Transcript Lymphoscintigraphy

Lymphoscintigraphy
SLN (Sentinel Lymph Node)
And Breast (cancer)
Flow – Primary Exam – defines the flow of the
radiocolloid through the lymph chains which can
reveal the following results
 Lymphedema
 Obstruction
 Leak
Mapping – determines the following
 Solid Epithelial Tumors
 SLN
 Selective lymphad Enctomy
Early Lymphatic Research
The following individuals were involved with
initial lymphatic research
1653 T. Bartholin
 1685-1770 H.F. LeDran
 1890 Halstead

SLN - Breast
The SLN was defined in breast cancer by the
following individuals
1907 Jaimseon and Dobson
1960 Gould – “Sentinal Node”
1977 Cabanas
1977 Norton
1977 Ege
Selective Lymphadenectomy
In the lymphatic system cancer spreads through the
lymph chains and usually resides in what is known
as the sentinel node. Removal of this node can
result in the following:



Improved Staging
Decreased Surgical Morbidity
Reduced Number Radical LN Dissections
The Concept
Lymphatic spread of cancer is not only
orderly, but also predictable
 The histological status of the SLN is
predictive of the status of the distant Lymph
node basin
 Skip metastases practically do not exist and
metastatic spread can be discovered via the
SLN

The above diagram shows the SLN which contains
The cancerous cells. These cells then spread down
The lymphatic channels to other lymph nodes (second,
Third tiers)
Patient Population
Early Breast Cancer will have the following
Clinically Negative Axilla
 Tier 1 less than 2 cm
 75% will be lymph node negative, beyond
the SLN

Adjuvant Therapy
Removal of the SLN
Lymphatic Anatomy
Accompany blood supply
 Ectoderm : mammary gland is organ of
skin - biologic unit
 Mammary lymph flow parallels lymph flow
from skin

Lymphatic Anatomy
Subcutaneous plexus : common drainage
location does not predict basin
Important for injection site
Radipharmaceuticals
Visualize lymphatic channels from site of
intestinal administration to first LN
encountered
 Biologic Trap
 Active phagocytes by macrophages

Left – Red dots idenfity radiocolloid migrating into the afferent lymph
from an intersitial injection where they are trapped by the macrophages
Within the sinusoid spaces.
Right – Magnification of a histoautoradiographh of the sentinel node
Black dots show retention of the radioactive agent in the sinusoid spaces.
Defines the ability to use radiocolloid to define the sentinel lymph node.
Radiopharmacenticals
Particle size
 Number of Particles (few)
 Specific Activity (high)
 Decrease heating time
 Too much clumping of the particles occurs
after two hours of preparation

Approximate Ranges of Particles Size For Various Radiocolloids
Estimates
Agent
Concordant
(nm)
Other
(nm)
Median
(nm)
99mTc-dextran
2-4
2
198Au-colloid
9-15
4-20/30
5-15
99mTc-antimony
trisulfide
3-12/30
15-25
17-22
99mTc-sulfur colloid
(prefiltered)
5/15-50
5-25
<30
99mTc-HSA-
4-100
99mTc-sulfur colloid
(unfiltered)
15/50-5000
5-80
100/2001000
100-600
Particle size varies in the different agents used for this procedure.
The next side discusses ideal particle size.
Ideal Drug
Radiocolloid between 100 – 200 nanometer
This is not currently available
Radiocolloid not used is:
Tc 99m DTPA – mannosyl – dextrin
Rapid clearance
Low secondary LN accumulation
Preferred Radiocolloid
Filtered Tc99m sulfur colloid
 Filter allows for particles that are < 30nm
 If unfiltered colloid is used the particles will
not travel as well through the system
 It is also suggested that the colloid be no
more than 2 hours post preparation

Tc99m sulfur colloid
Not FDA approved
Filtered : 220 nanometer
50 –200 nanometer particle
Not considered the ideal agent because of its
size
Technique
Techniques that must be considered in this procedure
are:
Site of the injection – most important
Volume – limited mL
Dose – to be discussed
Timing relative to surgery – after injecting the agent
and imaging the SLN the patient must be sent to
surgery for removal of the radioactive node
Site
Types of injection that could be done
Intratumeral : Not acceptable
Peritumeral : IM LNs (not acceptable
Intradermal – Subremal : Preferred
 The ideal injection is done just below skin
which is then picked up by the lymphatic
system
 Injections are done around the tumor site
ROI 1 – Shows the injection site
ROI 2 – Indicates the flow of the
colloid through the lymphatic
channel
ROI 3 – indicates the sentinel
Node
Graph displays the radiocolloid
traveling through the lymphatic
system over time.
This slide shows the difference between colloid size and its
ability to flow through the infected system. Note that as the
size of the particle increases, the amount of nodes that “light
up” decrease. Hence, smaller colloid size is preferred when
diagnosing disease.
Procedure
0.2 ml – preferred volume
0.5 mCi – dose
Injection is done just underneath the skin with
numerous injections around the tumor site, in a
circular pattern
Massage breast – after injection
90° Arm Abduction – location of arm
Dynamic /Static – Dynamic process with static
images are acquired
ANT/LAO - images
Mark patient – mark the SLN when it is identified
2 Hours – total time
Other Components
Vital Dye – can also be used along with the
radiocolloid
Gamma probe – is used in the OR to
determine which nodes are radioactive.
Those that are are then removed
Success Rate
Fraction of patients in whom this procedure
has been preformed identify 97 – 99% of
the SNL
False Negative : 1 – 4%
Cases
These images illustrate variable patterns
of lymphatic drainage. Imaging times
occurred between 31 to 60 min post
intradermal injection of 99mTc-HSA
nanocolloid
•(A) RAO view shows single lymphatic
vessel leading to single sentinel lymph
node, with serial visualization of
subsequent tier nodes
•(B) LAO view shows 2 separate
lymphatics leading through widely
diverging pathways, to 2 separate but
adjacent sentinel node and tier nodes
•(C) LAO view shows 3 separate
lymphatics leading, through widely
diverging pathways
•(D) RAO view shows multiple lymphatics
leading from site of infection in outer
upper quadrant to at least 3 separate
sentinel nodes and subsequent tier nodes
This procedure done at UofL Hospital shows:
•The injection site covered with a lead shield
•Over time the lymph chain is noted
•Sentinel node is defined
• The first image (L) shows the injection site that is located
POST. Because of the excessive activity this injection site it can
be seen in the ANT image. Note that slightly distal from the
injection site the SNL.
• Imaging is improved when (second image): A) the injection
site is extracts; and B) A transmission image is take with the Co57 flood.
• In the last image (R) a transmission scan is done in the groin
region to assure that there is no additional SNL.
Melanoma Upper Back
40 year old male presented
with superficial spreading
malignant melanoma of the
left upper back.
On dynamic images there is
tracer uptake inferior and
lateral to the melanoma site.
The intense focus is activity at
the injection sites around the
melanoma
Posterior Projection
Melanoma Upper Back (Cont)

Image on the left includes
activity from a transmission
source which helps to
outline the body.

There are 3 discrete foci of
tracer uptake (shown by
arrows) anterior, inferior and
lateral to the injection sites
(shown by arrowhead).

Micrometatses were found
in one of the marked lesions.
Anterior Projection
Static Images
Melanoma Left Cheek

A lateral static image
from patient who had
a left cheek melanoma
(arrowhead shows
sites of injection)
demonstrates tracer
uptake in the
submandibular and
posterior cervical
lymph nodes (shown
by arrows).
Pre-Operative Lymphatic Mapping
Breast Cancer

Cancer was on the lower
side of the breast and was
injected with the
radiocolloid (the dark black
area on the bottom of the
breast). You can easily see
that there are two
lymphatics which leave the
breast (labeled with blue L)
and go to two distinct
sentinel lymph nodes
(SLN).

The picture on the left
shows a sentinel lymph
node (N) which is tinted
blue because it has taken
up the blue dye which was
injected around the breast
cancer.

The blue dye got there by
traveling through the
lymphatics which leave the
breast and connect to the
SLN. This picture shows
the lymphatic vessel (L)
with blue dye in it.
Mapping
Breast Lymphoscintigraphy
Mapping of the breast is done in order to
surgically remove the SLN
 This can be done with blue dye
 This can be done with radiocolloid and a
gamma knife
 Usually both are done at the same time

Other Applications
This procedure may also be useful with the
following cancers
 Malignant melanoma
 Breast CA
 Cervical CA/Vulval CA
 Colorectal CA
 Head and Neck CA
 Thyroid CA
 Gastrial/Esophageal CA
 Penile CA