International journal of radiology & radiation therapy最新文献

{"title":"Dosimetric evaluation of accelerated partial breast irradiation (APBI) using volumetric modulated arc therapy (VMAT) technique","authors":"Jean L Peng, Daniel G McDonald, Lisa M Warwick, Jennifer L Harper","doi":"10.15406/ijrrt.2023.10.00363","DOIUrl":"https://doi.org/10.15406/ijrrt.2023.10.00363","url":null,"abstract":"Purpose: Five-fraction radiation therapy treatment regimens for accelerated partial breast irradiation (APBI) using intensity modulated radiotherapy (IMRT) have become increasingly used after several phase three trials demonstrated similar or reduced toxicity compared with whole breast irradiation. Improving the treatment efficiency of this technique could significantly improve delivery accuracy and tolerability, especially for treatment plans utilizing deep inspiration breath hold (DIBH) technique. The aim of this study was to determine the optimal technique for APBI, with a focus on volumetric modulated arc therapy technique (VMAT) and flattening-filter free (FFF) delivery. Methods: Ten APBI cases, five cases each left and right breast, were randomly selected. Each case was contoured following guidelines included in the APBI-IMRT-Florence Trial and planned to use both non-coplanar static-field IMRT with standard flattened-filter (FF) beam and VMAT techniques with both FF and FFF beam. For each VMAT plan, two partial arcs were used with patient-specific start and stop angles. Arc extents emulated opposed tangential fields and were chosen based on target and organ at risk (OAR) locations. Evaluated OARs included the heart, ipsilateral and contralateral lung, and normal breast. All plans were generated using the Eclipse treatment planning system (Version 15.6). A prescription dose of 30Gy delivered in 5 fractions was used for all cases. Plans were compared and evaluated using several dose metrics as well as treatment time. Results: For targets, VMAT exhibited similar coverage (V95%) but higher Dmax compared to IMRT (105% (IMRT) v.s .111% (VMAT), p=0.002. VMAT provided similar OAR avoidance compared to IMRT for the heart (Dmean, V3Gy, V0.5Gy), ipsilateral lung (V10Gy), contralateral lung (V5Gy) and contralateral breast Dmax within 10cGy/2% (p~0.005). VMAT contributed slightly lower dose outside the target in the ipsilateral breast, with an average difference in V15Gy of approximately 8% (37% (IMRT) v.s. 29% (VMAT)). Finally, because IMRT delivery is non-coplanar, and typically requires at least 5 treatment fields, co-planar VMAT reduced the total treatment significantly. VMAT with FF beam energies also used fewer monitor unites compared to IMRT with FF beam energies. The utilization of FFF beam energies for VMAT further improved delivery time compared to IMRT. Overall, VMAT with FFF beam energies reduced treatment time by approximately 20% compared to IMRT with FF beam. Conclusions: Co-planar partial-arc FFF VMAT technique produced equivalent target coverage, improved efficiency, better normal tissue sparing, and shorter delivery time compared to non-coplanar IMRT technique. Shorter delivery time also assists in the reduction of patient motion associated with breath hold. VMAT technique with FFF delivery is a suitable replacement for IMRT in APBI.","PeriodicalId":486498,"journal":{"name":"International journal of radiology & radiation therapy","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136379130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stereotactic ablative radiotherapy for stage I lung cancer: a retrospective single institution report in Western Australia","authors":"Caris Chong, Hendrick Tan, Cherie Vaz, Susan Mincham, Eugene Leong, Max Hoffman, Tee Lim","doi":"10.15406/ijrrt.2023.10.00352","DOIUrl":"https://doi.org/10.15406/ijrrt.2023.10.00352","url":null,"abstract":"Objectives: Stereotactic ablative radiotherapy (SABR) is now standard management of stage I non-small cell lung cancer in patients who are not medically operable. The purpose of this study was to assess clinical outcomes in our single institution to review comparability with worldwide outcomes. Methods: The institutional database was screened for all patients with Stage I NSCLC treated in between September 2010 to November 2018 with SABR. Local control was defined on PET/CT or CT imaging and survival status retrieved from electronic medical records. Overall survival and local control were calculated using Kaplan-Meier method. Results: 93 patients were treated with SBRT for stage I NSCLC. Median follow up time was 30 months (range 1-99 months). Overall survival was 67% and local control was 91% at 3 years respectively. Toxicity included grade 1-2 pneumonitis (16.5%), chest wall pain (3.3%) and rib fracture (2.1%) Conclusion: In our local institution SABR for Stage I NSCLC is a safe and effective form of management of medically inoperable patients.","PeriodicalId":486498,"journal":{"name":"International journal of radiology & radiation therapy","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135270494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}