C. Michel et al.: Radioprotection 2026, 61( 2), 146 – 155 149
Table 3. Equivalent dose rate coefficients for pure beta emitters and radionuclides with maximum beta energy above 1 MeV. Radionuclide Equivalent dose rate coefficient( mSv / h / GBq at 1 m) Reference
phosphorus-32 |
15.2 |
n. c. |
strontium-89 |
35.2 |
n. c. |
yttrium-90: Liquid form
SIR-sphere ®
Therasphere ®
20.3 4 2
erbium-169 |
8.3 |
n. c. |
rhenium-186 |
28.1 |
n. c. |
( Aubert et al., 2002)( McCann et al., 2012)( McCann et al., 2012)
n. c.: not concerned. The equivalent dose rate coefficients for these radionuclides were derived from the coefficient for yttrium-90( liquid form, i. e., 20.3 mSv / h / GBq at 1 m as indicated above), taken as a reference. The calculation assumed proportionality between the maximum beta energy of the radionuclide and that of yttrium-90, while also accounting for the beta emission intensity(%) and the ratio 21 / 7.9 corresponding to the ratio of the effective atomic numbers of bone to soft tissue.
Table 4. Effective half-lives of radionuclides considered in this study. Radionuclide Effective half-life considered( days) Reference
phosphorus-32 |
14.3( physical half-life) |
– |
strontium-89 |
50.7( physical half-life) |
– |
yttrium-90 |
2.7( physical half-life) |
– |
indium-111 |
0.6 |
( Jones, 2004) |
iodine-131: Thyroid non-cancer MIBG
Lipiocis ®
Thyroid cancer
5.2 2.0 5.5 0.9
( Jones, 2004; U. S. NRC, 2020)( Jones, 2004; Petyt et al., 2009; CIS bio international, 2017)( Jones, 2004; CIS bio international, 2006)( Venencia et al., 2002; Jones, 2004)
samarium-153 |
1.95( physical half-life) |
– |
holmium-166 |
1.1( physical half-life) |
Not concerned because the microspheres are considered |
|
|
with no biological elimination |
lutetium-177:
Lutathera ®
PSMA
|
1.0 2.1 |
( Calais et al., 2014; EMA, 2021)( Kurth et al., 2018) |
erbium-169 |
9.4( physical half-life) |
– |
rhenium-186 |
3.8( physical half-life) |
– |
radium-223 |
11.4( physical half-life) |
No reference found in literature. Only the physical half-life was considered, in a conservative approach |
actinium-225 |
10( physical half-life) |
No reference found in literature. Only the physical half-life was considered, in a conservative approach |
H ð10Þ ¼˙ H ð10Þ Dt
¼ G ⋅A⋅d ref 2 �lnð2Þ⋅t 1
T d 2 ⋅e eff ⋅e
�lnð2Þ⋅t 2 T phy Dt; ð1Þ where: – H_ ð10Þ: equivalent dose rate( mSv. h �1); – A: administered activity( GBq); – d: distance from the deceased patient, fixed at 0.5 m for the two post-mortem procedures considered( body transport and embalming); – d ref: reference distance, set at 1 m; – G: equivalent dose rate coefficient for the considered radionuclide( mSv. h �1. GBq �1); – T eff: effective half-life of the radiopharmaceutical( days);
– T phy: physical half-life of the radionuclide( days); – t 1: time between radiopharmaceutical administration and patient death( days);
– t 2: time between patient death and post-mortem procedure( days).
The equivalent dose rate reflecting the remaining body activity decreases: – according to the effective half-life, due to biological excretion and physical decay, between radiopharmaceutical administration and patient death
– according to the physical half-life, after the patient death.
Applying this approach leads to intentionally overestimated effective doses, for the following reasons: