Theoretical analysis of comparative patient skin dose and exposure technique approaches in planar radiography.

Ian Garbett

Research output: Contribution to journalArticle

Abstract

Abstract: A theoretical analysis of patient skin dose changes with manipulation of technique factors (mAs and kV) was carried out in order to obtain a description of the relationship between patient dose and the exposure technique approach employed. The standard exposure technique approaches in variable part thickness radiography of "fixed kVp" and "variable kVp" and the "15% rule" in constant part thickness radiography were analysed in terms of the changes in patient skin dose. Analytical expressions describing the variation of dose change ratios have been developed in respect of each approach and also in comparison between the two standard approaches. The resultant model is limited to essentially qualitative predictions due to its inherent limitation of neglecting secondary radiation at the entrance site of the beam, but nevertheless indicates some non intuitive benefits in utilisation of mAs (only) changes in compensating for the thinner part and for lower image densities, as well as indicating that most gain is to be had (in terms of lower skin dose), where only modest part thickness compensation is required. The model also describes the influence of the chosen voltage in a "reference technique" (upon which further compensatory changes in exposure factors are based) on the patient skin dose, when the variable kV approach is utilised.
Original languageEnglish
Pages (from-to)21-26
Number of pages6
JournalRadiographer
Volume56
Issue number1
Publication statusPublished - 2009

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Radiography
Skin
Radiation

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title = "Theoretical analysis of comparative patient skin dose and exposure technique approaches in planar radiography.",
abstract = "Abstract: A theoretical analysis of patient skin dose changes with manipulation of technique factors (mAs and kV) was carried out in order to obtain a description of the relationship between patient dose and the exposure technique approach employed. The standard exposure technique approaches in variable part thickness radiography of {"}fixed kVp{"} and {"}variable kVp{"} and the {"}15{\%} rule{"} in constant part thickness radiography were analysed in terms of the changes in patient skin dose. Analytical expressions describing the variation of dose change ratios have been developed in respect of each approach and also in comparison between the two standard approaches. The resultant model is limited to essentially qualitative predictions due to its inherent limitation of neglecting secondary radiation at the entrance site of the beam, but nevertheless indicates some non intuitive benefits in utilisation of mAs (only) changes in compensating for the thinner part and for lower image densities, as well as indicating that most gain is to be had (in terms of lower skin dose), where only modest part thickness compensation is required. The model also describes the influence of the chosen voltage in a {"}reference technique{"} (upon which further compensatory changes in exposure factors are based) on the patient skin dose, when the variable kV approach is utilised.",
keywords = "Exposure techniques, Mathematical models, Medical technology, Patient dose, Planar radiography, Radiation Dosage, Radiography",
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Theoretical analysis of comparative patient skin dose and exposure technique approaches in planar radiography. / Garbett, Ian.

In: Radiographer, Vol. 56, No. 1, 2009, p. 21-26.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Theoretical analysis of comparative patient skin dose and exposure technique approaches in planar radiography.

AU - Garbett, Ian

N1 - Imported on 12 Apr 2017 - DigiTool details were: Journal title (773t) = Radiographer. ISSNs: 0033-8273;

PY - 2009

Y1 - 2009

N2 - Abstract: A theoretical analysis of patient skin dose changes with manipulation of technique factors (mAs and kV) was carried out in order to obtain a description of the relationship between patient dose and the exposure technique approach employed. The standard exposure technique approaches in variable part thickness radiography of "fixed kVp" and "variable kVp" and the "15% rule" in constant part thickness radiography were analysed in terms of the changes in patient skin dose. Analytical expressions describing the variation of dose change ratios have been developed in respect of each approach and also in comparison between the two standard approaches. The resultant model is limited to essentially qualitative predictions due to its inherent limitation of neglecting secondary radiation at the entrance site of the beam, but nevertheless indicates some non intuitive benefits in utilisation of mAs (only) changes in compensating for the thinner part and for lower image densities, as well as indicating that most gain is to be had (in terms of lower skin dose), where only modest part thickness compensation is required. The model also describes the influence of the chosen voltage in a "reference technique" (upon which further compensatory changes in exposure factors are based) on the patient skin dose, when the variable kV approach is utilised.

AB - Abstract: A theoretical analysis of patient skin dose changes with manipulation of technique factors (mAs and kV) was carried out in order to obtain a description of the relationship between patient dose and the exposure technique approach employed. The standard exposure technique approaches in variable part thickness radiography of "fixed kVp" and "variable kVp" and the "15% rule" in constant part thickness radiography were analysed in terms of the changes in patient skin dose. Analytical expressions describing the variation of dose change ratios have been developed in respect of each approach and also in comparison between the two standard approaches. The resultant model is limited to essentially qualitative predictions due to its inherent limitation of neglecting secondary radiation at the entrance site of the beam, but nevertheless indicates some non intuitive benefits in utilisation of mAs (only) changes in compensating for the thinner part and for lower image densities, as well as indicating that most gain is to be had (in terms of lower skin dose), where only modest part thickness compensation is required. The model also describes the influence of the chosen voltage in a "reference technique" (upon which further compensatory changes in exposure factors are based) on the patient skin dose, when the variable kV approach is utilised.

KW - Exposure techniques

KW - Mathematical models

KW - Medical technology

KW - Patient dose

KW - Planar radiography

KW - Radiation Dosage

KW - Radiography

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VL - 56

SP - 21

EP - 26

JO - Radiographer

JF - Radiographer

SN - 0033-8273

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