1. SLN (Sentinel Lymph Node) And Breast (cancer)
Lymphoscintigraphy
SLN (Sentinel Lymph Node)
And Breast (cancer)

2. 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

3. Early Lymphatic Research
The following individuals were involved with initial lymphatic research
1653 T. Bartholin
H.F. LeDran
1890 Halstead

4. 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

5. 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

6. 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

7. 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)

8. 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

9. Adjuvant Therapy
Removal of the SLN

10. Lymphatic Anatomy Accompany blood supply
Ectoderm : mammary gland is organ of
skin - biologic unit
Mammary lymph flow parallels lymph flow from skin

11. Lymphatic Anatomy
Subcutaneous plexus : common drainage location does not predict basin
Important for injection site

12. Radipharmaceuticals
Visualize lymphatic channels from site of intestinal administration to first LN encountered
Biologic Trap
Active phagocytes by macrophages

13. 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.

14. 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

15. Approximate Ranges of Particles Size For Various Radiocolloids
Estimates
Agent
Concordant
(nm)
Other
Median
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
5-80
99mTc-sulfur colloid (unfiltered)
15/
100/
Particle size varies in the different agents used for this procedure.
The next side discusses ideal particle size.

16. 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

17. 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

18. Tc99m sulfur colloid Not FDA approved Filtered : 220 nanometer
50 –200 nanometer particle
Not considered the ideal agent because of its size

19. 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

20. 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

21. 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.

22. 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.

23. 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

24. 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

25. Success Rate
Fraction of patients in whom this procedure has been preformed identify 97 – 99% of the SNL
False Negative : 1 – 4%

26. Cases

27. These images illustrate variable patterns of lymphatic drainage
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

28. 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

29. 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 Co-57 flood.
In the last image (R) a transmission scan is done in the groin region to assure that there is no additional SNL.

30. 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

31. 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

32. 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).

33. 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).

34. 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

35. 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

36. 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