MOTION MANAGEMENT IN RADIOTHERAPY

1. MOTION MANAGEMENT IN RADIOTHERAPY
DR KANHU CHARAN PATRO

2. RADIATION ONCOLOGIST-THE ARJUN

3. SBRT WORK FLOW
Simulation Planning
TX
Deliver
y
Motion Verification Localization
Motion Management
Delivery

4. EVERYBODY IS A KING
WHEN EVERYTHING IS INSIDE THE RING [PTV]

5. PUSHING BACKWARD AND FORWARD
ALWAYS NOT THE POINT OF INTEREST
OAR
TARGET
5

6. BECAUSE
ORGANS DO NOT FOLLOW STATUE GAME

7. SYSTEMATIC
VS
RANDOM

8. 8/1/2023

9. 8/1/2023

11. 8/1/2023

12. THE HYSTERICAL MOTION

15. MOTION MANAGEMENT
1.Intrafraction
2.Interfraction

18. GATING
Delivery of radiation within a specified part of the patient’s
breathing cycle termed ‘the gate’. Phase or amplitude based.
Uses external respiration signals e.g. infrared, spirometry,
thermistors or internal fiducials. internal fiducials.
Can significantly reduce margins required, therefore
potential decrease in dose to OARs. Imaging and treatment
synchronised with patient’s breathing cycle
Increases time to deliver treatment. Assumes that fiducial signal and
its periodicity is reflective of tumour motion. Requires regular
imaging and therefore increased imaging dose. More complex quality
assurance procedures

21. PHASE BASED TREATMENT-
CHOOSING PART OF DUTY CYCLE
8/1/2023

26. HOLDING
Assists breath-hold by use of a valved spirometer. Often at
moderate or deep breath-hold.
Can reduce motion artefacts. Improvements in dose to
organs at risk. Potential for dose escalation compared
with free-breathing technique
Patient selection important; non-compliance of patients
with poor respiratory function. Increase in quality
assurance procedures

29. VOLUNTARY BREATH HOLD USING WIRELESS DOOR BELL
1. You can practice voluntary breath hold/DIBH for
breast /end expiratory breath hold for abdomen
SBRT system when there is no motion
management system available.
2. Needs proper training to the patient and the
technologist
3. When patient inside the treatment room he/she
holds the breath [sends signal] and technologist
switch on the beam.
4. When patient exhausted with breath holding again
sends signal , then technologist switch off the
beam .
5. Procedure repeats till the total treatment is over.
6. For all this procedure patient needs to send signal
by various means . it may cause positioning error.
7. Wireless house bell will help this condition. Just
switching the bell [on hand of the patient], signal
sending will be easier and more practical.
CLINICAL EXPERIENCE 22nd OCT 2018/PHYSICS

30. ABDOMINAL COMPRESSING
Abdominal compression plate can be used in conjunction
with stereotactic frames to limit diaphragmatic motion
by forced shallow breathing.
Permits normal respiration while reducing
diaphragmatic and hence tumor motion.
May be unsuitable for obese patients or those with poor respiratory
function. Can lead to more erratic breathing in some instances.
Requires regular imaging due to difficulties associated with plate
position reproducibility

33. TRACKING
Real-time delivery of radiation with simultaneous tracking
of internal or external surrogate.
Can significantly reduce margins required, therefore
subsequent decrease in dose to OARs. Decreased time to
deliver treatment compared to gating
Increased imaging dose with fluoroscopy.

34. 8/1/2023

36. 8/1/2023

41. SURROGATE MARKERS FOR TRACKING
• BILLIARY STENT
• INTERNAL FIDUCIARIES
• BONY MARKERS

43. Assessment of motion
• Fluoroscopy mode
• 4D CT
• SLOW CT
• MULTIPHASE CT

44. 4D CT
Enables correlation of computed tomography scanning with
patient’s respiration. Breathing cycle monitored by using
external surrogate
Reduced blurring/artefact compared with slow computed
tomography. Can evaluate mean tumour position and
tumour motion correlation with surrogates and
surrounding OARs.
Increase in imaging dose compared with conventional
computed tomography scan. May be unreliable in irregular
breathing patterns leading to artefact

47. SLOW CT
Computed tomography scan operated slowly and/or
multiple slices taken are averaged, i.e. multiple phases of
respiration are recorded by slice
Generally available on most computed tomography
scanners.
Loss of resolution, which may lead to tumour blurring and
subsequent increase in observer error in tumour and OAR
delineation

55. WHICH MOTION MANAGEMENT
SYSTEM IS BETTER?

56. GOSSIP- WHOSE SPOUSE IS BETTER?

57. ANSWER- WHAT MANAGEMENT ACQUIRES

58. THANKS