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Local diagnostic reference levels and effective doses: single institution levels for interventional cardiology procedures for adult patients

Kidoń Joanna, Polaczek-Grelik Kinga, Wojciuch Leszek

Polish Journal of Medical Physics and Engineering

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2022

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Vol. 28, Iss. 2

77--83

EN

Introduction: The current regulations in Poland in the field of interventional radiology only include diagnostic reference levels (DRL) for five procedures, containing only two for cardiological (hemodynamic) procedures, and only for adults. Given the insufficient number of DRLs, the need to introduce local levels based on the intervention procedures performed was identified. The purpose of this research was the evaluation of radiation doses (DRL, effective dose) received by patients in cardiological interventional procedures. Material and methods: The DRL level was defined as the 75th percentile of the distribution of dosimetric parameters KAP and Kair, ref for each type of cardiological procedure. Data include three different X-ray units and 27 interventional cardiologists, derived from February 2019 to June 2019 and from August 2021 to December 2021. In order to estimate the effective dose, the appropriate conversion factors for cardiological procedures were used. The total number of analyzed procedures was 3818. Results: The proposed local DRL levels were found to be mostly lower than data found in literature and in the current Polish national requirements (60%-70% lower for coronary angiography (CA) and percutaneous coronary angioplasty (PCI) procedures). Median equivalent doses for cardiological procedures were estimated at 2.66 mSv, 6.11 mSv and 7.22 mSv for CA, PCI and combined PCI with CA procedure, respectively. Conclusions: The proposed local/institutional DRLs seem to be suitable for use and could be utilized by other centers for comparison purposes.

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Dosimetric accuracy of a cross-calibration coefficient for plane-parallel ionization chamber obtained in low-energy electron beams using various cylindrical dosimeters

Polaczek-Grelik Kinga, Kawa-Iwanicka Aneta, Michalecki Łukasz

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 4

303--313

EN

Introduction: The accuracy of the cross-calibration procedure depends on ionization chamber type, both used as reference one and under consideration. Also, the beam energy and phantom medium could influence the precision of cross calibration coefficient, resulting in a systematic error in dose estimation and thus could influence the linac beam output checking. This will result in a systematic mismatch between dose calculated in treatment planning system and delivered to the patient. Material and methods: The usage of FC65-G, CC13 and CC01 thimble reference chambers as well as 6, 9, and 15 MeV electron beams has been analyzed. A plane-parallel PPC05 chamber was calibrated since scarce literature data are available for this dosimeter type. The influence of measurement medium and an effective point of measurement (EPOM) on obtained results are also presented. Results: Dose reconstruction precision of ~0.1% for PPC05 chamber could be obtained when cross-calibration is based on a thimble CC13 chamber. Nd,w,Qcross obtained in beam ≥ 9MeV gives 0.1 – 0.5% precision of dose reconstruction. Without beam quality correction, 15 MeV Nd,w,Qcross is 10% lower than Co-60 Nd,w,0. Various EPOM shifts resulted in up to 0.6% discrepancies in Nd,w,Qcross values. Conclusions: Ionization chamber with small active volume and tissue-equivalent materials supplies more accurate cross-calibration coefficients in the range of 6 – 15 MeV electron beams. In the case of 6 and 9 MeV beams, the exact position of an effective point of measurement is of minor importance. In-water cross-calibration coefficient can be used in a solid medium without loss of dose accuracy.

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Calibration of Gafchromic XR-RV3 film under interventional radiology conditions

Kidoń Joanna, Polaczek-Grelik Kinga, Gołba Krzysztof, Wojakowski Wojciech, Ochała Andrzej

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 2

165--173

EN

Introduction: The purpose of the study was the calibration of Gafchromic films in clinical interventional radiology conditions and the assessment of the influence of dose range, the shape of the fitting curve, and its practical application. The aim of the work was to show how practically perform calibration in a wide range of doses. Material and methods: Gafchromic XR–RV3 films were included in the study. The calibration was performed for A and B film series separately. Doses from the range of 0 – 8 Gy were used. Film dosimeters were read out in reflective mode with a commercial flatbed scanner. Results: Among various degrees of a polynomial function, the best fit, which fulfilled the chosen criterion of 95% agreement between measured and reconstructed doses and simple equation criterion, was observed for third-degree polynomial. The fitting curve where the dose is the function of optical density (logMPV) was demonstrated to be more precise than the fitting curve based on MPV only. To minimize the difference between dose absorbed by the film and dose reconstructed from the fitting curve below 5% it is necessary to divide the calibration range of 0 – 8 Gy into two subranges for use in interventional radiology. This difference was set at a maximum level of 3.8% and 1.9% for the lowand high-dose range, respectively. Each series of films may have a slightly different calibration curve, especially for the low dose range. A deviation of up to 36% between two batches of Gafchromic film was observed. Conclusions: For the third-degree polynomial fitting function (one of the recommended in the literature) calibration should be done into low and high dose ranges and for each batch separately. A systematic error higher than 20% could be introduced when the fitting curve from one film batch is applied to the other film batch.

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Rola audytów zewnętrznych w zapewnianiu jakości procedur wysokospecjalistycznych w radioterapii

Stefańczyk Marta, Kostecki Tomasz, Polaczek-Grelik Kinga

Inżynier i Fizyk Medyczny

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2019

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Vol. 8, nr 3

185--190

PL

Artykuł ma na celu przybliżenie roli audytów zewnętrznych na przykładzie procesu weryfikacji ścieżki terapeutycznej w ośrodku radioterapii. W artykule prezentujemy wykonanie testu end-to- -end pozwalającego na uzyskanie akredytacji przez MD Anderson Cancer Center w zakresie procesu radioterapii. W styczniu 2019 r. Uniwersyteckie Centrum Kliniczne im. prof. K. Gibińskiego Śląskiego Uniwersytetu Medycznego w Katowicach przeszło pomyślnie przez tego typu proces akredytacji i otrzymało certyfikat jakości. Opis poszczególnych etapów tego audytu zewnętrznego być może przekona czytelników, że testy takie są istotne dla całościowego sprawdzenia procesu radioterapii oraz umożliwiają udział w międzynarodowych badaniach klinicznych. Ośrodek audytujący IROC Houston Quality Assurance Center należący do University of Texas MD Anderson Cancer Center oferuje całościową usługę dostarczenia dedykowanych fantomów wraz z instrukcjami przeprowadzenia testów, a także opracowuje ich wyniki w postaci skonsolidowanego raportu.

EN

The scope of this article is the discussion of the role of external audits in the verification process of therapeutic chain, in a radiotherapy department. In this article an end-to-end test is presented, which allows for the accreditation by MD Anderson Cancer Center in the field of radiotherapy. In January 2019 Uniwersyteckie Centrum Kliniczne im. prof. K. Gibińskiego Śląskiego Uniwersytetu Medycznego w Katowicach passed successfully the accreditation process and received a quality certificate. The description of particular stages of this external audit may convince the readers that such tests are essential for a comprehensive control of the radiotherapy process and enable the participation in international clinical trials. The IROC Houston Quality Assurance Center of the University of Texas MD Anderson Cancer Center provides a comprehensive service of delivering dedicated phantoms with test instructions, and also compiles the results in the form of a consolidated report.

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Teleradioterapia, neutrony i reakcje jądrowe

Konefał A., Szewczuk M., Orlef Andrzej, Polaczek-Grelik Kinga, Łaciak M.

Postępy Fizyki

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2012

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T. 63, z. 5

225--233

PL

Wysokoenergetyczne wiązki promieniowania X i wiązki elektronowe o energii maksymalnej przekraczającej 10 MeV, stosowane w teleradioterapii, generowane przez liniowe akceleratory medyczne, wywołują reakcje fotojądrowe (γ, n), (γ,2n) i reakcje elektrojądrowe (e,e′n). Powstałe neutrony wywołują kolejne reakcje, w tym reakcje wychwytu radiacyjnego neutronu (n,γ) zachodzące dla większości izotopów w zakresie energii termicznych i rezonansowych. Jedną z konsekwencji ww. reakcji jądrowych są niepożądane dawki neutronowe na całe ciało otrzymywane przez pacjentów poddanych teleradioterapii. Inną ważną konsekwencją jest produkcja radioizotopów głównie w komponentach głowicy akceleratora, ale także we wszystkich przedmiotach znajdujących się w pomieszczeniu do teleradioterapii w trakcie emisji ww. terapeutycznych wiązek promieniowania.