Total body irradiation

This is a presentation on total body irradiation. This presentation explains about various techniques. positions used for TBI. Advantages and disadvantages of TBI.
It also gives an idea on Dosage and side effects.

1. TOTAL BODY
IRRADIATION
BASIL PAUL SUNNY
RADIOTHERAPIST

2. INTRODUCTION
•TBI started using in 1956 by Dr. Donnall
Thomas to treat patients with end stage
leukemia
•He was awarded Nobel prize for medicine in
1990
•Rationale for use of TBI not changed
•Tremendous change in
Delivery of TBI
Radiation sources used –Co^60 / LINAC
Dose measure techniques-more reliable and accurate rather
than erythema dose for determination of dose delivered

3. INTRODUCTION
•One of main component in interdisciplinary
treatment of hematological malignancies-
leukemia, lymphoma, rarely solid tumors
•Enables myeloablativehigh dose therapy
(HDT) & immunoablativeconditioning therapy
prior to stem cell transplantation

4. TASKS OF TBI
•Eradicating diseased marrow
•Reducing tumor burden
•Immunosuppression-lymphocyte elimination to
allow grafting of donor bone marrow
•Deplete the BM to allow physical space for
engraftment of healthy donor marrow
•Eradication of cells with genetic disorders-
Fanconi’sanemia, thalassemia major, Wiskott-Aldrich
syndrome

5. TBI IN CONDITIONING REGIMENS
MALIGNANT
1. LUKEMIAS,
ACUTE MYELOID LUKEMIA (AML)
ACUTE LYMPHOBLASTIC LUKEMIA (ALL)
CHRONIC MYELOID LUKEMIA (CML)
HAIRY CELL LUKEMIA
2. LYMPHOMAS/ MYELOPROLIFERATIVE DISORDERS
NON HODGKINS LYMPHOMAS
REFRACTORY HODGKINS DISEASES
MYELODYSPLASIA
MULTIPLE MYELOMA

6. TBI IN CONDITIONING REGIMENS
•PEDIATRIC SOLID TUMORS
NEUROBLASTOMA
EWINGS SARCOMA
•ADULT SOLID TUMORS
SMALL CELL OF LUNG
TESTICULAR CARCINOMA

7. TBI IN CONDITIONING REGIMENS
•NON MALIGNANT CONDITIONS
IMMUNE DISORDERS
APLASTIC ANEMIA
GENETIC DISORDERS
WISKOTT AIDRICH SYNDROME
OSTEOPETEROSIS
TAR SYD
FANCONI ANEMIA

8. CURRENT INDICATIONS
•HIGH RISK AML/CML IN FIRST REMISSION
•SECOND REMISSION AML
•SECOND REMISSION ALL IF THERE IS HLA COMPATIBLE SIBLING
DONOR
•FIRST REMISSION ALL WITH CNS INVOLVEMENT / PH
CHROMOSOME POSTIVITY
•LOW GRADE LYMPHOMA AFTER CHEMO FAILURE
•CHILDHOOD AML/ ALL IN SECOND / SUBSEQUENT
REMISSIONS

9. ADVANTAGES
•No sparing of sanctuary sites (testis, brain)
•Dose homogeneity regardless of blood supply
•Independent of hepatic &renal functions
•No problems with excretion or detoxification
•Ability to tailor the dose distribution by
shielding specific organs or by boosting sites

10. DISADVANTAGES
•Potential late side effects
Sterility
Cataract
Growth retardation
Neurological toxicity
•Patient body contour irregularities causes
adding of compensators

11. PRE-REQUISITES FOR TBI
•Medical history and evaluation
•Interdisciplinary approach from doctors and
health professionals
•RT & BM transplantation facility must be in
same center
•Conditions with a low risk of infections is
recommended

12. PHYSICAL EXAMINATION
•Evaluation of oral cavity and dentition
•Neurological evaluation
•PS
•Organ function analysis
CCT> 60 ml/min
AST / ALT < twice the upper level of normal
PFT
EF> 40%
•Infectious disease evaluation
•Sperm banking

13. TECHNIQUES OF TBI
•Patient comfort and Reproducibility
•Position of patient and stability
•The common factor in the different techniques of TBI
is to deliver the prescribed dose of radiation to the
entire body in uniformity of +/-10% of the
prescription dose. +/-5% considered as the best.
IMPORTANT CRITERIAS

15. BILATERAL TBI

16. BILATERAL TBI
•Designed by Khan et al
•Patient sitting or lying down on a couch
Good Patient comfort
Less homogeneous dose distribution due to variable body
thickness, needs compensating blocks.

17. AP-PA TBI

18. AP-PA TBI
•Irradiated anteroposteriorly by parallel opposed
fields while positioned upright several meters from
the source
•More homogeneous dose distribution
•The principle of the technique is that the standing
TBI allows shielding of certain critical organs from
photons and boosting of superficial tissues in the
shadow of the blocks with electrons

19. OTHER TBI TECHNIQUES
MODIFIED CONVENTIONAL MACHINES
•Large stationary Beam , stationary patient
Extended SSD technique
Collimator removal method
•Moving techniques
Translational beam method
Sweeping beam method

20. McGill UNIVERSITY
SWEEPING BEAM TECHNIQUE

21. TBI: McGill TECHNIQUE

22. TBI-IRRADIATION METHODS

23. TRANSLATIONAL COUCH
Computer controlled

24. POSITION
•Patient lies supine
Length of patient -not more than 140 cm
If length greater than 140 cm –legs folded
with pillow tucked b/n both legs
•Arms flexed and placed near to chestwall
•Knees adjoined together, wrapped
•Positioned at extended SSD of 300 cm

25. 40 x 40 cm FieldSize,
Gantry 90, Collimation 45

26. Measurements
Skull
Neck
Shoulder
Chest
Abdomen
Thigh
Knee
Calf
Ankle

27. TARGET VOLUME
•All malignant cells including those circulating
•whole cellular immune system
•The Whole Body, including Skin

28. DOSE PRESCRIPTION
•High Dose TBI –13.2 Gyin 6 fractions over 3 days
•Standard dose TBI –12 Gyin 6 fractions over 3
days
•Low dose TBI –2 Gyin single fraction
•Lung is the dose-limiting organ (maximum 10 Gy).

29. DOSE REFERENCE POINTS
•The dose reference point is defined
at mid abdomen at the height of the umbilicus
according to an international consensus

30. TREATMENT DELIVERY
•Delivered in the position which measurements
are taken
•Under sterile conditions

31. OPTIMIZATION OF DOSE
•The homogeneity of dose in the target volume
•The effective sparing the lungs

32. DOSE VERIFICATION
•In vivo dosimetry is done with Semiconductor
diodes, mosfet,LiFTLD chips
•It is placed for skull, H&N , mediastinal regions

33. 1. COMPENSATORS
•Influences of irregular body contours have
to be compensated.
•Tissue compensators are used in
Head and neck region
Lower extremities and
Lungs (Not required usually as effective thickness at
mid mediastinum is greater than at umbilicals. Arms positioned
inline with lungs and increase total thickness)

34. TBI AAPM Report 17

35. 2. BEAM SPOILER
Skin/ surface doses in
Megavoltage beams is less
than D max
Beam spoiler has to be
positioned close to the
patient, For build-up the
surface dose up to at least
90% of the prescribed dose
1-2 cm thick acrylic is
sufficient to meet these
requirements
.

36. 3. DOSE HOMOGENIZATION in parts of the
target volume with reduced dose :
•Thoracic wall receives a lower dose due to
lung shielding.
•Additional irradiation however is not used
•Electron boost can be given if necessary

37. ACUTE COMPLICATIONS
•Nausea& Vomiting
•Headache
•Fatigue
•Ocular dryness
•Esophagitis
•Loss of apetite
•Erythema/hyperpigmentation
•Mucositis
•Diarrhea
•Fever

38. CHRONIC COMPLICATIONS
•Ocular –Cataract, dryness, keratitis
•Salivary glands –Xerostomia, dental caries, tooth
abnormalities
•Pneumonitis or pulmonary fibrosis
•Hepatotoxicity
•Radiation nephropathy
•Growth abnomalitiesin children
•Sterility and endocrine abnormalities
•Secondary mets

39. Targeted TBI –TMI and TMLI
•Total marrow irradiation -skeletal bone.
Conditioning regimen for multiple myeloma
•Total marrow and lymphoid irradiation (TMLI)
-bone, major lymph node chains, liver,
spleen, and sanctuary sites, such as brain.
Conditioning regimen for myeloid and
lymphoid leukemia

40. TOMOTHERAPY
•Desirable to deliver radiation only to immune
organs and bone marrow spaces sparing
sensitive structures like brain, lens, lungs,
kidneys
•IMRT planning could accomplish this, but
most systems are limited by field size issues
•Accurate IMRT depends on reproducible
patient position, which is complicated when
considering treating the entire marrow spaces

41. TOMOTHERAPY
•Tomotherapy-linear accelerator mounted in
head of a spiral CT unit
•IMRT delivered as beams spiral down axis of
patient supine on treatment couch
•The beams can be planned to deliver dose to
bones and bone marrow, liver and spleen as
well as major nodal groups and to relatively
spare the lungs and kidneys

42. TOMOTHERAPY ISODOSE
DISTRIBUTION

43. THANK YOU