To support epidemiological studies of radiation exposure but also to advance the science of radiation exposure assessment, Dosimetry Unit within the Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute develops new dosimetry methods and tools for medical, occupational and environmental radiation exposure scenarios. This website is designed to share the major developments in dose assessment tools and resources with other researchers. The currently available resources include: (1) computational human phantom series (binary voxel format or DICOM-image+structure); (2) National Cancer Institute dosimetry system for Computed Tomography (NCICT); and (3) dose coefficients for internal and external radiation exposure scenarios. Anyone who is interested in obtaining these resources for research can go to the Agreement tab and submit the Software Transfer Agreement to the NCI Technology Transfer Center.

Parties interested in commercial use of any materials on this website may contact Dr. Kevin Chang at the NCI Technology Transfer Center.



To support epidemiological studies of radiation exposure but also to advance the science of radiation exposure assessment, Dosimetry Unit within the Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute develops new dosimetry methods and tools for medical, occupational and environmental radiation exposure scenarios

National Cancer Institute computational human phantoms are now in the format of Digital Imaging and Communications in Medicine (DICOM) Radiation Therapy (RT) for radiotherapy dosimetry purpose. The original computational human phantom series is based on the computed tomography (CT) images of pediatric and adult patients whose body size was close to the International Commission on Radiological Protection (ICRP) reference data. Several international standard data including the ICRP Publication 89 (ICRP 2002) and 100 (ICRP 2006), the International Commission on Radiation Units and Measurements (ICRU) 46. The original format of the computational phantoms was converted to DICOM-RT files using an in-house processor (Lee et al 2015a). The DICOM-RT files include the DICOM-image and DICOM-structure representing newborn, 1-, 5-, 10-, 15-year-old, and adult male and female reference individuals. The DICOM-structure includes more than 50 radiosensitive organs and tissues. The DICOM-RT phantoms can be directly imported to commercial treatment planning systems.


Citation: Lee C, Jung J W, Pelletier C, Pyakuryal A, Lamart S, Kim J O and Lee C 2015 Reconstruction of organ dose for external radiotherapy patients in retrospective epidemiologic studies Physics in Medicine and Biology 60 2309–24.

DICOM-structure
Three dimensional visualization of the anatomical structures of the computational human phantom series, rendered by EclipseTM Treatment Planning System (Varian Medical Systems, Palo Alto, CA)
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National Cancer Institute dosimetry system for Computed Tomography (NCICT) is a computational solution to estimate organ doses for pediatric and adult patients undergoing Computed Tomography (CT) scans. The program provides absorbed dose to major radiosensitive organs and tissues based on the characteristics of patients and CT scan parameters. NCICT is based on several key technologies that previously published including computational human phantoms (Lee et al 2010), the simulation of reference CT scanner, the experimental validations of simulated organ dose (Dabin et al 2016), the library of normalized and weighted CTDI (Lee et al 2014), and the compilation of comprehensive dose conversion coefficients (Lee et al 2015b). NCICT features two computation modes: graphical user interface (GUI) Mode and Batch Calculation Mode. The GUI Mode is for users to interactively input patient and CT scanner data into NCICT and obtain organ doses instantly. The Batch Calculation Mode is designed to compute organ doses for a large number of patients by importing a set of parameters in formatted text file.

graphical user interface of NCICT
The graphical user interface of NCICT showing organ dose calculations for the head scan of a newborn female patient.

EXTERNAL PHOTON

We calculated dose coefficients for the International Commission on Radiological Protection (ICRP) reference pediatric phantoms externally exposed to mono-energetic photon radiation (X- and gamma-rays) over a wide energy range. Calculations used Monte Carlo radiation transport techniques. Dose coefficients, i.e., organ absorbed dose per unit air kerma (mGy/mGy), were calculated for 28 organs and tissues including the active marrow (or red bone marrow) for 10 phantoms (newborn, 1-year, 5-year, 10-year, and 15-year old male and female). Radiation exposure was simulated for 33 photon mono-energies (0.01 – 20 MeV) in six irradiation geometries: Anterior-Posterior (AP), Posterior-Anterior (PA), Right Lateral (RLAT), Left Lateral (LLAT), Rotational (ROT), and Isotropic (ISO).


Citation: LA Chang, SL Simon, TJ Jorgensen, DA Schauer, and C Lee, “Organ dose conversion coefficients for pediatric reference individuals exposed to idealized photon radiation,” Journal of Radiological Protection (in press)


External organ and effective dose coefficients
External organ and effective dose coefficients for age-dependent phantoms exposed to idealized photon beams in different irradiation geometries.

INTERNAL PHOTON/ELECTRON

To improve the estimates of organ doses from nuclear medicine procedures using iodine 131 (I-131), we calculated a comprehensive set of I-131 S values, defined as organ absorbed doses in target tissues per unit of nuclear transition in source regions, for different source and target combinations. We used the latest reference adult male and female voxel phantoms published by the International Commission on Radiological Protection (ICRP Publication 110) and the I-131 photon and electron spectra from the ICRP Publication 107 to perform Monte Carlo radiation transport calculations using MCNPX2.7 to compute the S values. For each phantom, we simulated 55 source regions assuming a uniform distribution of I-131. We directly computed the S values for 42 target tissues without calculating Specific Absorbed Fraction (SAF) values. From these calculations, we derived a comprehensive set of S values for I-131 for 55 source regions and 42 target tissues in the ICRP male and female voxel phantoms. The new dataset includes the S values for source regions and target tissues of interest in internal dosimetry of I-131, which are not available in the long-used stylized phantoms from Oak Ridge National Laboratory (ORNL).

Citation: S Lamart, SL Simon, A Bouville, BE Moroz, and C Lee, “S values for I-131 from the ICRP adult voxel phantoms and comparison with the previous reference values,” Radiation Protection Dosimetry, 168:92-110 (2016)

S values for various target organs in the ICRP adult male and female reference phantoms where I-131 is distributed in the source organs (thyroid, urinary bladder content, small intestine content, and salivary glands).
S values for various target organs in the ICRP adult male and female reference phantoms where I-131 is distributed in the source organs (thyroid, urinary bladder content, small intestine content, and salivary glands).

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SOFTWARE TRANSFER AGREEMENT

Dabin J, Mencarelli A, McMillan D, Romanyukha A, Struelens L and Lee C 2016 Validation of calculation algorithms for organ doses in CT by measurements on a 5 year old paediatric phantom Physics in Medicine and Biology 61 4168–82

ICRP 2002 Basic anatomical and physiological data for use in radiological protection : reference values ICRP publication 89, Ann. ICRP 32 1–277

ICRP 2006 Human alimentary tract model for radiological protection ICRP publication 100, Ann. ICRp 36 1–336

Lee C, Jung J W, Pelletier C, Pyakuryal A, Lamart S, Kim J O and Lee C 2015a Reconstruction of organ dose for external radiotherapy patients in retrospective epidemiologic studies Physics in Medicine and Biology 60 2309–24

Lee C, Kim K P, Bolch W E, Moroz B E and Folio Les 2015b NCICT: a computational solution to estimate organ doses for pediatric and adult patients undergoing CT scans Journal of Radiological Protection 35 891–909

Lee C, Lodwick D, Hurtado J, Pafundi D, Williams J L and Bolch W E 2010 The UF family of reference hybrid phantoms for computational radiation dosimetry. Physics in Medicine and Biology 55 339–63

Lee C, Lodwick D, Williams J L and Bolch W E 2008 Hybrid computational phantoms of the 15-year male and female adolescent: applications to CT organ dosimetry for patients of variable morphometry. Medical physics 35 2366–82

Lee E, Lamart S, Little M P and Lee C 2014 Database of normalised computed tomography dose index for retrospective CT dosimetry Journal of Radiological Protection 34 363–88