Determining paediatric patient thickness from a single digital radiograph – a proof of principle

Mark Worrall (Lead / Corresponding author), Sarah Vinnicombe, David G. Sutton

    Research output: Contribution to journalArticle

    48 Downloads (Pure)

    Abstract

    Objective: This work presents a proof of principle for a method of estimating the thickness of an attenuator from a single radiograph using the image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure. It is intended this could be developed into a clinical tool to assist with paediatric patient dose audit, for which a measurement of patient size is required. Methods: The proof of principle used measured pixel value and effective linear attenuation coefficient to estimate the thickness of a Solid Water attenuator. The kerma at the detector was estimated using a measurement of pixel value on the image and measured detector calibrations. The initial kerma was estimated using a lookup table of measured output values. The effective linear attenuation coefficient was measured for Solid Water at varying kVp. 11 test images of known and varying thicknesses of Solid Water were acquired at 60, 70 and 81 kVp. Estimates of attenuator thickness were made using the model and the results compared to the known thickness. Results: Estimates of attenuator thickness made using the model differed from the known thickness by 3.8 mm (3.2%) on average, with a range of 0.5-10.8 mm (0.5-9%). Conclusion: A proof of principle is presented for a method of estimating the thickness of an attenuator using a single radiograph of the attenuator. The method has been shown to be accurate using a Solid Water attenuator, with a maximum difference between estimated and known attenuator thickness of 10.8 mm (9%). The method shows promise as a clinical tool for estimating abdominal paediatric patient thickness for paediatric patient dose audit, and is only contingent on the type of data routinely collected by Medical Physics departments. Advances in knowledge: A computational model has been created that is capable of accurately estimating the thickness of a uniform attenuator using only the radiographic image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure.

    Original languageEnglish
    Article number20180139
    Pages (from-to)1-9
    Number of pages9
    JournalBritish Journal of Radiology
    Volume91
    Issue number1087
    Early online date27 Mar 2018
    DOIs
    Publication statusPublished - 5 Apr 2018

    Fingerprint

    Pediatrics
    Water
    X-Rays
    Physics
    Calibration

    Keywords

    • Biophysical Phenomena
    • Child
    • Computer Simulation
    • Humans
    • Models, Theoretical
    • Proof of Concept Study
    • Radiation Dosage
    • Radiographic Image Enhancement/instrumentation
    • Radiometry
    • Scattering, Radiation

    Cite this

    @article{1adc7e83d95e449383c3df20b48acc6d,
    title = "Determining paediatric patient thickness from a single digital radiograph – a proof of principle",
    abstract = "Objective: This work presents a proof of principle for a method of estimating the thickness of an attenuator from a single radiograph using the image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure. It is intended this could be developed into a clinical tool to assist with paediatric patient dose audit, for which a measurement of patient size is required. Methods: The proof of principle used measured pixel value and effective linear attenuation coefficient to estimate the thickness of a Solid Water attenuator. The kerma at the detector was estimated using a measurement of pixel value on the image and measured detector calibrations. The initial kerma was estimated using a lookup table of measured output values. The effective linear attenuation coefficient was measured for Solid Water at varying kVp. 11 test images of known and varying thicknesses of Solid Water were acquired at 60, 70 and 81 kVp. Estimates of attenuator thickness were made using the model and the results compared to the known thickness. Results: Estimates of attenuator thickness made using the model differed from the known thickness by 3.8 mm (3.2{\%}) on average, with a range of 0.5-10.8 mm (0.5-9{\%}). Conclusion: A proof of principle is presented for a method of estimating the thickness of an attenuator using a single radiograph of the attenuator. The method has been shown to be accurate using a Solid Water attenuator, with a maximum difference between estimated and known attenuator thickness of 10.8 mm (9{\%}). The method shows promise as a clinical tool for estimating abdominal paediatric patient thickness for paediatric patient dose audit, and is only contingent on the type of data routinely collected by Medical Physics departments. Advances in knowledge: A computational model has been created that is capable of accurately estimating the thickness of a uniform attenuator using only the radiographic image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure.",
    keywords = "Biophysical Phenomena, Child, Computer Simulation, Humans, Models, Theoretical, Proof of Concept Study, Radiation Dosage, Radiographic Image Enhancement/instrumentation, Radiometry, Scattering, Radiation",
    author = "Mark Worrall and Sarah Vinnicombe and Sutton, {David G.}",
    year = "2018",
    month = "4",
    day = "5",
    doi = "10.1259/bjr.20180139",
    language = "English",
    volume = "91",
    pages = "1--9",
    journal = "British Journal of Radiology",
    issn = "0007-1285",
    publisher = "British Institute of Radiology",
    number = "1087",

    }

    Determining paediatric patient thickness from a single digital radiograph – a proof of principle. / Worrall, Mark (Lead / Corresponding author); Vinnicombe, Sarah; Sutton, David G.

    In: British Journal of Radiology, Vol. 91, No. 1087, 20180139, 05.04.2018, p. 1-9.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Determining paediatric patient thickness from a single digital radiograph – a proof of principle

    AU - Worrall, Mark

    AU - Vinnicombe, Sarah

    AU - Sutton, David G.

    PY - 2018/4/5

    Y1 - 2018/4/5

    N2 - Objective: This work presents a proof of principle for a method of estimating the thickness of an attenuator from a single radiograph using the image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure. It is intended this could be developed into a clinical tool to assist with paediatric patient dose audit, for which a measurement of patient size is required. Methods: The proof of principle used measured pixel value and effective linear attenuation coefficient to estimate the thickness of a Solid Water attenuator. The kerma at the detector was estimated using a measurement of pixel value on the image and measured detector calibrations. The initial kerma was estimated using a lookup table of measured output values. The effective linear attenuation coefficient was measured for Solid Water at varying kVp. 11 test images of known and varying thicknesses of Solid Water were acquired at 60, 70 and 81 kVp. Estimates of attenuator thickness were made using the model and the results compared to the known thickness. Results: Estimates of attenuator thickness made using the model differed from the known thickness by 3.8 mm (3.2%) on average, with a range of 0.5-10.8 mm (0.5-9%). Conclusion: A proof of principle is presented for a method of estimating the thickness of an attenuator using a single radiograph of the attenuator. The method has been shown to be accurate using a Solid Water attenuator, with a maximum difference between estimated and known attenuator thickness of 10.8 mm (9%). The method shows promise as a clinical tool for estimating abdominal paediatric patient thickness for paediatric patient dose audit, and is only contingent on the type of data routinely collected by Medical Physics departments. Advances in knowledge: A computational model has been created that is capable of accurately estimating the thickness of a uniform attenuator using only the radiographic image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure.

    AB - Objective: This work presents a proof of principle for a method of estimating the thickness of an attenuator from a single radiograph using the image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure. It is intended this could be developed into a clinical tool to assist with paediatric patient dose audit, for which a measurement of patient size is required. Methods: The proof of principle used measured pixel value and effective linear attenuation coefficient to estimate the thickness of a Solid Water attenuator. The kerma at the detector was estimated using a measurement of pixel value on the image and measured detector calibrations. The initial kerma was estimated using a lookup table of measured output values. The effective linear attenuation coefficient was measured for Solid Water at varying kVp. 11 test images of known and varying thicknesses of Solid Water were acquired at 60, 70 and 81 kVp. Estimates of attenuator thickness were made using the model and the results compared to the known thickness. Results: Estimates of attenuator thickness made using the model differed from the known thickness by 3.8 mm (3.2%) on average, with a range of 0.5-10.8 mm (0.5-9%). Conclusion: A proof of principle is presented for a method of estimating the thickness of an attenuator using a single radiograph of the attenuator. The method has been shown to be accurate using a Solid Water attenuator, with a maximum difference between estimated and known attenuator thickness of 10.8 mm (9%). The method shows promise as a clinical tool for estimating abdominal paediatric patient thickness for paediatric patient dose audit, and is only contingent on the type of data routinely collected by Medical Physics departments. Advances in knowledge: A computational model has been created that is capable of accurately estimating the thickness of a uniform attenuator using only the radiographic image, the exposure factors with which it was acquired and a priori knowledge of the characteristics of the X-ray unit and detector used for the exposure.

    KW - Biophysical Phenomena

    KW - Child

    KW - Computer Simulation

    KW - Humans

    KW - Models, Theoretical

    KW - Proof of Concept Study

    KW - Radiation Dosage

    KW - Radiographic Image Enhancement/instrumentation

    KW - Radiometry

    KW - Scattering, Radiation

    UR - http://www.scopus.com/inward/record.url?scp=85049205712&partnerID=8YFLogxK

    U2 - 10.1259/bjr.20180139

    DO - 10.1259/bjr.20180139

    M3 - Article

    VL - 91

    SP - 1

    EP - 9

    JO - British Journal of Radiology

    JF - British Journal of Radiology

    SN - 0007-1285

    IS - 1087

    M1 - 20180139

    ER -