side 
(cathode-
anode).
ESD was measured 
using TLDs.
Known fact 
based on the 
literature review 
is that there is 
higher intensity 
of radiation on 
the cathode side 
of the tube.
When the patient's 
head is orientated 
towards the anode side 
of the x-ray tube, the 
ovaries and testicles 
received 17% and 
12% higher dose on 
average, respectively, 
in LAT projection and 
17% and 12% higher, 
respectively, in AP 
projection.
10 Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1)
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
RESEARCH COUNTRY
RESEARCH 
METHOD & 
SUBJECT
INSPECTED 
AREA
AIM OF THE 
STUDY
MEASURING 
EQUIPMENT KEYNOTES
RESULTS AND 
COCNLUSION
Doherty 
et al., 
2003 (21)
Ireland Experimental 
research 
-  Phantom 
and patient 
study  (n=59; 
70±10kg, 
1.65±0.1m)
Lumbar 
spine in AP 
and LAT 
projection
Increase of the 
anode voltage 
(kV) and its 
infl uence on 
ESD, eff ective 
dose (ED) and 
image quality.
The ESD was 
measured using 
TLDs, ED was 
calculated, and 
image quality 
assessment was 
performed by three 
radiologists based 
on quality criteria 
by the European 
Commission.
The increase of 
tube voltage 
results in faster 
termination 
of AEC due to 
higher energy of 
the photons.
The comparison 
of tube voltage 
in the patient 
study was 81 kV 
and 96 kV in the 
AP and 90 kV and 
102 kV in the LAT 
projection.
Decrease of ESD by 
40.4% in AP and 34.8% 
in LAT projection.
Decrease of ED for 
29.9% in AP and 24.6% 
in LAT projection.
The reduction of 
image quality in the 
AP projection was 
18.3% and 10.1% in 
LAT but all images 
were still diagnostically 
acceptable.
Grondin 
et al., 
2004 (22)
Ireland Experimental 
research 
-  Phantom 
study
Lumbar 
spine in AP 
and LAT 
projection
Increase of 
anode voltage 
(kV), FFD, c 
carbon fi bre 
cassette, a 
faster fi lm/
screen 
combination 
and their 
infl uence on 
radiation dose 
and image 
quality
ESD was measured 
using TLDs
Image quality 
assessment was 
performed by two 
radiographers and 
one physicist based 
on quality criteria 
by the European 
Commission.
Increase of tube 
voltage in the 
AP projection 
from 66 kV to 96 
kV and in LAT 
projection from 
81 kV to 102 kV 
and the increase 
of SID from 100 
cm to 130 cm
Dose reduction with 
the use of optimised 
procedure (higher kV, 
FFD, faster fi lm/screen 
combination and use of 
carbon fi bre cassette) 
has decreased by 66% 
with no signifi cant 
changes of image 
quality
Brindhaban 
et al., 
2005 (23)
Kuwait Experimental 
research 
-  Phantom 
study
Lumbar 
spine in AP 
projection
The eff ect of 
increased tube 
voltage on 
radiation dose 
and image 
quality in two 
CR systems.
A chamber 
dosimeter was used 
for ESD, ovary dose 
and eff ective dose 
were calculated 
using conversion 
factors.
Image quality was 
assessed using 
visual grading 
scale (VGS) based 
on quality criteria 
by the European 
Commission 
and the SNR was 
calculated.
Three diff erent 
tube voltages 
were used.
9 evaluators = 
5 radiologists, 1 
physicist and 3 
radiographers
The decrease of 
ESD, ovary dose 
and eff ective dose 
between 25% and 50% 
depending on the used 
CR system.
Signifi cant decrease 
of image quality, 
however the images 
were still diagnostically 
acceptable.
Geijer and 
Persliden, 
2005 (24)
Sweden Experimental 
research 
-  Phantom 
study
Lumbar 
spine in AP 
projection
To evaluate 
the relation 
between kV 
and image 
quality at 
the constant 
eff ective dose.
Entrance dose was 
recorded with a 
solid-state detector, 
while organ doses 
and eff ective dose 
were calculated 
with PCXMC 
program (Monte 
Carlo simulation).
Image quality was 
assessed using 
VGS bases on 
quality criteria 
by the European 
Commission by 
eight radiologists.
The tube 
voltage (kV) 
was changed 
between 48 and 
125 and the 
tube load (mAs) 
was adjusted to 
keep a constant 
eff ective dose.
At the constant 
eff ective dose, a lower 
tube voltage delivers 
better image quality 
than higher tube 
voltage. But due to the 
use of AEC which is set 
for a constant detector 
dose this cannot be 
done.
Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1) 11
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
RESEARCH COUNTRY
RESEARCH 
METHOD & 
SUBJECT
INSPECTED 
AREA
AIM OF THE 
STUDY
MEASURING 
EQUIPMENT KEYNOTES
RESULTS AND 
COCNLUSION
Clancy 
et al., 
2010 (25)
Ireland Experimental 
research 
-  Phantom 
study
Lumbar 
spine in AP 
and LAT 
projection
To determine 
the eff ect 
of the use 
and diff erent 
positioning of 
lead shielding 
on dose to 
ovaries, uterus 
and testicles in 
lumbar spine 
radiography.
Dose to the 
mentioned organs 
was measured using 
TLDs.
They used 
diff erent 
positioning of 
lead shielding 
(no shield, tube 
side, wrap-
around and 
Bucky side).
In the AP projection 
dose to the testicles 
was decreased by 42% 
when a tube side apron 
was used and for 36% 
when the wrap-around 
apron was used. In 
the LAT projection, 
the observed dose 
reduction to the 
testicles was 12% with 
the use of wrap-around 
apron. No reduction to 
other inspected organs 
was observed.
Olsson 
et al., 
2010 (26)
Sweden Experimental 
research -  
Phantom and 
patient study 
(n=3)
Lumbar 
spine in AP 
projection
To determine 
the eff ect of 
compression 
technique to 
obtain the 
optimal image 
quality and 
radiation dose.
Kerma-area product 
(KAP) was measured 
with a ionisation 
chamber.
Compression for 
three volunteers 
to determine 
the eff ect of 
compression was 
simulated with 
Comp-X (carbon 
fi bre plate)
With the use of 
compression dose 
reduction of up to 
50% or more can be 
obtained.
Davis in 
Hopkins, 
2013 (27)
UK Experimental 
research -  
Patient study 
(n=30)
Lumbar 
spine in LAT 
projection
Comparison of 
radiation dose 
received by 
the patient in 
LAT projection 
of lumbar 
spine when 
the patient Is 
lying on the 
side and on the 
back with the 
horizontal x-ray 
beam and its 
infl uence on 
image quality.
They measured DAP 
using a DAP meter.
Rotating the 
patients from 
their side to their 
back caused an 
increase in tissue 
thickness. The 
simulations of 
diff erent lateral 
thickness were 
carried out using 
PMMA.
59% of DAP decrease 
was found when the 
patient was lying on 
the side rather than on 
the back. With the use 
of horizontal central 
ray position, the tube 
voltage should be 
increased to decrease 
the radiation dose. 
Mekiš et al., 
2013 (28)
Slovenia Experimental 
research -  
Phantom and 
patient study 
(n=100 female 
patients)
Lumbar 
spine in AP 
and LAT 
projection
To evaluate the 
infl uence of 
lead shielding 
on dose to 
breasts in 
lumbar spine 
radiography.
Dose was measured 
using TLDs for both 
projections.
The use of 
tube voltage 
used in clinical 
environment 
was not in 
accordance 
with European 
guidelines.
The use of lead 
shielding has 
decreased the radiation 
dose to breasts by 
approximately 80%.
Chaparian 
et al., 
2014 (29)
Iran Experimental 
research 
-  Phantom 
study
Lumbar 
spine in 
diff erent 
projections
The aim of the 
study was to 
determine the 
ED, dose to 
radiosensitive 
organs and 
eff ective risk.
The measurements 
of entrance 
skin exposure 
were performed 
using solid-state 
dosimeter, while 
eff ective dose and 
risk of exposure 
induced cancer 
death were 
calculated using  
PCXMC program 
(Monte Carlo 
simulation).
The use of 
diff erent 
projections has 
a diff erent eff ect 
on radiosensitive 
organs as they lie 
closer or further 
from the primary 
fi eld.
Lower eff ective dose 
in PA projection by 
51% and eff ective 
dose and risk by 58% 
in comparison to AP 
projection.
Lower eff ective dose 
in LLAT projection 
by 53% and eff ective 
dose and risk by 58% 
in comparison to RLAT 
projection.
12 Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1)
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
RESEARCH COUNTRY
RESEARCH 
METHOD & 
SUBJECT
INSPECTED 
AREA
AIM OF THE 
STUDY
MEASURING 
EQUIPMENT KEYNOTES
RESULTS AND 
COCNLUSION
Davey in 
England, 
2015 (30)
United 
Kingdom
Experimental 
research 
-  Phantom 
study
Lumbar 
spine 
imaging in 
AP and PA 
projection
Comparing 
AP and PA 
projection 
at various 
tube voltage 
(kV) using CR 
and compare 
eff ective dose, 
dose to organs 
and image 
quality
ESD was measured 
using an ion 
chambers in Mult-
O-Meter. Eff ective 
dose and dose to 
selected organs was 
calculated using 
PCXMC program 
(Monte Carlo 
simulation). The 
image quality was 
assessed using VGA 
by 5 radiography 
students.
The use of PA 
projection has an 
eff ect of object 
magnifi cation 
in comparison 
to the AP 
projection.
Magnifi cation in the PA 
projection was 8%.
The eff ective dose 
reduction was 19.7% 
and the organ that 
had the most dose 
reduction (74%) was the 
stomach.
There were no 
signifi cant diff erences 
between the images 
made in AP and PA 
projection.
Ben-Shlomo 
et al., 
2016 (31)
Israel Experimental 
research 
-  Phantom 
study
Lumbar 
spine in four 
diff erent 
projections 
AP, PA, LLAT, 
RLAT
To calculate 
and compare 
the eff ective 
dose for 
lumbar spine 
radiography 
for adults and 
10-year-old 
children.
The calculations 
were made using 
PCXMC program 
(Monte Carlo 
simulation).
The authors want 
to determine 
the less 
radiosensitive 
side of the body 
for lumbar spine 
imaging.
RLAT projection has 
been proven to deliver 
28% lower ED in 
comparison to LLAT 
projection.
PA projection has been 
proven to deliver 48% 
lower ED in comparison 
to the AP projection.
Karami, in 
Zabihzadeh 
2017 (32)
Iran Retrospective 
study - 830 
images of 
lumbar spine 
in the AP 
projection
Lumbar 
spine in AP 
projection
To evaluate 
the collimation 
protocol in two 
Iranian general 
hospitals.
A mathematical 
formula to 
determine the 
oversized primary 
fi eld was used.
The authors state 
that this has 
happened due to 
implementation 
of digital 
detectors.
The area of diagnostic 
interest was 1.26 times 
higher than it is supposed 
to be – this cause higher 
dose too. In 62% of 
radiographs evaluated, 
ovaries were included in 
the primary beam.
Robinson 
et al., 
2017 (33)
Sweden Experimental 
research 
-  Phantom 
study
Thoraco-
lumbar 
spine 
(scoliosis 
protocol)
The aim was 
to determine 
the diff erences 
to organ dose, 
eff ective dose 
and eff ective 
risk comparing 
tight and loose 
collimation in 
thoraco-lumbar 
spine imaging.
The TLDs were used 
to measure ESD, 
organ doses and the 
eff ective risk were 
calculated using 
a mathematical 
formula.
The patients 
that suff er from 
scoliosis usually 
get imaged quite 
frequently and 
because they are 
at a young age a 
tight collimation 
protocol should 
be used to 
protect as many 
organs.
The organ dose with the 
use of loose collimation 
protocol increased from 
31 to 571%
The eff ective risk 
vas 3.3 times higher 
when using a loose 
collimation.
Shanahan, 
2017 (34)
Australia Phantom 
study
Lumbar 
spine in AP 
projection
To compare 
the ESD based 
on the 15% 
kVp rule and 
simplifi ed 10 
kVp rule for CR 
and DR systems 
(system 1 
and 2), and 
for Projection 
VR - virtual 
radiography 
simulation 
(system 3).
The ESD was 
measured using 
NanoDOT, single 
point dosimeters .
The 15% rule 
states that if you 
increase the tube 
voltage for 15%, 
then the tube 
time current 
product has to 
be decreased by 
50% to get the 
same exposure. 
The exposure 
maintenance 
formula uses the 
increase in SID.
Increasing kVp resulted 
in reduction of ESD 
by 59,5% (system1), 
60,8% (system2) and 
60,3% (system 3). 
Increasing SID resulted 
in reduction of ESD by 
22,3% (system1), 18,8% 
(system2) and 23,5% 
(system 3).
Alukić et al., 
2018 (35)
Slovenia Experimental 
research - 
Phantom and 
patient study 
(n=100)
Lumbar 
spine, AP 
and PA 
projection
Compare 
patient 
radiation dose 
and image 
quality using 
AP and PA 
projection.
DAP meter was 
used to measure 
DAP and eff ective 
dose was calculated 
using PCXMC 
program (Monte 
Carlo simulation). 
image quality was 
evaluate by three 
radiologists using 
criteria in European 
guidelines.
Body mass 
index (BMI), DAP, 
exposure index 
(EXI), mAs, image 
fi eld size and 
source to patient 
distance were 
acquired.
No signifi cant diff erence 
in image fi eld size, DAP 
and image quality but 
in a PA projection a 
signifi cant reduction of 
thickness of abdomen 
by 10%, DAP by 27% 
and eff ective dose 
by 53% compared 
to AP projection. No 
signifi cant diff erence in 
image quality between 
AP and PA projection.
Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1) 13
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
RESEARCH COUNTRY
RESEARCH 
METHOD & 
SUBJECT
INSPECTED 
AREA
AIM OF THE 
STUDY
MEASURING 
EQUIPMENT KEYNOTES
RESULTS AND 
COCNLUSION
Green et al., 
2019 (36)
United 
Kingdom
Experimental 
research - 
Patient  study 
(n=80; 60-100 
kg)
Lumbar 
spine, AP 
and PA 
projection
Evaluate dose 
and image 
quality in both 
projections and 
survey current 
UK practice
DAP meter was 
used to measure the 
DAP and eff ective 
dose was calculated  
using PCXMC 
program (Monte 
Carlo simulation). 
Image quality was 
evaluate by two 
radiologist using 
criteria in European 
guidelines.
BMI, DAP and 
mAs were 
acquired 
Eff ective dose was 
reduced by 41% when 
PA projection was used 
with no diff erence in 
image quality.
Alukić et al., 
2019 (37)
Slovenia Experimental 
research - 
Patient study 
(n=100)
Lumbar 
spine, AP 
and PA 
projection
Determine the 
eff ect of the 
PA projection 
on eff ective 
dose and the 
absorbed organ 
dose
Calculation with  
PCXMC program 
(Monte Carlo 
simulation).
Image quality 
was not 
measured.
Signifi cant reduction 
of ESD by 33% and, 
eff ective dose by 53% 
and 64% average 
reduction of the 
absorbed organ doses 
when the PA projection 
was used.
Pazanin 
et al., 
2020 (38)
Croatia Experimental 
research – 
Patient study 
(n=110)
Lumbar 
spine, AP 
and LAT 
projection
Determine 
the infl uence 
of optimal 
and standard 
(non-optimal) 
collimation on 
radiation dose 
and image 
quality
DAP meter was 
used to measure 
the DAP, absorbed 
and eff ective dose 
were calculated 
using PCXMC 
program (Monte 
Carlo simulation). 
Image quality was 
evaluate by two 
radiologist and a 
radiographer using 
criteria in European 
guidelines.
BMI, exposure 
conditions, 
image fi eld size 
and DAP were 
acquired.
Optimal collimation 
reduced image fi eld size 
by 40%, eff ective dose 
by 48% and absorbed 
dose by 41% for the 
AP and eff ective dose 
by 48% and absorbed 
dose by 10% for the 
LAT projection. Image 
quality improves 
by 24% in the LAT 
projection, and 
showed no statistically 
signifi cant diff erence 
for AP projection with 
the use of optimal 
collimation.
Peacock 
et al., 
2020 (39)
Australia Retrospective 
study - 91 
images of 
lumbar spine 
in the LAT 
projection
Lumbar 
spine in LAT 
projection 
To assess the 
eff ects of the 
high tube 
potential on 
image quality 
using DR 
system and 
validate eff ect 
on dose saving 
technique
Collection of data 
from PACS system. 
Image quality 
was assessed  
by fi ve senior 
radiographers using 
a 15-point visual 
grading analysis.
kV, mAs, 
deviation index 
and DAP were 
acquired.
The reduction of DAP 
with the use of higher 
kVp was shown for 40 
lateral lumbar spine 
radiographs with no 
statistically signifi cant 
diff erence in image 
quality.
Bellizzi 
et al., 
2020 (40)
Malta Experimental 
research –
Phantom and 
patient study 
(n=50) 
Lumbar 
spine in LAT 
projection
To investigate 
the possibility 
of replacing an 
antiscatter grid 
with an air gap 
technique to 
reduce dose.
DAP meter was 
used to measure the 
DAP. Image quality 
was assessed by fi ve 
radiologists using 
a 15-point visual 
grading analysis.
/ Application of air gap 
technique resulted in a 
statistically signifi cant 
reduction in DAP by 
72%, image quality 
between the two 
techniques was not 
signifi cant.
Lai et al., 
2020 (41)
Australia Experimental 
research - 
Phantom 
study 
Lumbar 
spine in LAT 
projection
Determine 
the infl uence 
of diff erent 
exposure 
parameters 
– source to 
detector 
distance, tube 
potential, tube 
time current 
and additional 
copper fi lter for 
reduction of 
eff ective dose.
Eff ective dose 
was calculated 
using PCXMC 
program (Monte 
Carlo simulation). 
Contrast-to-
noise ratio and 
magnifi cation were 
calculated using 
ImageJ. 
Exposure factors, 
SSD, focal-
skin distance, 
collimation fi eld 
and additional 
fi ltration 
parameters 
were acquired 
for each image 
acquisition. 
The highest eff ective 
dose was found with 
the use of lowest SSD, 
lowest tube potential, 
highest tube time 
current and without 
additional copper fi lter.
14 Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1)
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
the lumbar spine can be optimised based on their proposed 
methodology. The results cannot be generalised due to the 
uniqueness of each study methodology and measurement 
technique.
With the lowering of tube voltage (kV), the patient's dose 
can be reduced (21–24,34,39,41). It has already been proven 
that the increase of tube voltage increases the penetration 
of x-rays, and as a consequence, the automatic exposure 
control terminates exposure earlier due to more x-rays 
hitting the ionising chamber of AEC. The negative eff ect of 
tube voltage increase is its infl uence on image quality. The 
use of modern materials and digital technology that off ers 
image postprocessing, such as changing the window centre 
and level, can reduce the negative eff ect of tube voltage 
increase on image quality (24). In the past, the increase of 
tube voltage in screen-fi lm technology has led to a decrease 
of image contrast (4). The inspected papers investigated the 
infl uence of tube voltage increase performed on diff erent 
imaging systems (screen-fi lm and digital). Therefore, the 
results between studies diff er. A fi lm-screen system was in use 
in research until 2004. The research on two CR detectors was 
fi rstly mentioned in 2005 (23). 
Therefore, in the literature review, it could be observed how 
measurement equipment for dose has changed over the years 
and where they fi rst used TLDs and chamber dosimeters (16–
23,25,26). In 2013, Davis and Hopkins fi rst mentioned the use 
of the DAP meter (27).
In the early years, dose on organs could not be measured. The 
record of organ dose was fi rst mentioned in 2005 (24), and 
then again nine years later in 2014 (29). Since 2014, the Monte 
Carlo simulation has been used in eight diff erent articles (29–
31,35–38,41). For calculations of an eff ective dose, organ dose 
weight and height of the patient, imaging fi eld size, DAP, and 
total fi ltration are needed (42).
In studies that investigate an alternative projection in lumbar 
spine radiography (19,27,29–31,35–37), researchers should 
be careful that the radiograph's quality remains optimal and 
that the changing of the position does not result in excessive 
magnifi cation of the inspected object. As described in the 
reviewed papers, the magnifi cation of the inspected object can 
be enlarged up to the point that it still does not interfere with 
the diagnostically important information and radiologist's 
perception. The further away the inspected object is from the 
image receptor, the greater the magnifi cation is (19). The use 
of alternative projections is limited in its use since it cannot be 
used in all diagnostic departments due to the patient's status 
or mobility. Changing the projection from AP to PA projection 
in lumbar spine radiography greatly infl uences dose reduction 
to diff erent organs in the patient's body. Due to anatomy, 
some bones in the human body (pelvis) can work as a shield 
for some organs that lie behind the bone structure. Another 
advantage of the PA projection is that some radiosensitive 
organs lie further from the irradiation source and, due to the 
inverse square law, those organs receive a lower radiation 
dose than in the AP projection. 
Lead shielding has proven to be an eff ective dose reduction 
technique when used inside or outside the primary fi eld. The 
use of lead protection over the radiosensitive organs can 
decrease the dose received by those organs (25,28). Proper 
collimation of the primary beam also has a considerable eff ect 
on the patient's radiation dose (32,33,38). When deciding 
which organs to shield or put outside the primary fi eld, the 
ICRP document must be considered to determine which 
organs have the highest tissue weighting factors (3). However, 
tissue weighting factors change over time based on the 
results of studies investigating the ionising radiation eff ect on 
the human body, the organs, and cells. For example, before 
the year 2007, the gonads were the organ with the highest 
tissue weighting factor (6), so the research was mainly focused 
on dose reduction to the gonads. After the new publication 
from the ICRP in 2007, the gonads are now the sixth organ 
based on tissue weighting factor (3). The organs with the 
highest tissue weighting factor of 0.12 are now the breast, 
lungs, bone marrow, stomach, and colon, so the research of 
dose reduction has nowadays changed to described (most 
radiosensitive) organs. 
Along with the most frequently described research methods, 
other reviewed methods have also been proven to be 
eff ective as a dose reduction technique, such as the change of 
the patient position based on the tube side (cathode-anode) 
(20). It has been proven that the radiation intensity is lower on 
the anode side; therefore, the part of the body with a smaller 
diameter (legs) has to be on that side of the x-ray tube and 
the larger diameter (head) on the cathode side (14). Also, a 
well-known example of the compression of the body part is 
in daily use in mammography since the dose reduction to the 
patient and improved image quality were proven. That kind of 
dose reduction technique can also be implemented to other 
positioning in radiography (26). The ALARA principle states 
that even with a minimum dose, if receiving that dose has no 
benefi t, it should be avoided. This was indicated in a study that 
examined the necessity for a third projection (lumbosacral 
joint in lateral view).  It was found that the use of the third 
projection doubled the dose compared to two projections (AP 
and lateral) (16). Finally,  a signifi cant manner of optimising 
the dose is by using the air gap technique instead of the anti-
scatter grid (40). The reduction in scattered radiation reaching 
the detector is achieved by increasing the distance between 
the eff ective scatter point source and the image receptor. 
This increased distance increases the chance that the scatter 
radiations path will not reach the receptor and; therefore, not 
reduce image contrast.
We recommend that the studies that were performed 
only on an anthropomorphic phantom be conducted also 
on patients in order to determine their infl uence on dose 
reduction on actual patients before using them in the clinical 
environment. In dose optimisation, image quality cannot be 
decreased to the extent that the diagnostically important 
information is lost. If diagnostically important information 
was missed, this would result in even greater harm to the 
patient in comparison to the damage that would result 
due to ionising radiation. In a large variety of the reviewed 
papers, the infl uence of dose optimisation on image quality 
has not been inspected (17,20,34,37,25–29,31–33). When the 
image quality was inspected, all three groups of experts were 
used, but not all together. We propose that all three groups 
of experts (radiographer, radiologist, and medical physicist) 
evaluate the image quality to obtain the optimal results due 
to their diff erent backgrounds. Radiologists would inspect 
the diagnostic part of the image, radiographers the technical 
part of the image and the medical physicists would give an 
objective quality of the image. 
Medical Imaging and Radiotherapy Journal (MIRTJ) 38 (1) 15
Alukić E. et al./ Optimisation of radiographic procedures – lumbar spine imaging in general radiographic imaging
Due to rapid changes in technology, new ideas and methods of 
dose reduction techniques will surely appear. The researchers 
should remember to inspect the eff ects of the optimisation 
technique on image quality and not only on radiation dose. 
Limitations of the systematic review
This review has screened a variety of research papers in the 
fi eld of dose reduction in lumbar spine radiography that 
may lead to easier implication in a clinical setting. Based on 
the reviewed literature, this type of qualitative study was not 
found in this fi eld.
Limitations of our review are that only articles in English were 
included in the review and that not all papers examined the 
eff ects of dose optimisation on image quality.
CONCLUSION
Regardless of the many uses and advantages of ionising 
radiation in X-ray diagnostics, it has a negative eff ect on the 
human body, so the ALARA principle must be observed. This 
means that the patient is imaged with the lowest possible 
radiation dose with optimal image quality based on the 
expected pathology. Based on the inspected studies, it can be 
concluded that there are many diff erent ways to achieve dose 
reduction in lumbar spine radiography, while keeping the 
quality of the images in the diagnostically acceptable range. 
The methods studied for dose optimisation are diff erent lead 
shield positioning, proper collimation, alternative patient 
positioning, patient positioning based on the orientation 
of the X-ray tube, increasing the source-to-image receptor 
distance, and changing the exposure factors, among others. 
All the methods studied were found to be eff ective in dose 
optimisation as the average dose reduction in all the studies 
was 44%. The studies that investigated the eff ect of dose 
optimisation on image quality concluded that there was no 
signifi cant reduction in image quality and that all images 
were still diagnostically acceptable. We did not fi nd a large 
systematic review examining dose optimisation techniques 
and image quality in lumbar spine radiography. Due to a wide 
variety of procedures, techniques, and modalities in radiology, 
this cannot be generalised to all diagnostic procedures. 
Therefore, a targeted review should be performed separately 
for each procedure and modality. 
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