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This paper reports investigations led on the combination of the refractive index and morphological dilation to enhance performances towards breast tumour margin delineation during conserving surgeries. The refractive index map of invasive ductal and lobular carcinomas were constructed from an inverse electromagnetic problem. Morphological dilation...
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PurposeShave margins have been shown to decrease positive final margins in partial mastectomy. We investigated prognostic factors associated with residual disease in shave margins.Methods
Patients with invasive breast carcinoma and ductal carcinoma in situ (DCIS) who had circumferential shave margins excised during lumpectomy were abstracted from a...
Citations
... The complex refractive index n*(ω) at each pixel location can be extracted from the experimental transfer function Ts (ω) by solving an inverse electromagnetic problem 23 . This function denotes the disagreement between the experimental waveform E s (ω) and waveforms 24 . We performed the extraction on a flat area of the blue substrate near the main fracture. ...
In this paper, we present the potential of Terahertz Time-Domain Imaging (THz-TDI) as a tool to perform non-invasive 3D analysis of an ancient enamel plate manufactured by Longwy Company in France. The THz data collected in the reflection mode were processed using noise filtering procedures and an advanced imaging approach. The results validate the capability to identify glaze layers and the thickness of ceramic materials. To characterize the nature of the pigments, we also use with X-ray images, visible near-infrared hyperspectral imaging spectroscopy, and p-XRF (portable X-ray fluorescence) to qualitatively and quantitively identify the materials used. The obtained information enables a better understanding of the decoration chromogens nature and, thus, to determine the color palette of the artists who produced such decorative object. We also establish the efficiency of a focus, Z-tracker, which enables to perform THz imaging on non-flat samples and to attenuate artifacts obtained with a short focus lens. Then, 3D images are extracted and generated, providing a real vision. We also report the evaluation of the internal damage state through the detection of fractures.
... The non-ionising properties of THz radiation, paired with the non-contact nature of THz-TDS measurements, make this technique particularly attractive for applications in medical imaging [3][4][5]. THz-TDS has been applied to the delineation of tumour margins in skin [6] and breast [7] cancers, as well as imaging of skin conditions such as burns [8] and diabetic foot syndrome [9]. However, typical free-space THz-TDS systems suffer from bulky and cumbersome optics which, combined with the limited penetration depth of THz radiation in biological tissue [3,10], limits their applicability in medical imaging mainly to external, surface-based pathologies. ...
We demonstrate that asynchronous optical sampling (ASOPS) can be used to measure the propagation of terahertz (THz) bandwidth pulses in a coplanar waveguide device with integrated photoconductive switches used for signal excitation and detection. We assess the performance of the ASOPS technique as a function of measurement duration, showing the ability to acquire full THz time-domain traces at rates up to 100 Hz. We observe a peak dynamic range of 40 dB for the shortest measurement duration of 10 ms, increasing to 88 dB with a measurement time of 500 s. Our work opens a route to real-time video-rate imaging via modalities using scanned THz waveguides, as well as real-time THz sensing of small volume analytes; we benchmark our on-chip ASOPS measurements against previously published simulations of scanning THz sensor devices, demonstrating sufficient dynamic range to underpin future video-rate THz spectroscopy measurements with these devices.
... THz reflection imaging by RI at the frequency of 550 THz has no significance for the classification of low-density malignant edges. To overcome this limitation, Cassar et al. combined morphological expansion and RI threshold, which reported the high sensitivity of 80% and specificity of 82% (75). ...
Background and Objective
Terahertz (THz) imaging has wide applications in biomedical research due to its properties, such as non-ionizing, non-invasive and distinctive spectral fingerprints. Over the past 6 years, the application of THz imaging in tumor tissue has made encouraging progress. However, due to the strong absorption of THz by water, the large size, high cost, and low sensitivity of THz devices, it is still difficult to be widely used in clinical practice. This paper provides ideas for researchers and promotes the development of THz imaging in clinical research.
Methods
The literature search was conducted in the Web of Science and PubMed databases using the keywords “Terahertz imaging”, “Breast”, “Brain”, “Skin” and “Cancer”. A total of 94 English language articles from 1 January, 2017 to 30 December, 2022 were reviewed.
Key Content and Findings
In this review, we briefly introduced the recent advances in THz near-field imaging, single-pixel imaging and real-time imaging, the applications of THz imaging for detecting breast, brain and skin tissues in the last 6 years were reviewed, and the advantages and existing challenges were identified. It is necessary to combine machine learning and metamaterials to develop real-time THz devices with small size, low cost and high sensitivity that can be widely used in clinical practice. More powerful THz detectors can be developed by combining graphene, designing structures and other methods to improve the sensitivity of the devices and obtain more accurate information. Establishing a THz database is one of the important methods to improve the repeatability and accuracy of imaging results.
Conclusions
THz technology is an effective method for tumor imaging. We believe that with the joint efforts of researchers and clinicians, accurate, real-time, and safe THz imaging will be widely applied in clinical practice in the future.
... The exact determination of the effective refractive index is crucial in many application. Since cancerous and healthy tissue possess different refractive indices [47][48][49], it could be recently shown that modeling biological tissue as an effective medium allows to determine between malign and healthy tissue at an early stage of the cancerous disease [50,51]. To delimit the tumor, precise determination of the effective permittivity is needed, which requires more accurate mixing rules than the currently used MG mixing rule [51], especially when size effects are not negligible. ...
... To delimit the tumor, precise determination of the effective permittivity is needed, which requires more accurate mixing rules than the currently used MG mixing rule [51], especially when size effects are not negligible. This is the case for the frequently used THz regime, where the typical size of human cells (10 -100 µm [52]) can be in the range of used wavelengths (about 3 mm -40 µm for 0.1 -7 THz) while index contrasts between malign and healthy tissue are up to 1.8 at these frequencies [49]. ...
Considering light transport in disordered media, the medium is often treated as an effective medium requiring accurate evaluation of an effective refractive index. Because of its simplicity, the Maxwell-Garnett (MG) mixing rule is widely used, although its restriction to particles much smaller than the wavelength is rarely satisfied. Using 3D finite-difference time-domain simulations, we show that the MG theory indeed fails for large particles. Systematic investigation of size effects reveals that the effective refractive index can be instead approximated by a quadratic polynomial whose coefficients are given by an empirical formula. Hence, a simple mixing rule is derived which clearly outperforms established mixing rules for composite media containing large particles, a common condition in natural disordered media.
... Several groups including El-Shenawee et al, at Arkansas and Mounaix et al, in Bordeaux have used terahertz radiation to image breast cancer, and there has been further development of handheld terahertz imaging devices that could be used to detect breast cancer tumour margins during surgery [245]. Figure 26 shows the identification of tumour achieved applying refractive index-based morphological dilation to terahertz image data of breast tissue [246]. ...
... (i) Pathology image and correlated view of the respective zones (a)-(d); (ii) pathology mask; (iii) raw terahertz image at 550 GHz; (iv) refractive index map at 550 GHz. Reproduced from[246]. CC BY 4.0. ...
... The exact determination of the effective refractive index is crucial in many application. Since cancerous and healthy tissue possess different refractive indices [40][41][42], it could be recently shown that modeling biological tissue as an effective medium allows to determine between malign and healthy tissue at an early stage of the cancerous disease [43,44]. To delimit the tumor, precise determination of the effective permittivity is needed, which requires more accurate mixing rules than the currently used MG mixing rule [44], especially when size effects are not negligible. ...
... To delimit the tumor, precise determination of the effective permittivity is needed, which requires more accurate mixing rules than the currently used MG mixing rule [44], especially when size effects are not negligible. This is the case for the frequently used THz regime, where the typical size of human cells (10 -100 µm [45]) can be in the range of used wavelengths (about 3 mm -40 µm for 0.1 -7 THz) while index contrasts between malign and healthy tissue are up to 1.8 at these frequencies [42]. ...
Considering light transport in disordered media, the medium is often treated as an effective medium requiring accurate evaluation of an effective refractive index. Because of its simplicity, the Maxwell-Garnett (MG) mixing rule is widely used, although its restriction to particles much smaller than the wavelength is rarely satisfied. Using 3D finite-difference time-domain simulations, we show that the MG theory indeed fails for large particles. Systematic investigation of size effects reveals that the effective refractive index can be instead approximated by a quadratic polynomial whose coefficients are given by an empirical formula. Hence, a simple mixing rule is derived which clearly outperforms established mixing rules for composite media containing large particles, a common condition in natural disordered media.
... The science of THz pulse technology is a growing field of interest in fundamental research, security surveillance, pharmaceutical industries, the biomedical sector, telecommunications, spectroscopy and imaging applications [1][2][3]. THz technology has gained wide attention in the study of various materials. In particular, its research and spectroscopic application stems from the signature response of electrons, spins, phonons and the rotational modes of molecules in the THz spectral range [4][5][6]. ...
The THz pulse of a few picosecond durations have been generated and detected via optical rectification and electro-optic effect within the same ZnTe crystal. An unbalanced single-shot detection scheme was performed to characterize the signal. As a result, a multicycle signal was obtained, in which two-photon absorption and other associated nonlinear effects were reportedly negligible. The experimental set-up is compact, economical, easy to build and has the added simplicity of facilitating an independent analysis of the horizontal or vertical polarization arm of the THz-modulated chirped probe beam. This work finds a useful application in integrated THz devices, narrow-band THz phonon spectroscopy and spectroscopic investigation of fast-occurring processes.
... In a recent study as reported in [119], the authors have used a combination of morphological dilation and refractive index thresholding to classify malignant and benign breast tissues so as to enhance the performance of tumor margin delineation for conserving surgeries. The image acquisition has been performed employing TPS3000 THz system in reflection mode. ...
... Further, the authors have conducted a histology routine where dilation geometry performances are associated with different thresholds evaluation. The achieved results shows the great potential of the combination of tissue fundamental optical properties (based on refractive index) and morphological dilation for greatly aiding breast conserving surgeries [119]. A test-retest and validation of the contrast between healthy and cancerous tissue are examined using THz-TDS on dehydrated breast tissues mounted on Teflon plates as reported in [108]. ...
There is a keen interest in the exploration of new generation emitters and detectors due to advancements in innovation of new materials and device processing technologies which have opened up new frontiers in the Terahertz (THz) spectrum. Therefore, it is necessary to review the developments in THz technology for healthcare applications, their impact, implications and prospects for ongoing research and development. This paper provides a broad overview of the current status and prospects of application of THz imaging and sensing for the healthcare domain. We present current knowledge, identify existing challenges for wide scale clinical adoption of THz systems and prospective opinions to facilitate research and development towards optimized and miniaturized THz systems and biosensors that provide real operational convenience through emerging trends. Firstly, we provide an overview of the THz imaging and sensing techniques that exploit properties of THz generation and detection with emphasis on terahertz time domain spectroscopy (THz-TDS) and THz Metamaterials. The mechanisms of tissue image contrast and the application of THz imaging and sensing for biomedical applications in particular, the cancer detection application is reported. Secondly, an outlook toward the advancements in THz technology in the interface of healthcare 4.0 and its enabling technologies is explored for next generation smart and connected healthcare systems. Third, we identify the merits and existing challenges in THz cancer imaging and sensing and suggest prospective opinions to pave way to ongoing and future research. Further, we discuss the recent advances in THz imaging development and the contribution of near-field techniques based on plasmonic, and resonance based metasurfaces, waveguides etc. for breaking the diffraction limit towards development of THz systems that are convenient for point of care. We bring researchers a roadmap for future research scope.
... Investigations about various tissues to discriminate between healthy and malignant breast tissues were carried out [1,2,5,6,8,13,18,25,36,40,47,[51][52][53][54]56]. Okada et al. [32] who reported terahertz near-field microscopy of ductal carcinoma in situ (DCIS) of the breast, Vafapour et al. [42] who reported the potential of terahertz sensing for cancer diagnosis, Ke et al. [26,27] used THz technology in vivo sensing of rabbit cornea, Cassar et al. [7] who reported investigations led on the combination of the refractive index and morphological dilation to enhance performances toward breast tumor margin delineation during conserving surgeries. Smolyanskaya et al. [35] discussed in their review THz dielectric permittivity of water and water-containing media, using THz time-domain spectroscopy and spectroscopy, and sub-wavelength resolution THz imaging. ...
Background
The terahertz radiation is a specific part of the electromagnetic radiation spectrum and has multiple significant applications in multiple scientific researches such as the applications in the medicine. An important application of the terahertz is its use in tumor imaging which is very important in the tumor surgery; however, lots of physicians and workers in the medical field have little information or having no information at all, dealing with this significant part of the electromagnetic spectrum.
Results
In this work, we interviewed a number of local surgeons in Syrian Arab Republic, who reported that they visually delineate the contour of tumors to be removed, and in order to reduce the number of future possible interventions, a large margin of healthy tissue is often excised. Furthermore, a number of pathologists who reported that preparing samples of excised tissues for examination takes a long period of time which may extend to several days, and that the results of histopathology indicate in some cases the integrity of removed tissues.
Conclusion
We have found that a significant number of participants in the survey demonstrated that the importance of dealing with terahertz imaging and terahertz spectroscopy, encouraging to implement the technique in the Syrian Arab Republic.
... The science of THz pulse technology is a growing field of interest in fundamental research, security surveillance, pharmaceutical industries, the biomedical sector, telecommunications, spectroscopy and imaging applications [1][2][3]. THz technology has gained wide attention in the study of various materials. In particular, its research and spectroscopic application stems from the signature response of electrons, spins, phonons and the rotational modes of molecules in the THz spectral range [4][5][6]. ...
