PO-0848: Simultaneous integrated protection (SIP): a new concept for high precision radiation therapy

Brunner, Th.; Adebahr, S.; Gkika, Eleni; Zipfel, A.; Wiehle, R.; Nestle, Ursula; Grosu, Anca L.

doi:10.1016/s0167-8140(16)32098-9

Cited by 3 publications

(4 citation statements)

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“…In addition, we applied a novel intensity‐modulated radiotherapy technique called simultaneous integrated protection (SIP) 28,29 and dose gradient prescription to administer possible high BED 10 to the PTV while maintaining a low BED 3 to the PRV. This prescription provided a homogenous dose to the overlapping area of the PTV and PRV, while administering a steep dose gradient profile in the non‐overlapping PTV area and outside of the PTV.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, we applied a novel intensity-modulated radiotherapy technique called simultaneous integrated protection (SIP) 28,29 reported that the mean PTV dose correlates with local control 30,31 in radiotherapy for non-small cell lung cancer. Increasing the mean PTV dose by SIP and dose gradient prescription may be one of the reasons for the good local control rate.…”

Section: Discussionmentioning

confidence: 99%

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Hypofractionated radiotherapy for hepatocellular carcinomas adjacent to the gastrointestinal tract

Tsurugai

Takeda

Eriguchi

et al. 2021

Hepatology Research

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Aim: Decisions regarding therapeutic plans for inoperable patients with hepatocellular carcinoma (HCC) adjacent to the gastrointestinal (GI) tract are challenging because radiofrequency ablation has the potential risk of thermal injury. Moreover, the response rate of transcatheter arterial chemoembolization is relatively low and stereotactic body radiotherapy (SBRT) is believed to be too toxic. We have applied hypofractionated radiotherapy (HFRT) for such lesions. This study investigated the outcomes and toxicities of this treatment. Methods: Among consecutive HCC patients treated with radiotherapy with curative intent at our institution between 2015 and 2019, we retrospectively extracted those outside of the indication for SBRT due to exceeding the constraint of the GI tract and who were treated using HFRT with a prescription dose of 42 Gy in 14 fractions and prophylactic proton pump inhibitor administration for 6 months. The oncological outcomes and toxicities were investigated. Results: A total of 66 patients with 73 lesions were eligible. The median follow-up period was 24.0 months. The local recurrence, intrahepatic recurrence, liver-related death, and overall survival rates at 2 years were 11.3%, 50.6%, 15.9%, and 60.4%, respectively. Six (9.1%) patients experienced Child-Pugh score deterioration ≥2 within 6 months following treatment. Two and one patient developed grades 2 and 3 gastroduodenal bleeding, respectively. Conclusions: HFRT can achieve good local control in patients with HCC adjacent to the GI tract, with low GI toxicity incidence. Our study demonstrated that HFRT can be a potentially curative treatment option for lesions.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Hypofractionated radiotherapy for hepatocellular carcinomas adjacent to the gastrointestinal tract

Tsurugai

Takeda

Eriguchi

et al. 2021

Hepatology Research

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“…Inconsistencies in the delineation might lead to recurrences or higher exposure of organs at risk and subsequently to a higher risk for toxicities. Several attempts have been made to reduce exposure of organs at risk, either by reducing the dose or using a simultaneous integrated protection volume [ 1 , 2 ]. However, appropriate planning hinges on accurate definition of the target and the organs at risk.…”

Section: Introductionmentioning

confidence: 99%

Interobserver agreement on definition of the target volume in stereotactic radiotherapy for pancreatic adenocarcinoma using different imaging modalities

Gkika,

Kostyszyn,

Fechter

et al. 2023

Strahlenther Onkol

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Purpose The aim of this study was to evaluate interobserver agreement (IOA) on target volume definition for pancreatic cancer (PACA) within the Radiosurgery and Stereotactic Radiotherapy Working Group of the German Society of Radiation Oncology (DEGRO) and to identify the influence of imaging modalities on the definition of the target volumes. Methods Two cases of locally advanced PACA and one local recurrence were selected from a large SBRT database. Delineation was based on either a planning 4D CT with or without (w/wo) IV contrast, w/wo PET/CT, and w/wo diagnostic MRI. Novel compared to other studies, a combination of four metrics was used to integrate several aspects of target volume segmentation: the Dice coefficient (DSC), the Hausdorff distance (HD), the probabilistic distance (PBD), and the volumetric similarity (VS). Results For all three GTVs, the median DSC was 0.75 (range 0.17–0.95), the median HD 15 (range 3.22–67.11) mm, the median PBD 0.33 (range 0.06–4.86), and the median VS was 0.88 (range 0.31–1). For ITVs and PTVs the results were similar. When comparing the imaging modalities for delineation, the best agreement for the GTV was achieved using PET/CT, and for the ITV and PTV using 4D PET/CT, in treatment position with abdominal compression. Conclusion Overall, there was good GTV agreement (DSC). Combined metrics appeared to allow a more valid detection of interobserver variation. For SBRT, either 4D PET/CT or 3D PET/CT in treatment position with abdominal compression leads to better agreement and should be considered as a very useful imaging modality for the definition of treatment volumes in pancreatic SBRT. Contouring does not appear to be the weakest link in the treatment planning chain of SBRT for PACA.

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“…Concepts similar to DTV have been proposed by other authors, Stroom et al 10 defined iso‐probability maps for designing PTV. Simultaneous integrated protection was proposed by Brunner et al 11 In their methods, the authors set population‐derived objectives to design PTV. As opposed to a predefined population‐based method, evaluation of DTV plans including the effects of spatial uncertainty can validate the concept on a patient‐specific basis.…”

Section: Introductionmentioning

confidence: 99%

Dose escalation in the definite target volume

2020

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To introduce the definite target volume (DTV) and evaluate dosimetric consequences of boosting dose to this region of high clinical target volume (CTV)-and low organs at risk (OAR)probability. Methods: This work defines the DTV via occupancy probability and via contraction of the CTV by margin M less any planning risk volume (PRV) volumes. The equivalence to within varying occupancy probability of the two methods is established for spherical target volumes. We estimate a margin for four radiation treatment sites based on modern images guided radiation therapy-literature utilizing repeat volumetric imaging. Based on margins and patient-specific DTV targets, the ability to dose escalate the DTV including the effects of spatial uncertainty was evaluated. We simulate delivery assuming violation of the underlying spatial uncertainty of 130%. Results: Contracting the planning target volume (PTV) by M and excluding PRV volumes, the DTV ranged from 7.3 to 93.6 cc. In a brain treatment, DTV-Dmax increased to 66.8 Gy (145% of prescription isodose); in advanced lung DTV-Dmax increased to 122.2 Gy (204% of prescription isodose), in a pancreatic case DTV-Dmax was boosted up to 87.3 Gy (173% or prescription isodose), and in retroperitoneal sarcoma to 74.6 Gy (249% of prescription isodose). The high point doses were not associated with increased dose to OARs, even when considering the effects of spatial uncertainty. Simulated delivery at 130% of assumed spatial uncertainties revealed DTV-based planning can result in minor increases in OAR Dmean/Dmax of 2.7 AE 2.1 Gy/1.8 AE 2.2 Gy with duodenum Dmax > 110% of prescription isodose in the pancreatic case. These dose increases were consistent with simulation of clinical, homogenous PTV-dose distributions. Conclusion:We have proposed and tested a method to deliver extremely high doses to subvolumes of target volumes in multiple treatment sites by defining a new target volume, the DTV. Based on simulated delivery, the method does not result in significant increases in dose to OARs if spatial uncertainty can be estimated.

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PO-0848: Simultaneous integrated protection (SIP): a new concept for high precision radiation therapy

Cited by 3 publications

References 0 publications

Hypofractionated radiotherapy for hepatocellular carcinomas adjacent to the gastrointestinal tract

Hypofractionated radiotherapy for hepatocellular carcinomas adjacent to the gastrointestinal tract

Interobserver agreement on definition of the target volume in stereotactic radiotherapy for pancreatic adenocarcinoma using different imaging modalities

Dose escalation in the definite target volume

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