Accurate Kap Meter Calibration as a Prerequisite for Optimisation in Projection Radiography

Sandborg, Michael; Carlsson, Gudrun Alm

doi:10.1093/rpd/ncv524

Cited by 5 publications

(5 citation statements)

References 6 publications

(9 reference statements)

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“…In addition, our results with respect to the

values as functions of tube potential and spectral filter were consistent with the results reported by Malusek et al. 17 The American Association of Physicists in Medicine (AAPM) recommends that the measurement uncertainties in X‐ray dosimeter should be within 10% 10 and thus

should be applied to correct the obtained

values in the clinical settings. However, the X‐ray beam quality can be frequently altered as a function of the employed clinical modes (X‐ray parameters) and geometrical settings, such as working angles or patient physique.…”

Section: Discussionsupporting

confidence: 91%

Effect of equalization filters on measurements with kerma‐area product meter in a cardiovascular angiography system

Ichikawa

Fukuda

Hayashi

et al. 2021

J Applied Clin Med Phys

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This study aimed to evaluate the effect of equalization filters (EFs) on the kerma-area product (KAP KM Q ) and incident air-kerma (K KM a,i,Q ) using a kermaarea product (KAP) meter. In addition, potential underestimations of the K KM a,i,Q values by EFs were identified. Materials and methods: A portable flat-panel detector (FPD) was placed to measure the X-ray beam area (A) and EFs dimension at patient entrance reference point (PERP). Afterward, a 6-cm 3 external ionization chamber was placed to measure incident air-kerma (K ext a,i,Q ) at PERP instead of the portable FPD. KAP reading and K ext a,i,Q were simultaneously measured at several X-ray beam qualities with and without EFs. The X-ray beam quality correction factor by KAP meter (k KM Q,Q 0 ) was calculated by A, K ext a,i,Q and KAP reading to acquire the KAP KM Q and K KM a,i,Q .Upon completion of the measurements,KAP KM Q ,K KM a,i,Q ,and K ext a,i,Q were plotted as functions of tube potential, spectral filter, and EFs dimension. Moreover, K KM a,i,Q ∕K ext a,i,Q values were calculated to evaluate the K KM a,i,Q underestimation. Results: The k KM Q,Q 0 values increased with an increase in the X-ray tube potential and spectral filter, and the maximum k KM Q,Q 0 was 1.18. KAP KM Q and K KM a,i,Q decreased as functions of EFs dimension, whereas K ext a,i,Q was almost constant. K KM a,i,Q ∕K ext a,i,Q decreased with an increase in EFs dimension but increased with an increase in tube potential and spectral filter, and the range was 0.55-1.01. Conclusions: K KM a,i,Q value was up to approximately two times lower than the K ext a,i,Q values by EFs. When using the K KM a,i,Q value, the potential K KM a,i,Q underestimation with EFs should be considered.

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“…In addition, our results with respect to the

should be applied to correct the obtained

Section: Discussionsupporting

confidence: 91%

Effect of equalization filters on measurements with kerma‐area product meter in a cardiovascular angiography system

Ichikawa

Fukuda

Hayashi

et al. 2021

J Applied Clin Med Phys

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“…Toroi et al (2008a) and Malusek et al (2016) both report that it is possible to achieve an expanded uncertainty of <±7% (k = 2) if appropriate and careful KAP calibration is carried out across the range of diagnostic beam qualities encountered in clinical practice. Honey et al (2018) reports that in an analysis of the effectiveness of quality assurance measurements performed across the UK, a significant proportion of KAP meters (5.5%) were found to exceed a ±25% error margin.…”

Section: Methods and Resultsmentioning

confidence: 99%

“…The influence of uncertainties associated with the physical measurements of dose is more easily quantified and has been reported widely-examples being Worrall and Sutton (2015), Toroi et al (2008b), Hourdakis et al (2010), the International Atomic Energy Agency (IAEA 2007), Dewerd and Wagner (1999), Malusek et al (2016) and Martin (2007).…”

Section: Introductionmentioning

confidence: 99%

The influence of patient size on the overall uncertainty in radiographic dose audit

Sutton¹,

Worrall²,

Sexton³

et al. 2021

J. Radiol. Prot.

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The aim of this work was to investigate the effect of patient and cohort size on the overall uncertainty associated with dose audit using radiography of the abdomen as the exemplar. Water equivalent diameter Dw was used as the surrogate for patient size and its distribution (σ(Dw)) was used to quantify the effect of sample size. The more precise the kerma area product calibration, the more patients are required in the cohort to have the same impact on the overall uncertainty. Patient sample sizes of 300–400 will result in expanded uncertainties approaching the theoretical limit of double the measurement uncertainty when audits are performed with instruments having measurement uncertainties equal to ±7%, ±10% or ±12.5%. By way of example, for a field instrument with a measurement uncertainty of ±10%, a minimum sample size of 350 is required to achieve a total expanded uncertainty of ±21%. In the case of instruments with associated measurement uncertainty of ±3.5%, patient sample sizes of 300–400 will result in expanded uncertainties of approximately ±10%. From review of the literature and comparison with the results obtained here, it is conjectured that for radiographic dose audits of all parts of the trunk the contribution to overall uncertainty due to patient and sample size could be predicted using an indicative value for σ(Dw) of 3.4 where local data is not available.

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“…It has a built-in air kerma area product, PKA-meter (Diamentor, PTW, Freiburg, Germany) that integrates the air kerma over the x-ray beam. The reading from the PKA-meter, located in the collimator housing, was traceable to the Swedish secondary standards laboratory at the Swedish Radiation Safety Authority in Stockholm (7) .…”

Section: Imaging Equipmentmentioning

confidence: 99%

“…If no lag was present, the SNR was estimated to less than 6% (k=2) (7) . After the fourth measurement (see figure 2), the tube current increased from 26 mA to 34 mA and ⁄ with decreasing field of view.…”

Section: Snr 2 Rate Measurements and Analysismentioning

confidence: 99%

Assessing the Usefulness of the Quasi-Ideal Observer for Quality Control in Fluoroscopy

Tesselaar

Sandborg

2015

Radiat Prot Dosimetry

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Accurate Kap Meter Calibration as a Prerequisite for Optimisation in Projection Radiography

Cited by 5 publications

References 6 publications

Effect of equalization filters on measurements with kerma‐area product meter in a cardiovascular angiography system

Effect of equalization filters on measurements with kerma‐area product meter in a cardiovascular angiography system

The influence of patient size on the overall uncertainty in radiographic dose audit

Assessing the Usefulness of the Quasi-Ideal Observer for Quality Control in Fluoroscopy

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