{
    "abstract": "Linear scaling is used to convert raw computed tomography (CT) pixel values into Hounsfield units corresponding to different tissue values. Analysis of a benchmarking study, presented here, where the same CT scan was imported into and then exported from multiple radiotherapy treatment planning systems, found inconsistencies in HU scaling parameter values exported along with the images, particularly when images were exported using the Radiation Therapy Oncology Group format. Several methods of estimating conversion parameters, based on estimating pixel values corresponding to air and water within the image, for pelvic CT images from a large multi-centre trial were compared against original Digital Imaging and Communications in Medicine export parameters. In general using the mean of a sample region at the centroid of the bladder to estimate the value of water was more accurate than using the minimum or maximum or a single value at the centroid. Accuracy of methods of air estimation tested were dependent in part on features of the CT scanners and treatment planning systems, making it difficult to pick one method as superior that was independent of scanner and treatment planning system type. Based on the above analysis, methods for estimating air and water were selected for use in performing linear scaling of a set of pelvic CT images prior to their use in an interpatient image registration application. The selected methods were validated against a more recent and homogeneous dataset. Estimation error was found to be much lower within the validation set.",
    "authors": [
        {
            "affiliation": "Radiation Oncology, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, WA, 6009, Australia. Angel.Kennedy@health.wa.gov.au.",
            "firstname": "Angel",
            "initials": "A",
            "lastname": "Kennedy"
        },
        {
            "affiliation": "Australian e-Health Research Centre, CSIRO, Royal Brisbane and Women's Hospital, Brisbane, Australia.\nSchool of Mathematical and Physical Sciences, University of Newcastle, Newcastle, Australia.\nSouth Western Sydney Clinical School, University of New South Wales, Sydney, Australia.\nCentre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia.",
            "firstname": "Jason",
            "initials": "J",
            "lastname": "Dowling"
        },
        {
            "affiliation": "Calvary Mater Newcastle Hospital, Newcastle, Australia.\nSchool of Mathematical and Physical Sciences, University of Newcastle, Newcastle, Australia.",
            "firstname": "Peter B",
            "initials": "PB",
            "lastname": "Greer"
        },
        {
            "affiliation": "Radiation Oncology, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, WA, 6009, Australia.\nCentre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia.\nSchool of Physics and Astrophysics, University of Western Australia, Crawley, Australia.",
            "firstname": "Martin A",
            "initials": "MA",
            "lastname": "Ebert"
        }
    ],
    "conclusions": null,
    "copyrights": null,
    "doi": "10.1007/s13246-018-0651-x",
    "journal": "Australasian physical & engineering sciences in medicine",
    "keywords": [
        "DICOM",
        "Hounsfield units",
        "Interpatient registration",
        "Linear scaling estimation",
        "RTOG"
    ],
    "methods": null,
    "publication_date": "2018-06-09",
    "pubmed_id": "29881940",
    "results": null,
    "title": "Estimation of Hounsfield unit conversion parameters for pelvic CT images.",
    "xml": "<Element 'PubmedArticle' at 0x788504f4d530>"
}