Comparing the performance of some dedicated radioprotection disks in breast intraoperative electron radiotherapy: a Monte Carlo study

Baghani, Hamid Reza; Robatjazi, Mostafa; Mahdavi, Seyed Rabi

doi:10.1007/s00411-020-00836-z

Cited by 4 publications

(12 citation statements)

References 18 publications

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“…As mentioned previously, three different types of double‐layered IOERT radioprotection disks were considered in the current study. The main features of these radioprotection disks including the layer thickness, composing materials, and their relevant physical densities have been reported in Table 1 15 …”

Section: Methodsmentioning

confidence: 99%

“…According to the fact that the underlying healthy tissues such as ribs, superficial pectoral muscles, lung, and heart (in the case of left‐sided breast IOERT) may be directly exposed to the incident electron beam during the breast intraoperative electron radiotherapy, one should shield these organs at risk (OARs) during the radiotherapy in order to minimize the risk of normal tissue complications after the radiotherapy 14–17 . Accordingly, a dedicated radioprotection disk must be used during the breast IOERT to avoid overexposure of the underlying healthy tissues.…”

Section: Introductionmentioning

confidence: 99%

“…The employed radioprotection disks during the breast IOERT are mainly designed and constructed in a double‐layered format 15 . The first layer (which is exposed to the incident electron beam) is made from a low atomic number material (such as PMMA, Teflon, or Aluminum (Al)) to moderate and stop the transmitted electrons from the PTV without producing a remarkable photon contamination through bremsstrahlung process.…”

Section: Introductionmentioning

confidence: 99%

“…Up to now, different double‐layered disk compositions including PMMA+Cu, Al+Pb, and PTFE (Polytetrafluoroethylene, a synthetic type of Teflon)+steel have been used as the radioprotection disk during the breast cancer IOERT 15 …”

Section: Introductionmentioning

confidence: 99%

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Evaluating the induced photon contamination by different breast IOERT shields using Monte Carlo simulation

Baghani

Robatjazi

2023

J Applied Clin Med Phys

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Background and ObjectiveAvoiding the underlying healthy tissue over‐exposure during breast intraoperative electron radiotherapy (IOERT) is owing to the use of some dedicated radioprotection disks during patient irradiation. The originated contaminant photons from some widely used double‐layered shielding disks including PMMA+Cu, PTFE+steel, and Al+Pb configurations during the breast IOERT have been evaluated through a Monte Carlo (MC) simulation approach.MethodsProduced electron beam with energies of 6, 8, 10, and 12 MeV by a validated MC model of Liac12 dedicated IOERT accelerator was used for disk irradiations. Each of above‐mentioned radioprotection disks was simulated inside a water phantom, so that the upper disk surface was positioned at R90 depth of each considered electron energy. Simulations were performed by MCNPX (version 2.6.0) MC code. Then, the energy spectra of the contaminant photons at different disk surfaces (upper, middle, and lower one) and relevant contaminant dose beneath the studied disks were determined and compared.ResultsNone of studied shielding disks show significant photon contamination up to 10 MeV electron energy, so that the induced photon dose by the contaminant X‐rays was lower than those observed in the disk absence under the same conditions. In return, the induced photon dose at a close distance to the lower disk surface exceeded from calculated values in the disk absence at 12 MeV electron energy. The best performance in contaminant dose reduction at the energy range of 6–10 MeV belonged to the Al+Pb disk, while the PMMA+Cu configuration showed the best performance in this regard at 12 MeV energy.ConclusionFinally, it can be concluded that all studied shielding disks not only don't produce considerable photon contamination but also absorb the originated X‐rays from electron interactions with water at the electron energy range of 6–10 MeV. The only concern is related to 12 MeV energy where the induced photon dose exceeds the dose values in the disk absence. Nevertheless, the administered dose by contaminant photons to underlying healthy tissues remains beneath the tolerance dose level by these organs at the entire range of studied electron energies.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluating the induced photon contamination by different breast IOERT shields using Monte Carlo simulation

Baghani

Robatjazi

2023

J Applied Clin Med Phys

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“…proton or Carbon ion) can be employed for radiotherapy purposes [3][4][5][6]. The type of ionizing radiation selected for tumor irradiation depends on factors such as tumor location, size of the radiation eld (region to be covered by the ionizing radiation), treatment phase (main treatment or boost), treatment sessions, etc.. High energy electron beams are widely used for radiotherapy using different techniques such as external irradiation of super cial tumors, intraoperative radiotherapy (IORT) of the tumor bed after surgery in the operating theater, and total skin irradiation [7][8][9][10][11]. Although the use of electron beam for IORT purposes has been promoted in recent years, the most common application of electron beams is external radiotherapy of super cially distributed tumors [12,13].…”

Section: Introductionmentioning

confidence: 99%

On the measurement of scaling factors in the RW3 plastic phantom during high energy electron beam dosimetry

2023

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Ionometric electron dosimetry inside water-equivalent plastic phantoms demands special considerations including determination of depth scaling and uence scaling factors (c pl and h pl ) to shift from in-phantom measurements to those relevant to water. This study evaluates these scaling factors for RW3 slab phantom and also introduce a new coe cient, k(RW3), for direct conversion from RW3 measurements to water without involving scaling factors.The RW3 solid phantom developed by the PTW Company was used and the corresponding scaling factors including c pl , h pl , and k(RW3) were measured for conventional electron energies of 4, 6, 9, 12, and 16 MeV. Separate measurements were performed in water and in the RW3 slab phantom using the Advanced Markus chamber. The validity of the reported scaling factors was con rmed by comparing the direct and indirect percentage depth dose (PDD) measurement in water and in the RW3 phantom.The c pl values for the RW3 phantom were respectively equal to 0.915, 0.927, 0.934, 0.937, and 0.937 for 4, 6, 9, 12, and 16 MeV electron energies. The h pl and k(RW3) values were dependent on the investigation depth and on the electron energy. Application of the c pl -h pl factors and of the k(RW3) coe cients to measured data inside the RW3 can reliably reproduce the measured PDD curves in water. The mean difference between the PDDs measured directly and indirectly in water and in the RW3 phantom was less than 1.5% in both approaches for PDD conversion (c pl -h pl coupling and the use of k(RW3)).The scaling factors measured and the k(RW3) coe cients are su ciently relevant to mimic water-based dosimetry results through indirect measurements inside the RW3 slab phantom. Nevertheless, employing k(RW3) is more straightforward than the c pl -h pl approach because it does not involve scaling and it is also less time-consuming.

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On the measurement of scaling factors in the RW3 plastic phantom during high energy electron beam dosimetry

Baghani

Andreoli

Robatjazi

2022

Preprint

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Ionometric electron dosimetry inside water-equivalent plastic phantoms demands special considerations including determination of depth scaling and fluence scaling factors (cpl and hpl) to shift from in-phantom measurements to those relevant to water. This study evaluates these scaling factors for RW3 slab phantom and also introduce a new coefficient, k(RW3), for direct conversion from RW3 measurements to water without involving scaling factors. The RW3 solid phantom developed by the PTW Company was used and the corresponding scaling factors including cpl, hpl, and k(RW3) were measured for conventional electron energies of 4, 6, 9, 12, and 16 MeV. Separate measurements were performed in water and in the RW3 slab phantom using the Advanced Markus chamber. The validity of the reported scaling factors was confirmed by comparing the direct and indirect percentage depth dose (PDD) measurement in water and in the RW3 phantom. The cpl values for the RW3 phantom were respectively equal to 0.915, 0.927, 0.934, 0.937, and 0.937 for 4, 6, 9, 12, and 16 MeV electron energies. The hpl and k(RW3) values were dependent on the investigation depth and on the electron energy. Application of the cpl-hpl factors and of the k(RW3) coefficients to measured data inside the RW3 can reliably reproduce the measured PDD curves in water. The mean difference between the PDDs measured directly and indirectly in water and in the RW3 phantom was less than 1.5% in both approaches for PDD conversion (cpl-hpl coupling and the use of k(RW3)). The scaling factors measured and the k(RW3) coefficients are sufficiently relevant to mimic water-based dosimetry results through indirect measurements inside the RW3 slab phantom. Nevertheless, employing k(RW3) is more straightforward than the cpl-hpl approach because it does not involve scaling and it is also less time-consuming.

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Comparing the performance of some dedicated radioprotection disks in breast intraoperative electron radiotherapy: a Monte Carlo study

Cited by 4 publications

References 18 publications

Evaluating the induced photon contamination by different breast IOERT shields using Monte Carlo simulation

Evaluating the induced photon contamination by different breast IOERT shields using Monte Carlo simulation

On the measurement of scaling factors in the RW3 plastic phantom during high energy electron beam dosimetry

On the measurement of scaling factors in the RW3 plastic phantom during high energy electron beam dosimetry

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