Adaptive Radiotherapy is a closed-loop radiation treatment process where the treatment plan can be modified using a systematic feedback of measurements, Intending to improve radiation treatment by systematically monitoring treatment variations and incorporating them to re-optimize the treatment plan early on during the course of treatment.

1. A COMPLETE OVERVIEW ON ADAPTIVE
RADIOTHERAPY OVER DAILY IMAGE GUIDED
RADIOTHERAPY
SUBRATA ROY
SENIOR RADIOTHERAPIST

2. NATURE ALSO
ADAPTS
THE WORD ADAPTATION COMES FROM LATIN WORD ADAPTATRE WHICH MEAN TO FIT

3. What Adaptive Radiotherapy exactly
Basic Concepts Of Adaptive RT
Types of Adaptive RT
Process involved in Adaptive RT
How to justify the need of adaptive
Constituents Of Adaptive Radiotherapy
Image Registration Process
Challenges Of Adaptive Radiotherapy
Inadequacy of Adaptive RT
Adaptive Radiotherapy for Different Body Sites
Future of Adaptive with MRI guidance.
LINE OF PRESENTATION

4. ADAPTIVE RADIOTHERAPY
It is a closed-loop radiation treatment process where the
treatment plan can be modified using a systematic feedback
of measurements, Intending to improve radiation treatment
by systematically monitoring treatment variations and
incorporating them to re-optimize the treatment plan early on
during the course of treatment.

5. HROW BACK TO THE IGRT CONCEPT!
A procedure that refines the delivery of therapeutic radiation by applying image-based target re-
localization to allow proper patient repositioning for the purpose of ensuring accurate treatment and
minimizing the volume of normal tissue exposed to ionizing radiation” – ASTRO
When ART is included within the radiation therapy treatment process, image-guided radiation therapy (IGRT)
is essential. Images taken immediately before or during your treatment allow the radiation therapy team to
assess the shape and size of the area requiring treatment, every day. The treatment is then modified for any
observed changes, to deliver the most accurate treatment on a daily basis.
Although both IGRT and Adaptive Radiotherapy exists from long back,
With time… with improving technology…
Radiation techniques improved and so, THE OUTCOMES.
Adaptive Radiotherapy Is not having individual existence without IGRT..!!

6. IGRT VERSUS ART
Image Guided Radiation Therapy (IGRT)
Commonly referred to a process to re-position the patient
without modifying the initial treatment plan.
Adaptive Radiation Therapy (ART)
Involves the modification of the initial plan, including changing
beam apertures or intensity patterns.

7. BASIC CONCEPT OF
ADAPTIVE RT
The main concept of adaptive is on account for internal
anatomical changes,some organs in the body that require
radiation therapy can change in size and shape over the days
and weeks that a course of treatment can take.
The aim of ART is to account for these changes and deliver
the radiation dose to the tumour as accurately as possible.

8. TYPES OF ADAPTIVE RT
ADAPTIVE RT
MOTION ADAPTIVE
Ex: Plan of the Day IMRT
BIOLOGICAL ADAPTIVE
Ex: Theragnostic Planning
RESPONSE ADPTIVE
Ex: Shrinkage of GTV &
OAR
TIME ADAPTIVE
Ex: Mid Course CT &
Planning.
Motion
I,e-Intrafraction
Morphologic Changes
I,e-Interfraction

9. Adaptive radiotherapy can occur at three different timescales:
 Online - immediately prior to a treatment, and in.
 Offline - between treatments.
 Real time - during a treatment.
Proposed based on the idea that advancements in in-room imaging technologies would make the
process of target localization and definition more precise.

10. ONLINE ADAPTATION
Online Adaptation is typically referred to Imaging Just prior to each treatment and the plans
were adapted to changing anatomy daily.

11. OFFLINE
ADAPTATION
The imaging system used : Conventional CT
scanner or an in-room CT scanner.
The adaptation can be triggered by :
•As a protocol (for example after 20 and 40Gy
delivered dose),
•Clinical observations of masks not fitting, weight
loss, or other surface changes, or by changes
observed on an in-room imaging system

12. REAL TIME ADAPTIVE
RT
Imaging session and treatment session are intertwined
Time separation is shown to be on the order of seconds or less.
Rationale - significant drift in the mean position of a tumor
during radiotherapy treatment.
The concept of intra-fraction motion management arises…here !

13. PROCESS INVOLVED IN ADAPTIVE
RADIOTHERAPY
The importance of using an adaptive process in radiation therapy is that the treatment plan, especially the margin and
treatment dose, can eventually be customized to the individual patient. Adaptive radiation therapy has been introduced
to incorporate the position variation of the individual patient into the treatment optimization process during the course
of radiotherapy.

14. OW TO JUSTIFY THE NEED OF ADAPTIVE
 Clinical Assessment.
 Formation Of Gap between Immobilization Device and Skin.
 By Reviewing Image Registration.
 Patient Complaint against Pain Or Reaction.

15. NSTITUENTS OF ADAPTIVE RADIOTHERAPY
 Image Guided Solutions
 Deformable Registration
 Deformable Dose Accumulation
 Automatic Re-contouring
 Model Based Segmentation
 Tumour Growth/Regression Evaluation
 Patient-specific CL-PTV (Confidence-limited)
 Dose Reconstruction And Dose Imaging

16. CONSTITUENTS OF ADAPTIVE RADIOTHERAPY
(CONTINUE)
Adaptation to tumor motion
Adapt to tumor / organ deformation and volume change.
Adaptation to tumor motion
Move couch electronically to adapt to the moving tumor
Exactrac 6D Robotic couch
Move a charged particle beam electromagnetically
RPM system
Move a robotic lightweight linear accelerator
Cyber knife
Move aperture shaped by a dynamic MLC
Calypso system

17. IDEAS FOR THE MANAGEMENT OF
MOTION
 Respiration induced.
 Organ motion.
Methods to Control /Compensate for Lung Motion During
Treatment.
•Free breathing methods:
Internal Target Volume (ITV)-based treatment.
Gating
Tracking
•Breath-hold methods:
Active Breathing Coordinator (ABC) - DIBH

19. The goal of Bi GART is treatment adaptation in time and space
based on biological and anatomical features, maximizing the
therapeutic ratio for each individual patient.
1) Biology of tumors and normal tissue to guide patient selection,
target volumes and dose prescription in RT
2)Functional imaging of tumors and normal tissues with functional
imaging techniques based on magnetic resonance imaging (MRI)
and positron emission tomography (PET), and the use of such
images for dose painting and normal tissue avoidance in RT
3)Treatment planning and delivery challenges in adaptation of RT
and particle therapy based on changes in tumor and normal tissue
biology, anatomy and/or function
4)Clinical outcome of biology-guided and adaptive RT

20. MAGE REGISTRATION
According to the nature of transformation-
It is of 2 types- Rigid registration and Deformable
registration.
Rigid fusion-
Direct intensity match or point match
No compensation for motion or patient position
6 degrees of Couch freedom.
Image-1 An image is a N-dimensional mathematical function mapping coordinates to
intensity values.
Image-2 Principle of Image Registration process
IMAGE-1 IMAGE-2

21. EFORMABLE IMAGE REGISTRATION(DIR)
Aligning images rigidly allows some changes in
images to be easily detected. However such an
alignment does not model changes from organ
deformation, patient weight loss, or tumour
shrinkage. It is possible to take such changes into
account using deformable image registration (DIR)
which is a method for finding the mapping between
points in one image and the corresponding point in
another image.
The tasks of planning, delivery and evaluation of
radiotherapy can all be improved by taking organ
deformation into account.
Morphing one image into
another with correct
correspondence

22. REGISTRATION:
 Complicated
 Consists of a matrix with huge number of unknowns.
 Multimodality images can be fused
 Allows dose and contour information to be transferred between images,
substantially reducing workload.
 As the timescales for adaptation decrease, the computation time of
deformable image registration must correspondingly decrease.

23. RT
We treat patients assuming the shape, volume and relative positions of
structure will remain same throughout treatment
Since living patient is a dynamic treatment problem
None of ICRU margins accounts for these changes
At Simulation Time
After 20 Fractions Of Rx

24. DIR WORLFLOW

25. DIR
(1)Better Target Definition.
(2)Image Enhancement.
(3)Propagation Of Organ Contours From One Image Set To Another.
(4)Calculation Of Accumulated Dose In Organs Experiencing Inter- Or
Intra-fraction Organ Deformation For 4-D Or Adaptive Therapy
Planning.
(5) 4-D Image Reconstruction.
DIR plays a key role in implementation of adaptive radiotherapy.
Development of an accurate,robust DIR algorithm has been an active
area of research and optical free based Demons and B- Spline based
free form are two most popular registration algorithms used in clinical
RT planning systems.

26. WHEN THE DIR IMAGE IS USEFUL
Deformable registration warps moving image (M) via
deformation field (DF) to align (M) to the target image (T).
• DF defines the motion of each image voxel from M to T.
• This produces a registered image (R).
MOVING-M REGISTERED-R TARGET-T
DEFORMATION FIELD-DF

27. RADIOTHERAPY
Adaptive radiotherapy offers a great clinical promise in Iso-toxic
escalation of radiation dose to target structures and also in reduction
of normal tissue complications. Progresses have been made in
development of deformable dose accumulation and re-planning
techniques in the past years. The accuracy of DIR remains the major
concern in the clinical implementation of ART. It has been illustrated
that intensity-based DIR algorithms are prone to have errors in
regions with low image contrasts and consequently, errors in dose
reconstruction and response assessment may exist in these regions.

28. HEALTHY TISSUE
physiological changes caused by the musculoskeletal, respiratory,
cardiac, gastrointestinal, and genitourinary systems
Treatment-induced changes such as cell death and tumor shrinkage,
tumor growth resulting from accelerated repopulation, weight loss
or gain because of changes in appetite caused by radiation, concomitant
chemotherapy or hormone therapy, fibrosis of normal tissue, and so on

29. CT SCAN!
Is One CT Before Treatment is Ideally
Enough for Whole
Treatment Process???

30. Treatment related dynamic tumor volume changes
WEEK -1 WEEK-3

31. Does One DVH Dose Data Enough To Accept
The Plan and Continue daily treatment?
30# Treatment =30 DVH Graph Plot
A
B
DVH RECTUM DOSE DVH-A DVH-B
A single plan designed before treatment is insufficient to describe the actual delivered doses, and often leads to suboptimal
treatment.

32. TREATMENT
Changes in tumor size shape:-
Bulky neck ln changing body contours.
Retroperitoneal mass regression causing kidneys into treatment
field.
Proptotic eyeball regressing back with response.
Craniopharyngioma cyst swelling.
Changes in patient geometry:-
Weight loss.
Resolving postoperative changes/edema.

33. TREATMENT
PLANNED ACCUMULATED ADAPTED ACCUMULATED
Optimization of an adaptive plan requires radiation dose delivered to each image voxel to be accumulated appropriately
over the course of treatment. The accuracy of dose accumulation depends on the DIR and dose mapping methods used.

34. Tumor volume shrinkage in response to the treatment
Tumor shape deformation due to filling state change of
neighboring organs
Relative position change between tumor and normal organ
SOLUTIONS
Develop a new treatment plan that is optimal to patient’s new
geometry
Adaptive radiation therapy (ART)
RELATIVE PROBLEMS

35. PHICAL REPRESENTATION OF DOSE ACCUMULATION
Fig Shows the accumulated dose for the target volume during the treatment.

36. RADIOTHERAPY
 The technology is new and research in RT is in its infancy;
but the potential benefits remain to be seen.
 How often should new plans be generated? Once?
Weekly? Daily?
 Whether altering the target volume would adversely
impact tumor control ?

37. NADEQUACY OF ART DEPENDS ON
 Specifics of implementations.
 Specific tools that we are going to use.
 ART mitigates delivery uncertainties
 Uncertainties inherent to the ART process should be
evaluated and compared with treatment uncertainties
 Little information is available in literature about
uncertainties of ART On-line ART techniques:

38. ADAPTIVE RADIOTHERAPY FOR DIFFERENT BODY
SITES
 Head And Neck
 Prostate
 Lung
 Cervix
 Bladder

39. ADAPTIVE RADIATION THERAPY FOR HEAD AND NECK CANCERS
Adaptation Is occurring to changes in morphology of H&N tumor and OAR’s.
factors: weight loss, tumor response, progression of disease
Evaluated the impact of replanning patients with either significant weight loss or
tumor response during IMRT.
Compared to replanning, not replanning significantly decreased dose to the
target volume and increased doses to normal tissues (spinal cord and
brainstem). The doses to 95% of the PTV-GTV and the PTV-CTV decreased by
up to 6.3 Gy and 7.4 Gy, respectively.

40. Despite the relatively large number of studies published so
far, the heterogeneity between studies prevented
unambiguous conclusions on how to select patients for
adaptive radiotherapy in head and neck cancer.
A number of potential selection criteria for anatomic and
dosimetric changes were identified.

41. OSIMETRIC IMPACT OF ANATOMICAL MODIFICATION
Alteration in patient anatomy during treatment
Modifications of both target volumes and OARs
The dose distribution that is actually delivered to the patient might
significantly differ from what was planned.

42. ART PROSTATE
A large target margin has been the traditional approach of
accounting for treatment position variations in
conventional radiotherapy. This has been one of the
major limiting factors in the prostate cancer treatment
using external beam radiation therapy.
Planning target margin can be significantly reduced by
systematically accounting for patient-specific variations.
However, the management of patient-specific anatomical
variation requires multiple measurements of patient
anatomy accomplished by different image feedbacks.
Among them, volumetric image feedback, (including both
off-board conventional CT and onboard CBCT) has been
most commonly used.

43. DAPTIVE RT IN PROSTATE CANCER
•Aim Is to reduce the treatment margins to reduce normal
tissue toxicity.
•To incorporate set up errors and application of
predetermined set up margins.
•Individualized setup adjustments to reduce the magnitude of
setup error.

44. DAPTIVE RADIATION THERAPY LUNG
Lung cancer radiation therapy (RT) is associated
with complex geometrical uncertainties, such as
respiratory motion, differential baseline shifts
between primary tumor and involved lymph nodes,
and anatomical changes due to treatment
response.Generous safety margins required to
account for these uncertainties limit the potential of
dose escalation to improve treatment outcome..
More importantly, repetitive imaging during
treatment quantifies patient-specific intrafraction,
interfraction, and progressive geometrical
variations. These patient-specific parameters

45. •A total of 158 MVCT imaging sessions were performed on 7 lung patients.
•The GTV was reduced by 60–80% during the course of treatment.
•Based on these treatment planning studies, the absolute volume of ipsilateral lung
receiving 20 Gy can be reduced between 17% and 23% (21% mean) by adapting the
treatment delivery.
•The benefits of adaptive therapy are the greatest for tumor volumes >25 cm3 and
are directly dependent on GTV reduction during treatment.
Adaptive radiation therapy for lung cancer clinically relevant reductions in normal
tissue doses for frequencies of adaptation ranging from a single replan up to daily
replanning. Increased frequencies of adaptation result in additional benefit while

46. ART FOR CERVIX
Radiotherapy for cervix cancer is challenging in patients exhibiting
large daily changes in the pelvic anatomy, therefore adaptive
treatments (ART) have been proposed. The clinical implementation
and subsequent evaluation of plan-of-the-day.
Volumetric Arc plan consisting of an empty bladder plan, a full
bladder plan and a motion robust backup plan is developed. Daily
adaption was guided by cone beam computed tomography (CBCT)
imaging after which the best plan from the library was selected.
Daily doses in the rectum, bladder and cervix-uterus target (CTV-T)
we can compare to a simulated non-adapted treatment (non-ART),
which employed the robust plan for each fraction.

47. PLAN SELECTION
BLADDER POSITIONUTERUS MOTION

48. MRI-guided radiation therapy provides a method by which we are able to
observe daily changes in the patient’s internal anatomy. This can be
caused by many factors, ranging from reduction in tumor size to differing
amounts of content in the stomach, bladder and bowels. Consequently,
radiation treatment plans based on an image acquired weeks prior to
radiation delivery may not adequately represent the patient’s anatomy on
a daily basis.
Through this we can identify these anatomical changes and adapt the
patient’s treatment on a daily basis, which can produce a substantial
improvement in the radiation dose distribution. The doses to normal
tissues are also reduced with the adaptive plan.
FUTURE OF ADAPTIVE WITH MRI
GUIDENCE

49. INDICATIONS FOR ONLINE ADAPTIVE RADIOTHERAPY OF
INTERFRACTIONALPANCREAS-TO-DUODENUM MOTION
IN MR-GUIDED RT
Dose-limiting structures, such as the duodenum, render the treatment of pancreatic
cancer challenging. In this multi-institutional study,dosimetric differences caused by
interfraction pancreas-to-duodenum motion using MR-IGRT to determine the potential
impact of adaptive replanning.
In this the indication for adaptation through evaluation of pancreas-to-duodenum
interfraction motion. Adaptation was considered indicated when daily positional variations
enabled dose escalation to the target while maintaining duodenal constraints.

50. Adaptive Radiotherapy for Bladder CancerdA Systematic Review
Vickie C. Kong, MSc, MRT(T)a
*, Amy Taylor, MScb
and Tara Rosewall, PhD, FCAMRT(T)a
a
Radiation Medicine Program, Princess Margaret Cancer Centre and Department of Radiation Oncology, University of Toronto, Canada
b
Sheffield Hallam University, Sheffield, UK
Adaptive strategies have been developed for bladder cancer
radiotherapy to address the large interpatient and inter-fraction bladder
volume variation.
Dosimetric evaluations that incorporate the effect of OAR motion are
currently lacking.
PLAN OF THE DAY
Daily megavoltage (MV) imaging helped to choose the most appropriate
PTV encompassing bladder for the particular day (using plan-of-the-day
approach).
CONCLUSIONS:
Adaptive IGRT using plan-of-the-day approach for bladder preservation
is clinically feasible, with good oncological outcomes and low rates of
acute and late toxicities. Dose escalation is safe and possibly improves
outcomes in bladder preservation.

51. SBRT pancreatic radiotherapy case where adaptive radiotherapy was indicated due to interfraction
motion of pancreas tumor to duodenum.

52. CONCLUSION
Limits and Accuracy of adaptive Radiotherapy depend on particular
Implementation, Uncertainties are present. With technical advancements,
particularly in computer, network technology and optimization algorithms,
online adaptive practices is becoming increasingly feasible and may likely
become a “Standard Practice” in the near future. In conclusion, the
workflow and technology features are essential factors for introducing and
providing robust adaptation of the treatment plan throughout the course of
treatment. Indeed the useful measure to identify patients in need for an
adaptive treatment is the goal of strategy.

53. REFFERENCES:
1. Yan D, Vicini F, Wong J, Martinez A. Adaptive radiation therapy. Phys Med Biol. 1997;42(1):123–32.
[PubMed]
2. Wu C, Jeraj R,Olivera GH, Mackie TR. Re‐optimization in adaptive radiotherapy. Phys Med
Biol.2002;47(17):3181–95. [PubMed]
3. Image guided Adaptive Radiotherapy By Dr. Vijay Kumar.K.
4. Adaptive Radiotherapy By Mayur Mayank.
5. Deformable Image Registration in Radiation Oncology, Sarah Geneser, Ph.D.Medical Physicist Department
of Therapeautic Radiation Oncology Yale University and Yale-New Haven Hospital.
6.Online magnetic resonance image guided adaptive radiation therapy: first clinical applications. Acharya S,
Fischer- Valuck BW, Kashani R, et al. Int J Radiat Oncol Biol Phys. 2016;94:394–403. [PubMed] [Google
Scholar]
7. Simulated online adaptive magnetic resonance–guided stereotactic body radiation therapy for the treatment
of oligometastatic disease of the abdomen and central thorax: characterization of potential advantages. Henke
L, Kashani R, Yang D, et al. Int J Radiat Oncol Biol Phys. 2016;96:1078–1086.[PMC free
article] [PubMed] [Google Scholar]
8. Dosimetric validation of a magnetic resonance image gated radiotherapy system using a motion phantom
and radiochromic film. Lamb JM, Ginn JS, O'Connell DP, et al. J Appl Clin Med Phys. 2017;18:163–

54. THANK YOU FOR KIND ATTENTION