Instrument for scanning the angular variation of irradiance in ultraviolet phototherapy cabinets

Abstract

An instrument is described that measures irradiance and the angular distribution of the intensity of ultraviolet radiation sources inside phototherapy cabinets. Failed lamps and lamps with higher or lower outputs are readily identified. The measurements are controlled from outside the cabinet, thus reducing the risk to staff from exposure to ultraviolet radiation.

A study of the correction factor for ultraviolet phototherapy dose measurements made by the indirect method

“…An automated system has been developed for measurement of UV irradiances in all directions within a phototherapy cabin. This utilizes UV radiometer probes produced by Macam Ltd (Livingston, U.K.) (f 2 = 2%) to measure TL01 or UVA irradiances as required 7,8 . The probes are rotated around a vertical axis in 0·45° intervals and irradiance measured at 800 positions around the circumference of a 300‐mm diameter circle at a height of 1 m. The 300 mm diameter circle was chosen as an approximation to the skin position so that measurements could be made with the system on its own or with a simple phantom representing a patient.…”

Ultraviolet phototherapy: review of options for cabin dosimetry and operation

“…Since the year 2000, an automated UV dosimetry system, developed by the Clinical Physics Department, has been employed to measure the cabin irradiances and lamp radiant intensities. The system utilizes UV radiometer probes produced by Macam Ltd (Livingston, Scotland) (f 2 = 2%) to measure TL01 or UVA irradiances as required (Currie et al 2001, Evans et al 2002. The probes are rotated around a vertical axis and irradiance measured at 800 positions around the circumference of a 300 mm diameter circle, in order to approximate the human trunk, at a height of 1 m. The system also contains a collimated detector, which is used to obtain the distribution of radiant intensities from individual lamps.…”

Iron-based radiochromic systems for UV dosimetry applications

“…Due to the geometry of phototherapy treatments and the use of multiple UV sources from multiple directions, assessment of orientation dependence of such dosimeters are necessary especially since other UV meters have previously been demonstrated to have directional dependence (Martin et al 1999, Oliver and Moseley 2002. Accurate modeling and measurements of UV dose inside whole-body phototherapy cabinets have proven to be difficult due to the arrangement of the UV lamps and reflectors (Currie et al 2001, Evans et al 2002, Martin et al 2003, Amatiello and Martin 2006, Grimes 2012. Exact angular responses for modeling UV phototherapy dose for clinical usage have been proposed using a line source model (Grimes et al 2010).…”