Convolution and model-based dose calculation methods in radionuclide and external-beam photon therapy
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School of Science |
Doctoral thesis (article-based)
| Defence date: 2016-04-15
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Authors
Date
2016
Major/Subject
Mcode
Degree programme
Language
en
Pages
65 + app. 89
Series
Aalto University publication series DOCTORAL DISSERTATIONS, 57/2016
Abstract
Radiotherapy is an established treatment modality of cancer. Radiation is delivered to the patients from internal or external sources. This thesis explores and introduces improvements to computational methods that are used in the application of internal and external radiotherapy. The aims of the work were to develop a general methodology for 3D treatment planning of internal radionuclide therapy, to apply 3D treatment planning to analyze radionuclide therapy cases, and to develop a pencil-beam dose kernel based calculation method for external photon therapy that also accounts for local variations in tissue material densities in 3D space. The variability of biological uptake and clearance of the therapy agent were analyzed in various patients undergoing radionuclide therapy by serial single-photon emission computed tomography (SPECT), and estimates of absorbed doses were calculated. Patient-specific dose calculation with the dose kernel method was compared with the widely used MIRD S-factor model. Large inter-patient variation of biological clearance and localized differences for individual patients were observed. The dose estimates from the S-factor model and point dose kernel approach agreed on average, but at an individual patient level there were large variations between the methods. For external photon therapy, an advanced pencil beam dose calculation method was developed. The resulting Analytical Anisotropic Algorithm (AAA) includes a density-scaling method of both lateral and depth-dependent components of the model. The results indicate generally good agreement between the calculations utilizing the presented method and Monte Carlo simulations in various heterogeneous geometries. Most of the observed discrepancies were within 2% (or 2~mm). The method is computationally very efficient and suitable for routine use in clinical setting.Sädehoito on laajasti käytössä oleva syövän hoitomuoto. Potilaita hoidetaan joko ulkoisilla tai sisäisillä säteilylähteillä. Väitöskirja käsittelee sekä sisäisen että ulkoisen sädehoidon laskennallisia menetelmiä. Tutkimuksessa kehitettiin yleinen menetelmä isotooppihoitojen kolmiulotteiseen annossuunnitteluun ja sovellettiin tätä menetelmää isotooppihoitojen annosten analysointiin. Lisäksi kehitettiin ulkoisen sädehoidon annoslaskentamenetelmä, joka huomioi epähomogeenisen väliaineen vaikutukset säteilyn kulkeutumisessa. Tutkimuksessa analysoitiin isotooppihoitojen aktiivisuusjakaumia, isotooppien biologisia poistumia ja säteilyannoksia useissa potilastapauksissa SPECT-kuvantamisen avulla. Potilaskohtaisia annoslaskentoja suoritettiin konvoluutiomenetelmällä ja näitä verrattiin yleisesti käytössä olevan MIRD S -mallin tuloksiin. Analyysissä havaittiin isoja eroja potilastapausten välillä sekä annoslaskennan että isotoopin biologisten poistuma-aikojen suhteen. Tutkimuksessa kehitettiin uusi annoslaskentamenetelmä ulkoiseen fotonisädehoitoon. Kehitetty Pencil Beam -pohjainen menetelmä sisältää uuden tiheydestä riippuvan tavan mallintaa epähomogeenistä väliainetta. Annoslaskennan tulokset vastaavat hyvin Monte Carlo-menetelmällä laskettuja tuloksia useissa eri tapauksissa. Havaitut erovaisuudet olivat pienempiä kuin 2% (tai 2 mm). Kehitetty menetelmä on laskennallisesti tehokas ja soveltuu hyvin annossuunnittelukäyttöön sädehoidossa.Description
Supervising professor
Parkkonen, Lauri, Prof., Aalto University, Department of Neuroscience and Biomedical Engineering, FinlandThesis advisor
Kairemo, Kalevi, Visiting Prof., The University of Texas, Department of Nuclear Medicine, USATenhunen, Mikko, Chief Physicist, HUCH Comprehensive Cancer Center, Finland
Keywords
radiotherapy, radionuclide, pencil beam, point kernel, treatment planning, sädehoito, annossuunnittelu, isotooppihoidot
Other note
Parts
- [Publication 1]: J. Laitinen, J. Alakuijala, H. Helminen, S. Sallinen, M. Tenhunen, and K. Kairemo. Spect-based radioimmunotherapy planning system. In IEEE Engineering in Medicine and Biology 19th Annual Conference, Chicago, 781–784, 1997
- [Publication 2]: J.O. Laitinen, K.J. Kairemo, A.P. Jekunen, T. Korppi-Tommola, and M. Tenhunen. The effect of three dimensional activity distribution on the dose planning of radioimmunotherapy for patients with advanced intraperitoneal pseudomyxoma. Cancer 80, 2545–2552, 1997
- [Publication 3]: J.O. Laitinen, M. Tenhunen, and K.J. Kairemo. Absorbed dose estimates for I-131 labelled monoclonal antibody therapy in patients with intraperitoneal pseudomyxoma. Nucl Med Commun 21, 355–360, 2000
- [Publication 4]: J.O. Pyyry, J. Merenmies, M. Tenhunen, M. Heikinheimo, K. Parto, M. Arola,K. Rönnholm, H. Isoniemi, R. Karikoski, E.L. Kamarainen, M. Seppänen,J. Heikkonen, F. Augensen, W.H. Wegener, D.M. Goldenberg, and K.J. Kairemo. Radioimmunotherapy for recurrent childhood hepatoblastoma after liver transplantation. World Journal of Nuclear Medicine 7, 146–157, 2008
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[Publication 5]: W. Ulmer, J. Pyyry, and W. Kaissl. A 3D photon superposition/convolution algorithm and its foundation on results of Monte Carlo calculations. Physics in Medicine and Biology 50, 1767–1790, 2005.
DOI: 10.1088/0031-9155/50/8/010 View at publisher
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[Publication 6]: L. Tillikainen, H. Helminen, T. Torsti, S. Siljamäki, J. Alakuijala, J. Pyyry, and W. Ulmer. A 3D pencil-beam-based superposition algorithm for photon dose calculation in heterogeneous media. Physics in Medicine and Biology 53, 3821–3839, 2008.
DOI: 10.1088/0031-9155/53/14/008 View at publisher