The effect of fraction time in intensity modulated radiotherapy: theoretical and experimental evaluation of an optimisation problem

Mu, Xiangkui; Löfroth, Per‐Olov; Karlsson, Mikael; Zackrisson, Björn

doi:10.1016/s0167-8140(03)00165-8

Cited by 104 publications

(82 citation statements)

References 19 publications

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“…This is partly due to the time for movements, adjustment and verification of the leaf positions. Prolongation of the time to deliver each fraction may cause tumour sparing as a result of the low mean dose rate (37). The mixed beam technique has the potential of being faster than the pure photon IMRT owing to the smaller number of segments.…”

Section: Discussionmentioning

confidence: 99%

Can Photon IMRT be improved by combination with mixed electron and photon techniques?

Mu¹,

Olofsson²,

Karlsson³

et al. 2004

Acta Oncologica

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Section: Discussionmentioning

confidence: 99%

Can Photon IMRT be improved by combination with mixed electron and photon techniques?

Mu¹,

Olofsson²,

Karlsson³

et al. 2004

Acta Oncologica

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“…Nesta fase, as células se tornam mais vulneráveis a radiação e, ainda como as células tumorais apresentam um crescimento mais rápido que as células normais, a morte de células tumoraisé maior comparado a morte de normais. Naúltima década, vários autores têm apresentado estratégias de tratamento de câncer através da quimioterapia ou radioterapia [4][5][6]. Em [6] são descritas situações clínicas simuladas sobre o efeito da fração de tempo na modalidade de radioterapia intensiva modulada.…”

Section: Introductionunclassified

“…Naúltima década, vários autores têm apresentado estratégias de tratamento de câncer através da quimioterapia ou radioterapia [4][5][6]. Em [6] são descritas situações clínicas simuladas sobre o efeito da fração de tempo na modalidade de radioterapia intensiva modulada. O uso da radioterapia como tratamento seguem prescrições padrão que são obtidas a partir de observações empíricas.…”

Section: Introductionunclassified

Dinâmica do crescimento de tumores com controle através do modelo linear quadrático

Stiegelmeier¹,

Abreu²,

Neves³

2017

C.Q.D.

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Dinâmica do crescimento de tumores com controle através do modelo linear quadrático Control of tumor growth by squared linear modelResumo Neste trabalho será analisada a dinâmica de um modelo de crescimento tumoral com aplicação de controle através do modelo linear-quadrático para a radioterapia. O crescimento do tumoré modelado a partir das células normais, imunológicas e tumorais, representado por um sistema de equações diferenciais ordinárias. O objetivo principalé transferir o sistema de um regime com câncer para um ponto de equilíbrio estável livre de tumor através aplicação de controle por radioterapia. O efeito do tratamento por radioterapia será simulado pela aplicação do modelo linearquadrático. Com esta metodologiaé possível analisar o efeito de protocolos de tratamento de radioterapia, além de efeitos relativos ao grau de severidade do tumor eà resistência do sistema imunológico do paciente. Simulações numéricas mostram o tratamento utilizando diversos protocolos presentes na literatura. Palavras-chave: Sistema de equações diferencias ordinárias. Modelagem do crescimento tumoral. Modelo linear quadrático. Estabilidade. AbstractThe dynamic of tumor growth model with control using the squared linear model for radiotherapy is analised. The tumor growth is modeled by ordinary cells, immunological cells and tumor cells, represented by a ordinary differential equations system. The main objective is move the system of a regime with cancer for a free stable equilibrium point of tumor by radiotherapy. The effect of radiotherapy treatment will be simulated by squared linear model. Using this methodology is possible to analyze the effects of treatment protocols by radiotherapy, also effects for the severity grade of the tumor and system immunological resistance of patient. Numerical simulations show the treatment using several protocols in literature.

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“…The most relevant published studies were about MLC leaf sequence optimization for step‐and‐shoot IMRT plans in the treatment planning stage 10 , 11 , 12 , 13 . Comparisons of dynamic and segmental MLCs (i.e., DMLC and SMLC, respectively), were reported and discussed involving total delivery time for the purpose of deciding which method to use (14) .…”

Section: Introductionmentioning

confidence: 99%

Methods to model and predict the ViewRay treatment deliveries to aid patient scheduling and treatment planning

Shi

Wooten

et al. 2016

J Applied Clin Med Phys

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A software tool is developed, given a new treatment plan, to predict treatment delivery time for radiation therapy (RT) treatments of patients on ViewRay magnetic resonance image‐guided radiation therapy (MR‐IGRT) delivery system. This tool is necessary for managing patient treatment scheduling in our clinic. The predicted treatment delivery time and the assessment of plan complexities could also be useful to aid treatment planning. A patient's total treatment delivery time, not including time required for localization, is modeled as the sum of four components: 1) the treatment initialization time; 2) the total beam‐on time; 3) the gantry rotation time; and 4) the multileaf collimator (MLC) motion time. Each of the four components is predicted separately. The total beam‐on time can be calculated using both the planned beam‐on time and the decay‐corrected dose rate. To predict the remain‐ing components, we retrospectively analyzed the patient treatment delivery record files. The initialization time is demonstrated to be random since it depends on the final gantry angle of the previous treatment. Based on modeling the relationships between the gantry rotation angles and the corresponding rotation time, linear regression is applied to predict the gantry rotation time. The MLC motion time is calculated using the leaves delay modeling method and the leaf motion speed. A quantitative analysis was performed to understand the correlation between the total treatment time and the plan complexity. The proposed algorithm is able to predict the ViewRay treatment delivery time with the average prediction error 0.22 min or 1.82%, and the maximal prediction error 0.89 min or 7.88%. The analysis has shown the correlation between the plan modulation (PM) factor and the total treatment delivery time, as well as the treatment delivery duty cycle. A possibility has been identified to significantly reduce MLC motion time by optimizing the positions of closed MLC pairs. The accuracy of the proposed prediction algorithm is sufficient to support patient treatment appointment scheduling. This developed software tool is currently applied in use on a daily basis in our clinic, and could also be used as an important indicator for treatment plan complexity.PACS number(s): 87.55.N

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The effect of fraction time in intensity modulated radiotherapy: theoretical and experimental evaluation of an optimisation problem

Cited by 104 publications

References 19 publications

Can Photon IMRT be improved by combination with mixed electron and photon techniques?

Can Photon IMRT be improved by combination with mixed electron and photon techniques?

Dinâmica do crescimento de tumores com controle através do modelo linear quadrático

Methods to model and predict the ViewRay treatment deliveries to aid patient scheduling and treatment planning

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