Comparison of different TBI techniques in terms of dose homogeneity – review study

Zarghani, Elham Hoseinnezhad; Geraily, Ghazale; Hadisinia, Tahereh

doi:10.1016/j.canrad.2020.12.004

Cited by 6 publications

(6 citation statements)

References 58 publications

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“…The neutron fluences of the whole body and various organs were simulated by F4:n card. The energy deposition in tissues and organs from neutrons and secondary photons was determined using the F6:n,p card, in which the neutron absorption dose was estimated in the kerma approximation [10,12,13]. The ENDF/B-VIII.0 library was chosen for the simulation.…”

Section: Methodsmentioning

confidence: 99%

An optimized method for neutron dose evaluation based on ²⁴Na activity distribution in the human body

Xu¹,

Zhang²,

Ning³

et al. 2023

J. Radiol. Prot.

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The neutron dose resulting from external irradiation can be evaluated by measuring the counts of characteristic γ rays produced by 24Na in the human body. The detecting geometry with the highest detection efficiency for measuring the whole body 24Na activity has not been studied. In this work, the MCNP code is used to calculate the spatial distribution of 24Na in the human body irradiated by neutrons with different energies in different irradiation geometries. The fluence distribution of 24Na characteristic γ rays at the body surface is calculated. The counts of 24Na characteristic γ rays induced by monochromatic neutrons irradiation are simulated to fit the scenarios of neutron irradiation by a continuous energy spectrum neutrons. When the spontaneous neutrons from 252Cf with 1 Gy dose irradiate the human body, (3.63 - 4.35) × 1010 24Na atoms are produced. The lower detection limit for the neutron absorbed dose is reduced from ~100 mGy to less than 1 mGy when the radiation detector is placed over the back of the human body close to the liver. The relative error between the measured counts of 24Na characteristic γ rays caused by 252Cf neutrons irradiation and the counts fitted by monochromatic neutron irradiation data is less than 5.7%. The neutron dose received from a continuous energy spectrum neutron can be acquired quickly and accurately by weighted summing the data for monochromatic neutron irradiations calculated in this paper, which is more convenient and practical than the previous method.

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Section: Methodsmentioning

confidence: 99%

An optimized method for neutron dose evaluation based on ²⁴Na activity distribution in the human body

Xu¹,

Zhang²,

Ning³

et al. 2023

J. Radiol. Prot.

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“…These difficulties in the dose delivered in the organs is due mainly to the different experimental irradiation arrangements that are possible and proposed in TBI in different facilities [1][2][3]. A wide variation of parameters, e.g., positioning, gantry angle, source-to-surface distance (SSD), body mass, available space, and equipment technology, are specific factors of each institute and hinder the reproducibility of this modality.…”

Section: The International Commission On Radiation Units and Measurem...mentioning

confidence: 99%

“…However, the authors pointed out that the evidence for choosing the most appropriate therapy is indeed the limit to the technological and instrumental availability of each center, which makes it very particular. In particular, the lungs have a low tolerance dose limit, so dosimetry studies are needed to optimize dose distribution in TBI for radiosensitive organs such as the lung [1][2][3][4]. Treating the entire body is a difficult task for many reasons, including the size of the patient compared with the size of the conventional radiation field and the heterogeneous tissue composition of the body, among many other parameters.…”

Section: The International Commission On Radiation Units and Measurem...mentioning

confidence: 99%

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Assessment of dose heterogeneity in TBI using the thorax of the anthropomorphic Alderson-Rando phantom and TLDs in two different setups

Rodrigues

Nolasco²,

Belo

et al. 2023

Braz. J. Rad. Sci.

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Total body irradiation (TBI) is a treatment modality of radiotherapy. It can be used for immunosuppression of transplanted patients or for metastatic protocols. In this study, TBI was performed using the anthropomorphic Alderson-Rando phantom filled with thermoluminescent dosimeters (TLDs) and irradiated with a 6 MV photon beam from the Elekta linear accelerator in two different setups, one at the hospital São Francisco, BH, MG and second at the hospital Santa Casa in Lavras, MG. The dose distribution in the left and right lungs was estimated, analyzed, and compared with results from the literature. Our results showed that dose homogeneity is more adequate with dual-field irradiation.

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“…Cleuziou et al, (2021) discussed the methodology to set up the protocol, dosimetric evaluation and pretreatment QA and in-vivo dosimetry of TBI using Helical TomoTherapy ® (HT). TBI in HT provides good dose homogeneity and conformity with an acceptable organ at risk (OAR) tolerance which leads to reduced severity and less late complications (Sarradin et al, 2018, Zarghani et al, 2021, Peñagarícano et al, 2011. As a result, excellent conditioning is attained with minimal side-effects for lung and other body organs (Gruen et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Optimal Combination of Pitch, Modulation Factor and Dosimetric Considerations in Treatment Planning for Total Body Irradiation Using Helical Tomotherapy

Venkatesan

Kataria

Tamilselvan

et al. 2023

Asian Pac J Cancer Prev

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Objective: The aim of this study is to makethe standard total body irradiation (TBI) protocol for Helical tomotherapy© (HT) and to analyze the optimal pitch and modulation factor (MF) with respect to dose homogeneity index (HI), target dose coverage, target overdose, beam on time (BOT) and mean lung dose. Materials and Methods: Ten patients who underwent high-dose TBI were taken for this study. For each patient, 35 dose plans were created by different combination of pitch and MF. The optimal pitch and MF were deduced using scatter plot and regression methodology based on target coverage, HI, target volume receiving 103%(V 103% ), 105%(V 105% ) and 107% (V 107% ) of the prescription dose and BOT. Using these optimal pitch and MF, the final dose plan was made and the planning aim and achieved dose was compared using two tailed student’s t-test. Radiochromic films and ionization chambers were used to measure the delivered dose using anthropomorphic phantom on various points for the head and pelvis regions to verify the skin flash margin and its effect on skin dose. Results: The optimal pitch and MF value were 0.287 and 2.4 respectively. Based on optimal pitch and MF, the mean BOT was 1692 seconds with optimal inhomogeneity (7.4%). For target, D95 and D98 were 97.09% (range:94.7-99.6%, p=0.002) and 93.9% (range:91.5-94.4%,p=0.007) respectively, and mean D2 was within 107% with SD of ±1.22% (p=0.04). The mean of PTV receiving V 103 , V105 and V107 was 24.48% (range=7.7-36.6%, p=0.03), 5.76% (range=1.4-12.1%, SD=±3.3%), 1.93% (range=0.1-4.6%, p=0.008) respectively. Our measurements show that the flash margin did not increase the skin dose. Conclusion: In our study, the optimal combination of pitch value of 0.287 and MF value of 2.4 provided acceptable plans for all patients planned for TBI in HT. The flash margin can provide adequate coverage during patient position uncertainty without increasing the skin dose.

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Comparison of different TBI techniques in terms of dose homogeneity – review study

Cited by 6 publications

References 58 publications

An optimized method for neutron dose evaluation based on ²⁴Na activity distribution in the human body

An optimized method for neutron dose evaluation based on ²⁴Na activity distribution in the human body

Assessment of dose heterogeneity in TBI using the thorax of the anthropomorphic Alderson-Rando phantom and TLDs in two different setups

Optimal Combination of Pitch, Modulation Factor and Dosimetric Considerations in Treatment Planning for Total Body Irradiation Using Helical Tomotherapy

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Comparison of different TBI techniques in terms of dose homogeneity – review study

Cited by 6 publications

References 58 publications

An optimized method for neutron dose evaluation based on 24Na activity distribution in the human body

An optimized method for neutron dose evaluation based on 24Na activity distribution in the human body

Assessment of dose heterogeneity in TBI using the thorax of the anthropomorphic Alderson-Rando phantom and TLDs in two different setups

Optimal Combination of Pitch, Modulation Factor and Dosimetric Considerations in Treatment Planning for Total Body Irradiation Using Helical Tomotherapy

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Product

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An optimized method for neutron dose evaluation based on ²⁴Na activity distribution in the human body

An optimized method for neutron dose evaluation based on ²⁴Na activity distribution in the human body