Goals of radiation safety management
Organizational efforts at a hospital or other medical facility performing therapy with the labeled somatostatin analogue
Facilities at a hospital or other medical facility performing therapy with the labeled somatostatin analogue
Establishment of a safety management system at a hospital or other medical facility performing therapy with the labeled somatostatin analogue
Designation and role of a radiation safety supervisor in relation to therapy with the labeled somatostatin analogue
Designation and role of a radiation safety officer in relation to therapy with the labeled somatostatin analogue
Provisions to comply with when performing therapy with the labeled somatostatin analogue
Characteristics of Lu-177 and the labeled somatostatin analogue
Characteristics of Lu-177
Half-life | Type of decay | Maximum energy (MeV) of β rays and percentage emitted | Photon energy (MeV) and percentage emitted | Percentage of internal conversion electrons emitted | Effective dose rate constant (µSv・m2・MBq−1・h−1) |
---|---|---|---|---|---|
6.647 days | β− | 0.176–12.2% 0.385–9.1% 0.498–78.6% Other | 0.113–6.4% 0.208–11.0% Other 0.0555–4.5% Hf-Kα 0.0637–1.2% Hf-Kβ | 14.5% 0.73% | 0.00517 |
In vivo dynamics of Lu and the labeled somatostatin analogue
In vivo dynamics of Lu
In vivo dynamics of the labeled somatostatin analogue
Time after admin. | Effective half-life |
---|---|
0–24 h (early phase) | 1.28 h (range 0.93–1.52 h) |
24–168 h (late phase) | 49.5 h (range 45.1–56.6 h) |
Release of patients administered a radiopharmaceutical
Release criteria for patients administered a radiopharmaceutical
Nuclides used in therapy | Dose or level of residual radioactivity in the body (MBq) |
---|---|
Strontium-89 | 200a |
Iodine-131 | 500b |
Yttrium-90 | 1184a |
Nuclide used in therapy | 1-cm dose equivalent rate 1 m from the surface of the patient’s body (µSv/h) |
---|---|
Iodine-131 | 30a |
Nuclide used in therapy | Scope | Dose (MBq) |
---|---|---|
Iodine-131 | Destruction of residual thyroid tissue (ablation) after a complete thyroidectomy to treat differentiated thyroid cancer with no distant metastasisa | 1110b |
Factors related to the evaluation of release criteria
Release of a patient administered the labeled somatostatin analogue
Exposure dose for a third party from a patient administered the labeled somatostatin analogue
Evaluation of the dose from external exposure
Effective dose rate of external exposure at a distance of 1 m from a patient administered the labeled somatostatin analogue
Cumulative dose to which a third party is exposed from a patient administered the labeled somatostatin analogue
Factors for evaluation of the cumulative dose for caregivers and the general public from a patient administered the labeled somatostatin analogue
Provisional calculation of the cumulative dose of external exposure for a third party exposed to radiation from a patient administered the labeled somatostatin analogue
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Cumulative dose for caregivers (exposure factor: 0.5): 3.99 [mSv/course of treatment] × 0.5 = 2.00 [mSv/course of treatment].
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Cumulative dose for the general public (exposure factor: 0.25): 3.99 [mSv/course of treatment] × 0.25 = 1.00 [mSv/course of treatment].
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Cumulative dose for a caregiver (exposure factor: 0.5): 2.80 [mSv/course of treatment] × 0.5 = 1.40 [mSv/course of treatment]
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Cumulative dose for the general public (exposure factor: 0.25): 2.80 [mSv/course of treatment] × 0.25 = 0.70 [mSv/course of treatment]
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Cumulative dose for a caregiver (exposure factor: 0.5): 2.08 [mSv/course of treatment] × 0.5 = 1.04 [mSv/course of treatment]
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Cumulative dose for the general public (exposure factor: 0.25); 2.08 [mSv/course of treatment] × 0.25 = 0.52 [mSv/course of treatment]
Immediately after admin. (mSv/course of treatment) | 24 h after admin. (mSv/course of treatment) | 48 h after admin. (mSv/course of treatment) | |
---|---|---|---|
Caregiver | 2.00 | 1.40 | 1.04 |
General public | 1.00 | 0.70 | 0.52 |
Evaluation of the dose from internal exposure
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The average flow of the Yodo River water system is about 4.1 [TL] per year (annual average prior to 1991–1995).
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Population of the metropolitan Osaka area that obtains potable water from that water system: About 14.02 million (2012) (Osaka Prefecture + Nara Prefecture + Wakayama Prefecture + 1/2 of Hyogo Prefecture) [21].
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Total population of Japan: About 127.52 million (2012) [21].
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Population of the metropolitan Osaka area as a proportion of Japan’s total population: 10.99% (0.11).
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Number of patients with a gastroenteropancreatic neuroendocrine tumor in Japan: 11,642 (number of patients per 100,000 population: 2.69 with a pancreatic neuroendocrine tumor, 6.42 with a gastrointestinal neuroendocrine tumor) [22].
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Number of such patients with distant metastasis: 1176 (percent with distant metastasis: 19.9% with distant metastasis of a pancreatic endocrine tumor, 6.0% with distant metastasis of a gastrointestinal neuroendocrine tumor) [22].Assuming that Lu-177-DOTA-TATE will be administered to all of these patients.
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Number of patients in the metropolitan Osaka area eligible for treatment: 1176 × 0.11 = 129 (calculated with respect to the population).That said, Fig. 0.11 is with respect to the population of the metropolitan Osaka area. This is assuming that Lu-177-DOTA-TATE is administered to each patient at a dose of 7400 MBq in 4 rounds per year.
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Level of radioactivity of the total dose of Lu-177-DOTA-TATE administered to patients in the metropolitan Osaka area:7400 [MBq/administration] × 4 [rounds/patient] × 129 [patients] = 3.82 [TBq]Here, the entire quantity of Lu-177-DOTA-TATE is assumed to be discharged into the Yodo River water system, where it is entirely in a water-soluble form.
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Lu-177-DOTA-TATE concentration in the river:3.82 [TBq/] ÷ 4.1 [TL/y] = 0.93 [Bq/L].That said, 4.1 TL is the average annual flow of the Yodo River water system.
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Annual intake of Lu-177-DOTA-TATE per member of the general public (assuming 2 L of water for drinking per d) [23]:0.93 [Bq/L] × 2 [L/d] × 365 [d/y] = 678.90 [Bq/y]
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In the aforementioned instance, the dose from internal exposure in 1 y:678.90 [Bq/y] × 5.3 × 10−7 [mSv/Bq] = 0.36 [µSv/y].However, 5.3 × 10−7 [mSv/Bq] is the effective dose coefficient for ingestion of Lu-177 [24].0.36 µSv/year is substantially lower than 1 mSv, which is the annual dose limit for the general public. Even if the upper reaches of the Yodo River water system (e.g., Kyoto Prefecture) are contaminated to the same extent, Lu-177-DOTA-TATE would contribute less than 0.1% to the annual dose limit for the general public.
Comprehensive evaluation of the doses from external and internal exposure
Criteria for release of a patient administered the labeled somatostatin analogue from a room for patients undergoing the therapy
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If the patient lives with highly radiosensitive infants and children (under the age of 15) or pregnant women.
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If the patient is unable to sleep at least 2 m away from individuals in the same household (preferably in a separate room).
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If the patient is incontinent and he or she requires a diaper or urinary catheter.
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If the patient must use the same form of public transportation for 2 h or longer upon discharge.
Precautions for patients and their families
Precautions in the week following administration of the labeled somatostatin analogue (1st week after administration of a labeled somatostatin analogue)
Precautions in the 3 months after administration of the labeled somatostatin analogue (first 3 months after administration of a labeled somatostatin analogue)
Precautions in the 6 months after administration of the labeled somatostatin analogue (first 6 months after administration of a labeled somatostatin analogue)
Precautions for patients after administration of the labeled somatostatin analogue
Radiation safety management for a patient wearing a diaper or using a urinary catheter
Laws, ordinances, rules, and regulations on the clinical use of the labeled somatostatin analogue
Criteria for rooms where radiopharmaceuticals are used
Criteria for concentration limits in rooms where radiopharmaceuticals are used
Rooms where radiopharmaceuticals are used | Medical Services Act |
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Rooms where radiopharmaceuticals are used | Rooms where radiopharmaceuticals are useda |
Storage facilitiesb | |
Disposal facilitiesc | |
Rooms for patients undergoing radiation therapyd | |
Dose limits and concentration limits in controlled arease | The effective dose of external radiationf: 1.3 mSv every 3 months Concentration of RIs in the airf: the average concentration over 3 months is 1/10 of the concentration limit of an RI in the air Surface density of a material contaminated with an RIf: 1/10 of the surface concentration limit (RIs that do not emit alpha rays: 4 Bq/cm2) |
Dose limits and concentration limits at places in facilities using RIs where people are constantly enteringa,b,c | The effective dose on painted walls: 1 mSv or less every week Concentration of an RI in the airf: the average concentration over 1 week is equal to the concentration limit of an RI in the air Surface density of a material contaminated with an RIf: surface concentration limit (RIs that do not emit alpha rays: 40 Bq/cm2) |
Dose standards at boundaries in a hospital or other medical facility (including areas in the hospital where people stay)g | The effective dose is 250 µSv or lessf every 3 months |
Exposure dose for inpatientsh | The effective dose does not exceed 1.3 mSv every 3 months |
Restrictions on places where radiopharmaceuticals can be used (Article 30, Section 12 of the Ordinance for Enforcement of the Medical Services Act)
Safety management at radiation facilities in conjunction with use of the labeled somatostatin analogue
Management of radiation safety through usage records (Article 30, Section 23 of the Ordinance for Enforcement of the Medical Services Act)
Records of the receipt, use, storage, and disposal of the labeled somatostatin analogue (radiopharmaceutical usage records)
Measurement and recording in places where radiation injuries could occur (Article 30, Section 22 of the Ordinance for Enforcement of the Medical Services Act, Article 54 of the ionizing radiation ordinance)
Records of the measurement and calculation of the exposure dose for radiology technologists and technicians (Article 30, Section 18 of the Ordinance for Enforcement of the medical Services Act, Article 8 of the ionizing radiation Ordinance)
Ionizing radiation medical Examination, personal form (Article 57 of the ionizing radiation ordinance)
Records related to the release of a patient administered the labeled somatostatin analogue (Notice No. 70 from the safety Division, Pharmaceutical and medical safety Bureau, which was superseded by Notice No. 1108-2 from the division for guidance on medical care, Health Policy Bureau)
Radiation measurement
Dose (radiation) measurement
Dose measurement in places where radiopharmaceuticals are used
Training
Training for a radiation safety supervisor when therapy with the labeled somatostatin analogue is performed (physicians or radiology technologists with sufficient knowledge of and experience with radiation therapy)
Radiation protection for medical personnel and steps to prevent radioactive contamination
Radiation safeguards with regard to handling the labeled somatostatin analogue
Distance from the surface of the vial | Dose rate (µSv/h/MBq) |
---|---|
1 m | 0.00676 |
10 cm | 0.541–0.676 |
On the surface | > 1.351 |
Exposure to medical personnel (external exposure and internal exposure)
Stage | Effective dose (per person) | Skin dose (per person) | Dose limits | |||||
---|---|---|---|---|---|---|---|---|
Time procedures take (min) | Distance (cm) | Exposure dose (mSv) | Time procedures take (min) | Distance (cm) | Exposure dose (mSv) | Effective dose limit (whole body) | Equivalent dose limit (skin) | |
Preparations | 5 | 50 | 0.013 | 5 | 10 | 0.319 | Radiology technologists and technicians: 50 mSv/year 100 mSv/5 years Women who may be pregnant 5 mSv/3 months | 500 mSv/year |
Administration | 30 | 150 | 0.009 | 30 | 100 | 0.019 |