Radioprotection No 59-4 | Page 63

302 A . Bouzouita et al .: Radioprotection 2024 , 59 ( 4 ), 296 – 305
Table 3 . Averaged organ DCFs for male and female ICRP110 phantoms compared to the published values of the literature . Organs
238 U nSv h �1 per Bq kg �1 232 Th
40 K
Zankl et al . ( 1997 )
Sanusi et al . ( 2021 )
This work
Zankl et al . ( 1997 )
Sanusi et al . ( 2021 )
This work
Zankl et al . ( 1997 )
Sanusi et al . ( 2021 )
Adrenals
0.274
0.318
0.372
0.373
0.370
0.453
0.026
0.032
0.036
bladder
0.301
0.301
0.394
0.412
0.430
0.520
0.029
0.037
0.041
Brain
0.320
0.322
0.412
0.432
0.497
0.528
0.030
0.029
0.043
Breast
0.370
0.410
0.434
0.494
0.535
0.553
0.034
0.040
0.043
colon
0.291
0.353
0.384
0.396
0.512
0.501
0.028
0.034
0.040
Gonads
0.317
0.339
0.430
0.412
0.413
0.580
0.031
0.033
0.043
Kidneys
0.313
0.375
0.359
0.423
0.476
0.468
0.029
0.031
0.037
Liver
0.306
0.321
0.375
0.414
0.403
0.487
0.029
0.033
0.039
Lungs
0.329
0.346
0.425
0.443
0.445
0.546
0.031
0.033
0.045
Muscles
0.317
0.322
0.461
0.460
0.449
0.594
0.032
0.028
0.048
Oesophagus
0.282
0.313
0.357
0.384
0.386
0.468
0.027
0.030
0.037
Pancreas
0.279
0.312
0.359
0.379
0.404
0.465
0.028
0.031
0.037
Red bone marrow
0.305
0.339
0.244
0.411
0.456
0.303
0.029
0.033
0.024
Remainder tissues
0.300
0.326
0.376
0.412
0.456
0.478
0.029
0.030
0.039
Skeleton
0.358
0.422
0.441
0.479
0.470
0.590
0.032
0.034
0.047
Skin
0.394
0.448
0.526
0.522
0.565
0.663
0.036
0.041
0.055
Small intestine
0.288
0.302
0.371
0.394
0.446
0.484
0.027
0.034
0.039
Spleen
0.288
0.320
0.368
0.423
0.421
0.474
0.029
0.035
0.038
Stomach
0.300
0.338
0.372
0.406
0.471
0.480
0.029
0.036
0.039
Thymus
0.313
0.351
0.378
0.455
0.469
0.487
0.031
0.037
0.040
Thyroid
0.306
0.351
0.362
0.469
0.440
0.467
0.031
0.038
0.038
This work
Table 4 . Averaged organ DCFs for male and female ICRP110 phantoms for the 137 Cs radionuclide compared to published values by Sanusi et al . ( 2021 ).
Organs nSv h �1 per Bq kg �1
Sanusi et al .
This work
Adrenals
0.063
0.077
bladder
0.061
0.096
Brain
0.051
0.102
Breast
0.078
0.110
colon
0.060
0.092
Gonads
0.066
0.107
Kidneys
0.068
0.087
Liver
0.065
0.091
Lungs
0.070
0.103
Muscles
0.059
0.114
Oesophagus
0.064
0.091
Pancreas
0.060
0.084
Red bone marrow
0.065
0.050
Remainder tissues
0.064
0.090
Skeleton
0.068
0.120
Skin
0.081
0.136
Small intestine
0.070
0.089
Spleen
0.067
0.088
Stomach
0.064
0.090
Thymus
0.070
0.094
Thyroid
0.073
0.092
137 Cs , the comparison with Sanusi et al . ( 2021 ) in Table 4 shows
discrepancies due to different physical approximations . Sanusi et al .’ s method , which simplifies secondary electron energy deposition , likely underestimates absorbed doses in shielded organs . This effect is enhanced at energies of the same order of magnitude as the 137 Cs emission energy ( 662 keV ).
Table 5 shows the results of the present work compared to the results obtained indirectly from the ICRP 144 calculations using fitted DCF curves constructed from the planar source results at four depths and a numerical integration procedure . The data used is available via supplementary material to this report ( ICRP , 2020 ). The accuracy of the calculation method integrating the ICRP 144 data is estimated at 10 % as the available data is limited to four soil depths less than 20 cm , so our fitting and integration was performed up to a source thickness of 50 cm . Despite these limitations , good agreement is achieved between the two methods . Our DCFs values are higher than those indirectly derived from ICRP 144 data . This discrepancy is to be expected since we performed our calculation using volumetric source for soil depth up to 2 m .
The discrepancy between the results of the present work and the published ones using mathematical phantoms , expressed in percent of the published value of the organabsorbed dose , is presented in Figures 3 and 4 . The complexity of the biological human tissues is accurately represented by unit voxels rather than by mathematical forms , which lead to a loss of information at low scales . The optimised geometry and efficient particle transport algorithm used in this study resulted