| 1. |
- Grönlund, Eric, 1987-
(författare)
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Dose painting : Can radiotherapy be improved with image driven dose-responses derived from retrospective radiotherapy data?
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main aim of curative radiotherapy for cancer is to prescribe and deliver doses that eradicate the tumor and spare the normal healthy tissues. Radiotherapy is commonly performed by delivering a homogeneous radiation dose to the tumor. However, concern have been raised that functional imaging methods such as magnetic resonance imaging (MRI) and positron emission tomography (PET) can provide a basis for prescribing heterogeneous doses - higher doses in malignant regions of the tumor and less dose where the tumor is less malignant. This form of radiotherapy is called “dose painting” and has the aim of utilizing the radiant energy as efficiently as possible to increase the tumor control probability (TCP) and to reduce the risk for unwanted side effects of the neighboring normal tissues.In this project we have studied how dose painting prescriptions could be derived through retrospectively analyzing pre-RT image data and post-RT outcomes for two different patient groups: one diagnosed with head and neck cancer with pre-RT fluorodeoxyglucose (18F-FDG) PET image data; and one patient group diagnosed with prostate cancer with pre-RT Gleason score data that were constructed to be mapped from apparent diffusion coefficient (ADC) data acquired from MRI. The resulting dose painting prescriptions for each of these diagnoses indicated that the TCP could be increased without increasing the average dose to the tumor volumes as compared to homogeneous dose treatments. These TCP increases were more noticeable when the tumors were larger and more heterogeneous than for smaller and more homogeneous tumors.We have also studied the potential to realize TCP increases with dose painting in comparison to homogeneous dose treatments by optimizing clinically deliverable dose painting plans for both diagnoses, i.e. head and neck cancer and prostate cancer. These plans were optimized with minimax optimization that aimed to maximize a robust TCP increase by considering uncertainties of the patient geometry. These plan optimizations indicated that the TCP compared to homogeneous dose treatments was increasing and robust regarding uncertainties of the patient geometry.
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| 2. |
- Grönlund, Eric, 1987-, et al.
(författare)
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Robust maximization of tumor control probability for radicality constrained dose painting by numbers of head and neck cancer
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose The aim of this study was to evaluate the potential and robustness to increase the tumor control probability (TCP) for robustly optimized dose painting plans compared to conventional homogeneous dose plans for head and neck cancers.Material and Methods We optimized a set of dose painting plans with a robust TCP maximizing objective under different mean dose constraints for the primary clinical target volume (CTVT). These plans were optimized with the robust mini-max algorithm together with dose-responses driven by standardized uptake values (SUV) from 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). The robustness in TCP was evaluated through sampling treatment scenarios with iso-center displacements. We also analyzed the impact on TCP predictions by considering dose-response uncertainties.Results The average increase in TCP with dose painting ranged between 3 to 20 percentage points (p.p.) which depended on the allowed integral CTVT dose. The median deviation in TCP increase was below 1p.p. for all sampled treatment scenarios versus the nominal plans. Patients with large tumors and large spread of SUV gained the greatest TCP increases. By considering dose-response uncertainties, a decrease of the TCP for a homogeneous dose yielded an increasing dose painting potential.Conclusions We have found that it is feasible to optimize FDG-PET driven dose painting plans that robustly increase the TCP compared to homogeneous dose treatments for head and neck cancers. The greatest potential TCP increases were found for patients with larger and more SUV heterogeneous tumors, which may give guidance for patient selection to further test the presented dose painting formalism.
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| 3. |
- Grönlund, Eric, 1987-, et al.
(författare)
-
Robust maximization of tumor control probability for radicality constrained dose painting by numbers of head and neck cancer
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose The aim of this study was to evaluate the potential and robustness to increase the tumor control probability (TCP) for robustly optimized dose painting plans compared to conventional homogeneous dose plans for head and neck cancers.Material and Methods We optimized a set of dose painting plans with a robust TCP maximizing objective under different mean dose constraints for the primary clinical target volume (CTVT). These plans were optimized with the robust mini-max algorithm together with dose-responses driven by standardized uptake values (SUV) from 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). The robustness in TCP was evaluated through sampling treatment scenarios with iso-center displacements. We also analyzed the impact on TCP predictions by considering dose-response uncertainties.Results The average increase in TCP with dose painting ranged between 3 to 20 percentage points (p.p.) which depended on the allowed integral CTVT dose. The median deviation in TCP increase was below 1p.p. for all sampled treatment scenarios versus the nominal plans. Patients with large tumors and large spread of SUV gained the greatest TCP increases. By considering dose-response uncertainties, a decrease of the TCP for a homogeneous dose yielded an increasing dose painting potential.Conclusions We have found that it is feasible to optimize FDG-PET driven dose painting plans that robustly increase the TCP compared to homogeneous dose treatments for head and neck cancers. The greatest potential TCP increases were found for patients with larger and more SUV heterogeneous tumors, which may give guidance for patient selection to further test the presented dose painting formalism.
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| 4. |
- Grönlund, Eric, 1987-, et al.
(författare)
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Robust maximization of tumor control probability for radicality constrained radiotherapy dose painting by numbers of head and neck cancer
- 2019
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Ingår i: Physics and Imaging in Radiation Oncology. - : ELSEVIER. - 2405-6316. ; 12, s. 56-62
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Radiotherapy with dose painting by numbers (DPBN) needs another approach than conventional margins to ensure a geometrically robust dose coverage for the tumor. This study presents a method to optimize DPBN plans that as opposed to achieve a robust dose distribution instead robustly maximize the tumor control probability (TCP) for patients diagnosed with head and neck cancer. Material and methods: Volumetric-modulated arc therapy (VMAT) plans were optimized with a robust TCP maximizing objective for different dose constraints to the primary clinical target volume (CTVT) for a set of 20 patients. These plans were optimized with minimax optimization together with dose-responses driven by standardized uptake values (SUV) from F-18-fluorodeoxyglucose positron emission tomography ((18)FDG-PET). The robustness in TCP was evaluated through sampling treatment scenarios with isocenter displacements. Results: The average increase in TCP with DPBN compared to a homogeneous dose treatment ranged between 3 and 20 percentage points (p.p.) which depended on the different dose constraints for the CTVT. The median deviation in TCP increase was below 1p.p. for all sampled treatment scenarios versus the nominal plans. The standard deviation of SUV multiplied by the CTVT volume were found to correlate with the TCP gain with R-2 >= 0.9. Conclusions: Minimax optimization of DPBN plans yield, based on the presented TCP modelling, a robust increase of the TCP compared to homogeneous dose treatments for head and neck cancers. The greatest TCP gains were found for patients with large and SUV heterogeneous tumors, which may give guidance for patient selection in prospective trials.
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| 5. |
- Grönlund, Eric, 1987-, et al.
(författare)
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Robust treatment planning of dose painting for prostate cancer based on ADC-to-Gleason score mappings : what is the potential to increase the tumor control probability?
- 2021
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Ingår i: Acta Oncologica. - : Taylor & Francis. - 0284-186X .- 1651-226X. ; 60:2, s. 199-206
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose The aim of this study was to evaluate the potential to increase the tumor control probability (TCP) with ‘dose painting by numbers’ (DPBN) plans optimized in a treatment planning system (TPS) compared to uniform dose plans. The DPBN optimization was based on our earlier published formalism for prostate cancer that is driven by dose-responses of Gleason scores mapped from apparent diffusion coefficients (ADC).Material and MethodsFor 17 included patients, a set of DPBN plans were optimized in a TPS by maximizing the TCP for an equal average dose to the prostate volume (CTVT) as for a conventional uniform dose treatment. For the plan optimizations we applied different photon energies, different precisions for the ADC-to-Gleason mappings, and different CTVT positioning uncertainties. The TCP increasing potential was evaluated by the DPBN efficiency, defined as the ratio of TCP increases for DPBN plans by TCP increases for ideal DPBN prescriptions (optimized without considering radiation transport phenomena, uncertainties of the CTVT positioning, and uncertainties of the ADC-to-Gleason mapping).ResultsThe median DPBN efficiency for the most conservative planning scenario optimized with a low precision ADC-to-Gleason mapping, and a positioning uncertainty of 0.6 cm was 10%, meaning that more than half of the patients had a TCP gain of at least 10% of the TCP for an ideal DPBN prescription. By increasing the precision of the ADC-to-Gleason mapping, and decreasing the positioning uncertainty the median DPBN efficiency increased by up to 40%.ConclusionsTCP increases with DPBN plans optimized in a TPS were found more likely with a high precision mapping of image data into dose-responses and a high certainty of the tumor positioning. These findings motivate further development to ensure precise mappings of image data into dose-responses and to ensure a high spatial certainty of the tumor positioning when implementing DPBN clinically.
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