Abstract:It is not feasible to define very small or complex organs and tissues in the current voxel-type adult reference computational phantoms of the International Commission on Radiological Protection (ICRP), which limit dose coefficients for weakly penetrating radiations. To address the problem, the ICRP is converting the voxel-type reference phantoms into mesh-type phantoms. In the present study, as a part of the conversion project, the micrometer-thick target and source regions in the alimentary and respiratory tr… Show more
“…The target layer in the oral mucosa was defined in three parts: tongue, roof of mouth, and lip and cheek. More detailed information on the alimentary tract system can be found in Kim et al. (2017). Fig.…”
Section: Inclusion Of Thin Target and Source Regionsmentioning
confidence: 99%
“…5.5 shows the urinary bladder of the male mesh phantom including the target layer. Fig. 5.4.Lung voxel model (left) and lung mesh model (right) for the male phantom (Kim et al., 2017). Fig.…”
Section: Inclusion Of Thin Target and Source Regionsmentioning
confidence: 99%
“…For higher energies, on the other hand, significant differences can be found; that is, the MRCPs produce higher SAFs than the stylised models, by up to 77% and 74% for the male and female, respectively, mainly due to realisation of the cross-fires in the MRCPs. More detailed discussions on comparison of the SAFs for the alimentary and respiratory tract systems can be found in Kim et al. (2017). (97) The male MRCP was used to calculate the SAFs for alpha particles and electrons for the urinary bladder wall ← urinary bladder content case, and then the calculated values were compared with the values calculated using a stylised model for the male (Eckerman and Veinot, 2018).…”
Section: Dosimetric Impact Of the Adult Mesh-type Reference Phantomsmentioning
confidence: 99%
“…The MRCP values were found to be slightly less than the values of the stylised model, the differences being less than a few percent, mainly due to the slight difference (∼6%) in the target mass between the MRCP urinary bladder model and the idealised spherical stylised model used in Eckerman and Veniot (2018). Fig. 7.1.Specific absorbed fractions to the secretory cells of the bronchioles (bb sec ) as a target for electron exposures within the male mesh-type reference computational phantom (MRCP) (red circles), female MRCP (red squares), Publication 66 (ICRP, 1994a) stylised male model (blue upward triangles), Publication 66 stylised female model (blue downward triangles), Publication 133 (ICRP, 2016) male values (black solid line), and Publication 133 female values (black dashed line) (Kim et al., 2017). …”
Section: Dosimetric Impact Of the Adult Mesh-type Reference Phantomsmentioning
confidence: 99%
“…For higher energies, on the other hand, significant differences can be found; that is, the MRCPs produce higher SAFs than the stylised models, by up to 77% and 74% for the male and female, respectively, mainly due to realisation of the cross-fires in the MRCPs. More detailed discussions on comparison of the SAFs for the alimentary and respiratory tract systems can be found in Kim et al. (2017).…”
Section: Dosimetric Impact Of the Adult Mesh-type Reference Phantomsmentioning
Following the issuance of new radiological protection recommendations in ICRP Publication 103, the Commission released, in ICRP Publication 110, the adult male and female voxel-type reference computational phantoms to be used for calculation of the reference dose coefficients (DCs) for both external and internal exposures. While providing more anatomically realistic representations of internal anatomy than the older stylised phantoms, the voxel phantoms have their limitations, mainly due to voxel resolution, especially with respect to small tissue structures (e.g. lens of the eye) and very thin tissue layers (e.g. stem cell layers in the stomach wall mucosa and intestinal epithelium). This publication describes the construction of the adult mesh-type reference computational phantoms (MRCPs) that are the modelling counterparts of the Publication 110 voxel-type reference computational phantoms. The MRCPs include all source and target regions needed for estimating effective dose, even the micrometre-thick target regions in the respiratory and alimentary tract organs, skin, and urinary bladder, assimilating the supplementary stylised models. The MRCPs can be implemented directly into Monte Carlo particle transport codes for dose calculations (i.e. without voxelisation), fully maintaining the advantages of the mesh geometry. DCs of organ dose and effective dose and specific absorbed fractions (SAFs) calculated with the MRCPs for some external and internal exposures show that À while some differences were observed for small tissue structures and for weakly-penetrating radiations À the MRCPs provide the same or very similar values as the previously published reference DCs and SAFs, which were calculated with the Publication 110 reference phantoms and supplementary stylised models, for most tissues and penetrating radiations. Consequently, the DCs for effective dose (i.e. the fundamental protection quantity) were not found to be different. The DCs of ICRP Publication 116 and the SAFs of ICRP Publication 133 thus remain valid.
“…The target layer in the oral mucosa was defined in three parts: tongue, roof of mouth, and lip and cheek. More detailed information on the alimentary tract system can be found in Kim et al. (2017). Fig.…”
Section: Inclusion Of Thin Target and Source Regionsmentioning
confidence: 99%
“…5.5 shows the urinary bladder of the male mesh phantom including the target layer. Fig. 5.4.Lung voxel model (left) and lung mesh model (right) for the male phantom (Kim et al., 2017). Fig.…”
Section: Inclusion Of Thin Target and Source Regionsmentioning
confidence: 99%
“…For higher energies, on the other hand, significant differences can be found; that is, the MRCPs produce higher SAFs than the stylised models, by up to 77% and 74% for the male and female, respectively, mainly due to realisation of the cross-fires in the MRCPs. More detailed discussions on comparison of the SAFs for the alimentary and respiratory tract systems can be found in Kim et al. (2017). (97) The male MRCP was used to calculate the SAFs for alpha particles and electrons for the urinary bladder wall ← urinary bladder content case, and then the calculated values were compared with the values calculated using a stylised model for the male (Eckerman and Veinot, 2018).…”
Section: Dosimetric Impact Of the Adult Mesh-type Reference Phantomsmentioning
confidence: 99%
“…The MRCP values were found to be slightly less than the values of the stylised model, the differences being less than a few percent, mainly due to the slight difference (∼6%) in the target mass between the MRCP urinary bladder model and the idealised spherical stylised model used in Eckerman and Veniot (2018). Fig. 7.1.Specific absorbed fractions to the secretory cells of the bronchioles (bb sec ) as a target for electron exposures within the male mesh-type reference computational phantom (MRCP) (red circles), female MRCP (red squares), Publication 66 (ICRP, 1994a) stylised male model (blue upward triangles), Publication 66 stylised female model (blue downward triangles), Publication 133 (ICRP, 2016) male values (black solid line), and Publication 133 female values (black dashed line) (Kim et al., 2017). …”
Section: Dosimetric Impact Of the Adult Mesh-type Reference Phantomsmentioning
confidence: 99%
“…For higher energies, on the other hand, significant differences can be found; that is, the MRCPs produce higher SAFs than the stylised models, by up to 77% and 74% for the male and female, respectively, mainly due to realisation of the cross-fires in the MRCPs. More detailed discussions on comparison of the SAFs for the alimentary and respiratory tract systems can be found in Kim et al. (2017).…”
Section: Dosimetric Impact Of the Adult Mesh-type Reference Phantomsmentioning
Following the issuance of new radiological protection recommendations in ICRP Publication 103, the Commission released, in ICRP Publication 110, the adult male and female voxel-type reference computational phantoms to be used for calculation of the reference dose coefficients (DCs) for both external and internal exposures. While providing more anatomically realistic representations of internal anatomy than the older stylised phantoms, the voxel phantoms have their limitations, mainly due to voxel resolution, especially with respect to small tissue structures (e.g. lens of the eye) and very thin tissue layers (e.g. stem cell layers in the stomach wall mucosa and intestinal epithelium). This publication describes the construction of the adult mesh-type reference computational phantoms (MRCPs) that are the modelling counterparts of the Publication 110 voxel-type reference computational phantoms. The MRCPs include all source and target regions needed for estimating effective dose, even the micrometre-thick target regions in the respiratory and alimentary tract organs, skin, and urinary bladder, assimilating the supplementary stylised models. The MRCPs can be implemented directly into Monte Carlo particle transport codes for dose calculations (i.e. without voxelisation), fully maintaining the advantages of the mesh geometry. DCs of organ dose and effective dose and specific absorbed fractions (SAFs) calculated with the MRCPs for some external and internal exposures show that À while some differences were observed for small tissue structures and for weakly-penetrating radiations À the MRCPs provide the same or very similar values as the previously published reference DCs and SAFs, which were calculated with the Publication 110 reference phantoms and supplementary stylised models, for most tissues and penetrating radiations. Consequently, the DCs for effective dose (i.e. the fundamental protection quantity) were not found to be different. The DCs of ICRP Publication 116 and the SAFs of ICRP Publication 133 thus remain valid.
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