brachytherapy in ca prostate.PERMANENT SEED IMPLANT IN PROSTATE CANCER,HDR brachytherapy in ca prostate

1. Brachytherapy in carcinoma
prostate
Dr Sailendra
Senior resident
Dept of radiotherapy
Maulana azad medical college

2. rationale
• prostate adenocarcinoma has a low α/β-ratio
of 1.2–3.0 Gy
• Late reacting tiisues are more sensitive to
higher does per fraction
• It is a form of conformal radiotherapy that
avoids dose to normal structures
• Shorter duration of treatment

3. History of brachytherapy
1910 - Young used urethral radium for treatment of
prostate cancer
1930 - Flocks first injected radioactive gold liquid
into prostate
1970 -Whitmer et al. at MSKCC in New York first
performed prostate seed implants using iodine
seeds
1983 - Holm performed the first closed
implant,using needles and ultrasound guidance

4. INCLUSION CRITERIA
PATIENT FACTORS
• Life expectancy >5 years
• IPSS <15
• Prostate volume <60 cm3
• No defect if previous TURP
• Minimal pubic arch
interference
TUMOUR FACTORS
• Monotherapy: T1–T2b,
Gleason score ≤7, PSA ≤15a
• Boost therapy: ≥T2 c,
Gleason score ≥7, PSA ≥10
IPSS , International Prostate Symptom Score

5. TYPES
• LDR
– CLASSIC LDR
– ULTRA LDR
• HDR

6. TYPES
LDR(0.4-2Gy/hr)
LDR brachytherapy or ‘seed’ implant involves the
insertion of permanent radioactive sources
directly into the prostate.
HDR(>12Gy/hr)
HDR brachytherapy also involves radioactive
material being placed directly into the prostate
but, unlike LDR seeds, the placement of the
material is temporary and for shorter periods –
usually for a day or two at a time

7. TYPES OF PERMANENT IMPLANTS
Classic LDR
• 222Rn seeds, 198Au seeds
• Half-lives of a few days
• High-energy γ-rays emitted by
these sources
• Monoenergetic
• The patient must be confined to
the hospital until the source
strength decays to a safe level (two
to three half-lives or about 10 days)
Ultra LDR
• 103Pd, 125I and 131Cs
• Uses longer half life
• Low-energy photon emitters
• cascade of rays with different
energy
• The patient’s tissues or a thin
lead foil are sufficient to reduce
ambient exposure rates to
negligible levels, eliminating the
need to hospitalize
• Reduce radiation exposure to
operating room personnel

8. TYPES OF SEEDS

9. Loose seeds Vs stranded seeds
• Stranded seeds are fabricated with absorbable spacer
material,which fix the distance of 1 cm between the
centers of two serial seeds.
• capability of minimizing the risk for seed loss
• Loose seeds can migrate through the venous system to
the lungs, abdomen and pelvis or are excreted with
urine or ejaculated
• Most of the seeds get lost within 30days of PSI
• Loose seeds are used in centre to prevent higher dose
to urethra
• Stranded seeds can be used in cases where margin is
required around prostate

10. Factors predicting seed loss
• Number of needles
• Number of seeds
• Preoperative prostate volume
• Expertise of the brachytherapy team
• Surprisingly, overall seed loss was more frequent in the
patient group with stranded seeds, which might be biased
by low patient number (n = 40) or wrong technique.
Miyazawa et al. 2012; Kono et al. 2010

13. PROCEDURE OF LDR
• Preplanned interstitial implant
• Intraoperative interstitial implant

14. Preplanned interstitial implant
• Patient selection
• Ultrasound simulation and volume assesment
• Treatment planning
• Implant process
• Post-implant dosimetry
• Follow-up

15. Ultrasound simulation and volume assesment
TRUS imaging is obtained before the planned
procedure to assess the prostate volume
Treatment planning
A computerized plan is generated from the transverse
ultrasound images, producing isodose distributions and
the ideal location of seeds within the gland to deliver
the prescription dose to the prostate.

16. THINGS TO ENSURE PRIOR TO THE
IMPLANT PROCEDURE
• Patient is admitted the night prior to the day of the
procedure
• Enema to clear bowel prior to the procedure
• Preanesthetic check up should be done
• Fasting for atleast 6hrs before the procedure
• Shaving the hair from the genital area
• Medication that need to stop before the procedure, e.g.
anticoagulants, anti-inflammatories, herbal or
complementary supplements

17. IMPLANT PROCESS
• Done under general anaesthetia or spinal anaesthesia
• Patient in lithotomy position
• Patient is catheterised
• Real time TRUS guided
• 60-100 small radioactive seeds are placed inside the
prostate
• Seeds are inserted using Needles or Mick applicator guided
by a template placed over the perineum according to the
coordinates determined by the preplan

19. Mick applicator

22. POST IMPLANT DOSIMETRY
• Post implant CT scan is done and images transferred to TPS
• At first, the actual number of seeds in the target area is
detected.
• If there are missing seeds, a chest X-ray is recommended.
CONTOURING
– CTV-P (prostate)
– CTV-PM (prostate + 3mm margin)
– Rectum (“r”)
– intraprostatic urethra (“u”)
• The detection of the seeds in the CT / MRI images is
performed by the automatic seed finder feature of the
planning software

23. TARGET DELINEATION
• The clinical target volume (CTV) is defined as the whole
prostate as seen in rectal ultrasound
• The seminal vesicles are not usually included within the
clinical target volume.
• A margin of 2–3 mm is added to generate the planning
target volume (PTV).
• In high risk prostate cancer, the PTV may consist of the
prostate gland with a 5 mm margin (posteriorly 2 mm).
• The proximal 1 cm of the seminal vesicles should also be
included in the planning target volume in high risk
cases(Bittner et al. 2012)
• The whole plan is then correlated with the pre plan for
verification.

24. Does prescription
The dose constraints for the PTV (prostate plus margin) are:
– pD90 > 100 % of prescribed dose(PD)
– pV100 ≥95 %,
– pV150 ≤50 %
• Rectum
– rD2cc ≤ PD and rD0.1cc<200 Gy
• Prostatic urethra
– uD10 <150 % of PD
– uD30 <130 % of PD
The GTV should be encompassed by the 150 % isodose.

25. Post procedure
• Antibiotics to prevent infection.
• Stool softeners to avoid constipation
• Can resume eating and drinking once patient is
awake
• Barrier contraception is recommended for use for
the first two months after implantation
• Patient is advised to come after 1month for
follow up
• it is important to remember that………………. the
seeds are radioactive, you are not

26. Intraoperative Planning
• An ultrasound probe is positioned in the rectum and the prostate
and normal anatomies are identified.
• Needles are inserted through the perineal template
• The prostate is subsequently scanned from apex to base, and these
0.5-cm images are transferred to the treatment-planning system
• On the computer monitor, the prostate contours and the urethra
are digitized on each axial image.
• Needle positions are identified on each image, and their
coordinates are incorporated into a genetic algorithm optimization
program.
• After the optimization program identifies the optimal seed-loading
pattern and the dose calculations are completed

27. LDR
advantage
• Usually only requires one night
in hospital
• Less invasive procedure than
prostatectomy
• Repeated treatments not
required
• Lesser risk of long term effects
to normal tissues (rectum,
bladder, urethra)
• Probably better preservation
of erectile function
disadvantage
• Not available in all centres
• Urinary side effects may occur
which might last over several
weeks or months
• Anaesthetic and surgical
procedure required
• You will have minor temporary
changes to lifestyle as a result
of radioactive implant
• Costly

28. Rationale for HDR Brachytherapy
• Higher dose per fraction as carcinoma prostate behaves as
a late responding tissue
• Without unacceptable dosimetric changes caused by
source migration and tissue deformity as in LDR implants
• No intrafraction motions as in EBRT
• Temporary HDR BRT is not limited by positioning
uncertainties as the target is immobilized by the implanted
catheters and treated within very short treatment times.
• Since there is no permanent implant with HDR, no long-
term radiation protection issues exist as in the case of LDR
BRT

30. Brachytherapy Techniques
• performed under spinal or general anesthesia
• Patient in lithotomy position
• Real-time TRUS-guided implantation
• Treatment planning after TRUS-guided
implantation is commonly performed using
either CT or TRUS imaging
• Perineal template to aid catheter placement

31. • For CT based planning, 3 mm slice thickness in
the axial plane is used
• Imaging should extend the prostate in the
craniocaudal extension and should include
sufficient normal anatomy for meaningful
normal tissue dosimetry
• PTV is defined as the entire prostate gland
without margins

32. • Based on the acquired 3D anatomy, the appropriate virtual
needle positions are generated, the needle source dwell
positions located within the PTV are activated, and the
radioactive source dwell times are calculated using an
intraoperative treatment planning system
• If the pre-planning dosimetry parameters fulfill the
dosimetric protocol, TRUSguided implantation of catheters
is performed at the previously determined positions
• After completion of implantation, a final 3D TRUS data set
is acquired for intraoperative real-time treatment planning.
• Real needle positions are reconstructed and dwell positions
located within the PTV are activated ensuring the 3D dose
distribution fulfills the dosimetric protocol

34. • Irrespective of the imaging modality for
interventional guidance or treatment
planning, HDR is performed using a remote
afterloading system.
• Iridium 192 is the most commonly used
isotope with an average energy of 380 keV, a
half-life of 73.8 days and a half value layer of
2.5 mm of lead

35. DEMERITS OF CT BASED AND TRUS BASED PLANS
CT PLANNING
• The potential disadvantages of CT dosimetry are the need to move the patient and
the time it takes to go from one location to another to perform serial functions.
• There may occur changes in catheter positions during transfer
TRUS PLANNING
• The image distortions (“shadows”) produced by the posterior (dorsal) catheters
can obscure the view of more anterior (ventral) catheters during treatment
planning, and the catheters themselves can obscure the prostate contour
especially near the apex.
• Definition of contours of the rectum and to a lesser extent the bladder may be less
accurately rendered with real time TRUS planning than with CT-based planning.
• Newer 3D ultrasound probes will likely reduce some of these technical difficulties

36. D. Jeffrey Demanes, Michel I. Ghilezan
High-dose-rate brachytherapy as monotherapy for prostate cancer
Brachytherapy, Volume 13, Issue 6, 2014, 529–541
Fig. 1. CT-based dosimetry. Transverse, sagittal, coronal, and three-dimensional views.

37. D. Jeffrey Demanes, Michel I. Ghilezan
High-dose-rate brachytherapy as monotherapy for prostate cancer
Brachytherapy, Volume 13, Issue 6, 2014, 529–541
Fig. 2. Ultrasound-based dosimetry. Coronal, transverse, sagittal, and 3D views with 100% isodose lines and 3D cloud (red). 3D =
three-dimensional. (For interpretation of the references to color in this figure legend, the reader is referred to the web version ...

38. DOSE SCHEDULES

39. HDR
ADVANTAGES
• Shorter course of treatment
• Usually minimal side effects
are experienced around the
time of treatment
• Minimal post procedure
recovery time required
DISADVANTAGES
• Needs hospitalisation
• Not available in all centres
• Having to lie flat while the
implant catheters are in place,
sometimes overnight, which
can be uncomfortable.
• Side effects affecting bladder,
bowel and erectile function
can occur in the longer term
• Costly

40. TOXICITY
• URINARY TOXICITY
• RECTAL TOXICITY
• ERECTILE DISFUNCTION

41. URINARY TOXICITY
• Acute urinary retention
• urinary frequency
• Urgency
• occasional urge incontinence.
• Depending on the isotope used, these symptoms often peak at 1 to
3 months after the procedure and subsequently gradually decline
over the ensuing 3 to 6 months.
• Most patients benefit with the use of an α-blocker, which
ameliorates such symptoms in 60% to 70% of patients.
• Most urinary symptoms resolved within 12 months after the
procedure, and significant residual toxicity was unusual.

42. Multivariate analysis demonstrated that the
– use of androgen-deprivation therapy before
implantation
– High prostate volume
– higher baseline IPSS
– use of higher number of needles
was associated with increased rate of grade 2 acute
toxicity

43. RECTAL TOXICITY
• Symptoms manifest as rectal bleeding or
increased mucous discharge.
• The onset of symptoms often peaks at 8 to 12
months and is self-limited in nature
ERECTILE DYSFUNCTION
• Erectile dysfunction after brachytherapy has been
reported to occur in from 20% to 80% of patients.
• Excellent responses were observed with sildenafil
citrate