Characterization of Nylon-12 as a water-equivalent solid phantom material for dosimetric measurements in therapeutic photon and electron beams

Ade, Nicholas; Eeden, Déte van; Plessis, F.C.P. du

doi:10.1016/j.apradiso.2019.108919

Cited by 7 publications

(9 citation statements)

References 30 publications

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“…Polyvinylpyrrolidone (PVP) was reported [21] to have dielectric properties equivalent to soft tissue. Nylon-12 have been used as water equivalent solid phantom, and the characterization was reported [22]. Plaster of Paris, PoP was used to mimic the pediatric bone while polymethyl methacrylate, PMMA was used as the soft tissue equivalent [15].…”

Section: A Tissue Equivalent Substitutesmentioning

confidence: 99%

Characterization of the Urethane Based Tissue Equivalent Substitute for Phantom Construction: Model Molding, XCOM and MCNPX Studies

Bello¹,

Nor²,

Hassan³

2022

International Journal on Advanced Science, Engineering and Information Technology

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The Soft and Lung tissue equivalent substitute (STES and LTES) were developed from urethane PMC121/30 Dry (A and B) of Smooth-On, USA. The part A and B were mixed in the ratio 1:1 and further mixed with calcium carbonate (CaCO3) at a ratio 2:1 by mass. Air moisture was extracted from the mixture for 10minutes. This is the STES and the density after air extraction was 1.04gcm -3 . The LTES was developed by mixing the STES and polystyrene beads at a ratio 10:1 by mass. The density of the LTES was 0.25gcm -3 after air extraction. The STES and the LTES were subjected to compression test for stress-strain analysis. The elemental composition of STES and LTES was achieved using XCOM software with the IUPAC nomenclatures of the source compounds as inputs. The elemental composition obtained was used to modify the lung and the soft tissue material of the AMALE and AFEMALE computational phantom of ORNL. The phantom was subjected to photon exposure (0.06MeV-15.00MeV) using MCNPX Version 27e. The results from MCNPX provided the bremsstrahlung, positron annihilation, and the fluorescence energies that was used to estimate the g-factor. The mass-energy transfer coefficient (μtra/ρ) and the mass-energy absorption coefficient (μen/ρ) were calculated using the values of g-factor, the fluence and the Kerma. The μen/ρ of the tissue-equivalent agrees with the National Institute of Standard values and the ICRU 44. The STES and LTES are technically proper research and teaching models for dose measurements with these results.

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Section: A Tissue Equivalent Substitutesmentioning

confidence: 99%

Characterization of the Urethane Based Tissue Equivalent Substitute for Phantom Construction: Model Molding, XCOM and MCNPX Studies

Bello¹,

Nor²,

Hassan³

2022

International Journal on Advanced Science, Engineering and Information Technology

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“…Different types of in vivo dosimeters are used in external photon beam radiotherapy. In this research, GafChromic 1 EBT2 film (produced by International Specialty Products, NJ, USA) was used because of the following characteristics: ease of handling, thin width, good spatial resolution, self-developing, nearly tissue equivalent characteristics (with an effective atomic number of 6.84) [28][29][30], and wide dose range (between 0.01 and 10 Gy) [29,31,32]. After the film is irradiated, the active component in the film undergoes a polymerization process resulting in a color change to blue.…”

Section: Introductionmentioning

confidence: 99%

Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine

et al. 2022

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Purpose In vivo dosimetry is a quality assurance tool that provides post-treatment measurement of the absorbed dose as delivered to the patient. This dosimetry compares the prescribed and measured dose delivered to the target volume. In this study, a tissue-equivalent water phantom provided the simulation of the human environment. The skin and entrance doses were measured using GafChromic EBT2 film for a Theratron® Equinox Cobalt-60 teletherapy machine. Methods We examined the behaviors of unencapsulated films and custom-made film encapsulation. Films were cut to 1 cm × 1 cm, calibrated, and used to assess skin dose depositions and entrance dose. We examined the response of the film for variations in field size, source to skin distance (SSD), gantry angle and wedge angle. Results The estimated uncertainty in EBT2 film for absorbed dose measurement in phantom was ±1.72%. Comparison of the measurements of the two film configurations for the various irradiation parameters were field size (p = 0.0193, α = 0.05, n = 11), gantry angle (p = 0.0018, α = 0.05, n = 24), SSD (p = 0.1802, α = 0.05, n = 11) and wedge angle (p = 0.6834, α = 0.05, n = 4). For a prescribed dose of 200 cGy and at reference conditions (open field 10 cm x 10 cm, SSD = 100 cm, and gantry angle = 0º), the measured skin dose using the encapsulation material was 70% while that measured with the unencapsulated film was 24%. At reference irradiation conditions, the measured skin dose using the unencapsulated film was higher for open field configurations (24%) than wedged field configurations (19%). Estimation of the entrance dose using the unencapsulated film was within 3% of the prescribed dose. Conclusions GafChromic EBT2 film measurements were significantly affected at larger field sizes and gantry angles. Furthermore, we determined a high accuracy in entrance dose estimations using the film.

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“…Radiotherapy, as the most widely used treatment to kill cancer cells, use a high ionization radiation [1]. Radiotherapy can be categorized as a fairly complex method because it involves many staff groups and consists of multiple steps in preparing and delivering radiation doses during treatment, aiming to improve the accuracy of radiation dose delivery in radiotherapy [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…Using water phantom in the calibration process of LINAC needs long preparation time [2,13]. The less efficiency of preparation using water phantom will impact the number of daily treated-patients in the hospital.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, to shorten the preparation time, the hospital uses slab phantom to substitute the water phantom on daily LINAC calibration. Slab phantom have been widely applied in several foreign institutions, such as Iran using PMMA plastic slab phantom [13], India using tissue equivalent slab phantom with lithium tetraborate [3], Canada using polystyrene slab phantom [17], Turkey with slab head phantom [18], and South Africa with Nylon-12 water equivalent solid phantom [2].This research aims to determine the correction factor of slab phantom to water phantom for accuracy of absorbed dose measurement in LINAC calibration.…”

Section: Introductionmentioning

confidence: 99%

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Implementation of TRS-398 Protocol in Routine Calibration of Linac by Determination of Slab Phantom on Water Phantom Correction Factor

Fauzi

Aliyah

Darmawati

2022

SPEKTRA

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The water phantom is used for LINAC calibration to measure absorbed dose radiation. Practically, it requires a long preparation time and is considered less efficient. To increase efficiency, the medical physics team in a hospital uses slab phantom as the calibration tool. Consequently, the correction factor is crucial to define the equivalence of the absorbed doses resulted from slab phantom. The absorbed dose measurement was performed according to the IAEA TRS-398 dosimetry protocol with a cylindrical ionization chamber detector for 6 MV photon beam and electron beams from Elekta Synergy Platform 154029 LINAC with 6 MeV, 8 MeV, 10 MeV, and 12 MeV energy variations. The field size for slab and water phantom is 30 cm x 30 cm x 30 cm. Based on the TRS-398 protocol, the correction factor of the slab phantom calculated based on absolute dosimetry for 6 MV photons beam, the electron beam of 6 MeV, 8 MeV, 10 MeV, and 12 MeV are 1.0018; 0.9995; 0.9979; 1.0041 and 1.0068, respectively. As a result, the absorbed dose radiation measured by the calibrated slab phantom using the resulted correction factor has an equivalent amount to the water phantom.

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Characterization of Nylon-12 as a water-equivalent solid phantom material for dosimetric measurements in therapeutic photon and electron beams

Cited by 7 publications

References 30 publications

Characterization of the Urethane Based Tissue Equivalent Substitute for Phantom Construction: Model Molding, XCOM and MCNPX Studies

Characterization of the Urethane Based Tissue Equivalent Substitute for Phantom Construction: Model Molding, XCOM and MCNPX Studies

Characterization of GafChromic EBT2 film dose measurements using a tissue-equivalent water phantom for a Theratron® Equinox Cobalt-60 teletherapy machine

Implementation of TRS-398 Protocol in Routine Calibration of Linac by Determination of Slab Phantom on Water Phantom Correction Factor

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