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The proapoptotic BCL-2 homology (BH3)-only endoplasmic reticulum (ER)-resident protein BCL-2 interacting killer (BIK) positively regulates mitochondrial outer membrane permeabilization, the point of no return in apoptosis. It is generally accepted that BIK functions at a distance from mitochondria by binding and sequestering antiapoptotic proteins at the ER, thereby promoting ER calcium release. Although BIK is predominantly localized to the ER, we detect by fluorescence lifetime imaging microscopy-FRET microscopy, BH3 region-dependent direct binding between BIK and mitochondria-localized chimeric mutants of the antiapoptotic proteins BCL-XL and BCL-2 in both baby mouse kidney (BMK) and MCF-7 cells. Direct binding was accompanied by cell type-specific differential relocalization in response to coexpression of either BIK or one of its target binding partners, BCL-XL, when coexpressed in cells. In BMK cells with genetic deletion of both BAX and BAK (BMK-double KO), our data suggest that a fraction of BIK protein moves toward mitochondria in response to the expression of a mitochondria-localized BCL-XL mutant. In contrast, in MCF-7 cells, our data suggest that BIK is localized at both ER and mitochondria-associated ER membranes and binds to the mitochondria-localized BCL-XL mutant via relocalization of BCL-XL to ER and mitochondria-associated ER membrane. Rather than functioning at a distance, our data suggest that BIK initiates mitochondrial outer membrane permeabilization via direct interactions with ER and mitochondria-localized antiapoptotic proteins, which occur via ER-mitochondria contact sites, and/or by relocalization of either BIK or antiapoptotic proteins in cells.
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Proteínas Reguladoras de la Apoptosis , Apoptosis , Retículo Endoplásmico , Proteínas Mitocondriales , Animales , Ratones , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Proteína bcl-X/genética , Proteína bcl-X/metabolismo , Retículo Endoplásmico/genética , Retículo Endoplásmico/metabolismo , Proteínas de la Membrana/metabolismo , Mitocondrias/metabolismo , Proteínas Mitocondriales/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismoRESUMEN
OBJECTIVES: A major challenge in non-small cell lung cancer surgery is the occurrence of positive tumor margins. This may lead to the need for additional surgeries and has been linked to poor patient prognosis. This study aims to develop an in vivo surgical tool that can differentiate cancerous from noncancerous lung tissue at the margin. METHODS: A time-resolved fluorescence and diffuse reflectance bimodal device was used to measure the lifetime, spectra, and intensities of endogenous fluorophores as well as optical properties of lung tissue. The tumor and fibrotic tissue data, each containing 36 samples, was obtained from patients who underwent surgical removal of lung tissue after being diagnosed with squamous carcinoma but before any other treatment was administered. The normal lung tissue data were obtained from nine normal tissue samples. RESULTS: The results show a statistically significant difference between cancerous and noncancerous tissue. The results also show a difference in metabolic related optical properties between fibrotic and normal lung tissue samples. CONCLUSIONS: This work demonstrates the feasibility of a device that can differentiate cancerous and noncancerous lung tissue for patients diagnosed with squamous cell carcinoma.
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Carcinoma de Pulmón de Células no Pequeñas , Carcinoma de Células Escamosas , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/cirugía , Carcinoma de Células Escamosas/diagnóstico por imagen , Carcinoma de Células Escamosas/cirugía , Espectrometría de Fluorescencia , PulmónRESUMEN
Older adults who are frail are one of the most sedentary and the least physically active age groups. Prolonged sedentary time is associated with increased risk of negative health outcomes. To help design effective and sustainable content and optimize the uptake of sedentary behaviour interventions, an in-depth understanding of older adults' perceptions of sedentary behaviour is needed; however, most qualitative studies have been conducted in healthy older adults. The aim of this study was to explore perspectives of sedentary behaviour within the context of older adults who are pre-frail and frail after the winter and spring. We included participants if they: (1) spoke English or attended with a translator or caregiver, (2) were ≥ 60 years, and (3) were frail on the Morley Frail Scale. We utilized a qualitative description methodology including a semi-structured in-depth interview and thematic content analysis. Concepts from the COM-B (Capability Opportunity Motivation-Behaviour) model were used to guide the semi-structured interviews and analysis. To ensure credibility of the data, we used an audit trail and analyst triangulation. We recruited 21 older adults (72 ± 7.3 years, 13 females, 13 frail) from southwestern Ontario, Canada. Two individuals were lost to follow-up due to medical mistrust and worse health. We transcribed 39 audio recordings. We identified three salient themes: (1) older adults rationalize their sedentary behaviours through cognitive dissonance (reflective motivation), (2) urban cities in southwestern Ontario may not be "age-friendly" (physical opportunity), and (3) exercise is something people "have to do", but hobbies are for enjoyment despite medical conditions (psychological capability). Perspectives of sedentary behaviour were different in the winter versus spring, with participants perceiving themselves to be less active in winter. Incorporating dissonance-based interventions as part of an educational program could be used to target the reflective motivation and psychological capability components. Future research should consider interdisciplinary collaborations with environmental gerontology to develop age-friendly communities that promote meaningful mobility to target physical opportunity.
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Anciano Frágil , Investigación Cualitativa , Conducta Sedentaria , Humanos , Femenino , Anciano , Masculino , Anciano Frágil/psicología , Persona de Mediana Edad , Ontario , Anciano de 80 o más Años , Entrevistas como Asunto , Ejercicio Físico/psicologíaRESUMEN
OBJECTIVE: This work aims to develop a clinically compatible system that can perform breast tissue analysis in a more time efficient process than conventional histopathological assessment. The potential for such a system to be used in vivo in the operating room or surgical suite to improve patient outcome is investigated. METHOD: In this work, 80 matched pairs of invasive ductal carcinoma and adjacent normal breast tissue were measured in a combined time-resolved fluorescence and diffuse reflectance (DA) system. Following measurement, the fluorescence intensity of collagen and flavin adenine dinucleotide (FAD); the fluorescence lifetime of collagen, nicotinamide adenine dinucleotide (NADH), and FAD; the DA; absorption coefficient; and reduced scattering coefficient were extracted. Samples then underwent histological processing and H&E staining to classify composition as tumor, fibroglandular, and/or adipose tissue. RESULTS: Statistically significant differences in the collagen and FAD fluorescence intensity, collagen and FAD fluorescence lifetime, DA, and scattering coefficient were found between each tissue group. The NADH fluorescence lifetime and absorption coefficient were statistically different between the tumor and fibroglandular groups, and the tumor and adipose groups. While many breast tissue analysis studies label fibroglandular and adipose together as "normal" breast tissue, this work indicates that some differences between tumor and fibroglandular tissue are not the same as differences between tumor and adipose tissue. Observations of the reduced scatter coefficient may also indicate further classification to include fibro-adipose may be necessary. Future work would benefit from the additional tissue classification. CONCLUSION: With observable differences in optical parameters between the three tissue types, this system shows promise as a breast analysis tool in a clinical setting. With further work involving samples of mixed composition, this combined system could potentially be used intraoperatively for rapid margin assessment.
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Neoplasias de la Mama , Neoplasias , Humanos , Femenino , Flavina-Adenina Dinucleótido , NAD , Mama/patología , Neoplasias/patología , Espectrometría de Fluorescencia , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/cirugía , Neoplasias de la Mama/patologíaRESUMEN
We report the development of a three-dimensional optical model to predict the propagation of light through multilayer optical fluorescence sensors employing total internal reflection. The ray-tracing-based model visualizes the propagation of light from a light source through the optical sensor allowing optimization of the optical path, optical properties of the materials, and the coupling strategy. The model demonstrates how light can be guided through different layers of the sensor structure by controlling the incident angle of light and the relationship between the incident angle and the relative sensitivity. Simulation results are compared against experimental data to validate the model in a fluorescence-based dissolved oxygen sensor. Customization of the light source parameters, coupling optics, sensor optical properties, and sensor dimensions could allow developers to refine and optimize sensor prototypes before conducting bench testing.
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The streak camera is a picosecond resolution photodetector with parallel input capability; however, the degree of multiplexing is limited by crosstalk and temporal uncertainty in the sweeping field. We introduced a fixed time delay between adjacent fibers to reduce crosstalk in the synchroscan mode. The fixed delay and a tunable electronic delay between the input pulse and the synchroscan unit allows robust separation modes between the streaks, while spatial and temporal nonlinearities can be calibrated in. The efficacy of the design is demonstrated through a 100-fold multiplexed confocal fluorescence lifetime imaging microscope in live cells.
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PURPOSE: One of the major problems in breast cancer surgery is defining surgical margins and establishing complete tumor excision within a single surgical procedure. The goal of this work is to establish instrumentation that can differentiate between tumor and normal breast tissue with the potential to be implemented in vivo during a surgical procedure. METHODS: A time-resolved fluorescence and reflectance spectroscopy (tr-FRS) system is used to measure fluorescence intensity and lifetime as well as collect diffuse reflectance (DR) of breast tissue, which can subsequently be used to extract optical properties (absorption and reduced scatter coefficient) of the tissue. The tr-FRS data obtained from patients with Invasive Ductal Carcinoma (IDC) whom have undergone lumpectomy and mastectomy surgeries is presented. A preliminary study was conducted to determine the validity of using banked pre-frozen breast tissue samples to study the fluorescence response and optical properties. Once the validity was established, the tr-FRS system was used on a data-set of 40 pre-frozen matched pair cases to differentiate between tumor and normal breast tissue. All measurements have been conducted on excised normal and tumor breast samples post surgery. RESULTS: Our results showed the process of freezing and thawing did not cause any significant differences between fresh and pre-frozen normal or tumor breast tissue. The tr-FRS optical data obtained from 40 banked matched pairs showed significant differences between normal and tumor breast tissue. CONCLUSION: The work detailed in the main study showed the tr-FRS system has the potential to differentiate malignant from normal breast tissue in women undergoing surgery for known invasive ductal carcinoma. With further work, this successful outcome may result in the development of an accurate intraoperative real-time margin assessment system. Lasers Surg. Med. 50:236-245, 2018. © 2018 Wiley Periodicals, Inc.
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Neoplasias de la Mama/diagnóstico por imagen , Carcinoma Ductal de Mama/diagnóstico por imagen , Márgenes de Escisión , Espectrometría de Fluorescencia , Neoplasias de la Mama/cirugía , Carcinoma Ductal de Mama/cirugía , Femenino , Humanos , Mastectomía , Reproducibilidad de los ResultadosRESUMEN
Counting of Escherichia coli DH5α-cell suspensions in PBS is performed using a microflow cytometer based on a photonic-microfluidic integrated device. Side-scattered light signals are used to count the E. coli cells. A detection efficiency of 92% is achieved when compared with the expected count from a hemocytometer. The detection efficiency is correlated to the ratio of sample to sheath flow rates. It is demonstrated that E. coli can be easily distinguished from beads of similar sizes (2-4 µm) as their scattering intensities are different.
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Escherichia coli , Citometría de Flujo/instrumentación , Citometría de Flujo/métodos , Técnicas Analíticas Microfluídicas , Técnicas Bacteriológicas/instrumentación , Técnicas Bacteriológicas/métodos , Diseño de Equipo , PoliestirenosRESUMEN
Older adults who are frail are likely to be sedentary. Prior interventions to reduce sedentary time in older adults have not been effective as there is little research about the context of sedentary behaviour (posture, location, purpose, social environment). Moreover, there is limited evidence on feasible measures to assess context of sedentary behaviour in older adults. The aim of our study was to determine the feasibility of measuring context of sedentary behaviour in older adults with pre-frailty or frailty using a combination of objective and self-report measures. We defined "feasibility process" using recruitment (20 participants within two-months), retention (85%), and refusal (20%) rates and "feasibility resource" if the measures capture context and can be linked (e.g., sitting-kitchen-eating-alone) and are all participants willing to use the measures. Context was assessed using a wearable sensor to assess posture, a smart home monitoring system for location, and an electronic or hard-copy diary for purpose and social context over three days in winter and spring. We approached 80 potential individuals, and 58 expressed interest; of the 58 individuals, 37 did not enroll due to lack of interest or medical mistrust (64% refusal). We recruited 21 older adults (72±7.3 years, 13 females, 13 frail) within two months and experienced two dropouts due to medical mistrust or worsening health (90% retention). The wearable sensor, indoor positioning system, and electronic diary accurately captured one domain of context, but the hard copy was often not completed with enough detail, so it was challenging to link it to the other devices. Although not all participants were willing to use the wearable sensor, indoor positioning system, or electronic diary, we were able to triage the measures of those who did. The use of wearable sensors and electronic diaries may be a feasible method to assess context of sedentary behaviour, but more research is needed with device-based measures in diverse groups.
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Estudios de Factibilidad , Estaciones del Año , Conducta Sedentaria , Dispositivos Electrónicos Vestibles , Humanos , Anciano , Femenino , Masculino , Estudios Longitudinales , Anciano Frágil , Anciano de 80 o más Años , Autoinforme , Sistemas de Información GeográficaRESUMEN
Oxygen concentration measurement in 3D hydrogels is vital in 3D cell culture and tissue engineering. However, standard 3D imaging systems capable of measuring oxygen concentration with adequate precision are based on advanced microscopy platforms, which are not accessible in many laboratories due to the system's complexity and the high price. In this work, we present a fast and low-cost phosphorescence lifetime imaging design for measuring the lifetime of oxygen-quenched phosphorescence emission with 0.25 µs temporal precision and sub-millimeter spatial resolution in 3D. By combining light-sheet illumination and the frequency-domain lifetime measurement using a commercial rolling-shutter CMOS camera in the structure of a conventional optical microscope, this design is highly customizable to accommodate application-specific research needs while also being low-cost as compared to advanced instruments. As a demonstration, we made a fluidic device with a gas-permeable film to create an artificial oxygen gradient in the hydrogel sample. Dye-embedded beads were distributed in the hydrogel to conduct continuous emission lifetime monitoring when nitrogen was pumped through the fluidic channel and changed oxygen distribution in the sample. The dynamics of the changes in lifetime co-related with their location in the gel of size 0.5â mm×1.5â mm×700â µm demonstrate the ability of this design to measure the oxygen concentration stably and precisely in 3D samples.
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Context awareness is a field in pervasive computing, which has begun to impact medical systems via an increasing number of healthcare applications that are starting to use context awareness. The present work seeks to determine which contexts are important for medical applications and which domains of context-aware applications exist in healthcare. A systematic scoping review of context-aware medical systems currently used by patients or healthcare providers (inclusion criteria) was conducted between April 2021 and June 2023. A search strategy was designed and applied to Pub Med, EBSCO, IEEE Explore, Wiley, Science Direct, Springer Link, and ACM, articles from the databases were then filtered based on their abstract, and relevant articles were screened using a questionnaire applied to their full texts prior to data extraction. Applications were grouped into context-aware healthcare application domains based on past reviews and screening results. A total of 25 articles passed all screening levels and underwent data extraction. The most common contexts used were user location (8 out of 25 studies), demographic information (6 out of 25 studies), movement status/activity level (7 out of 25 studies), time of day (5 out of 25 studies), phone usage patterns (5 out of 25 studies), lab/vitals (7 out of 25 studies), and patient history data (8 out of 23 studies). Through a systematic review process, the current study determined the key contexts within context-aware healthcare applications that have reached healthcare providers and patients. The present work has illuminated many of the early successful context-aware healthcare applications. Additionally, the primary contexts leveraged by these systems have been identified, allowing future systems to focus on prioritizing the integration of these key contexts.
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Atención a la Salud , Personal de Salud , HumanosRESUMEN
Significance: Breast conservation therapy is the preferred technique for treating primary breast cancers. However, breast tumor margins are hard to determine as tumor borders are often ill-defined. As such, there exists a need for a clinically compatible tumor margin detection system. Aim: A combined time-resolved fluorescence and diffuse reflectance (TRF-DR) system has been developed to determine the optical properties of breast tissue. This study aims to improve tissue classification to aid in surgical decision making. Approach: Normal and tumor breast tissue were collected from 80 patients with invasive ductal carcinoma and measured in the optical system. Optical parameters were extracted, and the tissue underwent histopathological examination. In total, 761 adipose, 77 fibroglandular, and 347 tumor spectra were analyzed. Principal component analysis and decision tree modeling were performed using only TRF optical parameters, only DR optical parameters, and using the combined datasets. Results: The classification modeling using TRF data alone resulted in a tumor margin detection sensitivity of 72.3% and specificity of 88.3%. Prediction modeling using DR data alone resulted in greater sensitivity and specificity of 80.4% and 94.0%, respectively. Combining both datasets resulted in the improved sensitivity and specificity of 85.6% and 95.3%, respectively. While both sensitivity and specificity improved with the combined modeling, further study of fibroglandular tissue could result in improved classification. Conclusion: The combined TRF-DR system showed greater tissue classification capability than either technique alone. Further work studying more fibroglandular tissue and tissue of mixed composition would develop this system for intraoperative use for tumor margin detection.
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Mama , Dispositivos Ópticos , Humanos , Análisis Multivariante , Mama/diagnóstico por imagen , Mastectomía Segmentaria , Obesidad , RadiofármacosRESUMEN
The additive manufacturing of titanium into porous geometries offers a means to generate low-stiffness endosseous implants with a greater surface area available for osseointegration. In this work, selective laser melting was used to produce gyroid-based scaffolds with a uniform pore size of 300 µm or functionally graded pore size from 600 µm to 300 µm. Initial in vitro assessment with Saos-2 cells showed favourable cell proliferation at pore sizes of 300 and 600 µm. Following implantation into rabbit tibiae, early histological observations at four weeks indicated some residual inflammation alongside neovessel infiltration into the scaffold interior and some early apposition of mineralized bone tissue. At twelve weeks, both scaffolds were filled with a mixture of adipocyte-rich marrow, micro-capillaries, and mineralized bone tissue. X-ray microcomputed tomography showed a higher bone volume fraction (BV/TV) and percentage of bone-implant contact (BIC) in the implants with 300 µm pores than in the functionally graded specimens. In functionally graded specimens, localized BV/TV measurement was observed to be higher in the innermost region containing smaller pores (estimated at 300-400 µm) than in larger pores at the implant exterior. The unit cell topology of the porous implant was also observed to guide the direction of bone ingrowth by conducting along the implant struts. These results suggest that in vivo experimentation is necessary alongside parametric optimization of functionally graded porous implants to predict short-term and long-term bone apposition.
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Oseointegración , Titanio , Animales , Conejos , Porosidad , Microtomografía por Rayos XRESUMEN
The streak camera is one of the fastest photodetection systems, while its capability of multiplexing is particularly attractive to many applications requiring parallel data acquisition. The degree of multiplexing in a streak camera is limited by the crosstalk between input channels. We developed a technique that introducing a fixed time delay between adjacent fiber channels in a customized two-dimensional to one-dimensional fiber array to significantly reduce crosstalk both at the sample plane and at the input of a streak camera. A prototype system has been developed that supports 100 input channels, and its performance in fluorescence microscopy is demonstrated.
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Fibras Ópticas , Fenómenos Ópticos , Convallaria/citología , Diseño de Equipo , Procesamiento de Imagen Asistido por ComputadorRESUMEN
In order to simplify the design process of microfabricated concave gratings, simplified algorithms for fast characterization of the concave grating were developed. These algorithms can be used to assist system designers using ray-tracing software in the determination of optimum design parameters considering the requirements and restrictions for specific applications. According to the algorithms, it is feasible to design a flat field microconcave grating with a 4 mm grating radius as a key component in a micro-Raman spectrometer system for inline environmental monitoring applications. This microspectrometer operates over the spectral wavelength band from 785 nm to 1000 nm and has a spectral resolution of 2 nm at 900 nm. The total size of the system is 1 mm×4 mm×3.7 mm, making it one of the smallest for this wavelength range and spectrum resolution.
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Algoritmos , Monitoreo del Ambiente/instrumentación , Espectrometría Raman/instrumentación , Diseño de Equipo , Miniaturización/instrumentación , Modelos Teóricos , Espectrometría Raman/métodosRESUMEN
OBJECTIVE: In colonoscopy, it is desirable to accurately localize the position of the endoscope's distal tip. Current tip localization techniques are not sufficient for recording the position and movement of the tip, nor is its rotation measured. We hypothesize that integration of multiple tracking modalities can effectively record the endoscope's motion in real time and continuously corrects cumulative errors. METHODS: A dual modality tracking method is developed to measure the motion of the endoscope's insertion tube in real time, including insertion length, rotation angle, and their velocities. Optical trackballs were used to measure the endoscope insertion tube's motion and cameras were used to correct cumulative errors. RESULTS: The accuracy of insertion length and rotational angle were measured. For speeds ≤ 10 mm/s, the median and 90th percentile insertion position errors were 0.88 mm and 2.2 mm, respectively. The insertion position error increases with the speed, reaching a maximum of 10 mm for speeds < 40 mm/s. 11° and 21° were the median and 90th percentile rotation angle errors for angular speeds < 40°/s. Cumulative errors are sufficiently reduced by the imaging modality. CONCLUSION: The prototype device can precisely measure an unmodified endoscope's position, rotation, and motion in real time without significant accumulative error. The prototype device is small and compatible with existing commercial endoscopes as an add-on accessory, which could be used for reporting, localizing the lesions in follow up procedures, operational guidance, quality assurance, and training. Clinical and Translational Impact Statement-This preclinical research develops an endoscope tracker that can be integrated into colonoscopy training, automatically record endoscope motion, and be further developed to improve polyp and tumor localization during colonoscopy.
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Endoscopios , Pólipos , Humanos , Rotación , Colonoscopía , MovimientoRESUMEN
Cytoplasmic and membrane-bound BCL-2 family proteins regulate apoptosis, a form of programmed cell death, via dozens of binary protein interactions confounding measurement of the effects of inhibitors in live cells. In cancer, apoptosis is frequently dysregulated, and cell survival depends on antiapoptotic proteins binding to and inhibiting proapoptotic BH3 proteins. The clinical success of BH3 mimetic inhibitors of antiapoptotic proteins has spawned major efforts by the pharmaceutical industry to develop molecules with different specificities and higher affinities. Here, quantitative fast fluorescence lifetime imaging microscopy enabled comparison of BH3 mimetic drugs in trials and preclinical development by measuring drug effects on binding affinities of interacting protein pairs in live cells. Both selectivity and efficacy were assessed for 15 inhibitors of four antiapoptotic proteins for each of six BH3 protein ligands. While many drugs target the designed interaction, most also have unexpected selectivity and poor efficacy in cells.
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Proteínas Reguladoras de la Apoptosis , Proteínas Proto-Oncogénicas , Apoptosis , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismoRESUMEN
Skin erythema may present owing to many causes. One of the common causes is prolonged exposure to sunrays. Other than sun exposure, skin erythema is an accompanying sign of dermatologic diseases, such as psoriasis and acne. Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Quantitative assessment of skin erythema has been the focus of several studies. The clinical standard for erythema evaluation is visual assessment; however, this standard has some deficiencies. For instance, visual assessment is subjective and ineffectual for precise color information exchange. To overcome these limitations, in the past three decades various methodologies have been developed in an attempt to achieve objective erythema assessments, such as diffuse reflectance spectroscopy and both optical and nonoptical systems. This review considers the studies published during the past three decades and discusses the performance, the mathematical tactics for computation, and the limited capabilities of erythema assessment techniques for cutaneous diseases. The achievements and limitations of the current techniques in erythema assessment are presented. The advantages and development trends of optical and nonoptical methods are presented to make the reader aware of the present technological advances and their potential for dermatological disease research.
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Eritema , Psoriasis , Eritema/diagnóstico , Eritema/etiología , Humanos , Piel , Pigmentación de la PielRESUMEN
BACKGROUND: Skin erythema may present due to many causes. One of the common causes is prolonged exposure to sun rays. Other than sun exposure, skin erythema is an accompanying sign of dermatological diseases such as acne, psoriasis, melasma, post inflammatory hyperpigmentation, fever, as well as exposure to specific electromagnetic wave bands. METHODS: Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Therefore, quantitative assessment of skin erythema was the target of several studies. The clinical standard for erythema evaluation is visual assessment. However, the former standard has some imperfections. For instance, it is subjective, and unqualified for precise color information exchange. To overcome these shortcomings, the past three decades witnessed various methodologies that aimed to achieve erythema objective assessment, such as diffuse reflectance spectroscopy (DRS), and both optical and non-optical systems. DISCUSSION: This review article reports on the studies published in the past three decades where the performance, the mathematical tactics for computation, and the capabilities of erythema assessment techniques for cutaneous diseases are discussed. In particular, the achievements and limitations of the current techniques in erythema assessment are presented. CONCLUSION: The profits and development trends of optical and non-optical methods are displayed to provide the researcher with awareness into the present technological advances and its potential for dermatological diseases research.
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Eritema , Fotoquimioterapia , Eritema/diagnóstico , Humanos , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes , Piel , Pigmentación de la Piel , Rayos UltravioletaRESUMEN
Skin cancer (SC) is a widely spread disease in the USA, Canada, and Australia. Skin cancer patients may be treated by many different techniques including radiation therapy. However, radiation therapy has side effects, which may range from skin erythema to skin necrosis. As erythema is the early evidence of exposure to radiation, monitoring erythema is important to prevent more severe reactions. Visual assessment (VA) is the gold standard for evaluating erythema. Nevertheless, VA is not ideal, since it depends on the observer's experience and skills. Digital photography and hyperspectral imaging (HSI) are optical techniques that provide an opportunity for objective assessment of erythema. Erythema indices were computed from the spectral data using Dawson's technique. The Dawson relative erythema index proved to be highly correlated (97.1 %) with clinical visual assessment scores. In addition, on the 7th session of radiation therapy, the relative erythema index differentiates with 99 % significance between irradiated and non-radiated skin regions. In this study, HSI is compared to digital photography for skin erythema statistical classification.