Production of Ytterbium Ceramic for Medical Radioactive Sources

Akulinichev, S. V.; Antanovich, A. A.; Derzhiev, V. I.; Зибров, И. П.; Semakina, T. S.; Филоненко, В. П.; Chaushanskii, S A

doi:10.1007/s10717-018-0026-5

Cited by 3 publications

(5 citation statements)

References 4 publications

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“…169 Yb can be produced by irradiating the precursor in a research nuclear reactor, with or without the presence of existing 169 Yb within the active source. The precursor can be in many forms including a pellet, glass, or ceramic . A wide range of thermal neutron fluxes is available at various research reactors, and examples of maximum available thermal neutron fluxes are 6.0 × 10 13 n cm −2 s −1 at the Massachusetts Institute of Technology Research Reactor (MITR‐II), 6.0 × 10 14 n cm −2 s −1 at the University of Missouri Research Reactor (MURR), and 5 × 10 15 n cm −2 s −1 for the SM‐3 reactor at the State Scientific Center — Research Institute of Atomic Reactors (RIAR) in Dimitrovgrad, Russia .…”

Section: Methodsmentioning

confidence: 99%

Efficient ¹⁶⁹Yb high‐dose‐rate brachytherapy source production using reactivation

et al. 2019

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Purpose: To present and quantify the effectiveness of a method for the efficient production of 169 Yb high-dose-rate brachytherapy sources with 27 Ci activity upon clinical delivery, which have about the same dose rate in water at 1 cm from the source center as 10 Ci 192 Ir sources. Materials: A theoretical framework for 169 Yb source activation and reactivation using thermal neutrons in a research reactor and 168 Yb-Yb 2 O 3 precursor is derived and benchmarked against published data. The model is dependent primarily on precursor 168 Yb enrichment percentage, active source volume of the active element, and average thermal neutron flux within the active source. Results: Efficiency gains in 169 Yb source production are achievable through reactivation, and the gains increase with active source volume. For an average thermal neutron flux within the active source of 1 9 10 14 n cm À2 s À1 , increasing the active source volume from 1 to 3 mm 3 decreased reactor-days needed to generate one clinic-year of 169 Yb from 256 days yr À1 to 59 days yr À1 , and 82%-enriched precursor dropped from 80 mg yr À1 to 21 mg yr À1 . A resource reduction of 74%-77% is predicted for an active source volume increase from 1 to 3 mm 3 . Conclusions: Dramatic cost savings are achievable in 169 Yb source production costs through reactivation if active sources larger than 1 mm 3 are used.

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Section: Methodsmentioning

confidence: 99%

Efficient ¹⁶⁹Yb high‐dose‐rate brachytherapy source production using reactivation

et al. 2019

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“…Current enrichment levels of 85% of 168 Yb are shown to be achievable, which generates a 169 Yb source with a high enough specific activity to be feasible for HDR‐BT, but such a source requires neutron activation in a nuclear reactor over the course of several weeks 38 . Several sources of different sizes using ytterbium oxide (Yb 2 O 3 ) have been suggested and shown to have high enough apparent activity for HDR‐BT sources 39–41 . The active source length of 10.5 mm long, 3 mm 3 , 169 Yb source considered in the current work can be theoretically activated 10 times, providing a cost savings of around 75% relative to a more conventional‐sized 1 mm 3 source.…”

Section: Discussionmentioning

confidence: 99%

“…38 Several sources of different sizes using ytterbium oxide (Yb 2 O 3 ) have been suggested and shown to have high enough apparent activity for HDR-BT sources. [39][40][41] The active source length of 10.5 mm long, 3 mm 3 , 169 Yb source considered in the current work can be theoretically activated 10 times, providing a cost savings of around 75% relative to a more conventionalsized 1 mm 3 source.…”

Section: Discussionmentioning

confidence: 99%

Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the ¹⁶⁹Yb Isotope

et al. 2020

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Purpose: To assess the capability of an intracavitary 169 Yb-based helical multishield rotating shield brachytherapy (RSBT) delivery system to treat cervical cancer. The proposed RSBT delivery system contains a pair of 1.25 mm thick platinum partial shields with 45°and 180°emission angles, which travel in a helical pattern within the applicator. Methods: A helically threaded tandem applicator with a 45°tandem curvature containing a helically threaded catheter was designed. A 0.6 mm diameter 169 Yb source with a length of 10.5 mm was simulated. A 37-patient treatment planning study, based on Monte Carlo dose calculations using MCNP5, was conducted with high-risk clinical target volumes (HR-CTVs) of 41.2-192.8 cm 3 (average AE standard deviation of 79.9 AE 35.8 cm 3 ). All patients were assumed to receive 25 fractions of 1.8 Gy of external beam radiation therapy (EBRT) before receiving 5 fractions of high-dose-rate brachytherapy (HDR-BT). For each patient, 192 Ir-based intracavitary (IC) HDR- BT, 192 Ir-based intracavitary/interstitial (IC/IS) HDR-BT using a hybrid applicator with eight IS needles, and 169 Yb-based RSBT plans were generated. Results: For the IC, IC/IS, and RSBT treatment plans, 38%, 84%, and 86% of the plans, respectively, met the planning goal of an HR-CTV D 90 (minimum dose to hottest 90%) of 85 Gy EQD2 (a/ b = 10 Gy). Median (25th percentile, 75th percentile) treatment times for IC, IC/IS, and RSBT were 11.71 (6.62, 15.40) min, 68.00 (45.02, 80.02) min, and 25.30 (13.87, 35.39) min, respectively. 192 Ir activities ranging from 159.1-370 GBq (4.3-10 Ci) and 169 Yb activities ranging from 429.2-999 GBq (11.6-27 Ci) were used, which correspond to the same clinical ranges of dose rates at 1 cm off-source-axis in water. Extra needle insertion and planning time beyond that needed for intracavitary-only approaches was accounted for in the IC/IS treatment time calculations. Conclusion: 169 Yb-based RSBT for cervical cancer met the HR-CTV D 90 goal of 85 Gy in a greater percentage of the patients considered than IC/IS (86% vs 84%, respectively) and can reduce overall treatment time relative to IC/IS. 169 Yb-based RSBT could be used to replace IC/IS in instances where IC/IS treatment is not available, especially in instances when HR-CTV volumes are ≥30 cm 3 .

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“…Due to the lower half‐life of 169 Yb compared to 192 Ir (32.0 days vs 73.8 days), source exchanges may need to be performed every month instead of every 3–4 months, to ensure delivery times are kept under 40 mins. Mass production techniques are currently under development to achieve higher specific activities which can reduce the delivery times and the frequency of source exchanges . Treatment times with the proposed system can be reduced by manufacturing a source with a longer active core.…”

Section: Discussionmentioning

confidence: 99%

“…Mass production techniques are currently under development to achieve higher specific activities which can reduce the delivery times and the frequency of source exchanges. 49 Treatment times with the proposed system can be reduced by manufacturing a source with a longer active core. While the source length was designed to match the length of most commercially available HDR BT sources, the AIM-Brachy system can accommodate source models of variable length as long as the source diameter is respected.…”

Section: Discussionmentioning

confidence: 99%

A novel ¹⁶⁹Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer

Famulari

Duclos²,

Enger

2019

Medical Physics

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Purpose Intensity modulated brachytherapy (IMBT) is a novel high dose rate brachytherapy (HDR BT) technique which incorporates static or dynamic shielding to increase tumor coverage and/or spare healthy tissues. The purpose of this study is to present a novel delivery system (AIM‐Brachy) design that can enable dynamic‐shield IMBT for prostate cancer. Methods The AIM‐Brachy system dynamically controls the rotation of platinum shields, placed within interstitial catheters, which partially collimate the radiation emitted from an 169Yb source. Conventional HDR BT (10 Ci 192Ir) and IMBT (18 Ci 169Yb) plans were generated for 12 patients using an in‐house column generation‐based optimizer, coupled to a Geant4‐based dose calculation engine, RapidBrachyMC. Treatment plans were normalized to match the same PTV D90 coverage as the clinical plan. Intershield attenuation effects were taken into account. A sensitivity analysis was performed to evaluate the dosimetric impact of systematic longitudinal source positioning errors (±1 mm, ±2 mm, and ±3 mm) and rotational errors (±5∘, ±10∘, and ±15∘) on clinically relevant parameters (PTV D90 and urethra D10). Results The platinum shield reduced the dose rate on the shielded side at 1 cm to 18.1% of the dose rate on the unshielded side. For equal PTV D90 coverage, the urethral D10 was reduced by 13.3% ± 4.7%, without change to other plan quality indices (PTV V100, V150, V200, bladder V75, rectum V75, HI, COIN). Delivery times for HDR BT and IMBT were 9.2 ± 1.6 min and 18.6 ± 4.0 min, respectively. In general, the PTV D90 was more sensitive to source positioning errors than rotational errors, while the urethral D10 was more sensitive to rotational errors than source positioning errors. For a typical range of positioning errors (±1 mm, ±5∘), the overall tolerance was <2%. Conclusions The AIM‐Brachy system was proposed to deliver dynamic‐shield IMBT for prostate cancer with the potential to create a low dose tunnel within the urethra. The urethra‐sparing properties are desirable to minimize the occurrence and severity of urethral strictures or, alternatively, to provide a method for dose escalation.

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Production of Ytterbium Ceramic for Medical Radioactive Sources

Cited by 3 publications

References 4 publications

Efficient ¹⁶⁹Yb high‐dose‐rate brachytherapy source production using reactivation

Efficient ¹⁶⁹Yb high‐dose‐rate brachytherapy source production using reactivation

Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the ¹⁶⁹Yb Isotope

A novel ¹⁶⁹Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer

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Production of Ytterbium Ceramic for Medical Radioactive Sources

Cited by 3 publications

References 4 publications

Efficient 169Yb high‐dose‐rate brachytherapy source production using reactivation

Efficient 169Yb high‐dose‐rate brachytherapy source production using reactivation

Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the 169Yb Isotope

A novel 169Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer

Contact Info

Product

Resources

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Efficient ¹⁶⁹Yb high‐dose‐rate brachytherapy source production using reactivation

Efficient ¹⁶⁹Yb high‐dose‐rate brachytherapy source production using reactivation

Needle‐free cervical cancer treatment using helical multishield intracavitary rotating shield brachytherapy with the ¹⁶⁹Yb Isotope

A novel ¹⁶⁹Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer