Nearly all cervical cancers are caused by persistent high-risk human papillomavirus (hrHPV) infection. There are 14 recognized hrHPV genotypes (HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68), and hrHPV genotypes 16 and 18 comprise approximately 66% of all cases worldwide. An additional 15% of cervical cancers are caused by hrHPV genotypes 31, 33, 45, 52, and 58.
View Article and Find Full Text PDFBackground: Photodynamic therapy (PDT) is widely used as a treatment for actinic keratoses (AK), with new sunlight-based regimens proposed as alternatives to lamp-based treatments. Prescribing indoor daylight activation could help address the seasonal temperature, clinical supervision, and access variability associated with outdoor treatments.
Objective: To compare the AK lesion clearance efficacy of indoor daylight PDT treatment (30 min of 5-aminolevulinic acid (ALA) pre-incubation, followed by 2 h of indoor sunlight) versus a lamp-based PDT treatment (30 min of ALA preincubation, followed by 10 min of red light).
Significance: Skin-based photodynamic therapy (PDT) is used for the clinical treatment of actinic keratosis (AKs) and other skin lesions with continued expansion into the standard of care. Due to the spectral dependency of photosensitizer activation and skin optical fluence, there is a need for more accurate methods to estimate the delivered dose at depth from different PDT light sources and treatment regimens.
Aim: Develop radiometric methods for calculating photosensitizer-effective fluence and dose at depth and determine differences between red-lamp, blue-lamp, and daylight-based PDT treatments.
Purpose: Interventional fluorescence imaging is increasingly being utilized to quantify cancer biomarkers in both clinical and preclinical models, yet absolute quantification is complicated by many factors. The use of optical phantoms has been suggested by multiple professional organizations for quantitative performance assessment of fluorescence guidance imaging systems. This concept can be further extended to provide standardized tools to compare and assess image analysis metrics.
View Article and Find Full Text PDFThe 3D printing of fluorescent materials could help develop, validate, and translate imaging technologies, including systems for fluorescence-guided surgery. Despite advances in 3D printing techniques for optical targets, no comprehensive method has been demonstrated for the simultaneous incorporation of fluorophores and fine-tuning of absorption and scattering properties. Here, we introduce a photopolymer-based 3D printing method for manufacturing fluorescent material with tunable optical properties.
View Article and Find Full Text PDFPurpose: Unlike fluorescence imaging utilizing an external excitation source, Cherenkov emissions and Cherenkov-excited luminescence occur within a medium when irradiated with high-energy x-rays. Methods to improve the understanding of the lateral spread and axial depth distribution of these emissions are needed as an initial step to improve the overall system resolution.
Methods: Monte Carlo simulations were developed to investigate the lateral spread of thin sheets of high-energy sources and compared to experimental measurements of similar sources in water.
Real-world conditions test effectiveness, the next step after establishing efficacy in controlled settings. From the annual flu shot to HPV vaccination, effectiveness measures what happens when best efforts for vaccine development meet the realities of challenging viruses and changing subtypes in regions around the world. After testing 2,645 women from multiple locations in Honduras for types of high-risk HPV (hrHPV) and finding the prevalence of virus types to be quite different from those in the US, we asked what vaccine would be the most efficacious for the local situation, and which hrHPV types are most commonly found in cervical cancer tissues from Honduran women.
View Article and Find Full Text PDFSignificance: Expanded use of fluorescence-guided surgery with devices approved for use with indocyanine green (ICG) has led to a range of commercial systems available. There is a compelling need to be able to independently characterize system performance and allow for cross-system comparisons.
Aim: The goal of this work is to expand on previous proposed fluorescence imaging standard designs to develop a long-term stable phantom that spectrally matches ICG characteristics and utilizes 3D printing technology for incorporating tissue-equivalent materials.
Purpose: To evaluate the feasibility of brigade-style, multiphasic cancer screening in Honduras, exploring data from 3 screening events that each tested for multiple cancers on single occasions.
Methods: This series of 3 studies each used a single-arm, post-test-only design to explore the feasibility of implementing multiphasic, community-based cancer screening at the same rural location in 2013, 2016, and 2017. The 2013 event for women screened for 2 cancers (breast and cervix), and the 2016 event for women screened for 3 cancers (breast, cervix, and thyroid).
This study demonstrates remote imaging for in vivo detection of radiation-induced tumor microstructural changes by tracking the diffusive spread of injected intratumor UV excited tattoo ink using Cherenkov-excited luminescence imaging (CELI). Micro-liter quantities of luminescent tattoo ink with UV absorption and visible emission were injected at a depth of 2 mm into mouse tumors prior to receiving a high dose treatment of radiation. X-rays from a clinical linear accelerator were used to excite phosphorescent compounds within the tattoo ink through Cherenkov emission.
View Article and Find Full Text PDFPurpose: Tattoo fiducials are commonly used in radiotherapy patient alignment, and recent studies have examined the use of UV-excited luminescent tattoo ink as a cosmetic substitute to make these visible under UV illumination. The goal of this study was to show how luminescent tattoo inks could be excited with MV radiation and imaged during beam delivery for direct visualization of field position.
Methods: A survey of nine UV-sensitive tattoo inks with various emission spectra were investigated using both UV and MV excitation.
Background: X-Ray induced phototherapy is highly sought after as it provides a deep tissue, synergistic method of treating cancers via standard-of-care radiotherapy. When this is combined with releasable chemotherapy agents, it can provide high target selectivity, with reduced off-target organ effects that limit current systemic therapies. We have recently developed a unique light-activated drug delivery system whereby the drug is conjugated to an alkylcobalamin scaffold.
View Article and Find Full Text PDF: While clinical treatment of actinic keratosis by photodynamic therapy (PDT) is widely practiced, there is a well-known variability in response, primarily caused by heterogeneous accumulation of the photosensitizer protoporphyrin IX (PpIX) between patients and between lesions, but measurement of this is rarely done. : Develop a smartphone-based fluorescence imager for simple quantitative photography of the lesions and their PpIX levels that can be used in a new clinical workflow to guide the reliability of aminolevulinic acid (ALA) application for improved lesion clearance. : The smartphone fluorescence imager uses an iPhone and a custom iOS application for image acquisition, a 3D-printed base for measurement standardization, an emission filter for PpIX fluorescence isolation, and a 405-nm LED ring for optical excitation.
View Article and Find Full Text PDFDaylight activation for photodynamic therapy (PDT) of skin lesions is now widely adopted in many countries as a less painful and equally effective treatment mechanism, as compared to red or blue light activation. However, seasonal daylight availability and transient weather conditions complicate light dose estimations. A method is presented for dose planning without placing a large burden on clinical staff, by limiting spectral measurements to a one-time site assessment, and then using automatically acquired weather reports to track transient conditions.
View Article and Find Full Text PDFPhotodiagnosis Photodyn Ther
March 2019
Background: Daylight-activated PDT has seen increased support in recent years as a treatment method for actinic keratosis and other non-melanoma skin cancers. The inherent variability observed in broad-spectrum light used in this methodology makes it difficult to plan and monitor light dose, or compare to lamp light doses.
Methods: The present study expands on the commonly used PpIX-weighted effective surface irradiance metric by introducing a Monte Carlo method for estimating effective fluence rates into depths of the skin.
J Glob Oncol
September 2018
Purpose: Cervical cancer is a leading cause of cancer-related mortality in low- and middle-income countries (LMICs) and screening in LMICs is extremely limited. We aimed to implement on-site high-risk human papillomavirus (hrHPV) DNA testing in cohorts of women from an urban factory and from a rural village.
Methods: A total of 802 women were recruited for this study in partnership with La Liga Contra el Cancer through the establishment of women's health resource fairs at two locations in Honduras: a textile factory (n = 401) in the city of San Pedro Sula and the rural village of El Rosario (n = 401) in Yoro.
During external beam radiotherapy (EBRT), in vivo Cherenkov optical emissions can be used as a dosimetry tool or to excite luminescence, termed Cherenkov-excited luminescence (CEL) with microsecond-level time-gated cameras. The goal of this work was to develop a complete theoretical foundation for the detectable signal strength, in order to provide guidance on optimization of the limits of detection and how to optimize near real time imaging. The key parameters affecting photon production, propagation and detection were considered and experimental validation with both tissue phantoms and a murine model are shown.
View Article and Find Full Text PDFCervical cancer rates in low- and middle-income countries (LMICs) are higher than in developed countries and account for 80% of an estimated 500,000 new cases annually. Factors that contribute to this are that diagnostic and prevention strategies designed for developed countries suffer from the combination of low vaccination rates and limitations due to lack of consistent access to both healthcare and supplies. Here we: 1) improve upon our LMIC deployable HPV test and 2) determine both the high and low-risk HPV genotype prevalence in an isolated Honduran population.
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