A new inhalation synchronised dosimeter triggered by low inspiratory flow rates has been assessed. The methacholine challenge test using dosimeter nebulisation with controlled tidal breathing was compared with continuous nebulisation using De Vilbiss No 40 nebulisers with deep inhalations in 11 asthmatic subjects. Within subject PD20 FEV1 values were lower with the dosimeter method than with th...

PURPOSE To evaluate the suitability of the GD-301 glass dosimeter for use in in vivo dose verification in proton therapy. METHODS The glass dosimeter was analyzed for its dosimetric characteristic in proton beam. Dosimeters were calibrated in a water phantom using a stair-like holder specially designed for this study. To determine the accuracy of the glass dosimeter in proton dose measurement...

Radiation processing in many areas, particularly in radiation sterilization, demands control of the absorbed dose. Many dosimeters have been proposed for the high-level dose range (region of 10 to 50 kGy). However, in addition to the required reproducibility, reliability or uncertainty (< 5%), it is desirable for radiation processing that the selected dosimetric system is easy to operate. One o...

background: in this study the basic radiation properties of n-isopropylacrylamaide polymer gel dosimeter were determined together with verification of its soft tissue equivalency. materials and methods: the nipam gel was prepared and irradiated approximately 2 h after manufacturing. the magnetic resonance (mr) images were made 24 h after irradiation. the nuclear magnetic resonance (nmr) respons...

PURPOSE In optical-CT, the use of a refractively matched polyurethane solid-tank in place of a fluid bath has the potential to greatly increase practical convenience, reduce cost, and possibly improve the efficacy of flood corrections. This work investigates the feasibility of solid-tank optical-CT imaging for 3D dosimetry through computer simulation. METHODS A matlab ray-tracing simulation p...

BACKGROUND Guidelines for the 2-min tidal-breathing and the five-breath dosimeter methods for methacholine challenge have recently been published by the American Thoracic Society (ATS). Although subjects are exposed to twice as much aerosol at any given concentration during the tidal-breathing method compared to the dosimeter method, they were thought to give equivalent results. OBJECTIVE To ...

Bronchial reactivity is being measured with increasing frequency in epidemiological studies, but there debate continues about the relative merits of the different methods used to measure reactivity, particularly for subjects with no previous experience of reactivity testing as is the case in epidemiological studies. Repeatability is likely to improve with practice, and laboratory based studies ...

Gafchromic films are increasingly being used for dosimetry in medical and industrial applications of ionizing radiation because of their favorable characteristics such as self developing in nature, easy to handle, dose rate independent response, insensitivity to normal room lights, high resolution and insensitivity to variation in the environment conditions. The dosimetry measurements using Gaf...

BACKGROUND Two bronchoprovocation methods are widely used. Compared to the tidal breathing method, the dosimeter method delivers approximately half the dose and involves five deep inhalations. Both the lower dose and the bronchoprotective deep inhalations contribute to the lesser airway response of the dosimeter. OBJECTIVE To determine the relative role of dose and deep inspiration in the dif...