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Gauter-Fleckenstein B, Schönig S, Mertens L, Oppitz H, Siebenlist K, Ehmann M, Fleckenstein J. Effect of simultaneous integrated boost concepts on photoneutron and distant out-of-field doses in VMAT for prostate cancer. Strahlenther Onkol 2024; 200:219-229. [PMID: 37707518 PMCID: PMC10876496 DOI: 10.1007/s00066-023-02138-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 08/08/2023] [Indexed: 09/15/2023]
Abstract
BACKGROUND A simultaneous integrated boost (SIB) may result in increased out-of-field (DOOF) and photoneutron (HPN) doses in volumetric modulated arc therapy (VMAT) for prostate cancer (PCA). This work therefore aimed to compare DOOF and HPN in flattened (FLAT) and flattening filter-free (FFF) 6‑MV and 10-MV VMAT treatment plans with and without SIB. METHODS Eight groups of 30 VMAT plans for PCA with 6 MV or 10 MV, with or without FF and with uniform (2 Gy) or SIB target dose (2.5/3.0 Gy) prescriptions (CONV, SIB), were generated. All 240 plans were delivered on a slab-phantom and compared with respect to measured DOOF and HPN in 61.8 cm distance from the isocenter. The 6‑ and 10-MV flattened VMAT plans with conventional fractionation (6- and 10-MV FLAT CONV) served as standard reference groups. Doses were analyzed as a function of delivered monitor units (MU) and weighted equivalent square field size Aeq. Pearson's correlation coefficients between the presented quantities were determined. RESULTS The SIB plans resulted in decreased HPN over an entire prostate RT treatment course (10-MV SIB vs. CONV -38.2%). Omission of the flattening filter yielded less HPN (10-MV CONV -17.2%; 10-MV SIB -22.5%). The SIB decreased DOOF likewise by 39% for all given scenarios, while the FFF mode reduced DOOF on average by 60%. A strong Pearson correlation was found between MU and HPN (r > 0.9) as well as DOOF (0.7 < r < 0.9). CONCLUSION For a complete treatment, SIB reduces both photoneutron and OOF doses to almost the same extent as FFF deliveries. It is recommended to apply moderately hypofractionated 6‑MV SIB FFF-VMAT when considering photoneutron or OOF doses.
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Affiliation(s)
- Benjamin Gauter-Fleckenstein
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany.
| | - Sebastian Schönig
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Lena Mertens
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Hans Oppitz
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Kerstin Siebenlist
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Michael Ehmann
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
| | - Jens Fleckenstein
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68167, Mannheim, Germany
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Dreher C, Sarria GR, Miebach G, Weiss C, Buergy D, Wojtal P, Tavakoli AA, Krug D, Oppitz H, Giordano FA, Both M, Lohr F, Dunst J, Blanck O, Boda-Heggemann J. Long-term characterization of MRI-morphologic alterations after active motion-compensated liver SBRT: a multi-institutional pooled analysis. Acta Oncol 2023; 62:281-289. [PMID: 37017543 DOI: 10.1080/0284186x.2023.2187707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
BACKGROUND Stereotactic body radiotherapy (SBRT) is an effective therapeutic approach in patients with liver metastases. However, long-term changes in hepatic normal tissue have to be taken into account in multimodal treatment regimes. Magnetic-resonance-imaging (MRI) based morphologic liver alterations (MMA) after liver SBRT have been analyzed longitudinally. MATERIAL AND METHODS 57 patients treated with gantry-based or robotic-based SBRT of 69 treatment volumes of liver metastases, who had long-term follow-up (FU) ≥6 months were included in this retrospective analysis. Post-SBRT MMAs were contoured on each contrast-enhanced-T1-weighted (T1w) MRI-sequence. Morphologic/volumetric data of the liver and MMAs were evaluated longitudinally, including the dependency on treatment-related factors of the planning target volume (PTV) and liver. RESULTS The median FU time was 1 year [6-48 months]. 66 of 69 treatment volumes developed MMAs (mean 143.8 ± 135.1 ccm at first appearance). 31.8% of MMAs resolved completely during FU. Of the persisting MMAs 82.2%/13.3% decreased/increased in size until last available FU. Morphological characterization of the MMAs at first appearance included 75% hypointense and 25% hyperintense T1w-MRI-based appearances. Hypointense as compared to hyperintense appearance was significantly associated with a higher mean liver dose EQD2α/β=3 Gy (p = 0.0212) and non-significantly greater MMA size. Variance analysis demonstrated a significant reduction of MMA and total liver volume after SBRT (p < 0.0001). The volume reduction decelerated longitudinally for both MMA (p < 0.0001) and liver size (p = 0.0033). Radiation doses (PTV-BEDα/β=3 Gy and 10 Gy) were not significantly associated with MMA volume reduction. SBRT of liver metastases with mean liver dose EQD2α/β=3 Gy > 18 Gy were characterized by greater MMA volumes (p = 0.0826) and steeper MMA reduction gradients during FU than those with EQD2α/β=3 Gy ≤ 18 Gy (p < 0.0001). CONCLUSION Radiogenic MMAs either completely resolve or usually decrease in volume with pronounced reduction during short-term FU. This course was independent of the MMA's morphological appearance. Further, increased mean liver dose was associated with greater MMA size and a greater gradient of MMA size reduction during FU.
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Affiliation(s)
- Constantin Dreher
- Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- DKFZ-Hector Cancer Institute, University Medical Center Mannheim, Mannheim, Germany
| | - Gustavo R Sarria
- Department of Radiation Oncology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Georgia Miebach
- Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Christel Weiss
- Department of Medical Statistics and Biomathematics, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Daniel Buergy
- Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- DKFZ-Hector Cancer Institute, University Medical Center Mannheim, Mannheim, Germany
| | - Paulina Wojtal
- Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Anoshirwan A Tavakoli
- Department of Radiology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - David Krug
- Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany
- Saphir Radiosurgery Center Northern Germany, Kiel, Germany
| | - Hans Oppitz
- Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Frank A Giordano
- Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- DKFZ-Hector Cancer Institute, University Medical Center Mannheim, Mannheim, Germany
| | - Marcus Both
- Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Frank Lohr
- Dipartimento di Oncologia, UO di Radioterapia, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy
| | - Jürgen Dunst
- Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Oliver Blanck
- Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany
- Saphir Radiosurgery Center Northern Germany, Kiel, Germany
| | - Judit Boda-Heggemann
- Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- DKFZ-Hector Cancer Institute, University Medical Center Mannheim, Mannheim, Germany
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Sarria G, Dreher C, Miebach G, Henkenberens C, Stera S, Wojtal P, Krug D, Oppitz H, Giordano F, Schäfer J, Lohr F, Dunst J, Blanck O, Boda-Heggemann J. Long-Term Characterization of MRI-Morphologic Alterations After Active Motion-Compensated Liver SBRT. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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