Abstract
Purpose: This study aimed to assess the feasibility to plan and deliver highly heterogeneous doses to symptomatic large tumors using volumetric modulated arc therapy (VMAT) and simultaneous integrated boost (SIB) during a short course palliative accelerated radiotherapy. Methods: A patient with a large symptomatic chordoma infiltrating the right gluteal region was selected. A modified SIB treatment was implemented to irradiate the central volume of the tumor (boost target volume, BTV) up to 10 Gy/fraction in a dose escalation trial while maintaining the remaining tumor volume (planning target volume, PTV) and the surrounding healthy tissues within 5 Gy/fraction in twice daily fractions for two consecutive days. Four SIB plans were generated in the dual-arc modality; a basal dose of 20 Gy was prescribed to the PTV, while the BTV was boosted up to 40 Gy. For comparison purposes, plans obtained with a sequential boost (SEQ plans) were also generated. All plans were optimized to deliver at least 95% of the prescription dose to the targets. Dose contrast index (DCI), conformity index (CI), integral dose (ID), and the irradiated body volumes at 5, 10, and 20 Gy were evaluated. Results: At equal targets coverage, SIB plans provided major improvement in DCI, CI, and ID with respect to SEQ plans. When BTV dose escalated up to 200% of PTV prescription, DCI resulted in 66% for SIB plans and 37% for SEQ plans; the ID increase was only 11% for SIB plans (vs 27% for SEQ plans) and the increase in healthy tissues receiving more than 5, 10, and 20 Gy was less than 2%. Pretreatment dose verification reported a γ-value passing rate greater than 95% with 3%(global)-2 mm. Conclusion: A modified SIB technique is dosimetrically feasible for large tumors, where doses higher than the tolerance dose of healthy tissues are necessary to increase the therapeutic gain.
| Original language | English |
|---|---|
| Pages (from-to) | 35-43 |
| Number of pages | 9 |
| Journal | Journal of Applied Clinical Medical Physics |
| Volume | 19 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Nov 1 2018 |
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Keywords
- palliative
- simultaneous integrated boost
- VMAT
ASJC Scopus subject areas
- Radiation
- Instrumentation
- Radiology Nuclear Medicine and imaging
Cite this
Partially ablative radiotherapy (PAR) for large mass tumors using simultaneous integrated boost : A dose-escalation feasibility study. / Cilla, Savino; Deodato, Francesco; Ianiro, Anna; Macchia, Gabriella; Picardi, Vincenzo; Buwenge, Milly; Cammelli, Silvia; Zamagni, Alice; Valentini, Vincenzo; Morganti, Alessio G.
In: Journal of Applied Clinical Medical Physics, Vol. 19, No. 6, 01.11.2018, p. 35-43.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Partially ablative radiotherapy (PAR) for large mass tumors using simultaneous integrated boost
T2 - A dose-escalation feasibility study
AU - Cilla, Savino
AU - Deodato, Francesco
AU - Ianiro, Anna
AU - Macchia, Gabriella
AU - Picardi, Vincenzo
AU - Buwenge, Milly
AU - Cammelli, Silvia
AU - Zamagni, Alice
AU - Valentini, Vincenzo
AU - Morganti, Alessio G.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - Purpose: This study aimed to assess the feasibility to plan and deliver highly heterogeneous doses to symptomatic large tumors using volumetric modulated arc therapy (VMAT) and simultaneous integrated boost (SIB) during a short course palliative accelerated radiotherapy. Methods: A patient with a large symptomatic chordoma infiltrating the right gluteal region was selected. A modified SIB treatment was implemented to irradiate the central volume of the tumor (boost target volume, BTV) up to 10 Gy/fraction in a dose escalation trial while maintaining the remaining tumor volume (planning target volume, PTV) and the surrounding healthy tissues within 5 Gy/fraction in twice daily fractions for two consecutive days. Four SIB plans were generated in the dual-arc modality; a basal dose of 20 Gy was prescribed to the PTV, while the BTV was boosted up to 40 Gy. For comparison purposes, plans obtained with a sequential boost (SEQ plans) were also generated. All plans were optimized to deliver at least 95% of the prescription dose to the targets. Dose contrast index (DCI), conformity index (CI), integral dose (ID), and the irradiated body volumes at 5, 10, and 20 Gy were evaluated. Results: At equal targets coverage, SIB plans provided major improvement in DCI, CI, and ID with respect to SEQ plans. When BTV dose escalated up to 200% of PTV prescription, DCI resulted in 66% for SIB plans and 37% for SEQ plans; the ID increase was only 11% for SIB plans (vs 27% for SEQ plans) and the increase in healthy tissues receiving more than 5, 10, and 20 Gy was less than 2%. Pretreatment dose verification reported a γ-value passing rate greater than 95% with 3%(global)-2 mm. Conclusion: A modified SIB technique is dosimetrically feasible for large tumors, where doses higher than the tolerance dose of healthy tissues are necessary to increase the therapeutic gain.
AB - Purpose: This study aimed to assess the feasibility to plan and deliver highly heterogeneous doses to symptomatic large tumors using volumetric modulated arc therapy (VMAT) and simultaneous integrated boost (SIB) during a short course palliative accelerated radiotherapy. Methods: A patient with a large symptomatic chordoma infiltrating the right gluteal region was selected. A modified SIB treatment was implemented to irradiate the central volume of the tumor (boost target volume, BTV) up to 10 Gy/fraction in a dose escalation trial while maintaining the remaining tumor volume (planning target volume, PTV) and the surrounding healthy tissues within 5 Gy/fraction in twice daily fractions for two consecutive days. Four SIB plans were generated in the dual-arc modality; a basal dose of 20 Gy was prescribed to the PTV, while the BTV was boosted up to 40 Gy. For comparison purposes, plans obtained with a sequential boost (SEQ plans) were also generated. All plans were optimized to deliver at least 95% of the prescription dose to the targets. Dose contrast index (DCI), conformity index (CI), integral dose (ID), and the irradiated body volumes at 5, 10, and 20 Gy were evaluated. Results: At equal targets coverage, SIB plans provided major improvement in DCI, CI, and ID with respect to SEQ plans. When BTV dose escalated up to 200% of PTV prescription, DCI resulted in 66% for SIB plans and 37% for SEQ plans; the ID increase was only 11% for SIB plans (vs 27% for SEQ plans) and the increase in healthy tissues receiving more than 5, 10, and 20 Gy was less than 2%. Pretreatment dose verification reported a γ-value passing rate greater than 95% with 3%(global)-2 mm. Conclusion: A modified SIB technique is dosimetrically feasible for large tumors, where doses higher than the tolerance dose of healthy tissues are necessary to increase the therapeutic gain.
KW - palliative
KW - simultaneous integrated boost
KW - VMAT
UR - http://www.scopus.com/inward/record.url?scp=85053462360&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85053462360&partnerID=8YFLogxK
U2 - 10.1002/acm2.12427
DO - 10.1002/acm2.12427
M3 - Article
C2 - 30220111
AN - SCOPUS:85053462360
VL - 19
SP - 35
EP - 43
JO - Journal of Applied Clinical Medical Physics
JF - Journal of Applied Clinical Medical Physics
SN - 1526-9914
IS - 6
ER -