Radiation exposure assessment of nuclear medicine staff administering [177Lu]Lu-DOTA-TATE with active and passive dosimetry

Abstract

Background: The use of lutetium-177 (¹⁷⁷Lu)-based radiopharmaceuticals in peptide receptor nuclear therapy is increasing, but so is the number of nuclear medicine workers exposed to higher levels of radiation. In recent years, [¹⁷⁷Lu]Lu-DOTA-TATE has begun to be widely used for the treatment of neuroendocrine tumours. However, there are few studies evaluating the occupational radiation exposure during its administration, and there are still some challenges that can result in higher doses to the staff, such as a lack of trained personnel or fully standardised procedures. In response, this study aims to provide a comprehensive analysis of occupational doses to the staff involved in the administration of [¹⁷⁷Lu]Lu-DOTA-TATE.

Results: A total of 32 administrations of [¹⁷⁷Lu]Lu-DOTA-TATE (7.4 GBq/session) carried out by a physician and a nurse, were studied. In total, two physicians and four nurses were independently monitored with cumulative (passive) and/or real-time (active) dosemeters. Extremity, eye lens and whole-body doses were evaluated in terms of the dosimetric quantities Hp(0.07), Hp(3) and Hp(10), respectively. It was obtained that lead aprons reduced dose rates and whole-body doses by 71% and 69% for the physicians, respectively, and by 56% and 68% for the nurses. On average, normalised Hp(10) values of 0.65 ± 0.18 µSv/GBq were obtained with active dosimetry, which is generally consistent with passive dosemeters. For physicians, the median of the maximum normalised Hp(0.07) values was 41.5 µSv/GBq on the non-dominant hand and 45.2 µSv/GBq on the dominant hand. For nurses 15.4 µSv/GBq on the non-dominant and 13.9 µSv/GBq on the dominant hand. The ratio or correction factor between the maximum dose measured on the hand and the dose measured on the base of the middle/ring finger of the non-dominant hand resulted in a factor of 5/6 for the physicians and 3/4 for the nurses. Finally, maximum normalised Hp(3) doses resulted in 2.02 µSv/GBq for physicians and 1.76 µSv/GBq for nurses.

Conclusions: If appropriate safety measures are taken, the administration of [¹⁷⁷Lu]Lu-DOTA-TATE is a safe procedure for workers. However, regular monitoring is recommended to ensure that the annual dose limits are not exceeded.

Keywords: Equivalent dose; Nuclear medicine; Occupational exposure; [177Lu]Lu-DOTA-TATE.

Fig. 1

Set up during PRRT-Lu treatment: a configuration of the vial during administration, showing the Lutathera vial outside the original lead container and shielded with the PMMA cylinder and case, with the short and long needle inside it; b positions of physician, nurse and patient at the end of the administration, during air infusion

Fig. 2

Radiation detectors used to monitor workers during ¹⁷⁷Lu therapy used in this study: a schematic representation of the location of each dosemeter; b whole-body dosemeters, both passive (InLight or OSL) and active (PED); c eye lens dosemeters attached to the head band; d example of a hand with the TLDs attached to the gloves, the ring and wrist dosemeters, subsequently covered by regular nitrile gloves; e schematic representation of the location of the TLDs across the gloves

Fig. 3

Boxplots comparing a whole-body dose, b maximum dose rates and c time of treatment between sessions with (blue) and without (red) lead apron for nurse (N1) and physician (P1). N = 29 sessions were monitored with apron for both physician and nurse, whereas N = 2 and N = 3 sessions for the physician and nurse, respectively, without apron. The middle line represents the median value, the top and bottom bars the maximum and minimum values, respectively, and the box limits the IQR. Single points are outliers

Fig. 4

Example of dose rates and cumulative doses recorded with PEDs during one session of PRRT-Lu performed by one physician and one nurse. Dose rates are represented as vertical bars and cumulative dose as lines. Dose rates are measured in µSv/h integrated per minute. The different steps are shown (AV: activity verification, End: end of administration)

Fig. 5

Relative time (left) and dose (right) associated to each step for each physician (P1, P2) and nurse (N1, N2, N3, N4), indicated by different colours

Fig. 6

Boxplot of hand doses by location and hand for a physician and b nurse. Outliers were excluded for visualisation purposes