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Uncertainties in the measurement of relative doses in radiotherapy

Buliński Krzysztof, Kuszewski Tomasz, Wnuk Katarzyna, Braziewicz Janusz, Ślosarek Krzysztof

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 1

1--9

EN

Both the measurement of the dose and the measurement of its distribution, like any other measurements, are subject to measurement uncertainties. These uncertainties affect all dose calculations and dose distributions in a patient’s body during treatment planning in radiotherapy. Measurement uncertainty is not a medical physicist's error, but an inevitable element of their work. Planning the dose distribution in a patient’s body, we often try to reduce it in the volume of critical organs (OaR - Organ at Risk) or increase the minimum dose in the PTV region by a few percent. It is believed that the measurement uncertainty should be taken into account in these calculations at the stage of treatment planning. The paper presents the method of calculating the measurement uncertainty for different physical quantities in radiotherapy as percentage depth dose, profile function and output factor, due to the fact that these quantities have a particular impact on the calculated dose distributions in a patient’s body. The uncertainties that must be taken into account in planning treatment the planned dose per fraction and real in PTV, maybe different up to 4%.

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Daily patient geometry correction: application of NAL and eNAL protocols

Dąbrowski Andrzej, Zielińska-Dąbrowska Sylwia, Kuszewski Tomasz, Lis Krzysztof

Polish Journal of Medical Physics and Engineering

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2020

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Vol. 26, Iss. 4

181--184

EN

Purpose: To test the NAL and eNAL correction protocols using daily patient setup displacements. Methods and material: In total, the analysis was performed for 749 and 797 kV CBCT images for gynecological and prostate patients, respectively, each of 30 patients. After the planning procedure, patients were set up on the treatment table in the treatment position every day. The on-line correction protocol was applied. KV CBCT images were acquired by means of x-ray lamp mounted orthogonally on Linac. Patient setup displacement was assigned. NAL and eNAL corrections protocols were simulated using daily data from online corrections for these two groups of patients. The overall systematic error and random error were calculated for each direction. Results: For the prostate group, the random errors for daily Raw data (no correction) in LAT, LONG, and VERT directions were 2.0 mm, 1.6 mm, and 3.2 mm, respectively. For NAL and eNAL protocols, they were in the range of 1.8 mm to 3.2 mm. For the gynecological group, the random errors were: for daily Raw data 2.2 mm, 1.7 mm, and 3.2 mm, respectively. For NAL and eNAL protocols, they were in the range of 2.0 to 3.4 mm. For the prostate group, values of systematic errors 1.8 mm, 1.8 mm, and 3.3 mm, respectively for Raw data. For NAL and eNAL protocols, these values were less than 1.8 mm. For the gynecological group, the systematic errors were 2.6 mm, 2.3 mm, and 2.8 mm, respectively, for Raw data. For NAL ana eNAL protocols less than 1.8 mm. For the gynecological group, for Raw data, 45% of the total displacement vectors exceeded 5 mm, whereas only 25% did after the NAL procedure and 29% after the eNAL procedure. For the prostate group, for Raw data, 34% of the total displacement vectors exceeded 5 mm, whereas only 22% did after NAL procedure and 28% after eNAL procedure Conclusions: For gynecological and prostate cancer patients, the NAL and eNAL correction protocols can be safely applied to substantially reduce setup errors.

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Wykorzystanie mieszanej rzeczywistości w zakresie wizualizacji obrazowych danych trójwymiarowych

Skalski Andrzej, Stanuch Maciej, Złahoda-Huzior Adriana, Kuszewski Tomasz

Inżynier i Fizyk Medyczny

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2020

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Vol. 9, nr 3

193--198

PL

W artykule przedstawiono wybrane zagadnienia związane z mieszaną rzeczywistością. W szczególności skupiono się na wykorzystaniu mieszanej rzeczywistości w kontekście wizualizacji obrazowych danych medycznych. Technologia została szczegółowo omówiona oraz porównana z wirtualną i rozszerzoną rzeczywistością oraz drukiem 3D. Zaprezentowano szerokie spektrum zastosowań, m.in. wykorzystanie mieszanej rzeczywistości w szkoleniu oraz do wizualizacji danych pacjentów onkologicznych zobrazowanych w tomografii komputerowej oraz w technice PET.

EN

This article covers the topics related to the use of the mixed reality in the field of medical data visualization. It enables the user to see the data as a 3D hologram that is a part of the users’ environment. There is a detailed comparison to the virtual and the augmented reality and the relation to the 3D printing. A wide variety of applications of the mixed reality in education and in visualization of the patients’ computed tomography and positron emission tomography data is presented.

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Wirtualna radioterapia – nowe narzędzie w procesie edukacji fizyków medycznych

Buliński Krzysztof, Kuszewski Tomasz, Wnuk Katarzyna, Kędzierawski Piotr, Braziewicz Janusz, Ślosarek Krzysztof

Inżynier i Fizyk Medyczny

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2020

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Vol. 9, nr 3

153--158

PL

Fizyk medyczny to zawód, który wymaga umiejętności zastosowania metod fizyki w medycynie. Jeżeli dziedziną medycyny jest radioterapia, wówczas należy nauczyć się wykorzystania metod pomiarowych promieniowania jonizującego (dozymetria kliniczna) oraz informatyki (systemy planowania leczenia) w praktyce klinicznej. W procesie dydaktycznym wymagane jest wykorzystanie sprzętu medycznego, który jest w codziennym użytku. Pojawia się konflikt (pozorny), czy aparatura medyczna ma być wykorzystywana do celów edukacyjnych, czy też leczenia chorych. W okresie, kiedy informatyka i związana z nią technologia bardzo dynamicznie się rozwijają, kwestią czasu było pojawienie się wirtualnych akceleratorów, symulatorów. Rozwiązanie to bardzo ułatwia, z punktu widzenia organizacji pracy, proces szkolenia nie tylko fizyków medycznych, ale również lekarzy oraz elektroradiologów obsługujących aparaty terapeutyczne w radioterapii.

EN

Medical physicist is a profession that requires the ability to apply physics methods in medicine. If the field of medicine is radiotherapy, then you should learn how to use radiation measurement methods (clinical dosimetry) and computer science (treatment planning systems) in clinical practice. The teaching process requires the use of medical equipment that is in use daily. There is a conflict (an apparent one) whether medical equipment is to be used for educational purposes or for treating patients. In the period when IT and related technology is developing very dynamically, it was just the matter of time when virtual accelerators, simulators appear. In such virtual reality we can use these programs to move virtual accelerator’s gantry, collimator... This solution greatly facilitates, from the point of view of work organization, the training process not only of medical physicists, but also doctors and technicians in radiotherapy.