Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser. I publikationen felaktig serieuppgift: Linköping studies in health sciences ; 989.

PURPOSE: To demonstrate the feasibility of using a knowledge base of prior treatment plans to generate new prostate intensity modulated radiation therapy (IMRT) plans. Each new case would be matched against others in the knowledge base. Once the best match is identified, that clinically approved plan is used to generate the new plan. METHODS: A database of 100 prostate IMRT treatment plans was assembled into an information-theoretic system. An algorithm based on mutual information was implemented to identify similar patient cases by matching 2D beam's eye view projections of contours. Ten randomly selected query cases were each matched with the most similar case from the database of prior clinically approved plans. Treatment parameters from the matched case were used to develop new treatment plans. A comparison of the differences in the dose-volume histograms between the new and the original treatment plans were analyzed. RESULTS: On average, the new knowledge-based plan is capable of achieving very comparable planning target volume coverage as the original plan, to within 2% as evaluated for D98, D95, and D1. Similarly, the dose to the rectum and dose to the bladder are also comparable to the original plan. For the rectum, the mean and standard deviation of the dose percentage differences for D20, D30, and D50 are 1.8% +/- 8.5%, -2.5% +/- 13.9%, and -13.9% +/- 23.6%, respectively. For the bladder, the mean and standard deviation of the dose percentage differences for D20, D30, and D50 are -5.9% +/- 10.8%, -12.2% +/- 14.6%, and -24.9% +/- 21.2%, respectively. A negative percentage difference indicates that the new plan has greater dose sparing as compared to the original plan. CONCLUSIONS: The authors demonstrate a knowledge-based approach of using prior clinically approved treatment plans to generate clinically acceptable treatment plans of high quality. This semiautomated approach has the potential to improve the efficiency of the treatment planning process while ensuring that high quality plans are developed. / Dissertation

Thesis--University of Oklahoma. / Bibliography: leaves 115-119.

Thesis--University of Oklahoma. / Bibliography: leaves 113-115.

Thesis--University of Oklahoma. / Bibliography: leaves 90-92.

<p>Studija je imala za cilj da pokaže značaj primene PET/CT pregleda u planiranju radiolo&scaron;ke terapije kod pacijenata obolelih od Hočkinovog linfoma. U Vojvodini je 2009. godine prema podacima Registra za maligne neoplazme Vojvodine incidence za Hočkinov limfom iznosila 2,7 na 100 000 dok je mortalitet bio 1,1 na 100 000 stanovnika. Na osnovu dostupnih podataka Registra za maligne neoplazme Vojvodine beleži se porast incidence u protekloj deceniji. Procenat obolelih u Vojvodini u korelaciji je sa podacima koje navodi i Međunarodna agencija za istraživanje raka iz Liona (IARC). U Evropi i u Sjedinjenim Američkim Državama postoji bimodularna kriva incidence po starosti koja pokazuje maksimalne vrednosti u period između 20 i 30 godina i nakon 55. godine. S obzirom da od Hočkinovog limfoma dominantnije obolevaju mlađe osobe a da bolest ima dobru prognozu neophodno je iznaći nove načine za inicijalno određivanje stadijuma bolesti, kao i metode koje mogu da unaprede kvalitet lečenja. Jedan od načina je primena &scaron;to savremenijih dijagnostičkih metoda. PET-CT je imidžing metoda koja poslednjih godina zauzima značajno mesto u određivanju stadijuma malignih bolesti kao i u proceni odgovora na primenjenu terapiju. Fuzionisanjem skenova PET-a i CT-a dobija se PET-CT slika koja prikazuje funkcionalno stanje pojedinih tkiva i organa (PET) sa anatomskim detaljima (CT). Cilj istraživanja je bio da se utvrdi prednost PET-CT pregleda u planiranju radioterapije kod pacijenata sa supradijafragmalnom lokalizacijom bolesti. Nakon postavljanja dijagnoze Hočkinovog limfoma kod pacijenata je urađen PET-CT i planiranje radiolo&scaron;ke terapije. Zračna terapija je planirana na osnovu nalaza PET-CT-a i njegovom fuzijom sa CT-om za planiranje radiolo&scaron;kog lečenja. Dobijeni planovi su poređeni sa onim koji su rađeni standardnom 3D konformalnom tehnikom bez fuzije. Poređeni su klinički volumeni (CTV) i planirani volumen (PTV) kao i razlike u njihovoj obuhvaćenosti preskribovanom dozom. Pokazano je da postoji statistički značajna razlika u ciljnim volumenima kao i u njihovoj obuhvaćenosti. Posmatrani su takođe i rizični organi- srce, pluća, dojke, &scaron;titasta žlezda, kičmena moždina i doze koje oni prime. Dokazano je da su sa statističkom značajno&scaron;ću dozna opterećenja na navedene rizične organe manja kada se planiranje vr&scaron;i na osnovu fuzije sa PET-CT-om, te se na osnovu toga može reći da će i očekivane manifestacije kasne toksičnosti biti manje. Istraživanjem je potvrđena hipoteza da PET/CT ima veliku prednost u planiranju radioterapije jer smanjuje zapremine ciljnih volumena i doprinosi pobolj&scaron;anju kvaliteta radiolo&scaron;kog lečenja.</p> / <p>This study aimed to prove that the use of PET/CT in radiotherapy planning makes a material change in the course of the treatment of the patients with Hodgkin&#39;s lymphoma. According to the data from the Registry of malignant neoplasms in Vojvodina, incidence of Hodgkin&#39;s lymphoma in Vojvodina in 2009 was 2.7 per 100 000, while the mortality rate was 1.1 per 100 000 inhabitants. Based on the available data, the said Register recorded an increase in the incidence over the past decade. The percentage of patients who were registered in Vojvodina is in correlation with the data cited by the International Agency for Research on Cancer in Lyon (IARC).In Europe and in the United States the disease has a bi-modular distribution distribution with the highest frequency rate in persons ageing from 20-30 years and people older than 55 years. Due to the fact that the dominant Hodgkin&#39;s lymphoma affects young people and having in mind the good prognosis of the disease, it is necessary to find a new modality for the initial staging of disease and methods which can improve the quality of treatment. PET/CT is the imaging method which has in recent years had an important role in the staging of malignancies, as well in the evaluation of response to therapy. PET/CT image is obtained by fusing PET scans with CT and it show functional status of certain tissues and organs (PET) with anatomical details (CT).The object of this study was to show that PET/CT examinations are preferred imaging method in radiotherapy planning in patients with localized disease above the diaphragm. After they had been diagnosed with HL, patients underwent PET/CT scan which was later used for delineation in radiotherapy planning. In this study, radiation therapy was planned on the basis of the findings of PET /CT and its fusion with CT for planning radiological treatment. The resulting plans were compared with those made using standard 3D conformal technique without fusion. Clinical volume (CTV) and the planned volume (PTV) and the differences in their coverage with the prescription dose in both plans were also compared. The study has shown a statistically significant difference in the target volume and their coverage. In addition, the dose which receive organs at risk was also examined. It has been shown that organs at risk were exposed to lower doses when using PET/CT fusion in radiotherapy planning and consequently, less incidence of late toxicity is to be expected. The study confirmed the hypothesis that PET /CT has a great advantage in the planning of radiotherapy because it reduces the volume of the target volume and improves the quality of radiation treatment.</p>

INTRODUÇÃO: Na Radioterapia, a acurácia da distribuição de dose em cálculos com correção de heterogeneidade está diretamente relacionada à escolha do algoritmo de cálculo. Existe uma variedade de algoritmos de cálculo disponíveis no mercado, variando em tempo de processamento e acurácia. Este estudo teve como objetivos quantificar a acurácia de dez diferentes algoritmos de cálculo em objetos simuladores de pulmão e analisar o impacto da escolha do algoritmo na distribuição de dose em radioterapia aplicada a tumores de pulmão. METODOLOGIA: Foram utilizados placas simuladoras de água (água sólida RW3) e pulmão (cortiça) para determinar a Porcentagem de Dose em Profundidade (PDP) e perfil transversal dentro da heterogeneidade (cortiça). As medidas foram realizadas em um Clinac Varian 6EX, com feixes de fótons de 6 MV e dois tamanhos de campo (5 x 5 cm2 e 10 x 10 cm2), irradiando-se filmes radiocrômicos Gafchromic EBT3 e câmara de ionização Scanditronix Wellhofer CC13. Planejamentos de 25 pacientes - 11 com técnica tridimendional (3D) e 14 com técnica de Radioterapia Estereotática Corpórea (SBRT) - foram realizados, inicialmente sem correção de heterogeneidade e, mantendo-se as UM, os cálculos com os diferentes algoritmos/métodos de correção foram comparados com o planejamento inicial. Foram avaliados as doses no volume alvo e nos órgãos em risco. RESULTADOS: As medidas realizadas em objetos simuladores revelaram que os algoritmos baseados no princípio da convolução (Eclipse® Pencil Beam Convolution com métodos de correção Batho, Batho Modificado e TAR equivalente; XiO® Clarkson e Convolution e iPlan® Pencil Beam) apresentaram diferenças de dose significativas na região da cortiça, sempre superestimando a medida, com uma sobredose superior a 8%. Algoritmos mais avançados, como o Eclipse® AAA e Acuros XB, XiO® Superposition e iPlan® XVMC, apresentaram desvios inferiores a 3% na região da heterogeneidade. A análise dos perfis mostra, igualmente, que a segunda classe de algoritmos apresenta melhor comportamento em meios de baixa densidade como a cortiça. A largura da penumbra apresentou desvios inferiores a 1 mm para os algoritmos mais avançados contra diferenças de até 4,5 mm entre os algoritmos baseados em convolução. A análise da distribuição de dose em planejamentos de tumores pulmonares mostrou que todos os cálculos com correção de heterogeneidade presentam doses superiores ao cálculo sem correção de heterogeneidade. O histograma dose-volume (DVH) do volume alvo sofreu um impacto maior do que dos órgãos em risco. Os cálculos realizados com algoritmos baseados em convolução apresentaram distribuições de dose semelhantes entre si, porém diferentes das do cálculo sem correção de heterogeneidade. Eclipse® AAA, Acuros XB, XiO® Superposition e iPlan® XVMC apresentaram distribuições de dose também semelhantes, porém Eclipse® Acuros XB e iPlan® XVMC são ainda mais similares. Os planejamentos de SBRT apresentaram resultados mais discrepantes do cálculo sem correção de heterogeneidade do que os planejamentos 3D. CONCLUSÕES: Os diferentes algoritmos de cálculo disponíveis possuem acurácias diferentes em meios de baixa densidade eletrônica. Essas diferenças possuem impacto nas distribuições de dose em planejamentos de tratamento de tumores pulmonares, sendo o impacto ainda maior para a técnica de SBRT. Entre os algoritmos avaliados, há pelo menos um de cada fabricante que apresentou bom desempenho em objetos simuladores de pulmão e que devem ser priorizados para o cálculo em planejamentos de tratamentos de câncer de pulmão / INTRODUCTION: In Radiotherapy, the dose distribution accuracy in heterogeneity correction calculations is directly related to the choice of calculation algorithm. There are many calculation algorithms commercially available. They vary in accuracy and processing time. This study aimed to quantify the accuracy of ten different calculation algorithms in lung equivalent material and to analyze the impact of the algorithm choice in the dose distribution in Radiotherapy applied to lung tumors. METHODS: It was used plates of water (solid water RW3) and lung (cork) equivalent materials to determine the Percentage of Depth Dose (PDD) and transversal profile inside the heterogeneity (cork). The measurements were performed in a Clinac Varian 6EX, with 6 MV photon beams and two field sizes (5 x 5 cm2 and 10 x 10 cm2), through irradiation of radiochromic films Gafchromic EBT3 and ionization chamber Scanditronix Wellhofer CC13. Treatment planning of 25 patients - 11 with tridimensional (3D) technique and 14 with Stereotactic Body Radiation Therapy (SBRT) technique - were performed, first without heterogeneity correction and, by keeping the Monitor Units (MU), the calculations were then performed with the different algorithms/methods of heterogeneity corrections and the results were compared with the initial planning. It was analyzed the target volume and organs at risk doses. RESULTS: The measurements performed in phantoms revealed that algorithms based on the convolution principle (Eclipse® Pencil Beam Convolution with correction methods Batho, Batho Modified and Equivalent TAR; XiO® Clarkson and Convolution e iPlan® Pencil Beam) presented significant dose differences in the cork region, overestimating the measurement, with a overdose higher than 8%. More advanced algorithms, as Eclipse® AAA and Acuros XB, XiO® Superposition and iPlan® XVMC, presented deviations below to 3% in the heterogeneity region. The profile analysis showed, similarly, that the second class of algorithms presents better performance in medium with low electronic density, like cork. The penumbra width presented deviations below to 1 mm for the more sophisticated algorithms against differences up to 4.5 mm between the convolution based algorithms. The dose distribution analysis in lung treatment planning showed that all the calculations performed with heterogeneity corrections presented doses higher than the calculation without heterogeneity corrections. The target volume dose-volume histogram (DVH) had a higher impact compared to the organs at risk. The calculation performed with convolution based algorithms presented dose distributions comparable, although different from the calculation performed without heterogeneity correction. Eclipse® AAA, Acuros XB, XiO® Superposition and iPlan® XVMC presented dose distribution similar, however Eclipse® Acuros XB and iPlan® XVMC are still more similar. The SBRT treatment planning presented higher deviations from the calculation with no heterogeneity correction, compared with the 3D treatment planning. CONCLUSIONS: The different calculation algorithms available have different accuracies in low density mediums. These differences have impact in the dose distributions in lung treatment planning, being the impact higher for the SBRT technique. Between the evaluated algorithms there is, at least one of each manufacturer, that presented acceptable performance in lung equivalent material and it should be the choice in lung treatment planning calculation

As técnicas de radioterapia vem sendo constantemente modificadas com a implementação de novas tecnologias visando aumentar a eficiência e diminuir a toxicidade dos tratamentos com radiação ionizante. Esse trabalho visa comparar as técnicas de radioterapia de intensidade modulada (IMRT) e a radioterapia em arco modulada volumetricamente (VMAT) em termos dosimétricos para o alvo e órgãos em risco além de avaliar a diferença do tempo de tratamento utilizando cada técnica. Para assegurar que os planejamentos seguiriam um padrão aceitável para ambas as técnicas, realizou-se primeiramente os planejamentos sugeridos pelo TG 119 da Associação Americana de Física Médica e compatibilidade dos resultados obtidos comparados com os dados da literatura. Tal comparação permitiu prosseguir para uma próxima etapa que consistiu da utilização de imagens de pacientes reais que foram submetidos a tratamentos de próstata e cabeça e pescoço, para a realização dos planejamentos utilizando as técnicas de IMRT e VMAT. A qualidade dosimétrica dos planejamentos utilizando ambas as técnicas foi avaliada em termos de conformidade e homogeneidade da dose no alvo e para os casos de pacientes com câncer de próstata, foram investigados os limites de dose em reto, bexiga e cabeça de fêmur, sendo avaliada a associação entre o volume de intersecção de reto e bexiga com o alvo. Para os   casos de pacientes com câncer de cabeça e pescoço, em termos dos limites de dose em medula, tronco cerebral e parótidas. Os planejamentos nos quais fez se uso da técnica de VMAT apresentaram valores semelhantes aos dos planos de IMRT. A análise dos tempos de tratamento para cada técnica avaliada mostrou que a VMAT reduz significativamente o tempo, até 67% para os casos de pacientes com câncer de próstata e até 36% para os casos de pacientes com câncer de cabeça e pescoço / The goal of this study was to compare the dosimetric aspects of volumetric-modulated arc therapy (VMAT) with those of intensity-modulated radiotherapy (IMRT) and to evaluate the delivery time and monitor unit differences between the two techniques, for applications in prostate and head and neck cancer treatment. First of all, to assure an acceptable pattern of treatment planning using both techniques, the TG119 of American Association of Medical Physics instructions were followed and the results of plans were compared to TG119 published data. The next step consisted of using real patients\' images, whose underwent prostate radiotherapy or head and neck radiotherapy, to planning IMRT and VMAT. The dosimetric quality of plans using both techniques was evaluated in terms of target dose conformity and target dose homogeneity The dose constraints for rectum, bladder and femoral head were analyzed and the association between the rectum intersection volume and bladder intersection volume to the target volume were evaluated for the prostate cases. The dose constraints for spinal cord, brainstem and parotids were investigated for the head and neck cases. Best or similar values were obtained for the VMAT plans in relation to IMRT plans. The analysis of treatment time indicated a significant reduction using VMAT, until 67% to the prostate cases and 36% to the head and neck cases

<p>Uvod: Učestalost neželjenih efekata uzrokovanih zračenjem kod pacijenata sa karcinomom glave i vrata zavisi od tehnike planiranja, sprovođenja radioterapije kao i primarne lokalizacije tumora. Cilj: Osnovna uloga na&scaron;eg istraživanja je da se utvrdi učestalost neželjenih efekata tokom zračne terapije kod pacijenata sa tumorom glave i vrata tretiranih 2D konvencionalnom radioterapijom, 3D konformalnom radioterapijom planiranoj samo na osnovu CT-a nasuprot 3D konformalnoj terapiji planiranoj na osnovu fuzije kompjuterizovane tomografije sa magnetno rezontnim imidžingom (CT-MRI). Metode: Prospektivno je analizirano 90 pacijenata sa karcinomom glave i vrata kod kojih je sprovedena zračna terapija. 30 pacijenata sa karcinomom glave i vrata je zračeno 2D konvencionalnom tehnikom, drugih 30 pacijenata je zračeno 3D konformalom tehnikom na osnovu CT-a, a preostalih 30 pacijenata sa fuzijom CT-MRI. Kod svih bolesnika je primenjena standardna frakcionacija sa 2 Gy dnevno, pet dana sedmično. Rezultati: Od ukupno 90 pacijenata lečenih primenom zračne terapije, kod 72 pacijenta (72/90; 64,8%) su zabeleženi neželjeni efekti zračne terapije a učestalost komplikacija je veća kod primene 2D tehnike zračenja (28/72; 38,9% for 2D RT vs 24/72; 33,3% for 3D CT RT vs 20/72; 27,8% for 3D CT-MRI; p=0,015). Zaključak: 3D tehnika radioterapije planirana samo na osnovu CT-a je povezana sa visokom stopom toksičnosti koje znatno utiču na kvalitet života zračenih pacijenata. 3D konformalna tehnika radioterapije planirana sa CT-MRI fuzijom smanjuje pojavu oralnih komplikacija. Slično razvijenim zemljama, trebalo bi razmotriti uvođenje ove tehnike kao standardnu metodu zračenja bolesnika sa tumorom glave i vrata. Za isporuku vi&scaron;ih tumorskih doza uz manju učestalost komplikacija je podesnija tehnika planiranja sa fuzionisanom tehnikom pomoću MR imidžinga. 2D tehnika radioterapije glave i vrata se preporučuje samo za palijativne zračne tretmane.</p> / <p>Introduction: The incidence of radiation-induced side effects in patients with head and neck cancer (H&amp;N) depends on technique of planning and the irradiation dose as well as primary tumor location within the H&amp;N region. Objective: The aim of our research is to establish the incidence of side effects in patients with head and neck cancer treated with 2D- conventional radiotherapy, 3D-conformal radiotherapy planning with computed tomography (CT) or computed tomography fusion with magnetic resonance imaging (CT-MRI fusion). Methods: Prospective analysis was performed on 90 patients with head and neck carcinoma prospectively followed after radiotherapy. 30 patients with H&amp;N cancer were irradiated by using 2D conventional radiotherapy, other 30 patients irradiated with 3D conformal radiotherapy planning with CT, while other 30 patients were treated using 3D conformal radiotherapy planning with CT-MRI fusion. In all cases standard fractionation was used at 2 Gy per day /5 days a week. Results: Of the total number (n=90) of treated patients, 72 patients (72/90; 64,8%) reported a side effect and the incidence of complications was higher in patients irradiated with 2D technique planning radiotherapy (28/72; 38,9% for 2D RT vs 24/72; 33,3% for 3D CT RT vs 20/72; 27,8% for 3D CT-MRI; p=0,015). Conclusion: 3D radiotherapy technique planned solely on the basis of CT is related to high incidence of toxicity which significantly affects the quality of life of irradiated patients. 3D conformal radiotherapy planned with CT-MRI fusion reduces the incidence of oral complications. Following the example of developed countries, this technique should be considered as a standard method for irradiating patients with head and neck cancer. Planning technique with fusion technique using MR imaging is more suitable for delivering higher doses to the tumor with fewer side effects. Recommendation 2D conventional radiotherapy is more for palliative treatments.</p>

INTRODUÇÃO: Na Radioterapia, a acurácia da distribuição de dose em cálculos com correção de heterogeneidade está diretamente relacionada à escolha do algoritmo de cálculo. Existe uma variedade de algoritmos de cálculo disponíveis no mercado, variando em tempo de processamento e acurácia. Este estudo teve como objetivos quantificar a acurácia de dez diferentes algoritmos de cálculo em objetos simuladores de pulmão e analisar o impacto da escolha do algoritmo na distribuição de dose em radioterapia aplicada a tumores de pulmão. METODOLOGIA: Foram utilizados placas simuladoras de água (água sólida RW3) e pulmão (cortiça) para determinar a Porcentagem de Dose em Profundidade (PDP) e perfil transversal dentro da heterogeneidade (cortiça). As medidas foram realizadas em um Clinac Varian 6EX, com feixes de fótons de 6 MV e dois tamanhos de campo (5 x 5 cm2 e 10 x 10 cm2), irradiando-se filmes radiocrômicos Gafchromic EBT3 e câmara de ionização Scanditronix Wellhofer CC13. Planejamentos de 25 pacientes - 11 com técnica tridimendional (3D) e 14 com técnica de Radioterapia Estereotática Corpórea (SBRT) - foram realizados, inicialmente sem correção de heterogeneidade e, mantendo-se as UM, os cálculos com os diferentes algoritmos/métodos de correção foram comparados com o planejamento inicial. Foram avaliados as doses no volume alvo e nos órgãos em risco. RESULTADOS: As medidas realizadas em objetos simuladores revelaram que os algoritmos baseados no princípio da convolução (Eclipse® Pencil Beam Convolution com métodos de correção Batho, Batho Modificado e TAR equivalente; XiO® Clarkson e Convolution e iPlan® Pencil Beam) apresentaram diferenças de dose significativas na região da cortiça, sempre superestimando a medida, com uma sobredose superior a 8%. Algoritmos mais avançados, como o Eclipse® AAA e Acuros XB, XiO® Superposition e iPlan® XVMC, apresentaram desvios inferiores a 3% na região da heterogeneidade. A análise dos perfis mostra, igualmente, que a segunda classe de algoritmos apresenta melhor comportamento em meios de baixa densidade como a cortiça. A largura da penumbra apresentou desvios inferiores a 1 mm para os algoritmos mais avançados contra diferenças de até 4,5 mm entre os algoritmos baseados em convolução. A análise da distribuição de dose em planejamentos de tumores pulmonares mostrou que todos os cálculos com correção de heterogeneidade presentam doses superiores ao cálculo sem correção de heterogeneidade. O histograma dose-volume (DVH) do volume alvo sofreu um impacto maior do que dos órgãos em risco. Os cálculos realizados com algoritmos baseados em convolução apresentaram distribuições de dose semelhantes entre si, porém diferentes das do cálculo sem correção de heterogeneidade. Eclipse® AAA, Acuros XB, XiO® Superposition e iPlan® XVMC apresentaram distribuições de dose também semelhantes, porém Eclipse® Acuros XB e iPlan® XVMC são ainda mais similares. Os planejamentos de SBRT apresentaram resultados mais discrepantes do cálculo sem correção de heterogeneidade do que os planejamentos 3D. CONCLUSÕES: Os diferentes algoritmos de cálculo disponíveis possuem acurácias diferentes em meios de baixa densidade eletrônica. Essas diferenças possuem impacto nas distribuições de dose em planejamentos de tratamento de tumores pulmonares, sendo o impacto ainda maior para a técnica de SBRT. Entre os algoritmos avaliados, há pelo menos um de cada fabricante que apresentou bom desempenho em objetos simuladores de pulmão e que devem ser priorizados para o cálculo em planejamentos de tratamentos de câncer de pulmão / INTRODUCTION: In Radiotherapy, the dose distribution accuracy in heterogeneity correction calculations is directly related to the choice of calculation algorithm. There are many calculation algorithms commercially available. They vary in accuracy and processing time. This study aimed to quantify the accuracy of ten different calculation algorithms in lung equivalent material and to analyze the impact of the algorithm choice in the dose distribution in Radiotherapy applied to lung tumors. METHODS: It was used plates of water (solid water RW3) and lung (cork) equivalent materials to determine the Percentage of Depth Dose (PDD) and transversal profile inside the heterogeneity (cork). The measurements were performed in a Clinac Varian 6EX, with 6 MV photon beams and two field sizes (5 x 5 cm2 and 10 x 10 cm2), through irradiation of radiochromic films Gafchromic EBT3 and ionization chamber Scanditronix Wellhofer CC13. Treatment planning of 25 patients - 11 with tridimensional (3D) technique and 14 with Stereotactic Body Radiation Therapy (SBRT) technique - were performed, first without heterogeneity correction and, by keeping the Monitor Units (MU), the calculations were then performed with the different algorithms/methods of heterogeneity corrections and the results were compared with the initial planning. It was analyzed the target volume and organs at risk doses. RESULTS: The measurements performed in phantoms revealed that algorithms based on the convolution principle (Eclipse® Pencil Beam Convolution with correction methods Batho, Batho Modified and Equivalent TAR; XiO® Clarkson and Convolution e iPlan® Pencil Beam) presented significant dose differences in the cork region, overestimating the measurement, with a overdose higher than 8%. More advanced algorithms, as Eclipse® AAA and Acuros XB, XiO® Superposition and iPlan® XVMC, presented deviations below to 3% in the heterogeneity region. The profile analysis showed, similarly, that the second class of algorithms presents better performance in medium with low electronic density, like cork. The penumbra width presented deviations below to 1 mm for the more sophisticated algorithms against differences up to 4.5 mm between the convolution based algorithms. The dose distribution analysis in lung treatment planning showed that all the calculations performed with heterogeneity corrections presented doses higher than the calculation without heterogeneity corrections. The target volume dose-volume histogram (DVH) had a higher impact compared to the organs at risk. The calculation performed with convolution based algorithms presented dose distributions comparable, although different from the calculation performed without heterogeneity correction. Eclipse® AAA, Acuros XB, XiO® Superposition and iPlan® XVMC presented dose distribution similar, however Eclipse® Acuros XB and iPlan® XVMC are still more similar. The SBRT treatment planning presented higher deviations from the calculation with no heterogeneity correction, compared with the 3D treatment planning. CONCLUSIONS: The different calculation algorithms available have different accuracies in low density mediums. These differences have impact in the dose distributions in lung treatment planning, being the impact higher for the SBRT technique. Between the evaluated algorithms there is, at least one of each manufacturer, that presented acceptable performance in lung equivalent material and it should be the choice in lung treatment planning calculation