Could psoralen plus ultraviolet A1 (‘
            <scp>PUVA</scp>
            1’) work? Depth penetration achieved by phototherapy lamps

Barnard, Isla Rose Mary; Eadie, Ewan; McMillan, Lewis; Moseley, Harry; Brown, C.T.A.; Wood, Kenneth; Dawe, Robert S.

doi:10.1111/bjd.18561

Cited by 4 publications

(4 citation statements)

References 8 publications

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Section: Introductionmentioning

confidence: 99%

“…MCRT has become an invaluable tool for treatment planning and dose finding in several areas of radiative medicine including phototherapy, radiographic imaging (e.g., x-ray investigations), and nuclear medicine (e.g., PET imaging). 15 – 17 MCRT has already been used many times to model PDT. For example, it has been used to simulate both standard and daylight PDT treatment with 5-ALA for various skin cancers, 18 , 19 as well as modeling interstitial PDT treatment of gliomas.…”

Section: Introductionmentioning

confidence: 99%

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Simulating photodynamic therapy for the treatment of glioblastoma using Monte Carlo radiative transport

Finlayson,

McMillan,

Suveges

et al. 2024

J. Biomed. Opt.

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Significance: Glioblastoma (GBM) is a rare but deadly form of brain tumor with a low median survival rate of 14.6 months, due to its resistance to treatment. An independent simulation of the INtraoperative photoDYnamic therapy for GliOblastoma (INDYGO) trial, a clinical trial aiming to treat the GBM resection cavity with photodynamic therapy (PDT) via a laser coupled balloon device, is demonstrated.Aim: To develop a framework providing increased understanding for the PDT treatment, its parameters, and their impact on the clinical outcome.Approach: We use Monte Carlo radiative transport techniques within a computational brain model containing a GBM to simulate light path and PDT effects. Treatment parameters (laser power, photosensitizer concentration, and irradiation time) are considered, as well as PDT's impact on brain tissue temperature. Results:The simulation suggests that 39% of post-resection GBM cells are killed at the end of treatment when using the standard INDYGO trial protocol (light fluence = 200 J∕cm 2 at balloon wall) and assuming an initial photosensitizer concentration of 5 μM. Increases in treatment time and light power (light fluence = 400 J∕cm 2 at balloon wall) result in further cell kill but increase brain cell temperature, which potentially affects treatment safety. Increasing the p hotosensitizer concentration produces the most significant increase in cell kill, with 61% of GBM cells killed when doubling concentration to 10 μM and keeping the treatment time and power the same. According to these simulations, the standard trial protocol is reasonably well optimized with improvements in cell kill difficult to achieve without potentially dangerous increases in temperature. To improve treatment outcome, focus should be placed on improving the photosensitizer.Conclusions: With further development and optimization, the simulation could have potential clinical benefit and be used to help plan and optimize intraoperative PDT treatment for GBM.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulating photodynamic therapy for the treatment of glioblastoma using Monte Carlo radiative transport

Finlayson,

McMillan,

Suveges

et al. 2024

J. Biomed. Opt.

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“…For example, one of the challenges faced by the clinicians who prescribe UV-phototherapies, psoralen-UVA (PUVA) photochemotherapy, photodynamic therapy (PDT) or laser therapy is that of gaining an accurate quantification of the most effective dose. This challenge stems from the difficulty in gaining a reliable picture of the fluence rate distribution that the phototherapeutic source will produce within an individual's skin as well as an accurate idea of where the light will be absorbed (7)(8)(9). A simple and accessible method to gain this information in order to produce this picture would therefore be of great benefit.…”

Section: Introductionmentioning

confidence: 99%

Depth Penetration of Light into Skin as a Function of Wavelength from 200 to 1000 nm

Finlayson

Barnard

McMillan

et al. 2021

Photochem & Photobiology

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147

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An increase in the use of light‐based technology and medical devices has created a demand for informative and accessible data showing the depth that light penetrates into skin and how this varies with wavelength. These data would be particularly beneficial in many areas of medical research and would support the use and development of disease‐targeted light‐based therapies for specific skin diseases, based on increased understanding of wavelength‐dependency of cutaneous penetration effects. We have used Monte Carlo radiative transport (MCRT) to simulate light propagation through a multi‐layered skin model for the wavelength range of 200–1000 nm. We further adapted the simulation to compare the effect of direct and diffuse light sources, varying incident angles and stratum corneum thickness. The lateral spread of light in skin was also investigated. As anticipated, we found that the penetration depth of light into skin varies with wavelength in accordance with the optical properties of skin. Penetration depth of ultraviolet radiation was also increased when the stratum corneum was thinner. These observations enhance understanding of the wavelength‐dependency and characteristics of light penetration of skin, which has potential for clinical impact regarding optimizing light‐based diagnostic and therapeutic approaches for skin disease.

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“…The modeling of light transport is important to our understanding of how light interacts with turbid media. It allows us to make predictions of the viability of treatment modalities, 1 , 2 simulate the behavior of complex shaped light in highly scattering media, 3 retrieve images of objects in highly scattering media, 4 and optimize light sensors in the food and drink industry 5 among other applications.…”

Section: Introductionmentioning

confidence: 99%

Meshless Monte Carlo radiation transfer method for curved geometries using signed distance functions

2022

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. Significance: Monte Carlo radiation transfer (MCRT) is the gold standard for modeling light transport in turbid media. Typical MCRT models use voxels or meshes to approximate experimental geometry. A voxel-based geometry does not allow for the precise modeling of smooth curved surfaces, such as may be found in biological systems or food and drink packaging. Mesh-based geometry allows arbitrary complex shapes with smooth curved surfaces to be modeled. However, mesh-based models also suffer from issues such as the computational cost of generating meshes and inaccuracies in how meshes handle reflections and refractions. Aim: We present our algorithm, which we term signedMCRT (sMCRT), a geometry-based method that uses signed distance functions (SDF) to represent the geometry of the model. SDFs are capable of modeling smooth curved surfaces precisely while also modeling complex geometries. Approach: We show that using SDFs to represent the problem’s geometry is more precise than voxel and mesh-based methods. Results: sMCRT is validated against theoretical expressions, and voxel and mesh-based MCRT codes. We show that sMCRT can precisely model arbitrary complex geometries such as microvascular vessel network using SDFs. In comparison with the current state-of-the-art in MCRT methods specifically for curved surfaces, sMCRT is more precise for cases where the geometry can be defined using combinations of shapes. Conclusions: We believe that SDF-based MCRT models are a complementary method to voxel and mesh models in terms of being able to model complex geometries and accurately treat curved surfaces, with a focus on precise simulation of reflections and refractions. sMCRT is publicly available at https://github.com/lewisfish/signedMCRT .

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Could psoralen plus ultraviolet A1 (‘ PUVA 1’) work? Depth penetration achieved by phototherapy lamps

Cited by 4 publications

References 8 publications

Simulating photodynamic therapy for the treatment of glioblastoma using Monte Carlo radiative transport

Simulating photodynamic therapy for the treatment of glioblastoma using Monte Carlo radiative transport

Depth Penetration of Light into Skin as a Function of Wavelength from 200 to 1000 nm

Meshless Monte Carlo radiation transfer method for curved geometries using signed distance functions

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