Substantial External Dose Rate Variability Observed in a Cohort of Lu-177 Patients Independent of Bmi and Sex

Bellamy, Michael; Chu, Bae P.; Serencsits, Brian; Quinn, Brian; Prasad, Kavya; Altamirano, J; Williamson, Matthew J.; Miodownik, Daniel; Abrahams, Natalie; Chen, Fanny; Bierman, David M.; Wutkowski, M; Dauer, Lawrence T.

doi:10.1093/rpd/ncac187

Cited by 6 publications

(6 citation statements)

References 18 publications

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“…It is worth noting that the phantom used in the study is not representative for all patients, especially for over-weighted or under-weighted patients. A study has demonstrated a significant negative correlation between extracorporeal dose rate and patient Body Mass Index (Bellamy et al 2022). Therefore, further studies on the introducing errors in the assessment and simulations are needed, and the results could be verified by patient measurements.…”

Section: Discussionmentioning

confidence: 99%

Radiation levels outside a patient undergoing ¹⁷⁷Lu-PSMA radioligand therapy

Li,

Liu,

Zhang

et al. 2024

J. Radiol. Prot.

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Understanding the spatial distribution of radiation levels outside of a patient undergoing 177Lu radioligand therapy is not only helpful for conducting correct tests for patient release, but also useful for estimation of its potential exposure to healthcare workers, caregivers, family members, and the general public. In this study, by mimicking the 177Lu-PSMA radioligand therapy for prostate cancers in an adult male, the spatial distribution of radiation levels outside of the phantom was simulated based on the Monte Carlo software of PHITS, and verified by a series of measurements. Moreover, the normalized dose rates were further formulized on the three transverse planes representing the heights of pelvis, abdomen and chest. The results showed that the distributions of radiation levels were quite complex. Multi-directional and multi-height measurements are needed to ensure the external dose rate to meet the release criteria. In general, the radiation level was higher at the horizontal plane where the source was located, and the levels in front and behind of the body were higher than those of the left and right sides at the same height. The ratio of simulated dose rates to measured ones ranged from 0.82 to 1.19 within 1 m away from the body surface in all directions. Based on the established functions, the relative root mean square deviation (RRMSD) between the calculated and simulated values were 0.21, 0.25 and 0.23 within a radius of 1 m on the pelvis, abdomen and chest transverse planes, respectively. It is expected that the results of this study would be helpful for guiding the test of extracorporeal radiation to determine the patient’s release, and of benefit to estimate the radiation exposure to others.

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Section: Discussionmentioning

confidence: 99%

Radiation levels outside a patient undergoing ¹⁷⁷Lu-PSMA radioligand therapy

Li,

Liu,

Zhang

et al. 2024

J. Radiol. Prot.

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“…In our data collection, most patients were of normal weight or overweight. There are studies, which have observed that medications (mTOR-Inhibitors or PRRT) are not ideally calculated according to BMI [50][51][52].…”

Section: Discussionmentioning

confidence: 99%

What have we learnt from the past – would treatment decisions for GEP-NET patients differ between 2012 to 2016 by the new recommendations in 2022?

et al. 2023

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Background Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of tumors with a broad range of local and systemic treatment options. Still a lack of data regarding treatment sequences exists. The aim of this study was to analyse outcomes in GEP-NETs depending on stage and treatment steps and compare our treatment decisions to the latest treatment recommendations of European Society of Medical Oncology (ESMO) 2020 for GEP-NETs. Methods Patients were included in this retrospective single-center analysis from 2012—2016. All patients suffering from a GEP-NET, who were screened, treated or evaluated at ENETS Center in Zurich, Switzerland were included in analysis. Patients with any other diagnosis of NET were not included. We used Kaplan Meier estimator as well as Cox regression to compare survival rates between different sites of localization, grades or stages and treatment sequences. Results Overall, we identified 256 GEP-NETs, most in advanced stage (62%) and located in small intestine tract or pancreatic gland. Survival depended on stage, grade, primary site and duration of response for the early systemic treatment. On average patients underwent 2.6 different treatment modalities, mostly depending on stage and higher tumor grade. Surgery was performed early but also in advanced stages, usually followed by Somatostatine-Agonist modalities. In distant disease (Stage IV), we investigated a positive effect of PFS after treatment with Somatostatine Analogues (SSA) (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.21 – 0.97; p = 0.04) and systemic treatment (HR, 0.51; 95% CI, 0.26 – 0.99; p = 0.047) if patients underwent prior surgery or endoscopic resection. Kaplan Meier distributions predict shorter OS in distant disease (Stage IV), (Figure. 1; HR, 2.06; 95% CI, 1.46 – 2.89; log-rank test, p < 0.001). Conclusion This retrospective analysis presents a great overview of all patients’, disease and treatment characteristics of GEP-NETs at ENETS Center in Zurich, Switzerland. We illustrated survival (PFS) depending on implemented therapies. According to these findings, we formed a suggested treatment algorithm for advanced GEP-NETs, which does not differ from the latest treatment recommendation by ESMO guidelines for GEP-NETs. The results of this project may define GEP-NET patients’ selection for upcoming clinical prospective studies.

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“…However, first the calculation is not straightforward, unless the exposure rate constant is used and thus the point source approximation. Second, whole-body or organ activity are highly variable: illustrative examples can be found in Kurth et al (2018), Mair et al (2018), Levart et al (2019) and Bellamy et al (2022) for lutetium therapy and in Berg et al (1996), Areberg et al (2005) and Hänscheid et al (2006) for radio-iodine therapy. As such, measurements of the patient dose rate merely serve as a normalisation of the dose rate pattern given by biokinetic models.…”

Section: Introductionmentioning

confidence: 99%

Contact restriction time after common nuclear medicine therapies: spreadsheet implementation based on conservative retention function and individual measurements

et al. 2023

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The increasing use of new radiopharmaceuticals invites to reconsider some radioprotection issues, such as the contact restriction time that limits the public exposure by nuclear medicine patients. Contact restriction time should be patient specific and conservative, and its assessment made easy for the clinicians. Here a method is proposed, based on conservative estimate of the whole-body retention function and at least one measurement of the patient’s dose rate. Recommended values of the retention function are given for eight therapies: 131I (Graves’ disease, remnant ablation, patient follow-up, mIBG), 177Lu-PSMA and 177Lu-DOTATATE therapies, 90Y and 166Ho microsphere injection of liver. The patient line source model for scaling dose rate from one distance to another is included in the restriction time calculation. The method is benchmarked against published values and the influence of the dose rate scaling and whole-body retention function illustrated. A spreadsheet is provided, along with the source code, with recommended values for the eight therapies. The recommended values can be changed as well as the dose rate scaling function, other radiopharmaceuticals can be included in the spreadsheet, provided retention functions are defined.

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Substantial External Dose Rate Variability Observed in a Cohort of Lu-177 Patients Independent of Bmi and Sex

Cited by 6 publications

References 18 publications

Radiation levels outside a patient undergoing ¹⁷⁷Lu-PSMA radioligand therapy

Radiation levels outside a patient undergoing ¹⁷⁷Lu-PSMA radioligand therapy

What have we learnt from the past – would treatment decisions for GEP-NET patients differ between 2012 to 2016 by the new recommendations in 2022?

Contact restriction time after common nuclear medicine therapies: spreadsheet implementation based on conservative retention function and individual measurements

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Substantial External Dose Rate Variability Observed in a Cohort of Lu-177 Patients Independent of Bmi and Sex

Cited by 6 publications

References 18 publications

Radiation levels outside a patient undergoing 177Lu-PSMA radioligand therapy

Radiation levels outside a patient undergoing 177Lu-PSMA radioligand therapy

What have we learnt from the past – would treatment decisions for GEP-NET patients differ between 2012 to 2016 by the new recommendations in 2022?

Contact restriction time after common nuclear medicine therapies: spreadsheet implementation based on conservative retention function and individual measurements

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Product

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Radiation levels outside a patient undergoing ¹⁷⁷Lu-PSMA radioligand therapy

Radiation levels outside a patient undergoing ¹⁷⁷Lu-PSMA radioligand therapy