150 C. Michel et al.: Radioprotection 2026, 61( 2), 146 – 155
– the equivalent dose rate at 0.5 m was derived from the equivalent dose rate at 1 m value using the inverse square law which applies strictly to a point source;
– the assumption of continuous presence of the professional at 0.5 m;
– the selection of highest values as reported in the literature for equivalent dose rate coefficients and effective halflives.
2.5 Dose criterion
Professionals involved in body transport or in embalming are workers who are not classified for radiation protection purposes. In France, regulation requires that the risk assessment demonstrating the effective dose likely to be received by these workers remains below 1 mSv per year for them to remain unclassified( JORF, 2023).
To ensure compliance with this limit and given that exposure situations for these workers are difficult to control because of their rarity, IRSN adopted a dose criterion below this value, corresponding to one-third( rounded to the nearest 100 mSv), i. e., 300 mSv per post-mortem procedure. In the even rarer scenario of a funeral professional handling three deceased patients in the same year, a dose of 300 mSv per operation would still result in a total annual dose below 1 mSv. For the longest operation( i. e., embalming which lasts 2 h) the 300 mSv criterion is met if the dose rate at the working distance of 0.5 m is below 150 mSv / h.
This approach allocating only a fraction of the 1 mSv limit has been used previously, for example in the European Commission’ s Radiation Protection 97 report( European Commission, 1998) on public exposure from iodine-131 patients. This fraction ensures compliance with the 1 mSv limit even if the public is exposed to other artificial sources during the year.
Ideally, to justify the selection of dose criterion value, it would be necessary to assess the annual number of early deaths after nuclear medicine treatment. In fact, this information is not systematically reported to the related authority since it is not considered as a significant event in radiation protection. The only relevant data was published by the Federal Agency for Nuclear Control for crematorium staff( FANC, 2011). Dose rate measurements were performed on more than 3,380 deceased individuals over a six-month period in a Belgian crematorium. Dose rates above background radiation( threshold) were detected in approximately 1 out of 500 deceased individuals. In fact, the positive cases corresponded to patients who underwent diagnostic nuclear medicine procedures and not therapeutic ones. These findings confirm that the early deaths after nuclear medicine treatment are very rare.
We considered that these results observed in the studied Belgian cohort could be generalized and applied in France. Therefore, we considered that the early deaths after nuclear medicine treatment are also very rare. This is also confirmed by the only two French cases occurred in 2007 and 2008 mentioned above. Consequently, the adoption of a 300 mSv criterion was deemed an appropriate and conservative hypothesis assuming three cases could occur per year and managed by the same funeral professional. This leads to meeting the annual limit of 1 mSv.
This 300 mSv criterion was used to calculate the waiting periods required before handling the deceased patient, based on the doses likely to be received by workers using Equation # 1.
More specifically, when it is not possible to manage the deceased patient immediately because the dose would exceed the criterion, two types of periods were calculated: – If the death occurs at the time of radiopharmaceutical administration( worst case for radiation protection), a minimum waiting period after death is calculated. Using Equation # 1, this case corresponds to t 1 = 0, and then t 2 corresponding to the waiting period is calculated.
– Otherwise, the minimum time interval between radiopharmaceutical administration and death that allows for immediate management of the deceased patient, is calculated. UsingEquation # 1, thiscase correspondstot 2 = 0, andthen t 1 corresponding to this time interval is calculated.
3 Results
Based on the calculated doses for body transport and embalming, and with respect to the 300 mSv dose criterion, two scenarios can be distinguished. Either the deceased patient can be managed immediately after death, or a waiting period is required before transport and / or embalming.
3.1 Immediate management of the deceased patient
This scenario corresponds to a dose rate below 150 mSv / h at 0.5 m from the deceased patient at the time of death, as explained above. The procedures include: – Phosphorus-32 for polycythemia treatment; – Strontium-89 for palliative treatment of bone metastases; – Yttrium-90 for treatment of non-Hodgkin’ s lymphoma with ibritumomab tiuxetan, treatment of liver cancers using microspheres, and radiation synovectomy;
– Iodine-131 for non-cancer thyroid treatment with administered activity below 700 MBq; – Erbium-169 and rhenium-186 for radiation synovectomy; – Radium-223 for palliative treatment of bone metastases; – Actinium-225 for treatment of metastatic prostate cancer targeting PSMA( prostate-specific membrane antigen).
3.2 Waiting periods required between death and postmortem procedure
The procedures include: – Indium-111 for treatment of tumors expressing somatostatin receptors;
– Iodine-131 for non-cancer thyroid treatment with an administered activity between 700 and 800 MBq, and for treatment of thyroid cancer; – Samarium-153 for palliative treatment of bone metastases; – Holmium-166 for treatment of liver cancers using microspheres;
– Lutetium-177 for treatment of intestine tumors with DOTATATE( Lutathera ®) and for treatment of metastatic prostate cancer targeting PSMA.