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SRS-ROSE CASE FOR PITUITARY ADENOMA
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 â 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 Ă 1.6 Ă 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 â 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
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
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
23. MRI - POSTOP
SEQUENCES FINDINGS
T1 & T2 1. Residual pituitary tissue
2. 16Ă11Ă7mm on Right side
3. 12Ă8Ă8mm on Left side
4. Bridging soft tissue is seen along
the floor of sella
5. B/L Cavernous sinus â normal
6. Optic chiasm â 4mm away from
tumor
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 â 1mm to GTV
2/26/2021 31
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
2/26/2021 32
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
2/26/2021 33
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
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
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
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 Ďr3
⢠r= (3V/4Ď)1/3
Equivalent radius
61. ⢠FORMULA
â 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
⢠HEREď 1.49--1.27= 0.21mm
⢠BETWEEN 80% AND 40%- IDEAL- <8mm
â HEREď 1.8--1.27= 0.53mm
EORTC-22952-26001
Distance between various isodose lines
66. ⢠MECHANICAL ISOCENTER CHECK
â WINSTON LUTZ TEST
⢠POINT DOSE VERIFICATION
⢠TOLERANCE-1MM
Travis R. Denton/JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS/2015
QA part
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
81. NORMAL PITUITARY- MRI PICTURES
The adenohypophysis is isointense & the
neurohypophysis is hyperintense- T1 PLANE
Sagittal postcontrast T1shows normal
diffuse enhancement of the gland
2/26/2021 81
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
2/26/2021 84
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
2/26/2021 93
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
2/26/2021 95
96. PITUITARY INSUFFICIENCY
ďź 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.
ďź 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
2/26/2021 97
98. CONTROL AFTER STEREOTAXY
Patients with GHâproducing 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