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S Ibbotson

Publications and source records attributed to S Ibbotson.

11 recordsLinked to original sources
PubMed2002

Guidelines for topical photodynamic therapy: report of a workshop of the British Photodermatology Group.

Topical photodynamic therapy (PDT) is effective in the treatment of certain non-melanoma skin cancers and is under evaluation in other dermatoses. Its development has been enhanced by a low rate of adverse events and good cosmesis. 5-Aminolaevulinic acid (ALA) is the main agent used, converted within cells into the photosensitizer protoporphyrin IX, with surface illumination then triggering the photodynamic reaction. Despite the relative simplicity of the technique, accurate dosimetry in PDT is complicated by multiple variables in drug formulation, delivery and duration of application, in addition to light-specific parameters. Several non-coherent and coherent light sources are effective in PDT. Optimal disease-specific irradiance, wavelength and total dose characteristics have yet to be established, and are compounded by difficulties comparing light sources. The carcinogenic risk of ALA-PDT appears to be low. Current evidence indicates topical PDT to be effective in actinic keratoses on the face and scalp, Bowen's disease and superficial basal cell carcinomas (BCCs). PDT may prove advantageous where size, site or number of lesions limits the efficacy and/or acceptability of conventional therapies. Topical ALA-PDT alone is a relatively poor option for both nodular BCCs and squamous cell carcinomas. Experience of the modality in other skin diseases remains limited; areas where there is potential benefit include viral warts, acne, psoriasis and cutaneous T-cell lymphoma. A recent British Photodermatology Group workshop considered published evidence on topical PDT in order to establish guidelines to promote the efficacy and safety of this increasingly practised treatment modality.

Aminolevulinic Acid↗
PubMed2002

Guidelines for dosimetry and calibration in ultraviolet radiation therapy: a report of a British Photodermatology Group workshop.

This report examines the dosimetry of ultraviolet (UV) radiation applied to dermatological treatments, and considers the definition of the radiation quantities and their measurement. Guidelines are offered for preferred measurement techniques and standard methods of dosimetry. The recommendations have been graded according to the American Joint Committee on Cancer classification of strength of recommendation and quality of evidence (summarized in Appendix 5).

Humans↗
PubMed2001

The application of a compact multispectral imaging system with integrated excitation source to in vivo monitoring of fluorescence during topical photodynamic therapy of superficial skin cancers.

A novel, compact and low-cost multispectral fluorescence imaging system with an integrated excitation light source is described. Data are presented demonstrating the application of this method to in vivo monitoring of fluorescence before, during and after topical 5-aminolevulinic acid photodynamic therapy of superficial skin cancers. The excitation source comprised a fluorescent tube with the phosphor selected to emit broadband violet light centered at 394 nm. The camera system simultaneously captured spectrally specific images of the fluorescence of the photosensitizer, protoporphyrin IX, the illumination profile and the skin autofluorescence. Real-time processing enabled images to be manipulated to create a composite image of high contrast. The application and validation of this method will allow further detailed studies of the characteristics and time-course of protoporphyrin IX fluorescence, during topical photodynamic therapy in human skin in vivo.

Aminolevulinic Acid↗
PubMed2000

Guidelines for topical PUVA: a report of a workshop of the British photodermatology group.

Psoralen photochemotherapy [psoralen ultraviolet A (PUVA)] plays an important part in dermatological therapeutics, being an effective and generally safe treatment for psoriasis and other dermatoses. In order to maintain optimal efficacy and safety, guidelines concerning best practice should be available to operators and supervisors. The British Photodermatology Group (BPG) have previously published recommendations on PUVA, including UVA dosimetry and calibration, patient pretreatment assessment, indications and contraindications, and the management of adverse reactions.1 While most current knowledge relates to oral PUVA, the use of topical PUVA regimens is also popular and presents a number of questions peculiar to this modality, including the choice of psoralen, formulation, method of application, optimal timing of treatment, UVA regimens and relative benefits or risks as compared with oral PUVA. Bath PUVA, i.e. generalized immersion, is the most frequently used modality of topical treatment, practised by about 100 centres in the U.K., while other topical preparations tend to be used for localized diseases such as those affecting the hands and feet. This paper is the product of a recent workshop of the BPG and includes guidelines for bath, local immersion and other topical PUVA. These recommendations are based, where possible, on the results of controlled studies, or otherwise on the consensus view on current practice.

Administration, Oral↗
PubMed1999

The idiopathic photodermatoses.

The idiopathic photodermatoses present a challenge for dermatologists. Although, as in other specialty areas, the classical clinical presentation produces few problems, it is the severe forms and overlap cases that cause the most difficulty. It is fortunate that the semi-objective investigation of phototesting is available, which, when conducted carefully, reveals so much about the nature of this group of conditions. This essential investigation not only helps achieve a diagnosis, but also affords material for study and a means of monitoring therapy response or progress towards spontaneous resolution. Although these conditions are grouped together, throughout this century we have seen a continuing process of distinct diseases emerging as a consequence of careful clinical observation and investigation.

Age Factors↗
PubMed1995

Reduced experimental contact sensitivity in squamous cell but not basal cell carcinomas of skin.

Basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) show clinical and epidemiological differences not accounted for by different ultraviolet radiation exposure. We have studied experimentally induced contact sensitivity to dinitrochlorobenzene by measuring increases in skin-fold thickness. Patients (n = 37) with squamous tumours had impaired responses compared with controls (33) and patients with BCCs (31) (mean increase 4.5 vs 7.8 and 8.6 mm, respectively; p = 0.002). This diminished immunological response may be causally related to the development of SCC. Because glutathione S-transferase (GST) metabolises dinitrochlorobenzene and polymorphisms of GST are associated with multiple skin tumours, variations in GST may underlie these differences.

Basal Cell Carcinoma↗