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Validation of the Usefulness of Dose Calculation Algorithms in Radiotherapy Planning System

100%

Kiełtyka B., Rawojć K., Kisielewicz K., Markiewicz I.

Acta Physica Polonica A

2016

vol. 129

issue 2

219-221

One of the main goals of radiotherapy is to achieve tumor control and minimize probability of normal-tissue complications. For this reason radiation oncology requires high accuracy, which implies no more than 2-3% uncertainty levels in the treatment planning calculations. That is challenging, when heterogeneous tissues such as lungs and bones are involved. To verify the accuracy of the dose calculation algorithms numerous approaches might be performed. The most common are point dose, one-dimensional profile and two-dimensional isodose line comparison with experimental measurements. In presented study, results of transport modeling and the deposited spatial distribution of the dose, obtained by anisotropic analytical algorithm and pencil beam convolution algorithm, were compared to measurements recorded during the experiment. To achieve meaningful conclusions, three parameters: dose difference, distance to agreement and gamma parameter (γ) were taken into consideration and examined. The irradiation was performed using CIRS anthropomorphic phantom. For dose detection gafchromic EBT films were used and scanned after exposure using Epson Scanner. Measured and planned dose distributions were analyzed via FilmQA software. Preliminary results showed that the anisotropic analytical algorithm, with its complex accounting of heterogeneities, provides more accurate dose calculation within an area of a high density gradient, than pencil beam convolution does. The level of the data accuracy derived from the experiment was: dose difference (5%) - 83.4% and 68% pixels passing, distance to agreement (3 mm) - 99.0% and 96.7%, gamma parameter (for dose difference (3%), distance to agreement (3 mm)) - 90% and 75.5%, respectively, for anisotropic analytical algorithm and pencil beam convolution algorithms. The comparison between studied parameters dose difference, distance to agreement and γ for both algorithms implicated anisotropic analytical algorithm as an appropriate approach in radiotherapy treatment planning.

Comparison of Methods in Studies of Cell Death Mechanisms

76%

Borkowska A., Nowakowski M., Miszczyk J., Lipiec E., Wiltowska-Zuber J., Rawojć K., Kwiatek W.

Acta Physica Polonica A

2018

vol. 133

issue 2

263-266

While studying the influence of ionizing radiation or certain chemical agents on cells, it is crucial to not only determine cytotoxicity, but also to follow cell death mechanisms. There are different methods to screen processes of cell death and still very important question remains unanswered about differences in results that could be caused by various experimental steps in procedures. Based on literature review two protocols of cell death determination were compared. First protocol regarded collecting cells floating in medium before trypsinization and following centrifugation of them. In the second protocol floating cells were discarded and attached ones were stained and fixed. In all experiments three different untreated cell lines (A172, DU145 as cancer cell lines and in comparison, fibroblasts (FB CCL 110), as a non- cancerous cell line) were used to test applied protocols. Cells were cultured and death processes were examined at different time points up to 120 h. Compared protocols showed statistically significant differences, especially in terms of necrosis, which was higher when included floating cells from culture medium and then centrifuging them. Therefore, presented results show importance of choosing a valid experimental procedure in case of evaluating cells viability and types of cell death pathways quantitatively.

Effects of 60 MeV Protons and 250 kV X-Rays on Cell Viability

76%

Miszczyk J., Panek A., Rawojć K., Swakoń J., Prasanna P., Rydygier M., Gałaś A.

Acta Physica Polonica A

2016

vol. 129

issue 2

222-225

Particle radiotherapy such as the one using proton beams, provides a successful treatment approach in many cancer types. However, the cellular and molecular mechanisms by which proton irradiation induces cell death, particularly in a human peripheral blood lymphocyte model has not been examined in detail. Comparative studies of the biological effects, such as cell death, of particle therapy versus conventional X-rays treatment are of utmost importance. Here, we compared the viability of human peripheral blood lymphocyte following in vitro irradiation with protons (therapeutic 60 MeV proton beam) and photon beam (250 kV, X-rays), by applying separate doses within the range of 0.3-4.0 Gy. Cell viability was assessed 1 and 4 h after irradiation with protons and X-rays by the FITC-Annexin V labelling procedure (Apoptotic & Necrotic & Healthy Cells Quantification Kit, Biotium). Results showed that irradiation with both radiation types reduced the number of viable cells in a dose-dependent manner, as assessed as a function of the duration of post-irradiation time. Protons proved more fatal to the cells treated than X-ray photons. This demonstrates a difference in cell viability after irradiation with protons and photons in a human peripheral blood lymphocyte model.

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3 Acta Physica Polonica A

1 2018

2 2016

3 Rawojć K.

2 Miszczyk J.

1 Borkowska A.

1 Gałaś A.

1 Kiełtyka B.

1 Kisielewicz K.

1 Kwiatek W.

1 Lipiec E.

1 Markiewicz I.

1 Nowakowski M.

1 Panek A.

1 Prasanna P.

1 Rydygier M.

1 Swakoń J.

1 Wiltowska-Zuber J.

Search results

Validation of the Usefulness of Dose Calculation Algorithms in Radiotherapy Planning System

Comparison of Methods in Studies of Cell Death Mechanisms

Effects of 60 MeV Protons and 250 kV X-Rays on Cell Viability