New target with low photoneutron yield for LINAC radiotherapy applications

Rojas-Arias, Nicolás; Sajó-Bohus, L.; Tolosa-Cetina, J.O.; Sandoval-Garzón, M.A.; Ovalle, Segundo Agustín Martínez

doi:10.1016/j.apradiso.2020.109142

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…In the frame of radiation therapy, high-energy photon beams delivered by medical accelerators are often used to deposit gamma doses locally on tumors. However, simultaneously, photoneutrons may lead to undesired neutron doses [1][2][3][4][5] deposited on the whole body of patients. In very different fields of applications, a linear electron accelerator (linac) enables to implement the photofission reactionwhich is the basis of the active photon interrogation techniquein view of detecting Special Nuclear Material (SNM) such as uranium and plutonium isotopes either for cargo containers security checks [6,7] or for nuclear waste packages characterization [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Characterization of photoneutron fluxes emitted by electron accelerators in the 4–20 MeV range using Monte Carlo codes: A critical review

Sari

2023

Applied Radiation and Isotopes

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Section: Introductionmentioning

confidence: 99%

Characterization of photoneutron fluxes emitted by electron accelerators in the 4–20 MeV range using Monte Carlo codes: A critical review

Sari

2023

Applied Radiation and Isotopes

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“…Recently, many researchers in the field of radiation protection have addressed the role and consequences of unwanted doses to the patient caused by photoneutrons [7][8][9]. Some efforts focused on reducing neutron production in the linac head through optimization of the Bremsstrahlung target [10]. Considering that the neutron is an uncharged particle that is difficult to detect, it is important to determine the neutron spectrum (F n (E)) and the ambient dose equivalent (H � n ð10Þ) to estimate the effective dose received by radiotherapy patients and staff.…”

Section: Introductionmentioning

confidence: 99%

How much should you worry about contaminant neutrons in spatially fractionated grid radiation therapy?

et al. 2023

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Neutron contamination in radiation therapy is of concern in treatment with high-energy photons (> 10 MV). With the development of new radiotherapy modalities such as spatially fractionated grid radiation therapy (SFGRT) or briefly grid radiotherapy, more studies are required to evaluate the risks associated with neutron contamination. In 15 MV SFGRT, high-Z materials such as lead and cerrobend are used as the block on the tray of linear accelerator (linac) which can probably increase the photoneutron production. On the other hand, the high-dose fractions (10–20 Gy) used in SFGRT can induce high neutron contamination. The current study was devoted to addressing these concerns via compression of neutron fluence (Φn) and ambient dose equivalent (Hn*(10)) at the patient table and inside the maze between SFGRT and conventional fractionated radiation therapy (CFRT). The main components of the 15 MV Siemens Primus equipped with different grids and located inside a typical radiotherapy bunker were simulated by the MCNPX® Monte Carlo code. Evidence showed that the material used for grid construction does not significantly increase neutron contamination inside the maze. However, at the end of the maze, neutron contamination in SFGRT is significantly higher than in CFRT. In this regard, a delay time of 15 minutes after SFGRT is recommended for all radiotherapy staff before entering the maze. It can be also concluded that Hn*(10) at the patient table is at least 10 times more pronounced than inside the maze. Therefore, the patient is more at risk of neutrons compared to the staff. The Hn*(10) at the isocenter in SFGRT with grids made of lead and cerrobend was nearly equal to CFRT. Nevertheless, it was dramatically lower than in CFRT by 30% if the brass grid is used. Accordingly, SFGRT with the brass grid is recommended, from radiation protection aspects.

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“…The target's materials and thickness significantly affect the photon beams produced. The target material used in the device was originally composed of gold, water, steel and graphite, and then materials such as tungsten and copper started to be used since the cross-section value was better determined (Berger & Seltzer, 1970;Rojas-Arias et al, 2020). Some researchers who have studied by using the Monte Carlo (MC) method have shown that the target material consisting of Tungsten (W), Titanium (Ti), Tantalum (Ta) is suitable because an effective photon beam is produced (Gao et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Some researchers who have studied by using the Monte Carlo (MC) method have shown that the target material consisting of Tungsten (W), Titanium (Ti), Tantalum (Ta) is suitable because an effective photon beam is produced (Gao et al, 2013). The use of aluminum and lead in the target material to provide photon-beam has also contributed significantly to radiotherapy technology (Rojas-Arias et al, 2020). Podgorsak et al suggested using Copper (Cu) alloy as target material to produce high-quality photon beams in linear accelerator (LINAC) devices (Podgorsak et al, 1974).…”

Section: Introductionmentioning

confidence: 99%

Effect of different target materials of LINAC head on photon spectrum

Tuğrul

2021

Journal of Radiation Research and Applied Sciences

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The X-rays were examined, which consist of the effect of 6 MeV energized electrons on different thickness and material of targets, using the MC method. When the PDDs are examined, we can see that the curves obtained for the Target 4 and Target 8 containing only tungsten material are very close PDD values to each other. The highest TPR 20,10 value was also obtained for Target 8. For Target 4 and Target 8, which are composed only of tungsten material, when we examine the mean photon energy distributions formed, we observe an increase in energy towards the edge of the field. We obtained the closest TPR 20,10 value for Target 6 to the TPR 20,10 value generated by the original LINAC target (Target 1). However, the mean photon energy distribution value obtained for Target 6 is higher than the mean photon energy distribution value obtained from the Target 1. The mean photon energy distribution generated by the selected material according to the desired X-ray penetration and the homogeneity of this energy should be considered. The results obtained in the study are of a guiding nature both in modeling studies and for companies that will make target production.

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New target with low photoneutron yield for LINAC radiotherapy applications

Cited by 5 publications

References 11 publications

Characterization of photoneutron fluxes emitted by electron accelerators in the 4–20 MeV range using Monte Carlo codes: A critical review

Characterization of photoneutron fluxes emitted by electron accelerators in the 4–20 MeV range using Monte Carlo codes: A critical review

How much should you worry about contaminant neutrons in spatially fractionated grid radiation therapy?

Effect of different target materials of LINAC head on photon spectrum

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