Publications by authors named "Costas J Hourdakis"

Purpose: To provide beam quality correction factors ( ) for detectors used in Ir brachytherapy dosimetry measurements.

Materials And Methods: Ten detectors were studied, including the PTW 30013 and Exrading12 Farmer large cavity chambers, seven medium (0.1-0.

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The radiological examination frequency, i.e. the number of examinations performed annually, is necessary for estimating the collective effective dose of the population from medical exposures with ionizing radiation.

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The escalating use of Computed Tomography (CT) imaging necessitates establishment and periodic revision of Diagnostic Reference Levels (DRLs) to ensure patient protection optimization. This paper presents the outcomes of a national survey conducted from 2019 to 2022, focusing on revising DRLs for adult CT examinations. Dosimetric data from 127 scanners in 120 medical facilities, representing 25% of the country's CT scanners, were collected, emphasizing geographic distribution and technology representation.

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Background: The Southeast European (SEE) region of 10 countries and about 43 million people differs from Western Europe in that most SEE countries lack active cancer registries and have fewer diagnostic imaging devices and radiotherapy (RT) units. The main objective of this research is to initiate a common platform for gathering SEE regional cancer data from the ground up to help these countries develop common cancer management strategies.

Methods: To obtain detailed on-the-ground information, we developed separate questionnaires for two SEE groups: a) ONCO - oncologists regarding cancer treatment modalities and the availability of diagnostic imaging and radiotherapy equipment; and b) REG - national radiation protection and safety regulatory bodies regarding diagnostic imaging and radiotherapy equipment in SEE facilities.

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Covid-19 pandemic imposes crucial social distancing rules and restriction measures; therefore, the access to facilities and sites, in order to perform on-site inspections, became difficult or not feasible. Greek Atomic Energy Commission (EEAE) adopted remote virtual inspections (RVIs) of facilities and practices applying ionising radiation and magnetic resonance imaging installations, in order to continue discharging its regulatory duty of inspection, effectively. This study presents the experience gained and lessons learnt from the implementation of the RVIs and explores the RVIs perception by the stakeholders.

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Purpose: To evaluate a commercially available Ferrous-Xylenol Orange-Gel (FXG) dosimeter (TrueView™) coupled with Optical-Computed Tomography (OCT) read out, for 3D dose verification in an Ir-192 superficial brachytherapy application.

Methods: Two identical polyethylene containers filled with gel from the same batch were used. One was irradiated with an 18 MeV electron field to examine the dose-response linearity and obtain a calibration curve.

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A comparison of calibration results and procedures in terms of air kerma length product, PKL, and air kerma, K, was conducted between eight dosimetry laboratories. A pencil-type ionization chamber (IC), generally used for computed tomography dose measurements, was calibrated according to three calibration methods, while its residual signal and other characteristics (sensitivity profile, active length) were assessed. The results showed that the "partial irradiation method" is the preferred method for the pencil-type IC calibration in terms of PKL and it could be applied by the calibration laboratories successfully.

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Objectives: To present a national survey that was performed for the establishment of national reference levels (RLs) for interventional cardiology (IC) procedures and to estimate the effective dose (E) received by the patient during these procedures.

Methods: Data concerning the fluoroscopy time and air kerma-area product (P KA) during coronary angiography (CA), percutaneous coronary intervention (PCI), pacemaker implantation (PMI) and radiofrequency cardiac ablation (RFCA) from 26 centres were collected. Moreover, measurements concerning the performance of X-ray systems used in IC were performed in order to set system-related reference levels.

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Objectives: (a) To measure the absorbed dose at certain anatomical sites of a RANDO phantom and to estimate the effective dose in radiographic imaging of the jaws using low dose Cone Beam computed tomography (CBCT) and (b) to compare the absorbed and the effective doses between thyroid and cervical spine shielding and non-shielding techniques.

Study Design: Thermoluminescent dosimeters (TLD-100) were placed at 14 sites in a RANDO phantom, using a Cone Beam CT device (Newtom, Model QR-DVT 9000, Verona, Italy). Dosimetry was carried out applying two techniques: in the first, there was no shielding device used while in the second one, a shielding device (EUREKA!, TRIX) was applied for protection of the thyroid gland and the cervical spine.

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