Organ S values and effective doses for family members exposed to adult patients following I-131 treatment: A Monte Carlo simulation study

Han, Eun Young; Lee, Choonsik; McGuire, Lynn; Brown, Tracy L.; Bolch, Wesley E.

doi:10.1118/1.4812425

Cited by 13 publications

(11 citation statements)

References 11 publications

(15 reference statements)

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“…Recently, several investigators have developed NURBS/polygonal mesh (PM)-based hybrid phantom that can address the limitations of the voxel phantom and be deformed in various postures. 12,[15][16][17][18] Based on this, the deformed hybrid phantom has been modeled with various ages and shapes. In addition, a program to convert the hybrid phantom to DICOM was developed for the purpose of clinical application.…”

Section: Introductionmentioning

confidence: 99%

Development of a novel program for conversion from tetrahedral‐mesh‐based phantoms to DICOM dataset for radiation treatment planning: TET2DICOM

Cheon

Lee

Han

et al. 2021

J Applied Clin Med Phys

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Purpose: Tetrahedral mesh (TM)-based computational human phantoms have recently been developed for evaluation of exposure dose with the merit of precisely representing human anatomy and the changing posture freely. However, conversion of recently developed TM phantoms to the Digital Imaging and Communications in Medicine (DICOM) file format, which can be utilized in the clinic, has not been attempted. The aim of this study was to develop a technique, called TET2DICOM, to convert the TM phantoms to DICOM datasets for accurate treatment planning. Materials and methods:The TM phantoms were sampled in voxel form to generate the DICOM computed tomography images. The DICOM-radiotherapy structure was defined based on the contour data. To evaluate TET2DICOM, the shape distortion of the TM phantoms during the conversion process was assessed, and the converted DICOM dataset was implemented in a commercial treatment planning system (TPS). Results:The volume difference between the TM phantoms and the converted DICOM dataset was evaluated as less than about 0.1% in each organ. Subsequently, the converted DICOM dataset was successfully implemented in MIM (MIM Software Inc., Cleveland, USA, version 6.5.6) and RayStation (RaySearch Laboratories, Stockholm, Sweden, version 5.0). Additionally, the various possibilities of clinical application of the program were confirmed using a deformed TM phantom in various postures. Conclusion:In conclusion, the TM phantom, currently the most advanced computational phantom, can be implemented in a commercial TPS and this technique can enable various TM-based applications, such as evaluation of secondary cancer risk in radiotherapy.

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Section: Introductionmentioning

confidence: 99%

Development of a novel program for conversion from tetrahedral‐mesh‐based phantoms to DICOM dataset for radiation treatment planning: TET2DICOM

Cheon

Lee

Han

et al. 2021

J Applied Clin Med Phys

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“…It was concluded that the line source model is a good approximation for 99m Tc, 18 F, and 131 I used for remnant ablations. In Han et al (2013), more realistic adult and child phantoms were used to compute dose rates with static activity distribution for hyperthyroid patients and patients with differentiated thyroid cancer. This study confirmed that the point source approximation is too conservative but also that the activity distribution inside the patient strongly affected the calculation results.…”

Section: Discussionmentioning

confidence: 99%

The Nuclear Medicine Patient as a Line Source: The Source Length Is Certainly Not the Patient Height, But It Is a Reasonable Approximation

Broggio

2022

Health Physics

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Nuclear medicine patients are a source of exposure and should receive instructions to restrict contact time with different categories of people. The calculation of the restriction time requires that the dose rate at a given distance, known from an initial measurement and a whole-body retention function, can be extrapolated at other distances. As a basis for this extrapolation, it has been suggested to consider the patient as a line source. However, the validity of this suggestion is based on a few studies and limited measurement distances. We collected from the literature dose rates of nuclear medicine patients measured at different distances and investigated the robustness of the line source model. The cases of 18F-FDG exams, 99mTc bone scan exams, and 131I for hyperthyroidism treatment and remnants ablation were considered. The data were pooled, different cases of measurement time after administration were considered, and the data were fitted according to the line source model in which the half patient thickness was introduced. It was found that the line source model fits well the data put with a source length that is radionuclide-specific and significantly different from the standard adult height. However, considering a standard source length of 176 cm and neglecting the patient thickness induced at maximum an overestimation by a factor of 2.5 when extrapolating from 1 m to 10 cm. Such an overestimation is not of considerable importance in the calculation of contact restriction times.

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“…Organ dose rates were estimated in the exposed individual using the kerma approximation. This approximation is known to be accurate to~2% for 131 I due to the primary photon energy of 364 keV (Han et al 2013). The kerma approximation was implemented using the volume-averaged track length fluence estimator along with the kerma factors (heating numbers) from the MCNP6 nuclear data tables.…”

Section: Computational Phantom Modelsmentioning

confidence: 97%

“…Han et al employed Monte Carlo simulation for stylized phantoms developed previously by ORNL for 131 I source distributions in the thyroid, abdomen and whole body (Han et al 2013). These phantoms were placed at various separation distances and two exposure scenarios (face-to-face, standing; and side-by-side, lying).…”

Section: Introductionmentioning

confidence: 99%

“…• For a standing hyperthyroid subject, the point-source method overestimates the dose rate to a standing exposed person by a factor of~1.9 at 8-240 h post administration at a separation distance of 1 m. For comparison, Han et al (2013) estimated that the point-source method overestimates the dose rate by a factor of~1.6 for this separation distance based on Monte Carlo simulations using a stylized phantom. • For a standing DTC patient, the present analysis indicates that the point-source method overestimates the dose rate to a standing exposed person by a factor of 3.3 at 8 h post administration for a separation distance of 1 m. Han et al (2013) estimated that the point-source method overestimates by a factor of 2.2 at 100 cm for a DTC patient.…”

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confidence: 99%

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Assessment of the Point-Source Method for Estimating Dose Rates to Members of the Public from Exposure to Patients with 131I Thyroid Treatment

et al. 2015

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The U.S. Nuclear Regulatory Commission (USNRC) initiated a contract with Oak Ridge National Laboratory (ORNL) to calculate radiation dose rates to members of the public that may result from exposure to patients recently administered iodine-131 ( 131 I) as part of medical therapy. The main purpose was to compare dose rate estimates based on a point source and target with values derived from more realistic simulations of a human source and target. The latter simulations considered the time-dependent distribution of 131 I in the patient and attenuation of emitted photons by the patient's tissues. The external dose rate estimates were derived using Monte Carlo methods and two representations of the Phantom with Movable Arms and Legs (PIMAL), previously developed by ORNL and the USNRC, to model the patient and a nearby member of the public. Dose rates to tissues and effective dose rates were calculated for distances ranging from 10 cm to 300 cm between the phantoms. Dose rates estimated from these simulations are compared to estimates based on the point-source method, as well as to results of previous studies that estimated exposure from 131 I patients. The point-source method overestimates dose rates to members of the public in very close proximity to an 131 I patient but is a broadly accurate method of dose rate estimation at separation distances of 300 cm or more at times closer to administration. Health Phys. 109(3):233-241; 2015

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Organ S values and effective doses for family members exposed to adult patients following I-131 treatment: A Monte Carlo simulation study

Cited by 13 publications

References 11 publications

Development of a novel program for conversion from tetrahedral‐mesh‐based phantoms to DICOM dataset for radiation treatment planning: TET2DICOM

Development of a novel program for conversion from tetrahedral‐mesh‐based phantoms to DICOM dataset for radiation treatment planning: TET2DICOM

The Nuclear Medicine Patient as a Line Source: The Source Length Is Certainly Not the Patient Height, But It Is a Reasonable Approximation

Assessment of the Point-Source Method for Estimating Dose Rates to Members of the Public from Exposure to Patients with 131I Thyroid Treatment

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