The document discusses total body irradiation (TBI), which involves delivering radiation to the entire body to condition patients for stem cell transplantation. It provides an overview of the history, concept, indications, doses, prerequisites, and treatment planning for TBI. Complications of TBI are also reviewed, including both immediate toxicities like nausea and vomiting as well as late effects such as salivary gland dysfunction and pneumonitis.

1. Dr Venkata Krishna Reddy P
PG Registrar
Dept of Radiation Oncology
TOTAL BODY IRRADIATION(TBI)

2. OVERVIEW
 Concept
 Indications
 Doses
 Pre-requisites of TBI
 Performance of TBI in CMC
 Treatment Planning
 Toxicity
 Total Marrow Irradiation

3. HISTORY OF TBI
Year Event
1907 X ray Bath
1940-1950 Lymphoma/Solid tumours
with disseminated
disease
1960 First exploration of BMT-
Nobel Laureate E
Donnall Thomas
1970-1980 TBI with low dose
1977 TBI Myeloabalative
2005 Total Marrow Irradiation

4. DEFINITION
When radiation is given in a way to cover the
whole body, is called total body irradiation, or
TBI.

5. CONCEPT OF TBI
 One of main component in interdisciplinary
treatment of hematological malignancies
 Enables myeloablative high dose therapy
(HDT) and immunoablative conditioning
therapy prior to stem cell transplantation

6. High dose Therapy (HDT)
 Intensive chemotherapy
 High dose Total Body Irradiation (TBI)
 Transplantation of HLA compatible blood or
marrow stem cells (HSCT), and
 Supportive care under sterile conditions
during the aplastic phase.

7.  Myeloablative therapy:
 The irreversible elimination of the clonogenic
malignant cells - therapeutic task of high
dose TBI in treatment.

8.  Immunoablative conditioning treatment:
 The induction of immuno-suppression is
the conditioning task of TBI in
allogeneic haematopoietic stem cell
transplantation to enable successful
engraftment.

9. INDICATIONS
Certain indications: Leukaemias in adults and
childhood:
 - Acute lymphoblastic leukaemia (ALL),
 - Acute myeloid leukaemia (AML),
 - Chronic myeloid leukaemia (CML),
 - Myelodysplastic syndrome (MDS).
Optional indications: Solid tumors in childhood:
 - Neuroblastomas
 - Ewing sarcomas
 - Plasmocytomas / multiple myeloma.
In clinical test:
 - Hodgkin`s disease
 - Non-Hodgkin`s lymphomas

10. DOSE USED IN TBI
 High Dose TBI – 13.2 Gy in 6 fractions over 3
days
 Standard dose TBI – 12 Gy in 6 fractions
over 3 days
 Low dose TBI – 2 Gy in single fraction

11. DOSE TO OARS
 Lung dose should be restricted to 8 Gy to
minimize pneumonitis

12. HIGH DOSE TBI- DOSE PRESCRIPTION
Disease Dose Fractions Dose Rate Reference
13.2 Gy 8 # , twice 10 cGy/min Dusenbery et
AML daily al. (Minnesota)
ALL 13.5 Gy 6 #, twice daily 3.25cGy/min Blaise et al.
CML (GEGMO)
Lymphom 12 Gy 6 #, twice daily NR Clift et al.
(Seattle)
a
MM 10-12 Gy 1-8 times/day 3.25cGy/min Devergie et al.
(SFGM)
8 Gy 4# Not mentioned Moreau et al.
(IFM)

13. LOW DOSE TBI- DOSE PRESCRIPTION
Disease Dose Fractions Dose Rate Reference
2 Gy 1 Fraction 7 cGy/min Hegenbart et
AML al.
CML 5.5 Gy 6 #, twice 27.6 – 36.4 Hallemeier et
Lymphom daily cGy/min al
a 4 Gy 1 fraction NR Schmid et al.
MDS
2.5 Gy 2 #, twice day NR Badros et al.
(Arkansas)

14. PRE- REQUISITES FOR TBI
 Interdisciplinary approach
Radio-oncologists, medical physicists and
haemato-oncologists
 RT and transplantation must be in same
centre
 Conditions with a low risk of infections is
recommended

15. PERFORMANCE OF TBI IN CMC
 Positioning
 Measurements
 Target volume and Dose ref. points
 Calculation of MU of target dose
 Compensator thickness calculation
 Treatment delivery

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

17. The patient
lying on the
side - utilizing
opposing
beams at large
distance
(4-6 m).
POSITIONING DURING TBI

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

19. TBI AAPM Report No 17

20. TARGET VOLUME
 All malignant cells including those
circulating as well as the whole cellular
immune system.
 The Whole Body, including Skin
 Organs with a high risk of recurrence
(“homing phenomenon”) and meninges,
testes, may require additional local
radiotherapy.

21. TREATMENT PLANNING
 AIM – homogenous high dose delivery with
sparing the organs at risk

22. DOSE SPECIFICATION
 The total dose to the target volume
 Reduced dose to the lungs
 The number of fractions and
 The lung dose rate.

23. DOSE REF POINTS
 The dose reference point (+) for dose
specification to the target volume is defined
at mid abdomen at the height of the
umbilicus
according to an international consensus

24. DOSE REFERENCE POINTS
Lung Ref
pt
D
reference,
Target Vol

25.  The dose reference points (∗) for lung dose
specification are defined as mid points of
both lungs
 The lung dose is defined as the mean of the
dose at both lung reference points.
 Corresponds to the minimum dose to the
lungs

26. PRESCRIPTION OF DOSE AND FRACTIONATION
OF TBI
 No general recommendation can be given.
 12 Gy in 6 fractions – considered standard
PETERS LJ (1980) : The radiobiological bases of TBI. Int J Radiat Oncol Biol Phys 6:
785.
 Single fraction TBI - too many complications have
been observed.
 In fractionated TBI the total dose (DRef) has to be
increased by 20-25 % compared to single fraction
irradiation.

27. RADIOBIOLOGY OF TBI
 SF2 calculated for leukemia for 7 x 2 Gy
regimen
 Range of 10 -2 to 10-21
 Average case – median of 10-5 clonogenic
cells are eliminated – which corresponds to
residual disease after good remission
 T E Wheldon : Radiobiological basis of TBI. The British Journal of Radiology,
1997

28. CALCULATION OF MID-PLANE DOSE
 Based on umbilical level separation
 Parallel Opposed lateral Beams
Dose per fraction
MU = ___________________
DR at Ext SSD * PDD (Ud)

29.  Does treatment with this MU s alone deliver
homogeneous dose to entire body ?

30. OPTIMIZATION OF DOSE
 The homogeneity of dose in the target
volume
 The effective sparing the lungs

31. 1. DOSE MODIFIERS
 Influences of irregular body contours have
to be compensated.
 For bilateral TBI - a tissue compensators
are used in front of and next to head, neck
and legs.

32. TBI AAPM Report 17

33. CALCULATION OF COMPENSATOR THICKNESS
I = Io e -mt
HVL
Thickness (t) = _________ * ln Io/I
0.693

34. 2. INCREASING THE
DOSE TO PARTS OF .
THE TARGET VOLUME
For build-up, for higher
energy photons :
scatter screen (spoiler)
has to be positioned
close to the patient.
In long term irradiation,
remotely positioned dose
modifyers are not
recommended due to
repositioning and
increased verification
problems

35. 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.
 Equivalent homogeneous dose is reduced
by only 5% (1-7%), e.g. from 12 Gy TBI
dose with 9 Gy lung dose to 11.5 Gy
equivalent homogeneous dose –
probability of cell kill is not reduced

36. 4. Fluence flattening
 Fluence modifying techniques can be used
for dose homogenization
 E.g. in wide angle collimator or sweeping
beam TBI or a wedge filter for oblique
incidence of the beam.

37. SPARING THE LUNGS
1. Dose reduction in the lung:
 To 80% of the prescribed target dose
 Primary radiation fluence had to reduced by 60-70
%.
 Shape and thickness of sheilds must be planned
 Skin-fixed shieldings are stacks of lead rubber cut-
outs, lead-moulds or stacks of thin lead sheets (for
high energy photons, the lead has to be covered
by low density material).
2 . Reduction of dose rate:
 For accelerators: A Lower dose rate

38. TREATMENT DELIVERY
 Delivered in the position which
measurements are taken
 Under sterile conditions
 In vivo dosimetry is done on first day with
Semiconductor diodes

39. OTHER MODALITIES OF TBI

40. IMMEDIATE TOXICITY
Symptom Single fraction TBI Fractionated TBI
Nausea& Vomiting 45 43
Parotid gland pain 74 6
Xerostomia 58 30
Headache 33 15
Fatigue NR 36
Ocular dryness 16 NR
Esophagitis NR 4
Loss of apetite NR 16
Erythema NR 41
Pruritis NR 4
Diarrhea NR 4
Fever 97 NR

41. LATE TOXICITY
 Salivary glands (22%) – Xerostomia, dental caries, tooth
abnormalities
 Pneumopathy(10-20%) – Doses greater than 9.4 Gy and single
dose TBI increase risk
 Cardiac toxicity (2-3%) – Rare, in pts who had anthracycline
based chemotherapy
 Hepatotoxicity / Venoocculusive disease (70%) – doses greater
than 13.2 Gy
 Catracts - MC complication. Asso. steroid use and cranial
irradiation
 Kidney Dysfunction - 17%
 Hypothyroidism – 25 %
 Growth abnomalities in children
 Sterility and endocrine abnormalities
 Secondary MDS or AML ( 1 % at 20 months and 24% at 43
months)

42. 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 leukemias

43. COLOUR WASH FOR TOMOTHERAPY PLANNED
TMI

44. DVH CURVES FOR TMI

45. ADVANTAGES OF TMI
 Escalate the dose to bone (and containing
marrow) up to 20 Gy, while maintaining
doses to normal organs at lower levels than
in conventional TBI to 12 Gy.
Jeffrey Y. C. Wong et al. Targeted Total Marrow Irradiation Using Three-
Dimensional Image-Guided Tomographic Intensity-Modulated Radiation
Therapy: An Alternative to Standard Total Body Irradiation, Biology of
Blood and Marrow Transplantation 12:306-315 (2006)

46. THANK YOU