Calibration of a thermoluminescent dosimeter worn over lead aprons in fluoroscopy guided procedures

Beryllium oxide nanoparticles: synthesis, characterization, and thermoluminescence evaluation for gamma radiation detection

In this study, beryllium oxide nanoparticles (BeO NPs) were synthesized by polymer-gel method with schlenk line. The products were then assessed using FESEM, TGA/DSC, XRD and BET analyses. The quality of two nanooxides, that were calcined at 700 and 800 °C, was studied and compared with bulk BeO particles. The results showed that nanoparticles calcined at 800 °C were more uniform and had ellipsoidal morphology with a particle size of ∼35 nm. Investigation thermoluminescence (TL) characteristics of BeO NPs showed that with the decreasing exposed dose/increasing the BeO particle size, TL peaks were observed at higher temperatures. The intensities of glow curves increase linearly with the increasing absorbed dose in the range of 0.001 mGy–1000 Gy. Various other studies including response fading, minimum temperature and minimum time for annealing, and response changes in repeatability cycles of dosimeter also approved the ability of the prepared BeO NPs for use in gamma radiation dosimetry.

Correlation between eye lens doses and over apron doses in interventional procedures

Measurements of eye lens dose using over apron dosimeters with a geometric correction factor is an international accepted practice. However, further knowledge regarding geometric correction factors in different contexts is required. The authors studied the correlation between eye lens dose and over apron dosimetry for different medical specialties in eleven hospitals, using a standardized protocol, two independent over apron dosimeters (worn at chest and at neck levels) and a dedicated calibration procedure. The results show good correlation between subjects working on the same medical specialty for 5 specialties: Interventional Radiology, Vascular Surgery, Vascular Radiology, Hemodynamics and Neuroradiology. The geometric correction factors resulting from this study could be used to estimate eye lens dose using over apron dosimeters, which are more comfortable than eye lens dosimeters, as reported by the study subjects, as long as the increased uncertainty of the over apron dosimetry compared to the dedicated eye lens dosimetry is acceptable.

Effect of the radiation protective apron on the response of active and passive personal dosemeters used in interventional radiology and cardiology

In fluoroscopy guided interventional procedures, workers use protective garments and often two personal dosemeters, the readings of which are used for the estimation of the effective dose; whereas the dosemeter above the protection can be used for the estimation of the equivalent dose of the lens of the eye. When a protective apron is worn the scattered field that reaches the dosemeter is different from the case where no protection is used; this study analyses the changes in the response of seven passive and eight active personal dosemeters (APDs) when they are placed above a lead or lead equivalent garment for S-Cs and x-ray diagnostic qualities. Monte Carlo simulations are used to support the experimental results. It is found that for passive dosemeters, the influence on the dosemeter's response to the lead or lead equivalent was within the range 15%-38% for the x-ray qualities. This effect is smaller, of the order of 10%, when lead-free garments are used, and much smaller, within 1%-10%, for most of the APDs used in the study. From these results it is concluded that when comparing passive and active dosemeter measurements worn above the protection, a difference of 20%-40% is expected. The effect is small when deriving the effective dose from double dosimetry algorithms, but it can be of major importance when eye lens monitoring is based on the use of the dosemeter worn above the protection.