Bladder protocol is routinely used for patients undergoing pelvic radiation to reduce radiation enteritis. It is very difficult to maintain constant volume, especially in the last two weeks due to radiation enteritis and cystitis

1. Subrata Roy
Senior Radiation Therapist
HCG-ICS Khubchandani Cancer Centre
South Mumbai
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Robust Challenges of Bladder Protocol Management
Knowledge & Understanding

2. Outlines
 Anatomy of Pelvis
 Bladder Protocol Overview
 Ascendancy of Bladder Protocol
 Steps of simulation Process - RTT note
 Diagnosis that need to be treat with Bladder Protocol
 Understanding of CBCT image-Therapist point of view
 Implementation Plan of the day Concept
 Dosimetric Impact on Partial Bladder treatment
 Intrafraction Motion adaptations
 Conclusions
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3. Anatomy of Pelvis
 Bladder is situated Just posterior to the pubic symphysis
It is a muscular sac in the pelvis,just above and behind the pubic
bone.
 In males, the rectum is located posterior to the bladder. Inferiorly, the
muscles of the pelvic diaphragm support the bladder.
 In females, the anterior wall of the vagina sits behind the bladder
 The bladder stores urine, allowing urination to be infrequent and
controlled. The bladder is lined by layers of muscle tissue that stretch
to hold urine. The normal capacity of the bladder is 400-600 mL.
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Male Pelvic Anatomy
Female Pelvic anatomy

4. Bladder Protocol Overview
 Bladder protocol is routinely used for patients undergoing pelvic
radiation to reduce side effects and toxicities
 The bladder and bowel are in close proximity to the
prostate(males),uterus(females),by ensuring the bladder is full and
the bowel is empty each day, we are able to keep the prostate in a
consistent position for each radiotherapy treatment.
 Full bladder protocol can potentially move the small intestine out of
the radiation treatment regions, and results in decreased small
bowel radiation dose and gastrointestinal toxicity and reduce the
exposure to those organs and reduce the possibility of side effects.
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5.  Bladder filling protocols specify a Policy of urine voiding and water drinking before RT, with the aim
of achieving consistent urine volume in the bladder each day at time of RT.
 Patients were instructed to void their bladder of urine and then drink 500 ml of water half an hour
before radiation or maintain a comfortably filled bladder
 The bladder volumes were calculated based on the planning CT and a weekly Cone Beam CT
(CBCT).
 Radiotherapy leads on accuracy and positioning that determine the treatment outcome.
 Correct positioning leads to greater accuracy. And accuracy aims for maximum dose to the tumour
and minimum dose to the nearby organs.
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6. Ascendancy of Bladder Protocol
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 For Radiation treatment of the Pelvic targets it is very necessary to have full
Bladder and empty Rectum of Patient during the CT scan acquisition and for
the duration of radiation therapy treatment
 Bladder volume significantly affected the dose of the target, rectum, and
bladder, but had no significant effect on the sigmoid, because of the
advantage of dose distribution including dose of target and OARs
 Taking an example the Bladder and the bowel are in close proximity to the
PTV Target ,by ensuring the bladder is full and the bowel is empty we are able
to keep the target area in a consistent position each day or each
Radiotherapy treatment .

7. Steps of simulation Process - RTT note
 It Is very important to execute Bowel & Bladder Preparation for
Radiotherapy of the Pelvic area Targets
 I believe this is very challenging and for Radiation Therapist to make the
Patient council and ready for those Protocols
 Always needs to make a note of the amount of water consumed and the
duration
 Encourage patient to hold the bladder and instruct them to wait in a normal
temperature room
 Over filled bladder and the patients who cant hold nominal bladder amount
its better to take scan with moderate filled bladder as it is convenient for
them and good for us to reproduce the bladder contour.
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8. These are the Following Steps RTT’s Should not miss while managing a
Bladder Protocol Patient
 At the CT appointment the Radiation Therapists Should explain the procedure and position
on the treatment couch.
 Patient should be instructed to report at least 30 min to 1 hr prior to your CT appointment
and drink 500 to 1Ltr water. (Depending upon Institutional Protocol)
 During the CT scan procedure, Therapist should check the volume of the bladder and
bowel with performing a check scan
 The CT scan can be repeated on the same day or may be arranged for an alternative day.
 At the time of Radiation treatment RTT should ask patient to empty bowels and bladder.
 If the bladder is not full enough, the Radiation Therapists should inform patient to drink
more water, alternatively a bladder which is too full may need some emptying.
 If the bowel is distended with solid/gas, the Therapists need to ask to go to the toilet again
to empty.
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9. Pre Simulation Note for patients for starting Bladder Preparation :-
 A week before CT scan planning appointment we need to instruct the patient to drink fluids regularly
throughout the day .
 Maintain a intake of at least 1.5-2 L per day.
 This will ensure patient remain well hydrated throughout the Treatment , and helpful for the radiation
therapists to achieve the full bladder during preparation for each treatment session
Bowel preparation
 To maintain daily bowel motions, begin taking ClearLax daily with water five days before your CT
planning appointment.
 By following the ‘Bowel preparation instructions’ and ‘Dietary guidelines for pelvis radiotherapy’, it
helps reduce the amount of gas and residue in your bowels which helps achieve a stable prostate
position as well.
 Once all this criteria's match we can Proceed with the CT Simulation of the patient and documented
the Bladder Holding Time
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10. Diagnosis we need to treat with Bladder Protocol
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Ca Prostate ( Preferably Using the full Bladder Protocol)rotocol)
Ca Bladder (Preferably Using the Empty & Full Bladder Protocol)otocol)
Ca Rectum (Preferably Using the full Bladder Protocol)
Carcinoma Cervix (Preferably Using the full Bladder Protocol)
GI Track and Pelvic Malignancies (Preferably Using the full Bladder Protocol)
These are the few pelvic cancers preferably treating with the Bladder protocol
Ca Uterus ( Preferably Using the full Bladder Protocol)rotocol)

11. Understanding of CBCT image Therapist point of view
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 There are few standpoints which can help to evaluate the pre
treatment CBCT image on daily basis to check the bladder
filling .
 Need to have a gross knowledge about the anatomy of the
Pelvis area and their movements
 Pre-treatment, in-room three-dimensional volumetric soft
tissue imaging provides anatomical information that can
feedback into the plan and adapt dose delivery
 Always needs to check the bladder filling on the sagital section
to evaluate the anterio- superior movement of the bladder.
Sagital Section Maching

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Axial Plane View Sagittal Plane view Coronal Plane view
CBCT Images of Pelvic Radiotherapy in 3 planes with Target-OAR dose coverage

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MVCT Images of Diagnosis : Ca Rectum
Day 1 & Day 2 Image
Found different Bladder Filling with
same consistent water & Time
Discussion :-
 What is the Ideal Bladder Filling?
 Can proceed with treatment, with
respect to 90%,80% 70% Bladder
filling /Rectum Filling ?

14. Implementation Plan of the day Concept
 One of the commonest adaptive methods in pelvic area radiotherapy is
‘Plan of the Day’ (POD) plan selection from a plan library
 The POD approach utilises volumetric image guidance with appropriate soft-
tissue-based plan selection to select the most appropriate Plan
 The margins applied around the target to create the various PTVs used for
the library of plans can be population-based.
 With the reduction in treatment volume superior to the target volume, this
suggests potential for reduced irradiation of small bowel
 The effect of intra-fractional bladder filling suggested that intra-fractional
bladder filling motion could result in three-dimensional directional variations
 The bladder motion can be be unpredictable and can increase
significantly between pre and post-treatment, thus intra-fractional filling
must be carefully assessed
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POD Plans are Respectively :-
1) Large PTV – Blue Colour
2) Medium PTV – Orange Colour
3) Small PTV – Green Colour
Margin kept 5mm from each PTV
Axial Plane Coronal Plane Sagittal Plane
Therapist can select the Plan for the day according to the
bladder filling and PTV coverage

16. Dosimetric Impact on Partial Bladder treatment
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Dosimetric impact of variable bladder filling on IMRT planning for
locally advanced Pelvic cancers have a Significant impact on
target and organ at risk (OARs)
Bladder filling variations have an impact on cervico-uterine
motion/shape,
It has an impact on the dose to the target and OARs. It is
recommended to have a threshold bladder volume of at least
70–75% of optimally filled bladder during daily treatment.

17. Intrafraction Motion adaptations
Adaptive Radiotherapy to Address Target Motion
 The bladder is relatively mobile target subject to filling variation and
deformation. It is fixed at the caudal pole and is abutted by the rectum or
uterus posteriorly.
 If the bladder volume increases non-uniform organ expansion generally
occurs which is more pronounced in the cranial and anterior directions .
 The intra-fractional bladder filling did increase with longer treatment duration
although the correlation was suggested to be weak
 MR-Linac offers opportunity for in-room and real-time MRI scanning with
ability of plan adaption at each fraction while the patient is on the treatment
couch.
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Intrafraction Motion of Pelvic area
Positive impact on time efficiency in terms of treatment time slot availability and department resources, but also
reduce the risk of intra-fractional bladder motion as an increase in time is associated with an increase in intra-
fractional bladder filling

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The use of image guidance protocols using soft tissue anatomy identification before treatment can reduce inter
fractional variation. This makes intrafraction clinical target volume (CTV) to planning target volume (PTV)
changes more important, including those resulting from intrafraction bladder filling and motion
Intrafraction motion of the bladder based on pre treatment and post treatment bladder imaging can be
significant particularly in the anterior and superior directions. Patient motion, bladder centroid motion, and
bladder filling all contribute to changes between pre treatment and post treatment imaging.
CTV to PTV margins based only on daily pre treatment soft tissue position.
Small bladders on pre treatment imaging had relatively the largest increase in pre treatment to
post treatment volume
Which Intrafraction margin Needs to Take in account

19. Conclusions
Very First day CT-Simulation is very Important key tool to achieve the desired bladder on
daily Treatment
Current bladder filling techniques for patients treated with EBRT result in non-consistent
volumes of urine in the urinary bladder at time of treatment.
CBCT prior each fraction of RT is useful for urine volume estimation in order to ensure
consistent bladder filling needs validation in preclinical and clinical studies to test
consistency of bladder filling protocols.
Further research is needed to develop non invasive methods of real-time urine
measurement that ensure highly consistent bladder filling
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