Dose coefficients for ICRP reference pediatric phantoms exposed to idealised external gamma fields

Chang, Lienard A; Simon, Steven L.; Jorgensen, Timothy J.; Schauer, David A; Lee, Choonsik

doi:10.1088/1361-6498/aa559e

Cited by 10 publications

(7 citation statements)

References 29 publications

(29 reference statements)

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“…2 Moreover, the absorbed radiation dose may be higher in newborns compared with that in older children. 3 Despite the low level of radiation absorbed from a single radiograph, the total radiation dose absorbed from repeated X-ray examinations can increase to significant levels. 4 Premature infants, in particular, have a wider radiographic exposure range and the susceptibility to radiation in extremely premature infants is uncertain.…”

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confidence: 99%

Radiation Exposure in the Neonatal Intensive Care Unit in Newborns and Staff

et al. 2021

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Objective Portable X-rays remain one of the most frequently used diagnostic procedures in neonatal intensive care units (NICU). Premature infants are more sensitive to radiation-induced harmful effects. Dangers from diagnostic radiation can occur with stochastic effects. We aimed to determine the radiation exposure in premature infants and staff and determine the scattering during X-ray examinations in the NICU. Study Design In this prospective study, dosimeters were placed on premature infants who were ≤1,250 g at birth and ≤30 weeks of gestational age who stayed in the NICU for at least 4 weeks. The doses were measured at each X-ray examination during their stay. The measurements of the nurses and the doctors in the NICU were also performed with dosimeters over the 1-month period. Other dosimeters were placed in certain areas outside the incubator and the results were obtained after 1 month. Results The mean radiation exposure of the 10 premature infants, monitored with dosimeters, was 3.65 ± 2.44 mGy. The mean skin dose of the six staff was 0.087 ± 0.0998 mSV. The mean scattered dose was 67.9 ± 26.5 µGy. Conclusion Relatively high exposures were observed in 90% of the patients and two staff. The radiation exposure levels of premature infants and staff may need to be monitored continuously. Key Points

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confidence: 99%

Radiation Exposure in the Neonatal Intensive Care Unit in Newborns and Staff

et al. 2021

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“…Considering the large number of pediatric cancer patients each year alone in the United States, it is vital to address the interest of patient-specific and even organ-specific dosimetry in pediatric applications [2]. The risk for pediatric applications was particularly relevant due to their increased radio-sensitivity [3][4][5][6][7][8]. Specifically, pediatric patients are more vulnerable to radiation-induced risks than adult patients mainly due to their swiftly growing tissues and increased cellular distribution of skeletal active marrow [2].…”

Section: Introductionmentioning

confidence: 99%

A comparative study on dispersed doses during photon and proton radiation therapy in pediatric applications

et al. 2021

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The Monte Carlo method was employed to simulate realistic treatment situations for photon and proton radiation therapy for a set of Oak Ridge National Laboratory (ORNL) pediatric phantoms for 15, 10, 5 and 1-year olds as well as newborns. Complete radiotherapy situations were simulated using the previously developed NRUrad input code for Monte Carlo N-Particle (MCNP) code package. Each pediatric phantom was irradiated at five different positions, namely, the testes, colon, liver, left lung and brain, and the doses in targeted organs (Dt) were determined using the track length estimate of energy. The dispersed photon and proton doses in non-targeted organs (Dd), namely, the skeleton, skin, brain, spine, left and right lungs were computed. The conversion coefficients (F = Dd/Dt) of the dispersed doses were used to study the dose dispersion in different non-targeted organs for phantoms for 15, 10, 5 and 1-year olds as well as newborns. In general, the F values were larger for younger patients. The F values for non-targeted organs for phantoms for 1-year olds and newborns were significantly larger compared to those for other phantoms. The dispersed doses from proton radiation therapy were also found to be significantly lower than those from conventional photon radiation therapy. For example, the largest F values for the brain were 65.6% and 0.206% of the dose delivered to the left lung (P4) for newborns during photon and proton radiation therapy, respectively. The present results demonstrated that dispersion of photons and generated electrons significantly affected the absorbed doses in non-targeted organs during pediatric photon therapy, and illustrated that proton therapy could in general bring benefits for treatment of pediatric cancer patients.

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“…A detailed study on posture has been conducted by Yeom et al (2019), who explored five non-standing postures (i.e., walking, sitting, bending, kneeling, and squatting) for photon sources. In addition, many works have focused on idealized ICRP Publication 116 (ICRP 2010) irradiation geometries (anteroposterior—AP, posteroanterior—PA, left lateral—LLAT, right lateral—RLAT, isotropic—ISO, rotational—ROT) from monoenergetic photon (Yeom et al 2019; ICRP 2010; Chang et al 2017) or neutron plane-parallel beams (Griffin et al 2018; Bales et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Neutron Organ and Effective Dose Coefficients for PIMAL Stylized Phantoms in Bent Postures in Cranial and Caudal Irradiation Geometries

Sivabhaskar

Dewji

2021

Health Physics

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Radiation dose estimations in the human body are performed using computational reference phantoms, which are anatomical representations of the human body. In previous studies, dose reconstructions have been performed focusing primarily on phantoms in an upright posture, which limits the accuracy of the dose estimations for postures observed in realistic work settings. In this work, the International Commission on Radiological Protection (ICRP) Publication 103 recommendations for monoenergetic neutron plane sources directed downward from above the head (cranial) and upward from below the feet (caudal) for adult female and male reference phantoms were used to calculate organ absorbed and effective dose coefficients. The Phantom with Moving Arms and Legs (PIMAL) and the Monte Carlo N-Particle (MCNP) radiation transport code were used to compute organ-absorbed dose and effective dose coefficients for the upright, half-bent (45°), and full-bent (90°) phantom postures. The doses calculated for each of the articulated positions were compared to those calculated for the upright posture by computing the ratios of the coefficients (45°/upright and 90°/upright). These ratios were used to assess the effectiveness of upright phantoms in providing a comparable estimate when conducting dose estimations and dose reconstructions for articulated positions. This work compiling neutron cranial and caudal posture-specific dose coefficients completes the series of dose coefficients computed for posture-specific ICRP Publication 116 irradiation geometries for monoenergetic photons and neutrons, in addition to cranial and caudal monoenergetic photons. Results reported demonstrated that organ-absorbed dose coefficients for most of the organs in the CRA and CAU irradiation geometries were significantly higher for the bent phantoms than for the upright phantom. Since the upright phantom underestimates the organ-absorbed dose, this demonstrates the impact of posture while performing dose calculations. Organ doses reported in past neutron dose coefficient data were found to omit effects from neutron resonances at energies of 0.435, 1.0, and 3.21 MeV from 16O in tissue. Reported data notes as high as 60% underestimation for neutron organ-absorbed doses, specifically at the neutron resonance energy region omitted by smoothing. Ongoing studies are examining the effect of resonances on reported neutron organ-absorbed dose coefficients in ICRP 116 geometries.

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Dose coefficients for ICRP reference pediatric phantoms exposed to idealised external gamma fields

Cited by 10 publications

References 29 publications

Radiation Exposure in the Neonatal Intensive Care Unit in Newborns and Staff

Radiation Exposure in the Neonatal Intensive Care Unit in Newborns and Staff

A comparative study on dispersed doses during photon and proton radiation therapy in pediatric applications

Comparison of Neutron Organ and Effective Dose Coefficients for PIMAL Stylized Phantoms in Bent Postures in Cranial and Caudal Irradiation Geometries

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