Low dose out-of-field radiotherapy, part 2: Calculating the mean photon energy values for the out-of-field photon energy spectrum from scattered radiation using Monte Carlo methods

Skrobała, A.; Adamczyk, S.; Kruszyna-Mochalska, Marta; Skórska, M.; Konefał, Adam; Suchorska, Wiktoria Maria; Zaleska, Karolina; Kowalik, Anna; Jackowiak, W.; Malicki, Julian

doi:10.1016/j.canrad.2017.04.010

Cited by 11 publications

(10 citation statements)

References 21 publications

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“…Some studies include Monte Carlo simulations for simple geometries calculated with high accuracy [ 16 , 17 ] and comparisons of complex techniques or different linacs [ 9 , 18 ], which have provided an overview of low doses produced by different modalities and techniques (e.g., 3DCRT vs. IMRT [ 1 , 2 ]; IMRT vs. Tomotherapy [ 3 ]). Other studies have evaluated how changes in a single parameter affects low doses, including MLC [ 19 ], field size [ 20 ], modulation [ 13 ], and FF vs. FFF [ 10 , 11 ].…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that 3DCRT results in the lowest out-of-field doses, which is consistent with our findings [ 2 ]. For most measured points, low doses were higher for VMAT than for IMRT [ 1 , 21 ], but this was strongly dependent on the degree of modulation and number of MUs [ 13 , 17 ], and the energy used (prostate IMRT is often 15 MV) [ 22 ]. It is worth noting that we compared techniques for the same energy (6 MV), although this is not the most common clinical dose.…”

Section: Discussionmentioning

confidence: 99%

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Influence of Specific Treatment Parameters on Nontarget and Out-of-Field Doses in a Phantom Model of Prostate SBRT with CyberKnife and TrueBeam

Kruszyna-Mochalska

Skrobała

Romański

et al. 2022

Life

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The aim of the study was to determine the influence of a key treatment plan and beam parameters on overall dose distribution and on doses in organs laying in further distance from the target during prostate SBRT. Multiple representative treatment plans (n = 12) for TrueBeam and CyberKnife were prepared and evaluated. Nontarget doses were measured with anionization chamber, in a quasi-humanoid phantom at four sites corresponding to the intestines, right lung, thyroid, and head. The following parameters were modified: radiotherapy technique, presence or not of a flattening filter, degree of modulation, and use or not of jaw tracking function for TrueBeam and beam orientation set-up, optimization techniques, and number of MUs for CyberKnife. After usual optimization doses in intestines (near the target) were 0.73% and 0.76%, in head (farthest from target) 0.05% and 0.19% for TrueBeam and CyberKnife, respectively. For TrueBeam the highest peripheral (head, thyroid, lung) doses occurred for the VMAT with the flattening filter while the lowest for 3DCRT. For CyberKnife the highest doses were for gantry with caudal direction beams blocked (gantry close to OARs) while the lowest was the low modulated VOLO optimization technique. The easiest method to reduce peripheral doses was to combine FFF with jaw tracking and reducing monitor units at TrueBeam and to avoid gantry position close to OARs together with reduction of monitor units at CyberKnife, respectively. The presented strategies allowed to significantly reduce out-of-field and nontarget doses during prostate radiotherapy delivered with TrueBeam and CyberKnife. A different approach was required to reduce peripheral doses because of the difference in dose delivery techniques: non-coplanar using CyberKnife and coplanar using TrueBeam, respectively.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Influence of Specific Treatment Parameters on Nontarget and Out-of-Field Doses in a Phantom Model of Prostate SBRT with CyberKnife and TrueBeam

Kruszyna-Mochalska

Skrobała

Romański

et al. 2022

Life

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“…To explain the overresponse phenomenon, the new model considers the softening of the energy spectrum of the incident X-ray/γ-ray and the secondary electrons, as well as the sensitivity of IOS to photons and secondary electrons with lower kinetic energies. As the photons penetrate into the water phantom, the mean energy of the photon beam and secondary electrons decreases due to photon interactions [87,88]. The IOS is more sensitive to photons with lower energy in the deeper depth.…”

Section: Pdd Deviation From the Standard Ic Measurementmentioning

confidence: 99%

Advances on inorganic scintillator-based optic fiber dosimeters

Ding

Wang³

et al. 2020

EJNMMI Phys

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This article presents a new perspective on the development of inorganic scintillator-based fiber dosimeters (IOSFDs) for medical radiotherapy dosimetry (RTD) focusing on real-time in vivo dosimetry. The scintillator-based optical fiber dosimeters (SFD) are compact, free of electromagnetic interference, radiation-resistant, and robust. They have shown great potential for real-time in vivo RTD. Compared with organic scintillators (OSs), inorganic scintillators (IOSs) have larger X-ray absorption and higher light output. Variable IOSs with maximum emission peaks in the red part of the spectrum offer convenient stem effect removal. This article outlines the main advantages and disadvantages of utilizing IOSs for SFD fabrication. IOSFDs with different configurations are presented, and their use for dosimetry in X-ray RT, brachytherapy (BT), proton therapy (PT), and boron neutron capture therapy (BNCT) is reviewed. Challenges including the percentage depth dose (PDD) deviation from the standard ion chamber (IC) measurement, the angular dependence, and the Cherenkov effect are discussed in detail; methods to overcome these problems are also presented.

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“…Although the use of intensity-modulated beams for SBRT yields satisfactory dose conformity, they also increase the doses to organs and tissues distant from the target (i.e., peripheral organs), due to the changing gantry locations during delivery, particularly when non-coplanar techniques are used. The radiation energy drops rapidly beyond the radiation field and, as Kirkby et al have suggested, it is the low energy component that contributes to the higher radiobiological effectiveness [ 7 , 8 ]. In recent years, several studies have investigated the effect of VMAT prostate radiotherapy on the organs adjacent to the target, with clinical data showing good sparing of the rectum and bladder.…”

Section: Introductionmentioning

confidence: 99%

Cellular Damage in the Target and Out-Of-Field Peripheral Organs during VMAT SBRT Prostate Radiotherapy: An In Vitro Phantom-Based Study

Piotrowski

Kulcenty

Suchorska

et al. 2022

Cancers

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Hypo-fractionated stereotactic body radiation therapy (SBRT) is an effective treatment for prostate cancer (PCa). Although many studies have investigated the effects of SBRT on the prostate and adjacent organs, little is known about the effects further out-of-field. The aim of this study was to investigate, both in vitro and in a quasi-humanoid phantom, the biological effects (using a dose-scaling approach) of radiation in the out-of-field peripheral organs delivered by 6 MV volumetric modulated arc therapy (VMAT) SBRT in a prostate cancer model. Healthy prostate cells were irradiated in a phantom at locations corresponding to the prostate, intestine, lung, thyroid, and brain. Seven 10 Gy fractions of VMAT SBRT were delivered to the target in a single session without intermission (scaled-up method). Radiochromic films were used to measure the doses. The radiobiological response was assessed by measuring DNA breaks, the cell survival fraction, and differences in gene expression profile. Our results showed a strong, multiparametric radiobiological response of the cells in the prostate. Outside of the radiation field, the highest doses were observed in the intestine and lung. A small increase (not statistically significant) in DNA damage and cell death was observed in the intestines. Several gene groups (cell cycle, DNA replication) were depleted in the lung and thyroid (DNA replication, endocytosis), but further analysis revealed no changes in the relevant biological processes. This study provides extensive evidence of the types and extent of radiobiological responses during VMAT SBRT in a prostate cancer model. Additional research is needed to determine whether the radiobiological effects observed in the peripheral organs are validated in a clinical context.

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Low dose out-of-field radiotherapy, part 2: Calculating the mean photon energy values for the out-of-field photon energy spectrum from scattered radiation using Monte Carlo methods

Cited by 11 publications

References 21 publications

Influence of Specific Treatment Parameters on Nontarget and Out-of-Field Doses in a Phantom Model of Prostate SBRT with CyberKnife and TrueBeam

Influence of Specific Treatment Parameters on Nontarget and Out-of-Field Doses in a Phantom Model of Prostate SBRT with CyberKnife and TrueBeam

Advances on inorganic scintillator-based optic fiber dosimeters

Cellular Damage in the Target and Out-Of-Field Peripheral Organs during VMAT SBRT Prostate Radiotherapy: An In Vitro Phantom-Based Study

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