Dual isotope subtraction SPECT-CT in the diagnosis of primary hyperparathyroidism

Abstract

light in treating actinic keratoses (AK) with a marked reduction in patient discomfort which is a limiting factor in c-PDT. The aim of this study was to quantify the radiant exposure received by patients having d-PDT between the months of April and July. A further objective was to compare it with artificial white light (wl-PDT) using a theatre light andwith two c-PDT units, an Omnilux© and an Akitilite©. Quantities measured using calibrated equipment during patient d-PDT included irradiance, illuminance, and light spectra. An IPL Radiometer with a PDT detector, an ATP data logger light meter and a Bentham DMc150-MDE compact double integrated spectroradiometer were used respectively. The effective dose (Jeff) was calculated, which is the spectrum weighted by the absorption spectrum of the photosensitizer. The impact of weather conditions and time of year on effective dose was evaluated. The effective dose from daylight ranged from 3.2 Jeff on an overcast day to 43 Jeff on a sunny day for 2 hour treatments. Effective dose for two hours across the treatment area for wl-PDT was between 4.1 and 9.1 Jeff. Typically c-PDT units deliver approximately 1 Jeff in 10–20 minutes. d-PDT is a viable treatment option in Ireland. A review of patients at one and three months showed treatment was effective in reducing AKs, with low pain scores. Treatment scheduling is limited to between April and September for patient comfort (average temperature at least 10 °C) and to avoid lengthier treatment times.