Brachy Mesh treatment for lung cancer, Cindy

Brachy Mesh
Implants for Lung Cancer
Cindy Thomason
Aurora HealthCare – Metro
Brachy Mesh Implants
• I-125 seeds sewn in mesh in a grid
• Indications
• Stage I nonsmall cell lung cancer
• Metastases
Model 6711
Emitted radiation: 26 - 35.4 keV photons
HVL ≈ 2.0 cm tissue, 0.025 cm lead
T ½ = 60 days
Seeds are 4.5 mm long, 0.8 mm diameter
Brachy Mesh
• Basis is a Vicryl mesh which is a
flexible, absorbable mesh
• Tensile strength of mesh is 10% is 6 weeks
• 125I seeds in suture are embedded in
mesh in grid array
• Size and spacing of array decided by
Radiation Oncologist and Thoracic
Brachy Mesh
• Typical size / spacing
• 4 rows x 10 seeds/row, 1cm spacing
between seeds and rows
• Ave activity / seed = 0.41 mCi
• Ave total activity = 16.5 mCi
Brachy Mesh
• Used for patients with lung cancer or
mets having a sublobar resection
• Mesh laid over
staple line and
sutured in place
Brachy Mesh
Most procedures can be done via
minimally invasive surgery
Brachy Mesh
• No adverse effects (e.g., loss of pulmonary
function, radiation induced pneumonitis) related
to placement of mesh have been seen
• Similar length of
hospital stay and
incidence of postoperative
complications to
resection alone
Brachy Mesh
110 patients
median 11 month follow-up
(range of 1-68 months)
significant improvement
in local recurrence
19% with sublobar alone
1% with sublobar resection + brachytherapy
Voynov, et al., Brachytherapy 4:278-285, 2005
Stantos, et al., Surgery 134:691-697, 2003
Dose Prescription
• 120 / 100 Gy to a point 0.5 cm above /
below plane of implant with margin of 1-2
cm along each side of the resection staple
• 100 Gy used for patients with previous
external beam treatment or tumor location
near heart, aorta or spinal cord
• We use 100 Gy because of difficulty in
predicting location of staple line / mesh
Treatment planning
• Johnson, et. al. (PMB 52:1237-1245, 2007)
prescribed to point average of peak over
row and trough between rows
• We chose to also average in points
between seeds Therefore, we created
our own nomogram for standard
configurations and spacing
• Spacing between rows and seeds can be
modified to adjust for seed activity
Treatment Planning
• BrachyVision commissioned for I-125
Model 6711
• Compared to hand calculation and
• Agreement with Johnson, to within
5% reasonable due to differences in
prescription point and uncertainty in
parameters used in publication
• Pre implant dosimetry based on
nomogram generated in house
• Prescription based solely on
preimplant geometry of mesh, not
patient anatomy
Estimated Personnel Exposure
from Brachy Mesh Procedure
• Thoracic Surgeon will receive greatest
• Estimated hand dose = 2.5 mrem
• Estimate
5 mrem / procedure x 50 procedures / year
 250 mrem / year
• This is less than 10% of the dose limit, 5000
mrem / yr
• Therefore, film or ring badges are not
necessary for any personnel
Regulatory Requirements for
Release of Brachy Mesh Patients
• Brachy Mesh patients can be
released to general public if the
exposure rate at 1 m from patient is
1 mrem / hr or less (WI HS 157, Appendix U,
Table 15)
• Expected exposure rate from
patient is 0.6 mrem / hr
For 1st 29 patients
Exposure range = 0.05 – 0.95 mR/hr
Average exposure rate = 0.42 mR/hr
( 0.13 mR/hr (energy corrected))
Brachy Mesh patient could be
released into general population as
soon as procedure is completed
OR Procedures
• Handled similarly to a prostate
• Seed count performed prior to patient
leaving OR
• Personnel and surroundings surveyed
Radiation Safety Procedures for
Dislodged Radioactive Source
• Patients in-house 1- 5 days
• Since 125I sources are embedded in Vicryl
mesh, it is very unlikely that a source will
be dislodged
• However, all patients leave surgery with a
chest tube and atrium
 only potential route for 125I seed to exit body
• Surveys performed
• When atrium replaced
• When chest tube replaced
• When chest tube and
atrium removed
• Minimal since patient could be
released immediately
• Posting on front of chart and patient
room door to save chest tube or
atrium if changed and to call physics
for survey
• Physics posts release notice after
survey completed
Brachy Mesh Patient
Radiation Safety Instruction
• For 3 months, avoid prolonged contact
with pregnant women or children at
distances closer than 3 feet; no limitations
at distances greater than 3 feet
• Patients are given wallet card with implant
information and facility information and
made aware of increased security and
monitoring for radioactivity
• Some (3) patients have received two
Brachy Mesh implants
• Request a minimum of 1 month between
• Exposure rates for second implant have
been comparable or less than for first
Challenges (cont.)
• Patients with defibrillators or
• Move device
• Perform worse case estimate of
minimum allowed distance
• Complicated by difficulty in estimating
distance between mesh and device
prior to implant
Challenges (cont.)
• Patients with malignant effusion
• Treatment consists of placing a pleural
catheter for sporadic drainage, potentially long
• First issue - exposure to personnel performing
• Second issue - seed migration into drainage
• As mesh dissolves, fibrosis forming around seeds
helps to keep them in place
• Treat drainage fluid similarly to urine from prostate
implant patients
Post planning?
In conclusion
• After start-up process, Brachy Mesh
implants are a relatively simple
procedure for the staff with
essentially no side effects for the
• Early results show improved survival
which hopefully will be reinforced as
more data becomes available
Related flashcards


38 cards


48 cards

Cancer organizations

24 cards

Tumor markers

15 cards

Cancer hospitals

29 cards

Create Flashcards