Simultaneously integrated boost (SIB) allows different doses to be delivered simultaneously to the planning target volume (PTV) and gross tumor volume (GTV), reducing the number of fractions needed. SIB provides a greater biological effective dose while allowing individual dose optimization to both targets in a single plan, overcoming limitations of conventional fractionation. An institutional study compared SIB to conventional 3D conformal radiation therapy in 30 patients with brain, breast, or bladder cancer, finding SIB reduced maximum doses to targets and organs at risk while shortening treatment duration by about a week.

1. Simultaneously Integrated Boost
(SIB)
Presenter
Sehrish Inam

2. Contents
• Introduction
• What is SIB
• Why SIB not any other
• BED calculation
• Institutional study
• Results
• Conclusion

3. Introduction
• Approx. 50% of cancer patients receive radiotherapy
• Curative intent treatment is divided into different phases
depending on the histology of tumor.
• The established protocols help to decide total dose, fraction
size and number of phases.
• We use different treatment techniques like 2D planning 3D-
CRT, IMRT , SIB etc as per need.

4. What is SIB
• It is the intensity modulation that offers simultaneously treat
two or more volumes concurrently.
• Provides different daily dose per volume to PTV and GTV
simultaneously
• Reducing the no. of fractions.
• Increase the tumor control probability
• Manifests a greater biological effective dose BED.

5. Why SIB not any other?
• Two conventional interdependent plans are unable to
determine how both plans influence each other.
• PTV1 receives additional dose due to fields of boost plan.
• SIB provides different dose to both PTVs in a single
fraction.
• Reduces no. of fractions using BED
• Only one plan for complete treatment course.
• Overcome the drawbacks of convention radiation therapy.

6. Biological Effective Dose
•BED is an approximate quantity by which different
radiotherapy regimens may be compared.
•BED = nd [1+d/(α/β)]
where n = no. of fractions
d = dose per fraction
nd = total dose

7. Institutional study
● We studied dosimetric comparison of SIB 3D-CRT with
conventional 3D CRT of sequential boost.
● Total 30 patients of brain breast and bladder were studied.
● Results were analyzed on the basis of
○ Coverage index
○ Conformity index
○ Homogeneity index
○ Dose gradient
○ OARs doses

8. BRAIN
Conventional 3D CRT SIB 3D CRT

9. BRAIN
Dose Volume Histogram Analysis

10. Breast
Conventional 3D CRT SIB 3D CRT

11. Breast
Dose Volume Histogram Analysis

12. Bladder
Conventional 3D CRT SIB 3D CRT

13. Bladder
Dose Volume Histogram Analysis

14. Indices Comparison Of 3DCRT & SIB
3D CRT

15. Comparison Of OAR doses in 3DCRT
& SIB 3D CRT

16. Conclusion
• SIB treatment is feasible in comparison to 3DCRT.
• SIB reduces the maximum dose to the target volume, and dose
to OAR.
• Provides better acute effects than conventional treatment.
• Reduce the overall treatment duration by about one week.
• However studies on late effects are still continued.