ncluding Sn117m Nigel R Stevenson PhD SNMMI Denver CO CE98 Targeting Radionuclide Therapy in Various NonMalignant Arthritic Conditions Using Radiosynoviorthesis RSO June 14 2017 ID: 653920
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Slide1
Characteristics and Comparison of RSO Isotopes including Sn-117m
Nigel R. Stevenson, Ph.D
.
SNMMI (Denver, CO)
CE98
: Targeting Radionuclide Therapy in Various Non-Malignant Arthritic Conditions Using Radiosynoviorthesis (RSO
)
June 14, 2017Slide2
DisclosuresEmployment with Serene, LLC – manufacturers of Sn-117m colloid
6/14/2017
SNMMI (Denver, CO)
1Slide3
Radiosynoviorthesis (RSO)
A.k.a.
Radiosynovectomy (RSV)
Treatment for
arthritis (synovitis)
Used worldwide for over 60 years
Radioactive colloid injected directly into the synovial cavity
Intracavitary
radiotherapy to reduce pain, effusion, perfusion and inflammation (synovitis)Commercial isotopes are Y-90, Re-186, Er-169Y-90 for large joints (knee)Re-186 for mid-size joints (elbow, wrist, ankle)Er-169 for small joints (fingers)
SNMMI (Denver, CO)
6/14/2017
2Slide4
Radiosynoviorthesis IsotopesSNMMI (Denver, CO)
6/14/2017
3Slide5
Commercial RSO Isotopes
Isotope
Joint size
Colloidal
compounds
Half-life (days)
Imaging particle
Therapy
particle
Tissue
range (mm)
mean, max
Typical dose
(
mCi
)
Standard isotopes currently
in use globally (human dose)
Er-169SmallCitrate9.3Noneβ0.14, 1.11Re-186MediumSulfide3.7γ (lower quality)β1.1, 4.42.5Y-90LargeSilicate, citrate2.7Brem.β4.1, 114FutureSn-117mSmall/MedHydroxide14γ (high quality)CE0.27, 0.300.5-2.0
4
All
(except Sn-117m) – wide particle size range allows for potential leakage from the joint resulting in systemic distributionAll (except Sn-117m) – irradiate beyond the targeted tissue (i.e., the synovium)Y-90, Re-186 – shorter half-life causes some logistical problems outside of EuropeEr-169 – supply, reliability issues reported.
6/14/2017
SNMMI (Denver, CO)Slide6
Colloid Manufacturing
Centralized manufacturing – unit doses and bulk
Limited availability in some countries and regions
Local - “kit” produced
Re-188 using cold Sn
c
olloid base
(Courtesy of Prof. Jae Min Jeong, SNU)6/14/2017
SNMMI (Denver, CO)
5Slide7
Sn-117m
(CE)
Alpha
Particles
Beta
Particles
Characteristics of Sn-117m
Conversion
Electron
(
CE)
#
Energy
Penetrates up to a
set distance
(discrete energy)
Beta
Energy
#Avg.Produces a range of tissue penetration
Range in tissue (µm)30040-9050-5000
Shielding needed during administrationNoNoYes
Sn-117m was extensively developed at BNL starting in the 1980s
Reactor productionChemistry development
Oncology trials
SNMMI (Denver, CO)
6/14/2017
6Slide8
Sn-117m RSO Colloid
Time
7 days
2 weeks
6 weeks
Retention
>99.9%
>99.9%
99.8%
Retention of colloid in normal rat joint:
Stability studies – colloid size particle distribution at manufacture
Mean =6.28
μ
m SD=2.76
μ
m
Stability studies – colloid size particle distribution at 5 weeks in room temperature
Mean =6.43
μm SD=2.47 μmSNMMI (Denver, CO)6/14/20177Slide9
Sn-117m RSO Colloid is Unique6/14/2017
SNMMI (Denver, CO)
8
Tin forms an
ideal colloid
Used as the base for some existing RSO colloids
Very stable/long-lived
Biocompatible
ReproducibleOptimal size range
No particles smaller than 1 μ
m – i.e., no leakage
No particles above ~ 20
μ
m – i.e.,
complete phagocytosis
Suitable
half-life
Phagocytosed radioactive colloids migrate to deeper synovial tissues – i.e., potential to
treat larger jointsIrradiation of unintended tissues is avoidedSlide10
Summary6/14/2017
SNMMI (Denver, CO)
9
RSO is a well established procedure to treat
arthritis/synovitis
Commercially available isotopes are:
Y-90
for
large jointsRe-186 for mid-size jointsEr-169 for
small jointsSn-117m
is a new isotope that is proving useful for small and
mid-size
joints (possibly also large)
Existing colloids
leak
out to some degree resulting in systemic distribution
New
Sn-117m colloid is unique
in having no leakage or systemic problemsSn-117m has the potential to treat all sizes of joints