| 1. |
- Hedman, Mattias, et al.
(författare)
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Fractionated Irradiation of Five Human Lung Cancer Cell Lines and Prediction of Survival According to a Radiobiology Model
- 2011
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Ingår i: Anticancer Research. - 0250-7005 .- 1791-7530. ; 31:4, s. 1125-1130
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study evaluates a predictive radiobiology model by measurements of surviving fraction (SF) by the clonogenic assay or the extrapolation method and the proliferation rate in vitro. It is hypothesized that incorporating proliferation to intrinsic radiosensitivity, measured by SF, to predict radiation responsiveness after fractionated irradiation adds to the model's accuracy. Materials and Methods. Five lung cancer cell lines with known SF after 1 Gy (SF1), and also SF2 and SF5, were irradiated with three different fractionation regimes; 10x1 Gy, 5x2 Gy or 2x5 Gy during the same total time to achieve empirical SF. In addition, the SF1, SF2 and SF5 after fractionated irradiation was calculated for each cell line based on the already known single fraction SF and with or without a proliferation factor. The results were compared to the empirical data. Results and Discussion: By using the clonogenic assay to measure radiosensitivity, prediction of radiosensitivity was improved after fractionated radiotherapy when proliferation was used in the radiobiology model. However, this was not the case in the cell lines where the extrapolation method was used to calculate SF. Thus, a radiobiology model including intrinsic radiosensitivity, measured by the clonogenic assay, as well as proliferation, is better at predicting survival after fractionated radiotherapy, compared to the use of intrinsic radiosensitivity alone.
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| 2. |
- Hedman, Mattias, et al.
(författare)
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Predictive value of modelled tumour control probability based on individual measurements of in vitro radiosensitivity and potential doubling time
- 2013
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Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 86:1025
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of this study was to compare patient-specific radiobiological parameters to population averages in predicting clinical outcome after radiotherapy using a tumor control probability (TCP) model based on BED.Methods: A previously published material of forty-six head and neck carcinomas with individually identified radiobiological parameters; SF2 and Tpot, and known tumor size was investigated. These patients had all been treated with external beam radiotherapy and the majority had also received brachytherapy. TCP for each individual based on BED using patient-specific radiobiological parameters was compared to TCP based on BED using average radiobiological parameters (α = 0.3 Gy-1 and Tpot = 3 days).Results: Forty-three patients remained in the final analysis. There was only a weak trend for increasing local tumor control with increasing BED in both groups. However, when TCP was calculated the use of patient-specific parameters was better to identify local control correctly. Sensitivity and specificity for tumor-specific parameters were 63% and 80%, respectively. The corresponding values for population-based averages were 0% and 91%, respectively. Positive predictive value was 92% when tumor-specific parameters were used compared to 0 % for population-based. A receiver operating characteristic (ROC) curve confirmed the superiority of patient-specific parameters over population averages in predicting local control.Conclusions: Individual radiobiological parameters are better than population derived averages when used in a mathematical model to predict tumor control probability after curative radiotherapy in head and neck carcinomas.Advances in knowledge: TCP based on individual radiobiological parameters are better than TCP based on population based averages.
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| 3. |
- Holgersson, Georg, et al.
(författare)
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The value of induction chemotherapy for survival in patients with non-small cell lung cancer treated with radiotherapy.
- 2012
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Ingår i: Anticancer research. - : The International Institute of Anticancer Research. - 1791-7530 .- 0250-7005. ; 32:4, s. 1339-46
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Tidskriftsartikel (refereegranskat)abstract
- AIM: The aim of the present study was to retrospectively investigate the impact of induction chemotherapy on treatment outcome in patients treated with curatively intended radiotherapy for non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients with a diagnosed NSCLC that have been subjected to curatively intended irradiation (≥50 Gy) and treated in an oncology department in Sweden during the years 1990-2000 were included in the study. Operated patients and patients having received concomitant chemotherapy were excluded. The included patients were localised by a manual search of all the oncology departments' medical records and radiation charts. RESULTS: Patients treated with induction chemotherapy (n=79) had a significantly better overall survival compared with patients treated with radiotherapy alone (p=0.0097) in a univariate Cox regression analysis. A platinum/taxane combination produced the greatest survival benefit; hazard ratio=0.49 (95% confidence interval=0.31 to 0.75). CONCLUSION: We found that patients treated with induction chemotherapy in addition to radiotherapy for NSCLC have a better overall survival than patients treated with radiotherapy alone and that the best results are achieved using a platinum/taxane combination.
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| 4. |
- Strondl, Annika, et al.
(författare)
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Characterisation and control of powder properties for additive manufacturing
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Powder characterization and handling in PM are important issues and required powder properties will vary between different component manufacturing processes. By understanding and controlling these, the final material properties for different applications can be improved and become more reliable. In this study, metal powders used in additive manufacturing have been investigated regarding particle size and shape using dynamic image analysis. In parallel, powder flow characteristics have been evaluated with a powder rheometer. Correlations within the results have been found between particle shape and powder flow characteristic that could explain certain effects of the powder processing in the additive manufacturing processes.
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