This document describes the case of a 52-year-old male who presented with vomiting and was found to have a pituitary adenoma. An MRI showed a 2.3x1.6 cm dumbbell shaped lesion in the sella turcica extending suprasellarly and compressing the optic chiasm. The patient underwent endoscopic transphenoidal resection, with near total excision. Post-op MRI showed residual tissue in the right and left sides of the sella. The patient was planned for stereotactic radiotherapy with 25Gy in 5 fractions to treat the residual tumor. Target and organ at risk volumes were delineated on planning MRI and CT scans. Treatment planning was performed to optimize dose distribution and minimize

1. ROSE CASE
STEREOTAXY FOR PITUITARY ADENOMA
RADIATION ONCOLOGY
SIMULATION TO EXECUTION
DR KANHU CHARAN PATRO
MD,DNB[RADIATION ONCOLOGY],MBA,FAROI,PDCR,CEPC

2. HISTORY
• 52 year male with no co morbidities
• Had complaints of vomiting on July 2020 – Projectile
type
• Associated with reeling sensation of head and
involuntary movements involving all four limbs
• Not associated with headache/ blurring of vision
• Admitted in hospital and evaluated

3. MRI Scan - Preop
SEQUENCES FINDINGS
MRI 1. 2.3 × 1.6 × 1.6 cm
2. Dumbbell shaped
3. Altered intensity lesion in sellar region
4. Extending into Suprasellar location
5. Pituitary gland not separated from lesion
6. Optic chiasm – compressed & superiorly
displaced
7. Doubtful B/L Parasellar extension (R>L) with
encasement of cavernous segment B/L ICA
(R>L)
CE MRI 1. Peripheral rim enhancement with irregular
non enhancing area within the matrix of
lesion - Necrosis

4. MRI – T1 Contrast

5. MRI – T2-NO CAVERNOUS SINUS INVOLVEMENT

6. MRI – T2 SAGITTAL SECTION
Dumdbell shaped

7. MRI – T1 Contrast saggittal section
?APOPLEXY

8. MRI – T1 Contrast coronal section

9. PREOP HORMONE
HORMONES LEVEL
PROLACTIN 20.85 ng/ml
CORTISOL 8.34 mcg/ml
T4 1.04 ng/dl
TESTOSTERONE 1.72 ng/ml
FSH 1.88 mIU/ml

10. SURGERY
• Patient underwent Endoscopic Trans sphenoid
Excision on 09-10-2020
• Near total excision
• Packed with packing material

11. Histopathology
• Histopathology
– F/S/O Pituitary Macro adenoma
– Focal hemorrhage noted
• Immunohistochemistry
– Synaptophysin +VE ,
– Chromogranin +VE
– Ki 67 – 2%

12. Investigations asked
• MRI POST OP
• VISUAL
– ACUITY
– FIELD

13. MRI PROTOCOL
• MRI POST OP CONTRAST
• FSPGR-ANATOMY
• FATSAT T1- PACKING MATERIAL DISTINGUISH
• DELAYED CONTRAST- NORMAL PTUITARY DISTINGUISH
• T2- TO SEE CAVERNOUS SINUS INVOLVEMNET
• 1MM
• NO GAP
• NO TILT
• 512 X 512 MATRIX
• NEUTRAL NECK
• FOV SHOULD INCLUDE BODY CONTOUR NOSE, EYE AND
SKULL

14. VISUAL ACUITY
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15. 2/26/2021 15

16. 2/26/2021 16

17. Visual assessment preop

18. Visual assessment post op

19. PREOP POSTOP
VISUAL ACUITY LEFT Normal Normal
VISUAL ACUITY RIGHT Normal Normal
VISUAL FIELD LEFT Near normal 100%
VISUAL FIELD RIGHT Near normal 100%
Visual assessment

20. HORMONAL TREATMENT DETAILS
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21. ENDOCRINE EVALUATION
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22. POST OP HORMONE
HORMONES LEVEL
PROLACTIN 20.2ng/ml
CORTISOL 10mcg/ml
T4 2.4ng/dl

23. MRI - POSTOP
SEQUENCES FINDINGS
T1 & T2 1. Residual pituitary tissue
2. 16×11×7mm on Right side
3. 12×8×8mm on Left side
4. Bridging soft tissue is seen along
the floor of sella
5. B/L Cavernous sinus – normal
6. Optic chiasm – 4mm away from
tumor

24. FSPGR CONTRAST

25. T2 FLAIR
NO CAVERNOUS
INVOLVEMENT

26. Imaging conclusion
• Residual diseases
• No cavernous sinus involvement
• No chiasm compression
• No Parasellar extension
• No Suprasellar extension
• Chiasm tumor distance-4mm
• Packing material seen
IMAGING CONCLUSION

27. DIFFERENTIATING PACKING MATERIAL
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28. Imaging conclusion
IDENTIFYING THE PACKING MATERIAL

29. 2/26/2021 29

30. 2/26/2021 30

31. • Contour the residual as GTV
• Be relax at caudal site and lateral side
• Do not include cavernous sinuses unless involved
• Differentiate from packing material
• CTV- Unnecessary unless it is an aggressive
adenoma with potential areas of microscopic
infiltration
• PTV – 1mm to GTV
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TARGET DELINEATION

32. • While SCRT is suitable for the treatment of all
pituitary tumours, irrespective of size, shape
or proximity to critical normal tissue
structures,
• SRS is only suitable for treatment of small
tumours away from the optic chiasm
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SCRT VS SRS

33. FSRT FOR PITUITARY
• Stereotactic radiotherapy originally referred to radiotherapy
treatment delivered to an intracranial target lesion that was located
by stereotactic means in a patient immobilised in a neurosurgical
stereotactic head frame. The improved patient immobilisation,
more accurate
• Tumour target localisation using cross-sectional image for treatment
planning, and high precision radiation treatment delivery to the
tumour target, enabled a reduction in the margins around the
radiotherapy target volume (the GTV to PTV margin), therefore
achieving greater sparing of surrounding normal tissues than can be
obtained with standard CRT techniques
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34. SCRT VS SRT
• While SCRT is suitable for the treatment of all
pituitary tumours, irrespective of size, shape
or proximity to critical normal tissue
structures,
• SRS is only suitable for treatment of small
tumours away from the optic chiasm
2/26/2021 34

35. IRSA Algorithm

36. IRSA Algorithm

37. Tumor board decision
• After group discussion with neurosurgeon,
radiation oncologist and patient, board
decided to plan for stereotactic radiotherapy
• Patient was explained about complications
and outcome of each procedure

38. Patient discussion
• Discussed about RT comparing with re-surgery
• Discussed about the procedure
• Discussed about visual preservation
• Discussed about follow up imaging ,hormonal and
visual evaluation
• Discussed about tumor response
• Discussed about need of surgery in future
• Discussed about need of RERT in future
• Discussed about post radiotherapy cyst formation
• Discussed about post radiotherapy hypopituitarism and
need of hormonal replacement

39. Dose selection

40. Dose selection
• Hypo fractionated SRT with a dose of 21Gy /
3# or 25Gy / 5# showed
– 98% Local control rate
– 1% Visual disorder
– 3% Hypopituitarism

41. • Planned for FSRT
• Plan multiple fraction
• 25Gy/5# - marginal dose
Radiation tumor board

42. Immobilization and set up

43. • 1mm slice
• Contrast
• Vertex to neck
• With fraxion
Planning CT

44. MRI protocol
• T1/T2/FLAIR sequence- Usual sequence
• 3D FSPGR sequence- Normal anatomy
• FATSAT sequence- Differentiate packing material
• 512x 512 matrix
• 1mm slice
• No gap
• No tilt
• Neutral neck
• FOV should include body contour nose, eye and skull

45. IMAGE FUSION
1. Soft tissue extension
2. Delineating optic
apparatus
3. Differentiating packing
material
4. Differentiating
cavernous sinus from
tumor
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46. • CT AND MRI FUSION
Image fusion

47. • GTV delineation
• VOLUME- 1.106 cc
• Multiplanar evaluation
Target delineation

48. • 1mm
• VOLUME- 2.456 CC
PTV

49. Multiplanar GTV and PTV

50. Smooth your contour

51. OAR DELINEATION
OAR delineation

52. • VMAT
• DCARC
• 3DCRT
• IMRT
Planning

53. Beam arrangement

54. SL NO PARAMETER VALUE
1 D MAX 31.49Gy
2 D95% 27.38Gy
3 D100% 24.61Gy
4 V95% 100%
5 V25 Gy[V100%] 99.96%
6 V110% 94.20%
7 V120% 19.28
8 V130% 0
1. Prescription Isodose level is usually not 100% PD covering 100% PTV
2. Often 95% PD covering 95% PTV or higher
3. Or 100% PD covering 95% PTV or higher.
Michael Torrens,/J Neurosurg (Suppl 2)/2014
PTV coverage index

55. • FORMULA
• VOLUME OF PRESCRIPTION ISODOSE/PTV VOLUME
• 4.956/4.161=1.19
• DESIRABLE=1
[Sonja Petkovska
Proceedings of the Second
Conference on Medical Physics
and Biomedical Engineering]
RTOG conformity index

56. • FORMULA
(VOLUME OF PRESCRIPTION ISODOSE IN AREA OF INTEREST)2
PTV VOLUME X VOLUME OF PRESCRIPTION ISODOSE
• 4.474x4.474/4.161X4.956=0.97
• IDEAL= > 0.85. AND <1
Michael Torrens,/J Neurosurg (Suppl 2)/2014
Paddick conformity index

57. • FORMULA
• MAXIMUM DOSE/PRESCRIPTION DOSE
• 31.49Gy/25Gy=1.25
• DESIRABLE = 1.1-1.3
HOMOGENITY index

58. • Dose fall off observation is very much needed in this
evaluation under headings
• Gradient index
• Difference between various isodose lines
• e.g between 80% and 60%- ideal- <2mm
• Between 80% and 40%- ideal- < 8mm
• For that reason we have to calculate equivalent
radius
Dose fall off

59. • To evaluate dose gradient we have to find out
difference between radius of various isodose line
• But none is iso spherical
• We have to find out equivalent radius from formula
• First find out the specified isodose volume
• Then calculate the radius
• V=4/3 πr3
• r= (3V/4π)1/3
Equivalent radius

60. SL NO PARAMETER VOLUME RADIUS
1 100% ISODOSE 4.956 1.06
2 80% ISODOSE 8.646 1.27
3 60% ISODOSE 13.761 1.49
4 50% ISODOSE 17.804 1.62
5 40% ISODOSE 24.334 1.8
r= (3V/4π)1/3
Equivalent radius

61. • FORMULA
– Difference of equivalent radius of prescription
isodose and equivalent radius of 50% isodose
• 1.62mm-1.06mm=0.56mm
• It should be between 0.3 to 0.9
Gradient index

62. • BETWEEN 80% AND 60%- IDEAL-<2mm
• HERE1.49--1.27= 0.21mm
• BETWEEN 80% AND 40%- IDEAL- <8mm
– HERE1.8--1.27= 0.53mm
EORTC-22952-26001
Distance between various isodose lines

63. CONSTRAINTS

64. SL NO ORGAN DESIRABLE ACHIEVED
1 RT. EYE MAX <22.5Gy 1Gy
2 LT. EYE MAX <22.5Gy 1.5Gy
3 RT. OPTIC NERVE MAX <22.5Gy 19.28Gy
4 LT. OPTIC NERVE MAX <22.5Gy 16Gy
5 OPTIC CHIASM MAX <22.5Gy 16.81Gy
8 BRAIN STEM MAX 23-31Gy
9 PIT STALK MEAN 24Gy
10 LT. cavernous sinus MEAN 21.26Gy
11 RT. cavernous sinus MEAN 24.35Gy
GG HANNA/CLINICAL ONCOLOGY/2016
OAR coverage

65. DVH STAT TABLE

66. • MECHANICAL ISOCENTER CHECK
– WINSTON LUTZ TEST
• POINT DOSE VERIFICATION
• TOLERANCE-1MM
Travis R. Denton/JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS/2015
QA part

67. Dry run

68. • CBCT CORRECTIONS
Set-up verification

69. • HEXAPOD CORRECTIONS
Set-up verification

70. PREMEDICATION
• TAB. DEXAMETHASONE 8MG THRICE DAILY
STARTING DAY BEFORE
• TAB. ONDANSETRON 8MG THRICE DAILY
STARTING DAY BEFORE
• TAB. PAN 4O ONCE DAILY STARTING DAY
BEFORE
• DIABETES CARE IF
Pre medication-optional

71. • TAPER THE STEROID OVER A WEEK
• ANTI EMETICS
• PPI
Post medication-optional

72. • Imaging after 6 months
Advised

73. LETS UNDERSTAND ANATOMY

74. 2/26/2021 74

75. CAVERNOUS SINUS
CAROTID ARTERY
OPTI C CHIASMA
INFUNDIBULUM
PITUITARY
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76. INFUNDIBULAR RECESS
SUPRA OPTIC RECESS
OPTI C CHIASMA
INFUNDIBULUM
PITUITARY
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77. 2/26/2021 77

78. THE DISTANCE
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79. 2/26/2021 79

80. 2/26/2021 80

81. NORMAL PITUITARY- MRI PICTURES
The adenohypophysis is isointense & the
neurohypophysis is hyperintense- T1 PLANE
Sagittal postcontrast T1shows normal
diffuse enhancement of the gland
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82. PITUITARY MICROADENOMA- MRI PICTURES
LEFT PART PITUITARY GLAND. WITHIN THE GLAND, A
FOCAL AREA OF HYPOINTENSITY IS SEEN IN T1 PLANE
Microadenoma remains hypointense while the
remainder of the gland enhances IN T1 CONT
2/26/2021 82

83. DELAYED IMAGE
2/26/2021 83
1. Imaging more than 30 minutes after intravenous contrast also
may help detect Microadenomas, which then appear as focal
hyperintense lesions relative to the surrounding gland.
2. Encasement of the intercavernous internal carotid artery by
adenoma greater than or equal to 67% was concluded to be a
specific sign of a cavernous sinus invasion in one study.
3. Fat packed in the surgical defect appears hyperintense on T1-
weighted sequences and requires the use of fat-saturated
sequences to distinguish contrast enhancement from packing
material

84. PITUITARY MACROADENOMA- MRI PICTURES
There is a well defined round lesion noted in
the pituitary fossa, the lesion is homogeneous
and isodense on T1
There is a well defined homogeneously
enhancing lesion in the pituitary fossa on
Sagittal T1 C+ suggestive of pituitary adenoma
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85. CONVEX UPPER MARGIN IN PUBERTY
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86. 2/26/2021 86

87. RIGHT CAVERNOUS SINUS
INVOLVEMENT
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88. HARDY’S CLASSIFICATION
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89. KNOSP CLASSIFICATION
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90. CAVERNOUS SINUS INVOLVEMENT
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91. DOCTORS
• DR P S BHATTACHARYA
• DR C R KUNDU
• DR V K REDDY
• DR SAJAL KAKKAR
PHYSICISTS
• MR A C PRABU
• MR A SRINU
• MR PRASAD
• DR ANIL KUMAR
TECHNOLOGIST TEAM
Acknowledgments

92. FOLLOW UP
• 3 MONTHLY FIRST 2 YEARS THEN 6 MONTHLY
• HORMONAL CHECK UP FOR NORMALIZATION
• HORMONAL CHECK UP FOR INSUFFICIENCY
• OPHTHALMIC EVALUATION FOR RECOVERY
• OPHTHALMIC EVALUATION FOR NEURITIS
2/26/2021 92

93. FOLLOW UP IMAGING
• BASELINE EVALUATION AT 3 MONTH OF POST
RADIATION
• MRI PREFERRED
• FURTHER IMAGING AT SYMPTOMATIC
PROGRESSION
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94. VISUAL COMPLICATION
2/26/2021 94

95. OPTIC NEUROPATHY
• Usual radiotherapy doses are 45 to 50Gy range.
• This dose is below the tolerance of optic pathway
including optic chiasm.
• It allows for the treatment of pituitary adenomas
of all sizes, including large tumors with
suprasellar extension frequently encasing or in
close proximity to the optic apparatus.
• The toxicity of fractionated external beam RT is
low, with a 1.5% risk of radiation-induced optic
neuropathy
• 0.2% risk of necrosis of normal brain structures
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96. PITUITARY INSUFFICIENCY
 The most frequent late morbidity of radiation
is hypopituitarism likely to be primarily the
result of hypothalamic injury, although
direct effect on the pituitary gland cannot be
excluded.
 In patients who have normal pituitary
function around the time of RT, hormone
replacement therapy is required in 20% to
40% at 10 years
2/26/2021 96

97. A. The 10-year PFS reported in seven large series
of conventional external beam RT for pituitary
adenoma is 80% to 94% .
B. In the largest series of 411 patients, the 10-
year PFS was 94% at 10 years and 89% at 20
years
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98. CONTROL AFTER STEREOTAXY
Patients with GH–producing pituitary adenomas should not
undergo further radiation therapy or surgery for at least 5
years after radiosurgery because GH and IGF-I levels
continue to normalize over that interval
2/26/2021 98

99. RADIOSURGERY OUTCOMES
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100. PROLACTINOMA IS MORE
RADIO-RESISTANCE
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101. TUMOR CONTROL
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102. DISEASE CONTROL
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103. LITERATURE REVIEW
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104. PATIENT COUNSELING
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