1. The patient presented with a 1.5 x 1.5 cm cancerous growth on their uvula. A biopsy confirmed it was a moderately differentiated squamous cell carcinoma.
2. A mould was prepared using alginate impression material and dental stone to create an intraoral prosthesis for brachytherapy treatment planning and delivery.
3. Brachytherapy treatment was planned using CT imaging and catheter reconstruction to deliver 60Gy in 13/14 fractions twice daily to adequately cover the clinical target volume while sparing nearby organs at risk.
52. TARGET DELINEATION
• Target definition of the Gross Tumor Volume (GTV)
and Clinical Target Volume (CTV) are usually
performed by clinical examination aided by imaging
and intraoperative findings.
• In brachytherapy, typically no additional margin is
required to ensure that theCTV receives the planned
dose and therefore.
• Unlike external beam irradiation, CTV and PTV
(Planning Target Volume) are considered equivalent
59. TARGET DOSE EVALUATION
• CTV coverage is adequate (i.e., D90 is at least 90% of
the prescribed dose)
• The prescription dose is usually the minimum dose
received by the CTV or a CTV surrogate (i.e., the D90 >
100, V100 > 90%)
• DNR should be equal or lower than 0.36 and in IMBT
(intensity modulated Brachytherapy) 0.42
• Dose non-uniformity ratio (DNR= V100/V150)
• The optimal spacing between applicators is <15 mm
60. TARGET DOSE EVALUATION
COVERAGE INDEX
CTV VOLUME 0.32CC DESIRABLE
DNR INDEX V150 / V100 = 34.04/96.42 =0.35 0.36 T0 0.5
D90
98.34% >90%-100%
V100
96.42% >90%
V150
34.04% ALARA
V200
8.94% ALARA
V300
2.67% ALARA
61. ISODOSE IN ALL PLANES
BLUE 85%
RED 100%
ORANGE 150%
WHITE 200%
GREEN 300%
79. SUMMARY
• Follow GEC-ESTRO guidelines
• Train your dentist
• Follow steps
• Wires should not touch necked to any surface
• Use lead /IOP
• Reactions usually observed after treatment- do not
get panic , wait
• Counsel
80. ACKNOWLEDGEMENT
DR RAMAYA REDDY –BDS
1. DR P S BHATTACHARYYA
2. DR C R KUNDU
3. DR V K R REDDY
4. DR M MRITYUNJYA
5. DR SRINIVAS REDDY
1. A C PRABU
2. AKETI SRINU
3. PRASAD
4. DR A ANIL KUMAR
1. DR PRIYASHA DAMODARA
2. DR PREMCHAND A
3. DR MOHANPRIYA A
4. DR KEERTHIGA K
1. SISTER SRITHA
2. SISTER VENKATLAXMI