Night 7k to 12k Navi Mumbai Call Girl Photo 👉 BOOK NOW 9833363713 👈 ♀️ night ...
Motion management in Radiation Oncology - 2020
1. Dr.V.Lokesh M.D.
Professor & HOD , Dept of Radiation Oncology
Kidwai Memorial Institute of Oncology
AROI KS Chapter2021
2. Introduction
Aim– Irradiate Tumour with minimal radiation dose to uninvolved
normal tissue
Era - common practice
Hypo fractionated regimens
Single Ablative doses of radiation
Reirraditon
Sophisticated RT Techniques
IMRT/SRS/SRT/SABR – under IG
Target Motion and normal tissue movements – confounding factor
Currently Quality RT – demands adequacy of proper equipment, proper
SOPs, trained staff (RO/RP/RTT) -- > to ensure setup accuracy - less
than few millimeters and safe delivery
3. patient positioning and immobilization
Often the weakest link in the chain of treatment
planning
Corrected by :
Appropriate - Mechanical immobilization
Patient
Education
Psychological preparation
Stabilization of Target etc.
8. respiratory motion is just one potential source of error in
radiotherapy :
Other important Contribution for errors are eg: Lung & Breast
cancer
Large inter-physician variations in GTV & CTV
Setup errors
The dosimetric consequences of these variations are almost
an order of magnitude larger than those caused by
respiration-induced motion
Respiratory motion varies
from day to day,
tumor and normal tissues can shrink, grow, and shift in response to
radiation therapy and potentially to other concomitant therapies.
Machine related – issues (CT sim / LA / Couch /planning System –
related issues also have an impact and QA – dosimetric issues.
9. Methods of limiting respiratory
motion
a. Abdominal compression
b. Respiratory gated RT : involves turning the beam ON
during position of respiratory cycle
a. RPM
b. ABC
10. Advances in IGRT – Addressing
Motion Issues
a) Image guided Target / Tissue delineation
1. PET
18 FDG
Non FDG Pet Miso
2. MRI
3. SPECT
b) 4D Imaging and Motion Management
c) In room Imaging
a. Ultrasound
b. Video surface imaging
c. Planar imaging : EPID / KV imaging devises
d. Fluroscopic – Fidutial based / non fidutial based
e. Volumetric Imaging : KV/Mv CBCT
d) MRI
e) Radiofrequency Localization System – Transponders
f) 4D imaging and motion management – 2D CBCT & fluoroscopic imaging
g) Tumour Tracking
11. Respiration induced Organ Motion
A significant problem in RT
T – located in Thorax & upper Abdomen
Ignored :
Substantial imaging artefact In treatment planning image
Inaccurate Target delineation
Unnecessary large target volume
13. Gating Strategy
Regardless of the gating system
patient respiration > divided - ten discrete time points (phases) per
period.
used to assess tumor motion and determine a gating strategy
0% phase corresponds to maximum inspiration
50% phase corresponds to maximum expiration
On average- most patients spend more time in expiration than
they do in inspiration, which creates a beneficial scenario for
respiratory gating around expiration
14. Respiratorty motion is arrested > no respiration-
induced tumor motion :: large window to treat the
tumor with limited motion
candidate for deep inspiration breath hold (DIBH)-
hold their breath for an extended amount of time,
creating a large window to treat the tumor with little
TARGET motion
15. Methods that are used in the management of
respiratory motion in radiation oncology
Motion-encompassing methods
respiratory gated techniques
breath-hold techniques
forced shallow-breathing methods
respiration-synchronized techniques
19. Active Breath Controller (ABC)
Elekta ABC system- helps in treating patients in deep
breath hold position.
It consists following components
1. Mouth piece
2. Spirometer
3. ABC control unit
4. Patient viewing monitor
5. Emergency button
6. Linac control Module.
20. Active Breath Controller (ABC)conti..
Indications for using ABC:
1. Carcinoma of Left breast ( conserved breast/ Chest wall)
2. Carcinoma lung- SBRT/ Radical RT for primary tumor
3. Carcinoma Liver
4. Carcinoma Pancreas
5. Mediastinal tumors
6. Metastatic tumor lesions in liver and lung.
21. Clinically suitable patient
Trained with spirometer for 3 days, patient is instrcuted to hold in deep inspiration
Patient is positioned in treatment position in mould room, the mouth piece is kept inside the
mouth of the patient, connected to the ABC system. Patient is asked to take the deep breath and
hold, the duration of breath hold and the volume is noted. The threshold levels are set.
Similarly patient is trained for 3 days
Patient is simulated in both free breathing (CT-1) and deep breath hold (CT-2), the external
fiducials are kept on body at the intersection of the orthogonal Lasers in DIBH position only.
The target structures and OARs are delineated on both CT-1 and CT-2
Planning is done on both CT-1 and CT-2
DIBH plan is implemented, then patient will positioned in the simulated position. In DIBH the
patient is aligned with in-room lasers, the necessary sifting of patient to the treatment isocenter
is done.
The verification image (CBCT/EPID) images are also taken in DIBH, couch corrections done and
radiation treatment is executed in DIBH
22. Study setting: Dept. of Radiation Oncology, Kidwai
Memorial Institute of Oncology
Study period: September 2019 to March 2020.
Total number of Patients: 49.
Carcinoma left Breast - where ever RT is indicated
Active Breath Controller (ABC)
23. Active Breath Controller (ABC)conti..
Dose: BCS: 50Gy/25# + 10Gy/5# boost or 40Gy/15# + boost
10Gy/5# & MRM: 50Gy/25 fractions or 40Gy/15
Technique: 3DCRT +/- free breathing or DIBH
Free Breathing
(n-25)
DIBH
(n-24)
Age 50±4.24 yrs 46±2.5yrs
Surgery type
BCS 3 6
MRM 22 18
Stage I - II 18 17
III 7 9
24. Active Breath Controller (ABC)conti..
Left breast patients treated with DIBH had statistically significant dose
reduction with respect to Mean dose to heart, percentage volume of
heart receiving 30Gy and Volume of lung receiving 20Gy compared to
free breathing technique.
Free Breathing
(n-25)
DIBH (n-24)
P-value
RT Technique 3DCRT
3DCRT +/-
hybrid VMAT
Left
Lung
Mean dose (Gy) 13.73±0.76 13.61±1.06 0.5876
V20Gy (volume-%) 29.5±8.71 24.7±4.94 0.005*
V15Gy(volume-%) 31.38±9.18 30.14±1.41 0.502
Heart Mean dose (Gy) 7.75±4.32 4.5±1.09 0.0003*
V30Gy (volume -%) 12.15±7.01 3.09±1.16 0.005*
V5Gy (volume- %)
26.16±9.12 25.08±21.21 0.75
25. Active Breath Controller (ABC)conti..
Advantage : Greater confidence in Tumour targeting
Limitations of ABC:
Time consuming
Cannot be integrated to the CT Simulator- Hence
automated gated simulation not possible.
Maintenance of the ABC system and laptops.
The superior threshold for the volume by which the chest
expands cannot be set.
recurring cost – Mouth Piece
Sterilization of mouth piece ???-
Limitations - ongoing COVID PANDEMIC?????
26. Real-time Position Management
(RPM) system
advantages
noninvasive,
easy to use,
well-tolerated by patients
because only an external respiratory signal is acquired, the correlation
between tumor motion and patient respiration must be closely
monitored throughout treatment.
Other system: ExacTrac X-Ray Monitoring System
combine Xray imaging of internal anatomy with an external respiratory
signal.
This technique allows the correlation between tumor position and
patient respiration to be continuously updated at a reasonable
frequency, keeping patient x-ray exposure in mind.
27. RPM – Attention to marker motion
and respiratory cycle – beam ON
mismatch
29. AAPM Task Group 76a
Intrafraction motion is an issue that is becoming
increasingly important in the era of image-guided
radiotherapy
Intrafraction motion can be caused by the respiratory,
skeletal muscular, cardiac, and gastrointestinal
systems.
Of these four systems, much research and
development to date has been directed towards
accounting for respiratory motion.
Respiratory motion affects all tumor sites in the thorax
and abdomen