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Numerical study of non-Fourier thermal ablation of benign thyroid tumor by focused ultrasound (FU)

Namakshenas Pouya, Mojra Afsaneh

Biocybernetics and Biomedical Engineering

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2019

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Vol. 39, no. 3

571--585

EN

Estimation of thermal response of tumoral tissue to the hyperthermia treatment is an important factor for increasing the effectiveness of therapeutic method. In this study, focused ultrasound (FU) is used to produce irreversible thermal damage for the treatment of benign thyroid tumor. To this end, a multi-layer model of the neck including internal organs from the skin toward the thyroid gland is exposed to ultrasound irradiation at powers of 3 W, 5 W, and 7 W and at the frequency of 3 MHz. It is observed that the acoustic pressure is noticeably increased by considering different neck's internal organs. The temperature profile is obtained by taking into account the non-Fourier thermal response for the thyroid gland. The thermal wave model and dual phase lag model are utilized along with the traditional Pennes bio-heat transfer model. Studying the temperature profile at 3 W power by non-Fourier thermal models illustrates that the maximum temperature with time delays of 11.32, 5.66 and 2.86 s is 20.51%, 14.1% and 8.65% lower than the corresponding value by the Fourier model. Deviation from the Fourier results is increased for higher powers of transducer. It is also inferred that in the presence of time delays, temperature variation in the focal area becomes smoother. Effect of non-Fourier heat transfer is studied on the area of necrotic tumoral region. It is concluded that region with irreversible thermal damage shrinks by considering the phase lags in the way that in 3 W power and 5.66 s time delay, no necrosis of the thyroid nodule is observed.

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Relation Between Structural Changes in B-Mode Ultrasound Images of Thyroid Parenchyma and the Presence of Thyroid Antibodies in Blood Sample

Holinka S., Šára R., Smutek D.

Machine Graphics and Vision

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2009

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Vol. 18, No. 1

67-82

EN

Ultrasonography is a cheap and quick non-invasive medical imaging technique, used as a diagnostic method for autoimmune thyroiditis. Another important diagnostic method for this chronic inflammation is measuring the increased level of thyroid antibodies (anti-thyroid peroxidase (TPOAb) and/or anti- thyroglobulin (TgAb)) in blood samples. This paper shows that B-mode ultrasound images contain weak information related to the presence or absence of these antibodies. Ultrasound image analysis is based on textural recognition using probabilistic spatial features. Two studies are performed. The results of the first study show that the spatial texture features we used contain weak information about the presence or absence of TPOAb and TgAb antibodies as measured by conditional entropy. In the second study, a classifier derived from Bayesian decision theory is tested on a set of 2820 sonograms of 94 subjects. The training set contains 67 subjects and the test set consists of 27 independent subjects. The results of classification to three classes (healthy, thyroiditis with positive antibody test, thyroiditis with negative antibody test) achieved sensitivity 29% and specificity 100% on the test set.

3

Joint analysis of histological and ultrasonic images to lean state of thyroid gland

Nedzved A., Zalesky B., Ablameyko S., Drozd V., Fridman M.

Machine Graphics and Vision

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2007

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Vol. 16, No. 3/4

293-304

EN

Simultaneous analysis of histological and ultrasonic (US) images of human thyroid glands for thyroid cancer diagnostics is proposed in the paper. It allows to explain the characteristics of US pictures of the thyroid gland via the sizes of its follicles. To show the dependence of US image features on the state of follicles, statistical analysis of US-texture is performed. In addition, the size of follicles in histological images is calculated by analysis of a distance map for the nuclei of cells. It is shown that echogenicity of the thyroid gland in US images depends essentially on the size of its follicles. The organ regions that contain many follicles of a size smaller than the size of healthy follicles, or contain many destroyed follicles, have low echogenicity. The same effect is observed for regions with oversized follicles. This information can be used to avoid a surgical procedure, including histological analysis.

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Monitorowanie leczenia izotopem J131 z zastosowaniem analizy scyntygraficznego obrazu tarczycy

Dyszkiewicz A., Koprowski R., Wróbel Z.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2001

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Vol. 7, nr 1-2

43-47

PL

Przedstawiono zarys symptomatologii oraz problematykę leczenia gruczołu tarczowego ze szczególnym uwzględnieniem nadczynności tarczycy. Wzorując się na znanych systemach ekspertowych uwypuklono konieczność standaryzacji procedur diagnostyczno-terapeutycznych. Zaproponowano skomputeryzowany system nadzoru skuteczności leczenia nadczynności tarczycy za pomocą izotopu J131, opierając się na analizie porównawczej rozkładu maksimów emisji w scyntygramach wyjściowych i kontrolnych. W odróżnieniu od stosowanego aktualnie uśrednionego pomiaru jodochwytność lub wzrokowej oceny scyntygrafii metoda umożliwia obserwację ewolucji nawet niewielkich ognisk patologii.

EN

The outline of symptomatology and problems connected with thyroid gland treatment, especially taking hyperthyroidism into consideration, are presented in the study. Modelling on known expert systems, the need for standardisation of diagnostic and therapeutic procedures is emphasised. A computerised system for supervision of efficacy in hyperthyroidism treatment with use of isotope J 131, based on comparative analysis of distribution of emission maximums in initial and test scintigrams was proposed. Contrary to the currently applied averaging measurement of thyroid iodine uptake or visual judgement of scintigraphy, the proposed method makes it possible to observe evolution of even not big focuses of pathology.