Absorbed dose profiles for radionuclides of frequent use in radiation synovectomy

Johnson, L. Scott; Yanch, J. C.

doi:10.1002/art.1780341208

Cited by 45 publications

(5 citation statements)

References 5 publications

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“…First, a more accurate assessment of the intratumoural distribution of 166 Ho-MS is possible because of a better spatial resolution of CT. The fact that the β radiation of 166 Ho has an average penetration range of only a few millimetres while 90% of the dose is absorbed whithin 2.1 mm [21] stresses the importance of using highresolution imaging. Additional injections, based on the current microsphere distribution, could provide a more homogeneously absorbed dose and subsequently a more favourable treatment outcome.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of CT quantification of intratumoural 166Ho-microspheres

et al. 2020

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Background: Microspheres loaded with radioactive 166 Ho (166 Ho-MS) are novel particles for radioembolisation and intratumoural treatment. Because of the limited penetration of β radiation, quantitative imaging of microsphere distribution is crucial for optimal intratumoural treatment. Computed tomography (CT) may provide high-resolution and fast imaging of the distribution of these microspheres, with lower costs and widespread availability in comparison with current standard single-photon emission tomography (SPECT) and magnetic resonance imaging. This phantom study investigated the feasibility of CT quantification of 166 Ho-MS. Methods: CT quantification was performed on a phantom with various concentrations of HoCl and Ho-MS to investigate the CT sensitivity and calibrate the CT recovery. 166 Ho-MS were injected into ex vivo tissues, in VX-2 cancer-bearing rabbits, and in patients with head-neck cancer, to demonstrate sensitivity and clinical visibility. The amount of Ho-MS was determined by CT scanning, using a density-based threshold method and compared with a validated 166 Ho SPECT quantification method. Results: In the phantom, a near perfect linearity (least squares R 2 > 0.99) between HU values and concentration of 166 Ho was found. Ex vivo tissue experiments showed an excellent correlation (r = 0.99, p < 0.01) between the dose calibrator, SPECT, and CT imaging. CT recovery was on average 86.4% ex vivo, 76.0% in rabbits, and 99.1% in humans. Conclusion: This study showed that CT-based quantification of Ho microspheres is feasible and is a high-resolution alternative to SPECT-based determination of their local distribution.

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Section: Discussionmentioning

confidence: 99%

Feasibility of CT quantification of intratumoural 166Ho-microspheres

et al. 2020

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“…Diese Vorgänge führen zu einer dringtiefe im Gewebe beträgt 3,9 mm, die maximale 11 mm. Die therapeutisch relevante Eindringtiefe, entsprechend der Wegstrecke, auf der 90 % der Energie im Gewebe deponiert werden, beträgt jedoch nur 2,8 mm [15]. Klinische Erfolge mit deutlicher Schmerzreduktion und verbesserter Gelenkbeweglichkeit werden in etwa 60 -80 % aller behandelten Gelenke erzielt [11,13,16,17].…”

Section: Radiosynoviorthese (Rso)unclassified

Die Bakerzyste – das stumpfe Damoklesschwert bei der Radiosynoviorthese (RSO)?

Kampen¹,

Freudenberg²,

Fischer³

et al. 2021

Nuklearmedizin

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ZusammenfassungDie popliteale Bakerzyste galt lange Zeit als Kontraindikation bei der Durchführung einer Radiosynoviorthese (RSO). Insbesondere bei einem vorliegenden „Ventilmechanismus“ der Zyste fürchtete man eine vermehrte Anreicherung des intraartikulär injizierten Radiopharmazeutikums Yttrium-90-Kolloid in der Zyste, die aus einer mit der Kniegelenkhöhle kommunizierenden Bursa unter dem medialen Kopf des M. gastrocnemius bei chronischer Arthritis mit Ergussneigung entstehen kann. Aufgrund der im Vergleich zur Kniegelenkkapsel deutlich dünneren Zystenwand wurde die Gefahr einer radiogenen Zystenruptur mit konsekutiver Freisetzung des hoch energetischen Betastrahlers in die umgebenden Weichteile und einer dadurch hervorgerufenen Weichteilnekrose diskutiert. Daher ist vor der Kniegelenk-RSO zwingend die sonografische Abklärung einer möglichen Bakerzyste erforderlich. Neue Studien zeigen hingegen keinen Hinweis auf die Gefahr einer Zystenruptur durch eine lege artis durchgeführte Kniegelenk-RSO.Bei bereits präexistierender Zystenwandruptur ist jedoch die Gefahr eines unkontrollierten Austritts des Radiopharmazeutikums mit nachfolgender Radionekrose auch weiterhin gegeben. Die Magnetresonanztomografie (MRT) ist die Methode der Wahl, um eine solche Zystenruptur im Vorfeld auszuschließen, liefert aber nicht immer zuverlässige Befunde. In derartigen Fällen ist die Binnenraumszintigrafie unter Verwendung von Tc-99m-Nanokolloid geeignet, die Integrität der Bakerzyste nachzuweisen und einen möglichen Aktivitätsaustritt aus der Zyste mit hinreichender Sicherheit auszuschließen. Die vorliegende Arbeit erläutert diese Methode an repräsentativen Fallbeispielen.

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“…Cationic lanthanides (Ln 3+ ) are of high relevance because of their magnetic and optical properties. For example, the symmetric 8 S ground state of Gd 3+ results in slow electron relaxation, which makes Gd 3+ complexes efficient contrast agents in magnetic resonance imaging (MRI). 1 Additionally almost all Ln 3+ ions (except La 3+ and Lu 3+ ) are luminescent with characteristic emission wavelengths for each Ln 3+ (from UV to NIR).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Additionally, DOTA-Ln 3+ complexes present an inner-sphere water molecule, leading to nonradiative quenching by proximate O−H oscillators. 12 Numerous chelators, often saturated azamacrocycles based on cyclen (1,4,7,10-tetraazacyclododecane), 13 tacn (1,4,7triazacyclononane), 14 or even on cyclam (1,4,8,11-tetraazacyclotetradecane), 15 have been developed to form stable and/or inert lanthanide complexes for medical and bioanalytical applications. Pyclen (3,6,9,15-tetraazabicyclo[9.3.1]-pentadeca-1(15),11,13-triene), less investigated until recently, leads rapidly to the formation of remarkably inert Ln 3+ complexes.…”

Section: ■ Introductionmentioning

confidence: 99%

Expanding the Scope of Pyclen-Picolinate Lanthanide Chelates to Potential Theranostic Applications

et al. 2020

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A family of three picolinate pyclen based ligands, previously investigated for the complexation of Y 3+ and some lanthanide ions (Gd 3+ , Eu 3+), was studied with 161 Tb and 177 Lu in view of potential radiotherapeutic applications. The set of six Tb 3+ and Lu 3+ complexes was synthesized and fully characterized. The coordination properties in the solid state and in solution were thoroughly studied. Potentiometric titrations, corroborated by Density Functional Theory (DFT) calculations, showed the very high stability constants of the Tb 3+ and Lu 3+ complexes, which are associated to remarkable kinetic inertness for up to 30 days in 1 M HCl. A complete radiolabeling study performed with both 161 Tb and 177 Lu radionuclides, including experiments with regard to the stability with and without scavengers and kinetic inertness using challenging agents, proved that the ligands could reasonably compete with the DOTA analogue. To conclude, the potential of using the same ligand for both radiotherapy and optical imaging was highlighted for the first time. short mission in Villigen in 2019. C.M. and N.vdM. acknowledge Fan Sozzi-Guo for assistance of the experiments involving 161 Tb.

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Absorbed dose profiles for radionuclides of frequent use in radiation synovectomy

Cited by 45 publications

References 5 publications

Feasibility of CT quantification of intratumoural 166Ho-microspheres

Feasibility of CT quantification of intratumoural 166Ho-microspheres

Die Bakerzyste – das stumpfe Damoklesschwert bei der Radiosynoviorthese (RSO)?

Expanding the Scope of Pyclen-Picolinate Lanthanide Chelates to Potential Theranostic Applications

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