THE APPLICATION OF NONLINEAR ANALYSIS FOR …



Biomagnetic findings in gynaecologic oncology (our experience)

AN. ANASTASIADIS, Athanasia Kotini, Photios A. Anninos, NIKOLETA KOUTLAKI*, Panagiotis ANASTASIADIS*

Lab of Medical Physics and *Dept of Obstetrics & Gynecology, Medical School, Democritus Univ. of Thrace, University Campus, Alex/polis, 68100,Greece

Abstract: This study aimed to investigate biomagnetic activity in benign and malignant ovarian and breast diseases using a biomagnetometer SQUID. Magnetic recordings were obtained from 30 patients with palpable ovarian lesions (14 of them were invasive carcinomas, and 16 were benign ovarian lesions) and 21 patients with palpable breast lumps (17 of them were invasive carcinomas and 4 were benign breast lesions). We used a one channel biomagnetometer SQUID (Superconducting QUantum Interference Device), in order to measure the magnetic field from benign and malignant ovarian and breast diseases. Interestingly, the ovarian and breast lesion waveforms and the corresponding spectral densities were of high amplitude in most malignant lesions, and of low amplitude in most benign diseases. These findings were of statistical significance (p < 0.001). It is suggested that biomagnetic measurements of benign and malignant ovarian and breast diseases, which is an entirely new application of SQUID technology, is a promising procedure for assessing tumors.

Keywords: SQUID; benign breast lesions; malignant breast lesions; benign ovarian lesions; malignant ovarian lesions

1.Introduction

Ovarian malignant neoplasms are the most common gynecological pelvic malignancy in most Western countries. The advent of vaginal ultrasound screening methods for ovarian cancer has made the ovaries more accessible. Dramatic changes in ovarian tissue vascularity during oncogenesis are mediated by numerous angiogenic factors and can be detected by using flow data from color Doppler. Malignant tumor vessels are usually dilated, saccular, and tortuous, and may contain tumor cells within the endothelial lining of the vessel wall. In view of the fact that ovarian malignancy is still an insidious and intractable disease, which is usually diagnosed at a late stage, is correlated with high rate of mortality and it is considered to be a "silent killer" and since there is a rather high incidence of these malignant tumors in the menopause, all means should be used to detect this disease at an early stage. Ovary lesions, like any other living tissue, emit spontaneous magnetic activity caused by ionic movements across the plasma membrane.

Breast cancer mortality rates have not changed during the past 60 years despite significant advances in screening mammography (1). Screening programs involving periodic physical examination and mammography in asymptomatic and high-risk women increase the detection rate of breast cancer and may improve the survival rate. Unfortunately most women who develop breast cancer do not have identifiable risk factors and analysis of epidemiologic data has failed to identify women who are not at significant risk and would not benefit from screening. New less expensive screening techniques such as two-view mammography are being investigated in an attempt to reduce the cost of widespread screening.

It is tempting, therefore, to use novel technology in order to achieve a better understanding of breast oncology. The female breast, like any other living tissue, emits spontaneous magnetic activity caused by ionic movements across the plasma membrane (2). The SQUID is a diagnostic tool capable of measuring the exceedingly weak magnetic fields emitted by the living tissues. The higher the concentration of living cells in the test area, the higher the biomagnetic fields produced and recorded from it. This non-invasive technique has been used successfully for studying fetal heart (3,4), brain activities and the hemodynamics of uterine artery and umbilical cord (5,6,7).

Methods

Biomagnetic recordings were obtained by a single channel second order gradiometer DC-SQUID (MODEL 601;Biomagnetic Technologies Inc., San Diego, USA). To attenuate the influence of electromagnetic artifacts, the measurements were performed in a shielded room of low magnetic noise. During the recording procedure the patient was relaxed lying on a wooden bed and the recordings were performed after positioning the SQUID sensor 3 mm above the target area. Thirty patients with palpable ovarian lesions were examined. Of these14 were invasive carcinomas, and 16 were benign ovarian lesions .For the ovarian examination, 5 points were selected for examination. Point 5 was located at the very center of the ovarian lesion, whereas points 1-4 were located at the periphery of the target area. Twenty-one patients with palpable breast lumps were included in the study. Of these 17 were invasive carcinomas and 4 were benign breast lesions. Only patients with lesions in the right breast were included. This was considered necessary so as to eliminated interference from the heart’s magnetic activity, which can affect the reliability of the measurements. For each point 32 recordings of 1-second duration each were taken and digitized by a 12 bit precision analogue-to –digital converter with a sampling frequency of 256 Hz. The biomagnetic signals were band-pass filtered, with cut-off-frequencies of 0.1-100 Hz. The associated Nyquist frequency limit, with the above-mentioned sampling frequency, is therefore 128 Hz, which is well above the constituent frequency components of interest in biomagnetic recordings and avoids aliasing artifacts. Informed consent for the study was obtained from all the patients prior to the procedure.

Results

The ovarian lesions raw data were of high amplitudes in most (95%) of the malignant ovarian lesions and low amplitudes in most (94%) of the benign ovarian diseases (Figures 1,2). In all cases the frequencies considered were distributed in the range 2-4 Hz. The corresponding spectral densities of the magnetic field were shown after statistical Fourier analysis: these were of high spectral amplitudes in the apparently malignant ovarian neoplasms and of low spectral amplitudes in benign ones. The above findings were of statistical significance (p ................
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