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    A multicenter quantitative evaluation of Organ-specific radiation doses in head and neck CT: A dosimetric assessment using the Alderson Rando phantom
    (Springer, 2025) Kesmezacar, Fahrettin Fatih; Gunay, Osman; Tuncman Kayaokay, Duygu; Yeyin, Nami; Demirci, Ali; Cavdar Karacam, Songul; Colpan Oksuz, Didem
    This multicentre phantom-based study aimed to quantitatively assess organ-specific radiation doses during head and neck CT imaging using four CT scanner models: Siemens Somatom Definition AS+, Philips Ingenuity, and two Philips Incisive CT units. Thermoluminescence dosimeters (TLDs) were placed at 16 anatomically significant locations within an Alderson Rando (R) phantom to simulate realistic patient exposures. The highest absorbed dose was consistently measured in the superficial thyroid gland, reaching up to 30.41 +/- 2.7 mSv, followed by the parotid glands, corneas, and spinal cord (C1-C2). Notable differences were found among scanners, with the Philips Incisive units generally delivering higher doses to superficial structures, despite harmonized scanning protocols. CTDIw values reported by the scanners deviated by less than 10% from TLD-based measurements, confirming system calibration accuracy. It can be concluded that device-specific optimization and ongoing dose audits are essential to ensure consistent patient safety and minimize radiation exposure during head and neck CT procedures.
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    Radiation dose variability in critical thoracic organs during CT imaging: A multi-centre phantom dosimetry study
    (Pergamon-Elsevier Science Ltd, 2026) Kesmezacar, Fahrettin Fatih; Gunay, Osman; Kayaokay, Duygu Tuncman; Yeyin, Nami; Demirci, Ali; Karacam, Songul Cavdar; Oksuz, Didem Colpan
    This multicenter phantom-based study quantified organ-specific radiation doses delivered during routine thoracic CT using five clinical systems from four major manufacturers. A total of 70 TLD-100 dosimeters were calibrated and strategically positioned in an Alderson Rando (R) phantom to measure absorbed doses in the lungs, heart apex, atrium, and bilateral breasts. Marked dose variability was observed across scanners, driven by differences in tube current, CTDIvol, pitch, and the implementation of dose modulation strategies. Lung doses ranged from 4.60 to 22.51 mGy, heart apex doses from 4.15 to 23.15 mGy, atrial doses from 4.73 to 20.77 mGy, and breast doses from 3.17 to 22.01 mGy. The CT-2 system consistently yielded the highest organ doses, while the CT-1 demonstrated the most effective dose reduction. Comparative assessment with literature confirmed strong alignment of our measured values with published experimental and Monte Carlo-based studies. It can be concluded that significant dose reductions to radiosensitive thoracic organs are achievable through advanced modulation technologies and tailored protocol adjustments.