Radiation protection in radionuclide therapies with (90)Y-conjugates: risks and safety.
OBJECTIVE
The widespread interest in (90)Y internal radionuclide treatments has drawn attention to the issue of radiation protection for staff. Our aim in this study was to identify personnel at risk and to validate the protection devices used.


METHODS
(90)Y-MoAb (Zevalin, 15 cases, 1.1 GBq/patient) and (90)Y-peptide ((90)Y-DOTATOC) systemic (i.v., 50 cases, 3.0 GBq/patient) and locoregional (l.r., 50 cases, 0.4 GBq/patient) treatments were considered. Radiolabelling was carried out in a dedicated hot cell. Tele-tongs, shielded (PMMA: polymethylmethacrylate) syringes/vials and an automatic dose fractionating system were used. Operators wore anti-X-ray and anti-contamination gloves, with TLD dosimeters placed over the fingertips. For i.v. administration, activity was administered by a dedicated system; for l.r. administration, during activity infusion in the brain cavity, tongs were used and TLDs were placed over the fingertips. The air kerma-rate was measured around the patients.


RESULTS
The use of devices provided a 75% dose reduction, with mean fingertip doses of 2.9 mGy (i.v. MoAbs), 0.6 mGy (i.v. peptides)/radiolabelling procedure and 0.5 mGy/l.r. administration. The mean effective dose to personnel was 5 microSv/patient. The air kerma-rate around the patients administered i.v. (90)Y-peptides were 3.5 (1 h) and 1.0 (48 h) microGy/h at 1 m. Patient hospitalisation of 6 h (l.r.)/48 h (i.v.) guaranteed that the recommended limits of 3 mSv/year to family members and 0.3 mSv/year to the general population (Council Directive 97/43/Euratom) were respected.


CONCLUSIONS
When specific procedures are adopted, a substantial improvement in (90)Y manipulation is attainable, reducing doses and increasing safety. For the widespread clinical use of (90)Y-conjugates, a completely automatic labelling procedure is desirable.
Cremonesi
Marta
M
Division of Medical Physics, European Institute of Oncology, Milan, Italy.
Ferrari
Mahila
M
Paganelli
Giovanni
G
Rossi
Annalisa
A
Chinol
Marco
M
Bartolomei
Mirco
M
Prisco
Gennaro
G
Tosi
Giampiero
G
D007558:Italy; D008505:Medical Staff, Hospital; D016273:Occupational Exposure / Q000032:analysis*; D016272:Occupational Health; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation / Q000379:methods; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods*; D019275:Radiopharmaceuticals / Q000032:analysis / Q000627:therapeutic use; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015021:Yttrium Radioisotopes / Q000032:analysis* / Q000627:therapeutic use*
D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes