Acceptance and Commissioning of a Treatment Planning System Based on Monte Carlo Calculations

López-Tarjuelo, Juan; García-Mollá, Rafael; Juan-Senabre, X.J.; Quirós-Higueras, Juan David; Santos-Serra, Agustín; Marco-Blancas, N. de; Calzada-Feliu, S.

doi:10.7785/tcrt.2012.500361

Cited by 10 publications

(6 citation statements)

References 16 publications

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“…In the past, the experimental validation study of Monaco was limited to the XVMC algorithm 15 , 16 . Although there exists an evaluation study of a standalone version of the GPUMCD algorithm for IMRT optimization, (17) no work has been done, to our knowledge, on the experimental evaluation of the GPUMCD algorithm implemented in the Monaco TPS.…”

Section: Introductionmentioning

confidence: 99%

Experimental evaluation of a GPU‐based Monte Carlo dose calculation algorithm in the Monaco treatment planning system

Paudel

Kim

Sarfehnia

et al. 2016

J Applied Clin Med Phys

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A new GPU‐based Monte Carlo dose calculation algorithm (GPUMCD), developed by the vendor Elekta for the Monaco treatment planning system (TPS), is capable of modeling dose for both a standard linear accelerator and an Elekta MRI linear accelerator. We have experimentally evaluated this algorithm for a standard Elekta Agility linear accelerator. A beam model was developed in the Monaco TPS (research version 5.09.06) using the commissioned beam data for a 6 MV Agility linac. A heterogeneous phantom representing several scenarios — tumor‐in‐lung, lung, and bone‐in‐tissue — was designed and built. Dose calculations in Monaco were done using both the current clinical Monte Carlo algorithm, XVMC, and the new GPUMCD algorithm. Dose calculations in a Pinnacle TPS were also produced using the collapsed cone convolution (CCC) algorithm with heterogeneity correction. Calculations were compared with the measured doses using an ionization chamber (A1SL) and Gafchromic EBT3 films for 2×2 cm2,5×5 cm2, and 10×2 cm2 field sizes. The percentage depth doses (PDDs) calculated by XVMC and GPUMCD in a homogeneous solid water phantom were within 2%/2 mm of film measurements and within 1% of ion chamber measurements. For the tumor‐in‐lung phantom, the calculated doses were within 2.5%/2.5 mm of film measurements for GPUMCD. For the lung phantom, doses calculated by all of the algorithms were within 3%/3 mm of film measurements, except for the 2×2 cm2 field size where the CCC algorithm underestimated the depth dose by ∼5% in a larger extent of the lung region. For the bone phantom, all of the algorithms were equivalent and calculated dose to within 2%/2 mm of film measurements, except at the interfaces. Both GPUMCD and XVMC showed interface effects, which were more pronounced for GPUMCD and were comparable to film measurements, whereas the CCC algorithm showed these effects poorly.PACS number(s): 87.53.Bn, 87.55.dh, 87.55.km

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Section: Introductionmentioning

confidence: 99%

Experimental evaluation of a GPU‐based Monte Carlo dose calculation algorithm in the Monaco treatment planning system

Paudel

Kim

Sarfehnia

et al. 2016

J Applied Clin Med Phys

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“…Our dosimetric results confirm that the XVMC algorithm implemented in iPlan can accurately calculate the dose under conditions of low density and small fields (IMRT) as reported by other studies. [23][24][25] It is known that the PB algorithm fails to calculate the correct dose when the tissue density varies significantly from the density of water and thus the range of lateral electrons is increased. This effect is intensified under deep inspiration breath hold conditions, where the lung density can be as low 11 as 0.16 g/cm 3 .…”

Section: Discussionmentioning

confidence: 99%

Clinical Evaluation of X-Ray Voxel Monte Carlo Versus Pencil Beam–Based Dose Calculation in Stereotactic Body Radiotherapy of Lung Cancer Under Normal and Deep Inspiration Breath Hold

Landoni

Borzì²,

Strolin

et al. 2014

Technol Cancer Res Treat

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The purpose of this study is to evaluate the differences between dose distributions calculated with the pencil beam (PB) and X-ray voxel Monte Carlo (MC) algorithms for patients with lung cancer using intensity-modulated radiotherapy (IMRT) or HybridArc techniques. The 2 algorithms were compared in terms of dose-volume histograms, under normal and deep inspiration breath hold, and in terms of the tumor control probability (TCP). The dependence of the differences in tumor volume and location was investigated. Dosimetric validation was performed using Gafchromic EBT3 (International Specialty Products, ISP, Wayne, NJ). Forty-five Computed Tomography (CT) data sets were used for this study; 40 Gy at 8 Gy/fraction was prescribed with 5 noncoplanar 6-MV IMRT beams or 3 to 4 dynamic conformal arcs with 3 to 5 IMRT beams distributed per arc. The plans were first calculated with PB and then recalculated with MC. The difference between the mean tumor doses was approximately 10% ± 4%; these differences were even larger under deep inspiration breath hold. Differences between the mean tumor dose correlated with tumor volume and path length of the beams. The TCP values changed from 99.87% ± 0.24% to 96.78% ± 4.81% for both PB- and MC-calculated plans (P = .009). When a fraction of hypoxic cells was considered, the mean TCP values changed from 76.01% ± 5.83% to 34.78% ± 18.06% for the differently calculated plans (P < .0001). When the plans were renormalized to the same mean dose at the tumor, the mean TCP for oxic cells was 99.05% ± 1.59% and for hypoxic cells was 60.20% ± 9.53%. This study confirms that the MC algorithm adequately accounts for inhomogeneities. The inclusion of the MC in the process of IMRT optimization could represent a further step in the complex problem of determining the optimal treatment plan.

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“…– 17 It is widely accepted that Monte Carlo (MC) algorithms model electron transport in different media and therefore perform better dose calculation in a heterogeneous medium than that of the less complex algorithms. MC algorithm also affords more elegant ways to deal with the complex scatter patterns of treatment machines and beam modifying equipment 18 . CMS Monaco (Elekta CMS, Sunnyvale, CA, USA) is a commercially available planning system which uses an X-ray voxel Monte Carlo (XVMC) algorithm 19 .…”

Section: Introductionmentioning

confidence: 99%

“…MC algorithm also affords more elegant ways to deal with the complex scatter patterns of treatment machines and beam modifying equipment. 18 CMS Monaco (Elekta CMS, Sunnyvale, CA, USA) is a commercially available planning system which uses an X-ray voxel Monte Carlo (XVMC) algorithm. 19 Not many studies on the validation of Monaco XVMC algorithm in an heterogeneous medium have been published concerning small fields.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of small photon field outputs in a heterogeneous medium using X-ray voxel Monte Carlo dose calculation algorithm

et al. 2017

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AimTo characterise small photon beams using the Monte Carlo dose calculation algorithm for small field ranges in a heterogeneous medium.Materials and methodAn in-house phantom constructed with three different mediums, foam, polymethyl methacrylate and delrin resembling the densities of lung, soft tissue and bone respectively, was used in this study. Photon beam energies of 6 and 15 MV and field sizes of 8×8, 16×16, 24×24, 32×32 and 40×40 mm using X-ray voxel Monte Carlo (XVMC) algorithm using different detectors were validated. The relative output factor was measured in three different mediums having six different tissue interfaces; at the depth of 0, 1, 2 and 3 cm. The planar dose verification was undertaken using gafchromic films and considered dose at the lung and bone medium interfaces. For all the measurements, 104×104 mm was taken as the reference field size. The relative output factor for all other field sizes was taken and compared with planning system calculated values.ResultsFrom field size 16×16 mm and above, the relative output factors were analysed in bone and soft tissue medium having lung as first medium. The maximum deviations were observed as 1·8 and 1·3% for 6 MV and 2·5 and 1·1% for 15 MV photon beams for bone and soft tissue, respectively. For lung as measurement medium, the maximum deviation of 14·8 and 19·2% were observed and having bone as first medium with 8×8 mm for 6 and 15 MV photon beams, respectively. The fluence verification of dose spectrum for the lung–bone interface scenarios with smaller field sizes were found within 2% of deviation with treatment planning system (TPS).ConclusionThe accuracy of dose calculations for small field sizes in XVMC-based treatment planning algorithm was studied in different inhomogeneous mediums. It was found that the results correlated with measurement data for field size 16×16 mm and above. Noticeable deviation was observed for the smallest field size of 8×8 mm with interfaces of significant change in density. The observed results demands further analysis of work with smaller field sizes.

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Acceptance and Commissioning of a Treatment Planning System Based on Monte Carlo Calculations

Cited by 10 publications

References 16 publications

Experimental evaluation of a GPU‐based Monte Carlo dose calculation algorithm in the Monaco treatment planning system

Experimental evaluation of a GPU‐based Monte Carlo dose calculation algorithm in the Monaco treatment planning system

Clinical Evaluation of X-Ray Voxel Monte Carlo Versus Pencil Beam–Based Dose Calculation in Stereotactic Body Radiotherapy of Lung Cancer Under Normal and Deep Inspiration Breath Hold

Characterisation of small photon field outputs in a heterogeneous medium using X-ray voxel Monte Carlo dose calculation algorithm

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