Radiation dose in balloon dacryocystoplasty: a study using Rando phantoms and thermoluminescent dosimetry

The radiation dose to the lens of the eye, skin, thyroid and brain of patients who underwent diagnostic and interventional radiological procedures of the lacrimal drainage system have been measured with thermoluminescent dosimeters (TLD-100 and TLD-700) by using an adult male and female Rando phantom. All dose values for one second of fluoroscopic exposure and one frame of digital subtraction dacryocystography (DS-DCG) exposure have been obtained individually in the pastero-anterior (PA) and lateral (LAT) projections.

An adult male and female Rando phantom was used instead of the patients. The procedures were performed by using an Advantx AFM C-arm unit coupled with a DX Hiline digital image acquisition and processing system. The 6-inch mode of a triplefield image intensifier (II) was used, with a circular collimation of the same or a slightly smaller size. Two different lithium floride (LiF) thermoluminescent chips were used for absorbed dose measurements: TLD700, approximately 4.5 mm in diameter and 0.9 mm in thickness; TLD100, 3.7 mm square and 0.9 mm in thickness.

The average values of absorbed doses (lens of the eye, skin, thyroid and brain) measured separately with TLD100 and TLD700 dosimeters after irradiation of the male and female Rando phantom are presented for LAT and PA projections.

This study suggests that useful information for dose determination can be obtained by use of the radiation dose to the lens of the eye, thyroid and brain received during radiological procedure of the LDS for one frame of DS-DCG and one second of fluoroscopy.