Measurement of Neutron Dose Equivalent within and Outside of a LINAC Treatment Vault Using a Neutron Survey Meter

Tài, Dương Thanh; Loan, Trương Thị Hồng; Sulieman, Abdelmoneim; Tamam, Nissren; Omer, Hammad; Bradley, D.A.

doi:10.3390/qubs5040033

Cited by 6 publications

(4 citation statements)

References 20 publications

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“…Duong et al investigated neutron dose rate for different field sizes at various locations within and outside of a 15 MV Siemens Primus M5497 electron accelerator treatment vault using a neutron survey meter. This study showed that low values ranging from unobservable to between 0.0001 to 0.0002 mSv/h neutron dose rate around the control room and patient waiting area where the greatest value at the level of the floor directly adjacent to the treatment couch is 8.6 mSv/h which exceeds the greatest value on the treatment table 5.5 mSv/h [14]. In the present study, we have measured neutron dose rate for 15 MV photon beam at various locations inside the Linac treatment room as a function of delivered photon dose, field size(s) and at various location inside the treatment room.…”

Section: Introductionmentioning

confidence: 77%

Measurements of photoneutron dose rate for 15 MV photon beam from medical linear accelerator using neutron survey meter

Musfika,

Jamil,

Siddiqua

et al. 2023

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High-energy medical linear accelerators (>10MV) are increasingly used in the medical field to treat cancer patients depending on the treatment organ and patient physic. Medical linear accelerators (Linacs) operating above 10 MV photon beam produce unwanted neutrons (photoneutron) by means of photonuclear reaction (γ, n) between bremsstrahlung photon beams and constituent materials of Linac head. This study involved the measurement of the neutron dose rate from photon beam of medical linear accelerator (Elekta Synergy) operated at 15 MV photon. For the measurement of dose rate, a neutron survey meter LB 6411 probe was used. Neutron dose rate was obtained as a function of delivered dose, field size and detector position. In the study neutron dose rate was found 13.14 mSv/h at a field size of 10 × 10 cm2 at position (0,90,0) cm for 350 cGy and 9.26 mSv/h at 5 × 5 cm2 field size at position (0,80,0) cm for 200 cGy photon dose delivery. The dose rate varied with respect to detector position in an irregular manner; 2.95 mSv/h at position (-100,0,0) cm -on the side of maze entrance and 4.85 mSv/h at position (100,0,0) cm -off side of maze entrance.

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Section: Introductionmentioning

confidence: 77%

Measurements of photoneutron dose rate for 15 MV photon beam from medical linear accelerator using neutron survey meter

Musfika,

Jamil,

Siddiqua

et al. 2023

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“…The calculation results of the neutron flux on the surface of the water phantom at a voltage of 15 MV, 18 and 25 MV are, respectively, 1.82  10 11 n/cm 2 .s, 2.12  10 11 n/cm 2 .s, and 4.94  10 11 n/ cm 2 .s. Neutron flux impinging on the phantom can cause an increase in the total dose, which is the sum of the photon dose and the neutron dose [19,20,21] . The addition of a neutron dose is formed through a fast neutron scattering mechanism with hydrogen atoms [22] .…”

Section: Visualization and Calculation Of Contaminant Neutron Fluxmentioning

confidence: 99%

Simulation Of Neutron Contamination In 6, 8, 10, 15, 18 and 25 MV Voltage Linac Device Using The Monte Carlo Method

Bilalodin

Haryadi²,

Haryanto³

2022

Indonesian J Appl Phys

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<p>A research on neutron contamination in LINAC device has been carried out using a Monte Carlo method. The simulation is based on the Siemens Primus LINAC machine model whose component consists of target, primary collimator, flattening filter and secondary collimator as its main components. A neutron contamination examination was carried out using a 10 x 10 cm radiation field and a 100 cm SSD. Subsequently, at a distance of 100 cm from the X-ray source, a water phantom is placed. Investigation of the presence of contaminants was carried out the LINAC operating voltages of 6, 8, 10, 15, 18 and 25 MV. The simulation results show that neutron contamination occurs due to the interaction of photons with the components of the LINAC device, namely the primary collimator, flattening filter and secondary collimator. The operating voltages that can produce neutron contaminant start at 10 MV. Increase in the voltage of the LINAC device causes consequent increase in neutron flux. Such increase in neutron flux has the potential to increase therapeutic dose.</p>

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Section: Introductionmentioning

confidence: 99%

“…In previous studies, the measurement of photoneutrons was more often carried out free-in-air at various locations in the patient plane [9,[11][12][13] or in the water phantom [11,14]. Various types of equipment can be used for measurement, including a Bonner sphere spectrometer [15], a nested neutron spectrometer (NNS, Detec Inc., Gatineau, QC, Canada) [16], a Meridian Neutron Survey Meter 5085 (HPI, Goleta, CA, USA) [12], and CR-39 detectors [14]. Photoneutron dosimetry is a challenge because the measurement is carried out in a mixed field with photons, which can lead to an uncertainty of about 10% due to the saturation of the detector and the strong dependence of the detector response on the neutron spectrum [17].…”

Section: Introductionmentioning

confidence: 99%

GEANT4 Simulation of Photoneutron Spectrum from Medical Linear Accelerator

Chernyaev,

Belikhin,

Lykova

et al. 2023

QuBS

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Photons with energy totaling more than 10 MeV provide efficient treatment for deeply seated tumors but interact with the nuclei of high-Z materials constituting a head of the linac. These interactions result in photoneutrons that deliver an additional out-of-field dose to the patient, which increases the risk of radiation-induced cancer. Monte Carlo simulation is an accurate strategy for estimating the effective photoneutron dose for a patient. In the current study, the possibility of using GEANT4 to calculate the photoneutron spectrum from the medical linac was investigated. The free-in-air photoneutron spectrum from a head of the linac was simulated using the NeutronHP experimental package. Validation of the simulated model was carried out based on a comparison of simulated and measured percentage depth–dose curves from photons in the water phantom. The obtained photoneutron spectrum was compared with the previously measured spectrum at the Varian Thilogy linac. GEANT4 may improve the accuracy of calculations of the effective dose based on photoneutrons. However, the simulated model should be improved and optimized. In the future, this model may constitute a physical basis for the prediction of the risk of radiation-induced cancer at our clinical center.

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Measurement of Neutron Dose Equivalent within and Outside of a LINAC Treatment Vault Using a Neutron Survey Meter

Cited by 6 publications

References 20 publications

Measurements of photoneutron dose rate for 15 MV photon beam from medical linear accelerator using neutron survey meter

Measurements of photoneutron dose rate for 15 MV photon beam from medical linear accelerator using neutron survey meter

Simulation Of Neutron Contamination In 6, 8, 10, 15, 18 and 25 MV Voltage Linac Device Using The Monte Carlo Method

GEANT4 Simulation of Photoneutron Spectrum from Medical Linear Accelerator

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