Intensity-modulated radiation therapy and volumetric modulated arc therapy versus conventional conformal techniques at high energy: Dose assessment and impact on second primary cancer in the out-of-field region

Sánchez‐Nieto, B.; Romero-Expósito, Maite; Terrón, José A.; Irazola, L.; Paiusco, M.; Cagni, E.; Ghetti, Caterina; Filice, Silvano; Sánchez‐Doblado, F.

doi:10.1016/j.rpor.2018.04.008

Cited by 9 publications

(5 citation statements)

References 25 publications

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“…16 Other authors have published on out-offield dose from IMRT. 17,18 Vassiliev et al compared flattened and FFF beam out-of-field dose for 6 MV on a Varian 21EX machine using an ion chamber and a water phantom. 19 Kragl et al compared 6X and 6X-FFF for Elekta Precise linac using a farmer ion chamber, TLD rods, and radiochromic films for SBRT and IMRT plans.…”

Section: Ramsay Et Al Reported Out-of-field Data For Tomotherapy and Amentioning

confidence: 99%

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Part I: Out‐of‐field dose mapping for 6X and 6X‐flattening‐filter‐free beams on the TrueBeam for extended distances

Wijesooriya

2019

Medical Physics

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Purpose With increasing cancer treatment success rates, many patients go on to live long, productive lives following recovery. Therefore, minimizing potential side effects due to dose outside the treated field is becoming a significant consideration in radiation therapy. With many potential treatment configurations available, it is important to quantify how out‐of‐field dose varies with common variables such as distance from isocenter, couch angle, jaw size, and flattening‐filter setting. The accurate quantification of out‐of‐field dose at extended distances could also benefit researchers and detector developers. While data exist for out‐of‐field dose from older linear accelerator (Linac) models, the phenomenon has not been described for the latest generation of machines, such as the Varian TrueBeam. The purpose of this study was to comprehensively quantify out‐of‐field dose for the Varian TrueBeam Linac low energy photons in a wide range of positions and treatment geometries. Method and Materials Out‐of‐field doses were measured using two phantom setups: (a) A large volume ion chamber with a buildup sleeve to quantify head leakage and collimator scatter background dose; and (b) A farmer ion chamber in solid water to incorporate phantom scatter in addition to collimator scatter, and head leakage background dose. In both cases, the ion chamber was positioned with its length along the slowly varying transverse direction (perpendicular to the radial from isocenter). Doses were measured for four symmetric jaw settings (2 × 2 cm2, 4 × 4 cm2, 10 × 10 cm2, and 20 × 20 cm2) for a range of distances from the isocenter (0–100 cm). The angular dependence of the out‐of‐field dose was measured using four different angles: 0°, 45°, 90°, and 135° with respect to the in‐plane direction. All measurements were performed for both 6X and 6X‐flattening‐filter‐free (FFF) beams. Results The lowest out‐of‐field doses were observed at 60 cm away from isocenter in both in‐plane and cross‐plane directions for fields smaller than 10 × 10 cm2. Out‐of‐field dose decreased with decreasing jaw size (a factor of 4.7 for 6X‐FFF and a factor of 3.1 for 6X going from 20 × 20 cm2 to 2 × 2 cm2 at 60 cm from isocenter in the in‐plane direction). The 6X‐FFF beam produced out‐of‐field doses as low as 64% of the 6X beam. Conclusion This study presents a comprehensive description of 6X and 6X‐FFF out‐of‐field doses on a Varian TrueBeam Linac including measurements at a range of positions, angles, and jaw settings and with and without phantom scatter.

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Section: Ramsay Et Al Reported Out-of-field Data For Tomotherapy and Amentioning

confidence: 99%

“…compared step and shoot IMRT with volumetric modulated arc therapy (VMAT) for a Siemens Primus accelerator using the Rando phantom with TLDs . Other authors have published on out‐of‐field dose from IMRT . Vassiliev et al.…”

Section: Introductionmentioning

confidence: 99%

Part I: Out‐of‐field dose mapping for 6X and 6X‐flattening‐filter‐free beams on the TrueBeam for extended distances

Wijesooriya

2019

Medical Physics

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“…Sánchez-Nieto et al [ 23 ] stated that technology advancements such as IMRT and VMAT were liable for an increase in doses received to out-of-field OARs. Fortunately, such a dose increase at a distance is greatly compensated by a significant reduction in the areas getting high doses.…”

Section: Discussionmentioning

confidence: 99%

Dose Estimation Using Optically Stimulated Luminescence Dosimeter and EBT3 Films for Various Treatment Techniques in Alderson Rando Phantom and Estimation of Secondary Cancer Incidence for Carcinoma of Left Breast

Ganesh

Sushma²,

Kaginelli³

et al. 2022

Journal of Medical Physics

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Aim: The aim of this study was to measure the dose to planning target and organ at risk (OAR) using Alderson Rando phantom for various treatment techniques in left breast radiotherapy and to estimate the secondary cancer incidence. Materials and Methods: Eleven different combinations of plans containing four techniques (three dimensional conformal radiotherapy, intensity-modulated radiation therapy [IMRT], volumetric modulated arc therapy [VMAT], and combination of 3DCRT and VMAT plans (HYBRID)) were created with 6 MV FF and 6 MV FFF (flattening filter and flattening filter-free) photon energies in phantom. Planned target volume and OAR doses in 23 different locations were measured using optically stimulated luminescence dosimeter (OSLD) and EBT3 films. Assuming the age of exposure as 30 years, lifetime attributable risk (LAR) was estimated based on excess absolute risk (EAR) models outlined in the Biological Effects of Ionizing Radiation VII report. Results: Film showed maximum deviations of 6.15% with IMRT_C_FF plan when compared with treatment planning system (TPS). The maximum percentage difference of 1.7% was found with OSLD measurement when compared with TPS for VMAT_T_FFF plan. EAR estimation was done for all the OARs including target. The LARs for left lung, right lung, and right breast were evaluated. The maximum LAR values of 2.92 ± 0.14 were found for left lung with VMAT_C_FFF plans. Conclusion: This study shows that both OSLD and EBT3 films are suitable for dose measurements using Rando phantom. OSLD shows superior results when compared with films, especially with relatively larger distances. Maximum LAR values were found with VMAT_C_FFF plans. Considering the secondary cancer risk associated with the patients treated in the younger age group, it is suggested that in vivo dose estimation should be a part of treatment quality audit whenever possible.

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“…[ 12 18 19 20 21 22 ] Several authors have measured doses of in-field and out-of-field organs in physical phantoms with passive detectors and compared their results with the TPS results. [ 8 12 21 22 23 24 25 ] All the investigators reported that the TPS cannot calculate the out-of-field dose accurately and the gold standard method to estimate this dose is MC simulation based on a patient’s DICOM data or using computational phantom. [ 12 17 26 27 28 29 ] Bednarz et al .,[ 26 ] Joosten et al .,[ 16 ] Berris et al .,[ 27 ] and Wang and Ding (2014)[ 30 ] evaluated the out-of-field dose calculated by different TPS and used the MC simulation to estimate the uncertainties of calculated organ doses.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Organ Dose Distribution (in-field and Out-of-field) in Breast Cancer Radiotherapy on RANDO Phantom Using GEANT4 Application for Tomographic Emission (Gate) Monte Carlo Simulation

Behmadi,

Toossi,

Nasseri

et al. 2024

Journal of Medical Signals &Amp; Sensors

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Introduction: Organ dose distribution calculation in radiotherapy and knowledge about its side effects in cancer etiology is the most concern for medical physicists. Calculation of organ dose distribution for breast cancer treatment plans with Monte Carlo (MC) simulation is the main goal of this study. Materials and Methods: Elekta Precise linear accelerator (LINAC) photon mode was simulated and verified using the GEANT4 application for tomographic emission. Eight different radiotherapy treatment plans on RANDO’s phantom left breast were produced with the ISOgray treatment planning system (TPS). The simulated plans verified photon dose distribution in clinical tumor volume (CTV) with TPS dose volume histogram (DVH) and gamma index tools. To verify photon dose distribution in out-of-field organs, the point dose measurement results were compared with the same point doses in the MC simulation. Eventually, the DVHs for out-of-field organs that were extracted from the TPS and MC simulation were compared. Results: Based on the implementation of gamma index tools with 2%/2 mm criteria, the simulated LINAC output demonstrated high agreement with the experimental measurements. Plan simulation for in-field and out-of-field organs had an acceptable agreement with TPS and experimental measurement, respectively. There was a difference between DVHs extracted from the TPS and MC simulation for out-of-field organs in low-dose parts. This difference is due to the inability of the TPS to calculate dose distribution in out-of-field organs. Conclusion and Discussion: Based on the results, it was concluded that the treatment plans with the MC simulation have a high accuracy for the calculation of out-of-field dose distribution and could play a significant role in evaluating the important role of dose distribution for second primary cancer estimation.

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Intensity-modulated radiation therapy and volumetric modulated arc therapy versus conventional conformal techniques at high energy: Dose assessment and impact on second primary cancer in the out-of-field region

Cited by 9 publications

References 25 publications

Part I: Out‐of‐field dose mapping for 6X and 6X‐flattening‐filter‐free beams on the TrueBeam for extended distances

Part I: Out‐of‐field dose mapping for 6X and 6X‐flattening‐filter‐free beams on the TrueBeam for extended distances

Dose Estimation Using Optically Stimulated Luminescence Dosimeter and EBT3 Films for Various Treatment Techniques in Alderson Rando Phantom and Estimation of Secondary Cancer Incidence for Carcinoma of Left Breast

Calculation of Organ Dose Distribution (in-field and Out-of-field) in Breast Cancer Radiotherapy on RANDO Phantom Using GEANT4 Application for Tomographic Emission (Gate) Monte Carlo Simulation

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