Multi-Phase Treatment Planning

Question 1

Explain sequential boost planning

Answer 1

• Treatment consists of multiple phases
• Initial phases is directed to the entire set of target volume
• Following phases (boost) are limited to the primary tumour with a margin

Question 2

Considerations for OARs in Sequential Boost Planning

Answer 2

• PH1 cannot reach dose tolerances as the contribution of the following Phases need to be considered
• Prescription for OAR’s is for the total dose delivered

Question 3

Disadvantages for Sequential Boost Planning

Answer 3

• The need for Multiple Treatment Plans
• More QA requirements
• More chances of planning errors
• Target volumes/anatomy may vary in size across the course of treatment

Question 4

Sequential Boost Planning Isocentre Considerations

Answer 4

• It is preferred to use only one isocentre
• An additional isocentre can be used if the distance between the high risk areas is large

Question 5

Can we use different planning techniques for the different phases in Sequential Boost Planning?

Answer 5

• Yes
• Example: EBRT + HDR

Question 6

Explain Simultaneous Integrated Boost (SIB)

Answer 6

• Delivering different doses per fraction in different target regions (simultaneously treating 2 or more volumes concurrently)
• Only 1 Phase and 1 Plan

Question 7

Benefits of SIB Planning

Answer 7

• Only one plan for the entirety of the treatment course
• Better target conformity
• Less dose to critical structures
• Moderate treatment acceleration with reduced total treatment time
• An option for dose escalation

Question 8

Clinical example for SIB in prostate

Answer 8

78gy in 39 fractions = prostate
64 Gy in 39 fractions = prostate +seminal vesicles

Question 9

Clinical example parotid for Sequential

Answer 9

44Gy in 22# - phase 1: upper neck and nodes
16Gy in 8 fractions- phase 2: upper neck

Question 10

Sequential boost rationale

Answer 10

nodal involvement
nodal curative dose is different to primary tumour curative dose

Question 11

Benefits of sequential boost

Answer 11

OAR dose reduction
Improved tumour control
Better QOL
Dose escalation

Question 12

Clinical example prostate Sequential

Answer 12

Prostate:
Phase 1: prostate and SV 56Gy in 28
Phase 2: prostate 18Gy in 9 fractions

Prostate:
Phase 1: pelvic nodes+prostate+sv 46Gy in 23
Prostate and SV 10 in 5
Prostate 18 in 9
74Gy in 37 total

Question 13

Clinical example gynae sequential

Answer 13

phase 1: EBRT 50.4/28#
phase 2: brachy 16/8#

Question 14

Clinical example breast sequential

Answer 14

EBRT: 50Gy/25#
EBRT: 16Gy/8#

Question 15

SIB Clinical example H+N

Answer 15

▪ PTV70: 70Gy in 35 fractions
▪ PTV63: 63Gy in 35 fractions
▪ PTV56: 56Gy in 35 fractions