DPM, a fast, accurate Monte Carlo code optimized for photon and electron radiotherapy treatment planning dose calculations

Sempau, J.; Wilderman, S.J.; Bielajew, Alex F.

doi:10.1088/0031-9155/45/8/315

Cited by 286 publications

(251 citation statements)

References 40 publications

(65 reference statements)

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“…Treatment planning for all patients was performed using the Dose Planning Method (18) Monte Carlo code integrated within the UMPlan radiotherapy planning software (RT_DPM (19) ). RT_DPM has been previously benchmarked against measurements in water and heterogeneous phantoms and has been found to be accurate (within 1% to 2% of measurements) even under conditions of lateral electronic disequilibrium (19) .…”

Section: Methodsmentioning

confidence: 99%

Monte Carlo‐based lung cancer treatment planning incorporating PET‐defined target volumes

Chetty

Fernando

Kessler

et al. 2005

J Applied Clin Med Phys

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Despite the well‐known benefits of positron emission tomography (PET) imaging in lung cancer diagnosis and staging, the poor spatial resolution of PET has limited its use in radiotherapy planning. Methods used for segmenting tumor from normal tissue, such as threshold boundaries using a fraction of the standardized uptake value (SUV), are subject to uncertainties. The issue of respiratory motion in the thorax confounds the problem of accurate target definition. In this work, we evaluate how changing the PET‐defined target volume by varying the threshold value in the segmentation process impacts target and normal lung tissue doses. For each of eight lung cancer patients we retrospectively generated multiple PET‐target volumes; each target volume corresponds to those voxels with intensities above a given threshold level, defined by a percentage of the maximum voxel intensity. PET‐defined targets were compared to those from CT; CT targets comprise a composite volume generated from breath‐hold inhale and exhale datasets; the CT dataset therefore also includes the extents of tumor motion. Treatment plans using Monte Carlo dose calculation were generated for all targets; the dose uniformity was approximately 100±5% within the internal target volume (ITV) (formed by a uniform 8‐mm expansion of the composite gross target volume (GTV)). In all cases differences were observed in the generalized equivalent uniform doses (gEUDs) to the targets and in the mean lung doses (MLDs) and normal tissue complication probabilities (NTCPs) to the normal lung tissues. The magnitudes of the dose differences were found to depend on the target volume, location, and amount of irradiated normal lung tissue, and in many instances were clinically meaningful (greater than a single 2 Gy fraction). For those patients studied, results indicate that accurate dosimetry using PET volumes is highly dependent on accurate target segmentation. Further study with correlation to clinical outcome will be helpful in determining how to apply these various PET and CT volumes in treatment planning, to potentially improve local tumor control and reduce normal tissue toxicities.PACS number: 87.52.Tf

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Section: Methodsmentioning

confidence: 99%

Monte Carlo‐based lung cancer treatment planning incorporating PET‐defined target volumes

Chetty

Fernando

Kessler

et al. 2005

J Applied Clin Med Phys

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“…The simulation of ionizing radiation behavior in a certain medium can be made provided that the various physical interac-ond phase, the particles constituting the phase space are transported thru the considered geometry, codified on the basis of the information contained in images acquired by an axial computed tomography and absorbed dose distribution (3,4) . The PENELOPE, an algorithm that uses the Monte Carlo method, is a computational code utilized for several simulations (3,5) .…”

Section: Introductionmentioning

confidence: 99%

“…The PENELOPE, an algorithm that uses the Monte Carlo method, is a computational code utilized for several simulations (3,5) . This algorithm is based on the scattering model which combines a numerical data base with shock section models for the different interaction mechanisms, being applicable to energies (kinetic energy in the case of electrons and positrons) from a few hundreds eV to approximately 1 GeV.…”

Section: Introductionmentioning

confidence: 99%

“…This algorithm is based on the scattering model which combines a numerical data base with shock section models for the different interaction mechanisms, being applicable to energies (kinetic energy in the case of electrons and positrons) from a few hundreds eV to approximately 1 GeV. The photons simulation is performed by means of the conventional method in detailed form, while the electrons and positrons simulation is performed by a mixed process (3,4) . An important characteristic of this code is that the most sensitive part of this simulation is internally treated, thus electrons, positrons and photons are simulated utilizing the same subroutine.…”

Section: Introductionmentioning

confidence: 99%

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Simulação computacional de um feixe de fótons de 6 MV em diferentes meios heterogêneos utilizando o código PENELOPE

et al. 2009

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OBJECTIVE: The PENELOPE code was utilized to simulate irradiation geometries where heterogeneities are present and to simulate a photon beam behavior under these conditions. MATERIALS AND METHODS: For the homogeneous case, the ionizing radiation behavior was simulated only with water, and different materials were introduced to simulate heterogeneous conditions. Cubic geometries were utilized for the homogeneous phantoms, and parallelepiped-shaped geometries for the heterogeneities with the following composition: bone and lung tissue simulators, as recommended by the International Commission on Radiological Protection, and titanium, aluminum and silver. Input parameters were defined as follows: energy and type of source, 6 MV photons; source-surface distance=100 cm; and radiation field of 10×10 cm 2. RESULTS: Percentage depth-dose curves were obtained for all the cases. As result, it was observed that for high electronic density materials, such as silver, the absorbed dose is higher than the absorbed dose in the homogeneous phantom, and for the lung tissue simulator, it is lower. CONCLUSION: Results clearly demonstrate the relevant role of heterogeneities in the treatment planning system algorithms utilized in the calculation of dose distribution in patients, increasing the accuracy of the dose delivered to the tumor and avoiding unnecessary irradiation of healthy tissues. Keywords: Radiotherapy; Monte Carlo; PENELOPE; Heterogeneities; Depth-dose distribution.OBJETIVO: Utilizar o código PENELOPE e desenvolver geometrias onde estão presentes heterogeneidades para simular o comportamento do feixe de fótons nessas condições. MATERIAIS E MÉTODOS: Foram feitas simulações do comportamento da radiação ionizante para o caso homogêneo, apenas água, e para os casos heterogêneos, com diferentes materiais. Consideraram-se geometrias cúbicas para os fantomas e geometrias em forma de paralelepípedos para as heterogeneidades com a seguinte composição: tecido simulador de osso e pulmão, seguindo recomendações da International Commission on Radiological Protection, e titânio, alumínio e prata. Definiram-se, como parâmetros de entrada: a energia e o tipo de partícula da fonte, 6 MV de fótons; a distância fonte-superfície de 100 cm; e o campo de radiação de 10×10 cm 2 . RESULTADOS: Obtiveram-se curvas de percentual de dose em profundidade para todos os casos. Observou-se que em materiais com densidade eletrônica alta, como a prata, a dose absorvida é maior em relação à dose absorvida no fantoma homogêneo, enquanto no tecido simulador de pulmão a dose é menor. CONCLUSÃO: Os resultados obtidos demonstram a importância de se considerar heterogeneidades nos algoritmos dos sistemas de planejamento usados no cálculo da distribuição de dose nos pacientes, evitando-se sub ou superdosagem dos tecidos próximos às heterogeneidades. Unitermos: Radioterapia; Monte Carlo; PENELOPE; Heterogeneidades; Dosimetria. AbstractResumo

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“…Various authors have investigated the accuracy with which calculation models can predict measured dose in lung equivalent material 10 – 16 . As physically realistic analytical approaches become more practical for dose calculation, e.g., Monte Carlo, 17 , 18 and convolution/superposition, 11 , 19 – 21 there is a need for reliable dose assessment 22 to validate them in various media densities.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric comparison of extended dose range film with ionization measurements in water and lung equivalent heterogeneous media exposed to megavoltage photons

Charland

Chetty

Yokoyama

et al. 2003

J Applied Clin Med Phys

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In this study, a dosimetric evaluation of the new Kodak extended dose range (EDR) film versus ionization measurements has been conducted in homogeneous solid water and water‐lung equivalent layered heterogeneous phantoms for a relevant range of field sizes (up to a field size of 25×25 cm2 and a depth of 15 cm) for 6 and 15 MV photon beams from a linear accelerator. The optical density of EDR film was found to be linear up to about 350 cGy and over‐responded for larger fields and depths (5% for 25×25 cm2 at depth of 15 cm compared to a 10×10 cm2, 5 cm depth reference value). Central axis depth dose measurements in solid water with the film in a perpendicular orientation were within 2% of the Wellhöfer IC‐10 measurements for the smaller field sizes. A maximum discrepancy of 8.4% and 3.9% was found for the 25×25 cm2 field at 15 cm depth for 6 and 15 MV photons, respectively (with curve normalization at a depth of 5 cm). Compared to IC‐10 measurements, film measured central axis depth dose inside the lung slab showed a slight over‐response (at most 2%). At a depth of 15 cm in the lung phantom the over‐response was found to be 7.4% and 3.7% for the 25×25 cm2 field for 6 and 15 MV photons, respectively. When results were presented as correction factors, the discrepancy between the IC‐10 and the EDR was greatest for the lowest energy and the largest field size. The effect of the finite size of the ion chamber was most evident at smaller field sizes where profile differences versus film were observed in the penumbral region. These differences were reduced at larger field sizes and in situations where lateral electron transport resulted in a lateral spread of the beam, such as inside lung material. Film profiles across a lung tumor geometry phantom agreed with the IC‐10 chamber within the experimental uncertainties. From this investigation EDR film appears to be a useful medium for relative dosimetry in higher dose ranges in both water and lung equivalent material for moderate field sizes and depths. © 2003 American College of Medical Physics.PACS number(s): 87.53.Dq, 87.66.Cd, 87.66.Jj, 87.66.Xa

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DPM, a fast, accurate Monte Carlo code optimized for photon and electron radiotherapy treatment planning dose calculations

Cited by 286 publications

References 40 publications

Monte Carlo‐based lung cancer treatment planning incorporating PET‐defined target volumes

Monte Carlo‐based lung cancer treatment planning incorporating PET‐defined target volumes

Simulação computacional de um feixe de fótons de 6 MV em diferentes meios heterogêneos utilizando o código PENELOPE

Dosimetric comparison of extended dose range film with ionization measurements in water and lung equivalent heterogeneous media exposed to megavoltage photons

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