Multiphoton tomography of skin tumors after ALA application

Riemann, Iris; Ehlers, Alexander; Dill-Müller, Dorothee; Martin, Sven; König, Karsten

doi:10.1117/12.702411

Cited by 4 publications

(6 citation statements)

References 12 publications

(13 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…using fluorescence excitation in the range of 750–800 nm [11, 15], did not reveal any specific fluorescence signal from PpIX. Therefore, a detailed study of the excitation and emission of endogenously formed PpIX was undertaken.…”

Section: Resultsmentioning

confidence: 99%

“…Preliminary data exist, but reports are mainly restricted to cell cultures [12–15]. Data from skin tumors are limited and lack thorough spectral investigations [11, 15]. …”

Section: Introductionmentioning

confidence: 99%

“…There are reports on multiphoton excitation of PpIX using NIR light in solution [19], gastrointestinal cancer tissue, cell cultures [12–14] and mouse tissue [20, 21]. A few studies report on multi-photon excitation of endogenously formed PpIX in skin tissue [11, 15], but detailed spectral investigations are lacking.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Anti‐Stokes fluorescence from endogenously formed protoporphyrin IX – Implications for clinical multiphoton diagnostics

Kantere

Guldbrand

Paoli

et al. 2012

Journal of Biophotonics

View full text Add to dashboard Cite

Multiphoton imaging based on two-photon excitation is making its way into the clinics, particularly for skin cancer diagnostics. It has been suggested that endogenously formed protoporphyrin IX (PpIX) induced by aminolevulinic acid or methylaminolevulinate can be applied to improve tumor contrast, in connection to imaging of tissue autofluorescence. However, previous reports are limited to cell studies and data from tissue are scarce. No report shows conclusive evidence that endogenously formed PpIX increases tumor contrast when performing multiphoton imaging in the clinical situation. We here demonstrate by spectral analysis that two-photon excitation of endogenously formed PpIX does not provide additional contrast in superficial basal cell carcinomas. In fact, the PpIX signal is overshadowed by the autofluorescent background. The results show that PpIX should be excited at a wavelength giving rise to one-photon anti-Stokes fluorescence, to overcome the autofluorescent background. Thus, this study reports on a plausible method, which can be implemented for clinical investigations on endogenously formed PpIX using multiphoton microscopy.Three-dimensional multiphoton microscopy images obtained from a superficial basal cell carcinoma illustrating higher porphyrin contrast when anti-stokes excitation (710 nm) is used compared to two-photon excitation (810 nm).

show abstract

Section: Resultsmentioning

confidence: 99%

“…Preliminary data exist, but reports are mainly restricted to cell cultures [12–15]. Data from skin tumors are limited and lack thorough spectral investigations [11, 15]. …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Anti‐Stokes fluorescence from endogenously formed protoporphyrin IX – Implications for clinical multiphoton diagnostics

Kantere

Guldbrand

Paoli

et al. 2012

Journal of Biophotonics

View full text Add to dashboard Cite

show abstract

“…To date, most studies using PpIX fluorescence for MPT-FLIM imaging are limited to cell cultures [98, 99] and solutions [100]. Riemann et al [101] used MPT on skin biopsies to study the biosynthesis of PpIX and also to evaluate the therapy. Cicchi et al [102] demonstrated enhanced tumor contrast and depth of imaging by using MAL-induced PpIX as the contrast agent, and two-photon excitation (TPE) in combination with FLIM as the imaging technique.…”

Section: Approaches For Measuring Ppix Beneath the Surface Of The Skinmentioning

confidence: 99%

Techniques for fluorescence detection of protoporphyrin IX in skin cancers associated with photodynamic therapy

Rollakanti

Kanick

Davis

et al. 2013

Photonics &Amp; Lasers in Medicine

View full text Add to dashboard Cite

Photodynamic therapy (PDT) is a treatment modality that uses a specific photosensitizing agent, molecular oxygen, and light of a particular wavelength to kill cells targeted by the therapy. Topically administered aminolevulinic acid (ALA) is widely used to effectively treat cancerous and precancerous skin lesions, resulting in targeted tissue damage and little to no scarring. The targeting aspect of the treatment arises from the fact that ALA is preferentially converted into protoporphyrin IX (PpIX) in neoplastic cells. To monitor the amount of PpIX in tissues, techniques have been developed to measure PpIX-specific fluorescence, which provides information useful for monitoring the abundance and location of the photosensitizer before and during the illumination phase of PDT. This review summarizes the current state of these fluorescence detection techniques. Non-invasive devices are available for point measurements, or for wide-field optical imaging, to enable monitoring of PpIX in superficial tissues. To gain access to information at greater tissue depths, multi-modal techniques are being developed which combine fluorescent measurements with ultrasound or optical coherence tomography, or with microscopic techniques such as confocal or multiphoton approaches. The tools available at present, and newer devices under development, offer the promise of better enabling clinicians to inform and guide PDT treatment planning, thereby optimizing therapeutic outcomes for patients.

show abstract

“…One also may gain information about the state of tissues themselves like determining irregularities leading to diagnosis of abnormal parts. The examination of the reaction of skin cells to UV irradiation as well as of pigmented skin cells and segments like nevi may help to investigate photo induced processes and disorders [12][13][14][15][16][17][18][19] . In ageing processes and certain diseases of skin certain changes of the collagen and elastin content of the dermis could be observed.…”

Section: Introductionmentioning

confidence: 99%

New developments in two-photon analysis of human skin in vivo

et al. 2009

View full text Add to dashboard Cite

Two-photon imaging of human skin using ultra short laser pulses can be used to obtain information about the state of cells and tissues by means of their natural autofluorescence. Using this method, it is possible to determine whether the normal cell pattern is disturbed or the autofluorescence is influenced by internal or external stimuli. Two-photon fluorescence lifetime imaging (FLIM) can further enhance this providing information about physiological processes, fluorophores (like NAD(P)H, collagen, keratin, elastin, flavins, melanin,...) and external applied probes inside cells and tissue parts. For example the part of the cells metabolism and energy level can be determined by analyzing the NADH regarding its free / bound state and its oxidized / reduced state. The combination of two-photon imaging with FLIM may lead to a better understanding and diagnosis of skin reactions and disorders. We also present some results of in vivo simultaneous collagen and elastin measurements in skin dermis. Changes of dermal collagen and elastin content are characteristic for skin aging as well as for pathological skin conditions

show abstract

Multiphoton tomography of skin tumors after ALA application

Cited by 4 publications

References 12 publications

Anti‐Stokes fluorescence from endogenously formed protoporphyrin IX – Implications for clinical multiphoton diagnostics

Anti‐Stokes fluorescence from endogenously formed protoporphyrin IX – Implications for clinical multiphoton diagnostics

Techniques for fluorescence detection of protoporphyrin IX in skin cancers associated with photodynamic therapy

New developments in two-photon analysis of human skin in vivo

Contact Info

Product

Resources

About