Monte Carlo dose calculations of shielding disks with different material combinations in intraoperative electron radiation therapy (IOERT)

Alhamada, Husein; Simon, Stéphane; Philippson, C.; Vandekerkhove, C.; Jourani, Y.; Pauly, Nicolas; Gestel, Dirk Van; Reynaert, N.

doi:10.1016/j.canrad.2020.02.006

Cited by 8 publications

(5 citation statements)

References 37 publications

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“…Besides, as provided in Table 1, the first disk layer is always constructed from a low atomic number element or composition with a light physical density to ensure minimizing the electron backscattering effect from the upper disk surface. This backscatter dose component can considerably affect the dose distribution uniformity inside the target volume, as established by some studies 14–16,20,28–30 …”

Section: Methodsmentioning

confidence: 97%

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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: 97%

“…This backscatter dose component can considerably affect the dose distribution uniformity inside the target volume, as established by some studies. [14][15][16]20,[28][29][30]…”

Section: Employed Ioert Shielding Disksmentioning

confidence: 99%

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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“…Muszą być one zbudowane z takich materiałów, aby osłabiać wiązkę elektronów i jednocześnie być źródłem niewielkiej ilości promieniowania wstecznego i promieniowania hamowania. Im wyższa liczba atomowa Z materiału osłony, tym wyższa składowa rozpraszania wstecznego, które zostanie w niej wygenerowana, jednak mocniej osłabi ona wiązkę elektronów niż osłona o mniejszej liczbie atomowej Z, która z kolei nie będzie źródłem rozpraszania wstecznego o dużym natężeniu [15]. Wobec tego wykorzystywane są dwuwarstwowe osłony, na przykład aluminiowo-ołowiane [16,17], z teflonu i stali nierdzewnej [18], z polimetakrylanu metylowego (PMMA) i miedzi [19] lub trójwarstwowe, na przykład krzemowo-aluminiowo-ołowiane [20].…”

Section: Aparatura Do Ioertunclassified

Radioterapia śródoperacyjna z wykorzystaniem elektronów

Graczyk

Kruszyna-Mochalska

Kijeska

2022

LOS

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Taktyki leczenia, które łączą ze sobą oszczędzającą operację chirurgiczną z radioterapią stały się standardem w leczeniu wczesnych nowotworów. Jednym z przykładów skojarzonego leczenia jest wykonanie radioterapii śródoperacyjnej, którą przeprowadza się w trakcie zabiegu chirurgicznego, gdy pacjent nadal znajduje się pod anestezją w sterylnej sali operacyjnej. Celem pracy jest omówienie techniki radioterapii śródoperacyjnej wykorzystującej wiązkę elektronów (IOERT) generowaną przez mobilne akceleratory. Metoda IOERT znajduje swoje zastosowanie w leczeniu nowotworów takich lokalizacji jak: pierś, prostata, trzustka, okrężnica i odbytnica. Na podstawie doniesień literaturowych omówione zostało: przebieg procedury, najczęściej stosowane parametry fizyczne oraz wyzwania związane z kontrolą jakości i ochroną radiologiczną personelu.

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“…The difficult modelling of the anatomical district to treat through proper imaging techniques—unlike EBRT, where pre-treatment accurate imaging solutions are available—seriously hinders the capacity of treatment planning systems to produce reliable, predictive and robust dose distributions. Beam shaping devices (applicators) and protective gear such as disk-shaped shields to use downstream the electron beam interfere with imaging devices and pose dosimetric issues due to their high-Z chemical composition [ 2 ].…”

Section: Introductionmentioning

confidence: 99%

Treatment Planning in Intraoperative Radiation Therapy (IORT): Where Should We Go?

Cavedon

Mazzarotto

2022

Cancers

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As opposed to external beam radiation therapy (EBRT), treatment planning systems (TPS) dedicated to intraoperative radiation therapy (IORT) were not subject to radical modifications in the last two decades. However, new treatment regimens such as ultrahigh dose rates and combination with multiple treatment modalities, as well as the prospected availability of dedicated in-room imaging, call for important new features in the next generation of treatment planning systems in IORT. Dosimetric accuracy should be guaranteed by means of advanced dose calculation algorithms, capable of modelling complex scattering phenomena and accounting for the non-tissue equivalent materials used to shape and compensate electron beams. Kilovoltage X-ray based IORT also presents special needs, including the correct description of extremely steep dose gradients and the accurate simulation of applicators. TPSs dedicated to IORT should also allow real-time imaging to be used for treatment adaptation at the time of irradiation. Other features implemented in TPSs should include deformable registration and capability of radiobiological planning, especially if unconventional irradiation schemes are used. Finally, patient safety requires that the multiple features be integrated in a comprehensive system in order to facilitate control of the whole process.

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Monte Carlo dose calculations of shielding disks with different material combinations in intraoperative electron radiation therapy (IOERT)

Cited by 8 publications

References 37 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

Radioterapia śródoperacyjna z wykorzystaniem elektronów

Treatment Planning in Intraoperative Radiation Therapy (IORT): Where Should We Go?

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