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Objective measurement of Radiation Induced Erythema by nonparametric hypothesis testing on indices from multivariate data
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Medicine, Radiation Sciences, Oncology.
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2008 (English)In: Chemometrics and Intelligent Laboratory Systems, Vol. 90, no 1, 43-8 p.Article in journal (Refereed) Published
Abstract [en]

Three instrumental measurement techniques: Laser-Doppler Imaging (LDI), Digital Colour Photography (DCP) and Near InfraRed (NIR) spectroscopy were tested for their potential to objectively measure radiation-based erythema in breast cancer patients. The irradiation dose intervals were 0, 8-16, 18-26, 28-34, 36-44 and 46-50 Gy. In addition, two types of skin lotion for reducing erythema were tested on the patients and these were compared to using no lotion. The measured results had very skew distributions for all three techniques making nonparametric testing necessary. The Wilcoxon Signed Rank Sum Test (WSRST) was used for this purpose. LDI was performed to produce univariate average perfusion values leading to a perfusion increment ratio. These ratios showed a good sensitivity to erythema, with a median detection limit of 18 Gy. DCP was used to extract average red-green-blue (RGB) values that were used in multivariate models. Results for a combination of principal component score values showed a marked increase in median erythema from 8 Gy on. The Multivariate data from NIR spectroscopy were data-reduced to principal component scores and combinations of these were tested. The score combinations were used to show median detection limits down to 8 Gy. The difference between the lotions and using no lotion gave no significant result for the WSRST paired comparison for any used measurement technique.

Place, publisher, year, edition, pages
2008. Vol. 90, no 1, 43-8 p.
Keyword [en]
objective erythema measurement, multivariate data analysis, Wilcoxon nonparametric test, skin lotion, instrumentation
URN: urn:nbn:se:umu:diva-16195DOI: doi:10.1016/j.chemolab.2007.08.005OAI: diva2:155868
15 January 2008Available from: 2007-12-10 Created: 2007-12-10 Last updated: 2011-02-24Bibliographically approved
In thesis
1. Multivariate non-invasive measurements of skin disorders
Open this publication in new window or tab >>Multivariate non-invasive measurements of skin disorders
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The present thesis proposes new methods for obtaining objective and accurate diagnoses in modern healthcare. Non-invasive techniques have been used to examine or diagnose three different medical conditions, namely neuropathy among diabetics, radiotherapy induced erythema (skin redness) among breast cancer patients and diagnoses of cutaneous malignant melanoma. The techniques used were Near-InfraRed spectroscopy (NIR), Multi Frequency Bio Impedance Analysis of whole body (MFBIA-body), Laser Doppler Imaging (LDI) and Digital Colour Photography (DCP).

The neuropathy for diabetics was studied in papers I and II. The first study was performed on diabetics and control subjects of both genders. A separation was seen between males and females and therefore the data had to be divided in order to obtain good models. NIR spectroscopy was shown to be a viable technique for measuring neuropathy once the division according to gender was made. The second study on diabetics, where MFBIA-body was added to the analysis, was performed on males exclusively. Principal component analysis showed that healthy reference subjects tend to separate from diabetics. Also, diabetics with severe neuropathy separate from persons less affected.

The preliminary study presented in paper III was performed on breast cancer patients in order to investigate if NIR, LDI and DCP were able to detect radiotherapy induced erythema. The promising results in the preliminary study motivated a new and larger study. This study, presented in papers IV and V, intended to investigate the measurement techniques further but also to examine the effect that two different skin lotions, Essex and Aloe vera have on the development of erythema. The Wilcoxon signed rank sum test showed that DCP and NIR could detect erythema, which is developed during one week of radiation treatment. LDI was able to detect erythema developed during two weeks of treatment. None of the techniques could detect any differences between the two lotions regarding the development of erythema.

The use of NIR to diagnose cutaneous malignant melanoma is presented as unpublished results in this thesis. This study gave promising but inconclusive results. NIR could be of interest for future development of instrumentation for diagnosis of skin cancer.

Place, publisher, year, edition, pages
Umeå: Kemi, 2006. 46 p.
Multivariate Data Analysis, Non-invasive techniques, Clinical studies, Principal Component Analysis, Partial Least Squares Discriminant Analysis, Wilcoxon Signed Rank Sum Test, Near-InfraRed spectroscopy, Frequency Bio Impedance Analysis of whole body, Laser Doppler Imaging, Digital Colour Photography
National Category
Analytical Chemistry
urn:nbn:se:umu:diva-865 (URN)91-7264-154-1 (ISBN)
Public defence
2006-10-06, KB3A9, KBC-huset, Umeå, 10:30
Available from: 2006-09-14 Created: 2006-09-14 Last updated: 2012-06-26Bibliographically approved

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