Dataset Information

Simultaneous integrated protection : A new concept for high-precision radiation therapy.

ABSTRACT:

Objective

Stereotactic radiotherapy near serial organs at risk (OAR) requires special caution. A novel intensity-modulated radiotherapy (IMRT) prescription concept termed simultaneous integrated protection (SIP) for quantifiable and comparable dose prescription to targets very close to OAR is described.

Materials and methods

An intersection volume of a planning risk volume (PRV) with the total planning target volume (PTV) defined the protection volume (PTV_SIP). The remainder of the PTV represented the dominant PTV (PTV_dom). Planning was performed using IMRT. Dose was prescribed to PTV_dom according to ICRU in 3, 5, 8, or 12 fractions. Constraints to OARs were expressed as absolute and as equieffective doses at 2 Gy (EQD2). Dose to the gross risk volume of an OAR was to respect constraints. Violation of constraints to OAR triggered a planning iteration at increased fractionation. Dose to PTV_SIP was required to be as high as possible within the constraints to avoid local relapse.

Results

SIP was applied in 6 patients with OAR being large airways (n = 2) or bowel (n = 4) in 3, 5, 8, and 12 fractions in 1, 3, 1, and 1 patients, respectively. PTVs were 14.5-84.9 ml and PTV_SIP 1.8-3.9 ml (2.9-13.4?% of PTV). Safety of the plans was analyzed from the absolute dose-volume histogram (dose to ml). The steepness of dose fall-off could be determined by comparing the dose constraints to the PRVs with those to the OARs (Wilcoxon test p = 0.001). Constraints were respected for the corresponding OARs. All patients had local control at a median 9 month follow-up and toxicity was low.

Conclusion

SIP results in a median dose of ?100?% to PTV, to achieve high local control and low toxicity. Longer follow-up is required to verify results and a prospective clinical trial is currently testing this new approach in chest and abdomen stereotactic body radiotherapy.

SUBMITTER: Brunner TB

PROVIDER: S-EPMC5122615 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Publications

Simultaneous integrated protection : A new concept for high-precision radiation therapy.

Brunner Thomas B TB Nestle Ursula U Adebahr Sonja S Gkika Eleni E Wiehle Rolf R Baltas Dimos D Grosu Anca-Ligia AL

Strahlentherapie und Onkologie : Organ der Deutschen Rontgengesellschaft ... [et al] 20161018 12

<h4>Objective</h4>Stereotactic radiotherapy near serial organs at risk (OAR) requires special caution. A novel intensity-modulated radiotherapy (IMRT) prescription concept termed simultaneous integrated protection (SIP) for quantifiable and comparable dose prescription to targets very close to OAR is described.<h4>Materials and methods</h4>An intersection volume of a planning risk volume (PRV) with the total planning target volume (PTV) defined the protection volume (PTV<sub>SIP</sub>). The rema ...[more]

PMID: 27757502

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Dataset Information

Simultaneous integrated protection : A new concept for high-precision radiation therapy.

Objective

Materials and methods

Results

Conclusion

Publications

Simultaneous integrated protection : A new concept for high-precision radiation therapy.

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