Development of measurement methods and dose evaluating algorithms for electronic personal dosimeter

For personal radiation dose monitoring, electronic personal dosimeters (EPD), also known as active personal dosimeter (APD), using silicon diode detector have the advantage capability of measuring and displaying directly the exposure results of gamma, beta and neutron radiations in real time. They are mainly considered as good complement to passive dosimeters to satisfy ALARA principle in the radiation protection. In this paper, the meansurement methods and algorithms for evaluating personal dose equivalents such as Hp(10) and Hp(0.07) from air-kerma are studied and developed in two directions: the first, named energy correction method based on incident energy determined by the ratio of two detector responses with the different filter configurations; the second new method is carried out in the way that matching the shape of a detector’s energy response curve to the kerma-to-personal dose equivalent conversion function provides an approximate means of determining the dose equivalent without the need to resolve the actual incident energies. The algorithm has also been experimentally verified at Secondary Standards Dosimetry Laboratory (SSDL) of INST by the beam of radiation defined in ISO 4037-1. The obtained results of personal dose equivalents with errors almost less than 30% in energy range from 20 keV to 1.5 MeV are partially met the EPD design requirements according to the IEC 61526 Standard. The work and results of described in this paper are important basics for design and construction of completed electronic personal dosimeter.

Download Full-text

WALL THICKNESS OPTIMISATION OF AN IONISATION CHAMBER FOR DIRECTIONAL DOSE EQUIVALENT RATE MEASUREMENT AT LOW AND MEDIUM PHOTON ENERGIES

Radiation Protection Dosimetry ◽

10.1093/rpd/ncy171 ◽

2018 ◽

Vol 183 (4) ◽

pp. 469-474

Author(s):

Sunil K Singh ◽

M S Kulkarni

Keyword(s):

Wall Thickness ◽

Interventional Cardiology ◽

Calibration Coefficient ◽

Eye Lens ◽

Energy Response ◽

Dose Equivalent ◽

Dose Monitoring ◽

Paramedical Staff ◽

Equivalent Rate ◽

Ionisation Chamber

Abstract A thin and plane wall ionisation chamber having 900 cc volume was designed and fabricated to study the calibration coefficient dependency on ionisation chamber wall thickness for directional dose equivalent rate (Ḣ′(d)) at various low and medium energy X-ray beam qualities. Optimised wall thickness was established through measurements to achieve a near flat energy response using the developed ionisation chamber. The measurement shows that in the energy range 12–213 keV, the average calibration coefficient for directional dose equivalent rate lies within ±10% for wall thickness 1.2 mg/cm2 and 480 mg/cm2 (4 mm poly methyl methacrylate) for skin and eye lens dose monitoring, respectively. The study could be useful for the estimation of skin and eye lens doses for the paramedical staff and patient during the interventional radiology and interventional cardiology procedures by monitoring the directional dose equivalent rate.

Download Full-text

Radiation Exposure of Anaesthetists Visualised by Real-time Dosimetry

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405613666171123151711 ◽

2019 ◽

Vol 15 (2) ◽

pp. 220-226

Author(s):

Marcus Christian Müller ◽

Michael Windemuth ◽

Sophie Frege ◽

Eva Nadine Striepens

Keyword(s):

Radiation Exposure ◽

Real Time ◽

Vertebral Fractures ◽

Plate Osteosynthesis ◽

Plate Fixation ◽

Femoral Fractures ◽

Dose Monitoring ◽

Osteoporotic Vertebral Fractures ◽

Radiation Dose Monitoring ◽

Dosimetry System

Background: Chronic exposure to occupational ionising radiation is seen as one reason for elevated cancer prevalence. </P><P> Objective: The aim of this retrospective study was to evaluate radiation exposure of anaesthetists by real-time dosimetry. Methods: Data of 296 patients were analyzed. Ten types of trauma operation procedures including osteosynthesis of upper and lower extremity fractures and minimally invasive stabilisation of traumatic and osteoporotic vertebral fractures were accomplished. Evaluation was performed by an occupational dosimetry system, which visualises anaesthetists radiation exposure feedback compared to surgeons in real-time. Results: A significantly lower radiation exposure to anaesthetists compared to surgeons was observed in four types of operative procedures: Plate fixation of proximal humerus fractures, osteosynthesis of proximal femoral fractures, stabilisation of traumatic and osteoporotic vertebral fractures. In four types of operations (plate osteosynthesis of proximal humeral, distal radial and tibial fractures and intramedullary nailing of the clavicle), anaesthetists` amount of radiation exceeded one-third of the surgeons' exposure, especially if the C-arm tube was positioned close to the anaesthetists work station at the patients' head. Conclusion: By using the occupational radiation dose monitoring system, radiation exposure to anaesthetists was visualised in real-time during trauma operations. Radiation exposure of anaesthetists depends on the type of operation and the position of the C-arm. The system may help to increase anaesthetists` awareness concerning radiation exposure and to enhance compliance in using radiation protection techniques.

Download Full-text