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Ahlstedt J, Förnvik K, Helms G, Salford LG, Ceberg C, Skagerberg G, Redebrandt HN. Growth pattern of experimental glioblastoma. Histol Histopathol 2020; 35:871-886. [PMID: 32022242 DOI: 10.14670/hh-18-207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Glioblastoma multiforme (GBM) is an aggressive primary brain malignancy with a very poor prognosis. Researchers employ animal models to develop potential therapies. It is important that these models have clinical relevance. This means that old models, propagated for decades in cultures, should be questioned. Parameters to be evaluated include whether animals are immune competent or not, the infiltrative growth pattern of the tumor, tumor volume resulting in symptoms and growth rate. We here describe the growth pattern of an experimental glioblastoma model in detail with GFP positive glioblastoma cells in fully immune competent animals and study tumor growth rate and tumor mass as a function of time from inoculation. We were able to correlate findings made with classical immunohistochemistry and MR findings. The tumor growth rate was fitted by a Gompertz function. The model predicted the time until onset of symptoms for 5000 inoculated cells to 18.7±0.4 days, and the tumor mass at days 10 and 14, which are commonly used as the start of treatment in therapeutic studies, were 5.97±0.62 mg and 29.1±3.0 mg, respectively. We want to raise the question regarding the clinical relevance of the outline of glioblastoma experiments, where treatment is often initiated at a very early stage. The approach presented here could potentially be modified to gain information also from other tumor models.
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Adrian G, Konradsson E, Lempart M, Bäck S, Ceberg C, Petersson K. The FLASH effect depends on oxygen concentration. Br J Radiol 2020; 93:20190702. [PMID: 31825653 PMCID: PMC7055454 DOI: 10.1259/bjr.20190702] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVE Recent in vivo results have shown prominent tissue sparing effect of radiotherapy with ultra-high dose rates (FLASH) compared to conventional dose rates (CONV). Oxygen depletion has been proposed as the underlying mechanism, but in vitro data to support this have been lacking. The aim of the current study was to compare FLASH to CONV irradiation under different oxygen concentrations in vitro. METHODS Prostate cancer cells were irradiated at different oxygen concentrations (relative partial pressure ranging between 1.6 and 20%) with a 10 MeV electron beam at a dose rate of either 600 Gy/s (FLASH) or 14 Gy/min (CONV), using a modified clinical linear accelerator. We evaluated the surviving fraction of cells using clonogenic assays after irradiation with doses ranging from 0 to 25 Gy. RESULTS Under normoxic conditions, no differences between FLASH and CONV irradiation were found. For hypoxic cells (1.6%), the radiation response was similar up to a dose of about 5-10 Gy, above which increased survival was shown for FLASH compared to CONV irradiation. The increased survival was shown to be significant at 18 Gy, and the effect was shown to depend on oxygen concentration. CONCLUSION The in vitro FLASH effect depends on oxygen concentration. Further studies to characterize and optimize the use of FLASH in order to widen the therapeutic window are indicated. ADVANCES IN KNOWLEDGE This paper shows in vitro evidence for the role of oxygen concentration underlying the difference between FLASH and CONV irradiation.
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Vilhelmsson Timmermand O, Strand SE, Ceberg C, Ceder JA. An aggressive RhoC phenotype is associated with relapse after external beam radiation therapy of a prostate cancer xenograft model. J Clin Oncol 2019. [DOI: 10.1200/jco.2019.37.15_suppl.e14748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e14748 Background: Relapsed treatment resistant prostate cancer remains the second most common cause of male mortality in the western world. New therapies for therapy resistant prostate cancer depend on defining tumor cell sub-populations capable of surviving, reinitiating, and sustaining net growth of the cancer. In this study we focused on RhoC expression in a prostate cancer model after external beam radiation therapy (EBRT). RhoC has earlier been implicated in metastatic processes in most solid tumors. Methods: In mice, established s.c. LNCaP xenografts (n = 12) were irradiated, the beam collimated with lead to restrict it to the xenograft, with X-rays (200 kV, 1 Gymin-1, Gulmay Medical) for an absorbed dose of 15 Gy. Tumor tissue was collected after seven days or after 3-4 weeks when recurrent growth was seen. RhoC, AR, CD166 and Ki67 immunohistochemistry in tumor sections was visualized by using DAB or Peroxidase Green and nuclear red or haematoxylin blue as counter stain. Sections stained for RhoC and Ki67 were quantified with the Halo software (v2.3.2089.34) using the Indica Labs – cytonuclear v1.6 algorithm. The intensity of the RhoC staining was also quantified in a separate set of sections only stained for RhoC. Results: The RhoC staining intensity was significantly higher in relapsed xenografts (P = 0.003). Also, a significant difference in percentage of RhoC expressing cells in the two populations (P = 0.045) with 40.6 ± 5.8% (mean ± SEM) in relapsed tumors as compared to 15.0 ± 8.1% after 7d. The percentage of cells expressing Ki67 was not significantly different (P = 0.477). However, the percentage of double positive cells (Ki67, RhoC) was significantly higher in treated relapsed xenografts (P = 0.042). Further, a subpopulation of RhoC-positive cells were positive for AR and the stem cell marker CD166. Conclusions: Here we show that a subpopulation of proliferating RhoC-positive cells are more prevalent in relapsing PCa xenografts after EBRT, suggesting an aggressive phenotype that is associated with both proliferation and invasiveness. Another subpopulation of RhoC cells was found to express the prostate stem cell marker CD166, suggesting that pathways and properties involved in cellular self-renewal and invasiveness may be responsible for survival and recurrent growth in relapsed prostate tumors.
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Lempart M, Blad B, Adrian G, Bäck S, Knöös T, Ceberg C, Petersson K. Modifying a clinical linear accelerator for delivery of ultra-high dose rate irradiation. Radiother Oncol 2019; 139:40-45. [PMID: 30755324 DOI: 10.1016/j.radonc.2019.01.031] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/24/2019] [Accepted: 01/25/2019] [Indexed: 12/31/2022]
Abstract
OBJECTIVES The purpose of this study was to modify a clinical linear accelerator, making it capable of electron beam ultra-high dose rate (FLASH) irradiation. Modifications had to be quick, reversible, and without interfering with clinical treatments. METHODS Performed modifications: (1) reduced distance with three setup positions, (2) adjusted/optimized gun current, modulator charge rate and beam steering values for a high dose rate, (3) delivery was controlled with a microcontroller on an electron pulse level, and (4) moving the primary and/or secondary scattering foils from the beam path. RESULTS The variation in dose for a five-pulse delivery was measured to be 1% (using a diode, 4% using film) during 10 minutes after a warm-up procedure, later increasing to 7% (11% using film). A FLASH irradiation dose rate was reached at the cross-hair foil, MLC, and wedge position, with ≥30, ≥80, and ≥300 Gy/s, respectively. Moving the scattering foils resulted in an increased output of ≥120, ≥250, and ≥1000 Gy/s, at the three positions. The beam flatness was 5% at the cross-hair position for a 20 × 20 and a 10 × 10 cm2 area, with and without both scattering foils in the beam. The beam flatness was 10% at the wedge position for a 6 and 2.5 cm diametric area, with and without the scattering foils in the beam path. CONCLUSIONS A clinical accelerator was modified to produce ultra-high dose rates, high enough for FLASH irradiation. Future work aims to fine-tune the dose delivery, using the on-board transmission chamber signal and adjusting the dose-per-pulse.
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Edvardsson A, Scherman J, Nilsson MP, Wennberg B, Nordström F, Ceberg C, Ceberg S. Breathing-motion induced interplay effects for stereotactic body radiotherapy of liver tumours using flattening-filter free volumetric modulated arc therapy. ACTA ACUST UNITED AC 2019; 64:025006. [DOI: 10.1088/1361-6560/aaf5d9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Stervik L, Pettersson N, Scherman-Rydhög J, Behrens CF, Ceberg C, Vogelius I, Bäck A. [OA077] Modelling the risk of fatal acute toxicity following radiotherapy of lung cancer. Phys Med 2018. [DOI: 10.1016/j.ejmp.2018.06.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Dalaryd M, Knöös T, Ceberg C. [P190] Investigation of beam quality correction factors for flattening filter free photon beams. Phys Med 2018. [DOI: 10.1016/j.ejmp.2018.06.489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Sunjic S, Ceberg C, Bokulic T. Statistical analysis of the gamma evaluation acceptance criteria: A simulation study of 2D dose distributions under error free conditions. Phys Med 2018; 52:42-47. [PMID: 30139608 DOI: 10.1016/j.ejmp.2018.06.633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/03/2018] [Accepted: 06/15/2018] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To investigate the statistical distribution of the gamma value under error-free conditions, in order to study the relation between the gamma evaluation failure rate and statistically significant deviations in the general situation. METHODS The 2D absorbed dose distribution for 30 clinical head-and-neck IMRT fields were calculated in a QC phantom. For the same fields, dose measurements were simulated by assuming that the calculated value represented the expectation value, and by adding a random spatial uncertainty of 1-9 mm (1SD) and a random dose uncertainty of 1%-3% (1SD). The simulated measurements were then compared to the calculated dose using the gamma evaluation, and the distribution of the failure rate (i.e. the probability of gamma values above unity) was analysed. RESULTS For a wide range of the random measurement uncertainty, a distinct peak in the failure rate distribution was observed. The presence of higher failure rates was associated with large values of the second order derivative of the dose distribution. For spatial uncertainties larger than or equal to the resolution of the dose matrix, and for reasonable dose uncertainties, the median value of the failure rate distribution was fairly constant. CONCLUSIONS Simulations showed, in the general case, that the probability of having a gamma value above unity under error-free conditions was not spatially uniform. We believe that this shortcoming may be partly responsible for the limited ability of the gamma evaluation method to detect errors in clinically relevant situations.
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Benedek H, Lerner M, Nilsson P, Knöös T, Gunnlaugsson A, Ceberg C. The effect of prostate motion during hypofractionated radiotherapy can be reduced by using flattening filter free beams. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 6:66-70. [PMID: 33458391 PMCID: PMC7807632 DOI: 10.1016/j.phro.2018.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 05/04/2018] [Accepted: 05/06/2018] [Indexed: 11/29/2022]
Abstract
Background and purpose Hypofractionated radiotherapy of prostate cancer reduces the overall treatment time but increases the per-fraction beam-on time due to the higher fraction doses. This increased fraction treatment time results in a larger uncertainty of the prostate position. The purpose of this study was to investigate the effect of prostate motion during flattening filter free (FFF) Volumetric Modulated Arc Therapy (VMAT) in ultrahypofractionation of prostate cancer radiotherapy with preserved plan quality compared to conventional flattened beams. Materials and methods Nine prostate patients from the Scandinavian HYPO-RT-PC trial were re-planned using VMAT technique with both conventional and flattening filter free beams. Two fractionation schedules were used, one hypofractionated (42.7 Gy in 7 fractions), and one conventional (78.0 Gy in 39 fractions). Pre-treatment verification measurements were performed on all plans and the treatment time was recorded. Measurements with simulated prostate motion were performed for the plans with the longest treatment times. Results All the 10FFF plans fulfilled the clinical gamma pass rate, 90% (3%, 2 mm), during all simulated prostate motion trajectories. The 10MV plans only fulfilled the clinical pass rate for three of the trajectories. The mean beam-on-time for the hypofractionated plans were reduced from 2.3 min to 1.0 min when using 10FFF compared to 10MV. No clinically relevant differences in dose distribution were identified when comparing the plans with different beam qualities. Conclusion Flattening-filter free VMAT reduces treatment times, limiting the dosimetric effect of organ motion for ultrahypofractionated prostate cancer with preserved plan quality.
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Chakwizira A, Ahlstedt J, Nittby Redebrandt H, Ceberg C. Mathematical modelling of the synergistic combination of radiotherapy and indoleamine-2,3-dioxygenase (IDO) inhibitory immunotherapy against glioblastoma. Br J Radiol 2018; 91:20170857. [PMID: 29688039 PMCID: PMC6221783 DOI: 10.1259/bjr.20170857] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Objective: Recent research has shown that combining radiotherapy and immunotherapy can counteract the ability of cancer to evade and suppress the native immune system. To optimise the synergy of the combined therapies, factors such as radiation dose and fractionation must be considered, alongside numerous parameters resulting from the complexity of cancer–immune system interactions. It is instructive to use mathematical models to tackle this problem. Methods: In this work, we adapted a model primarily to describe the synergistic effect between single-fraction radiotherapy and immunotherapy (1-methyl tryptophan) observed in previous experiments with glioblastoma-carrying rats. We also showed how the model can be used to generate hypotheses on the outcome of other treatment fractionation schemes. Results: The model successfully reproduced the results of the experiments. Moreover, it provided support for the hypothesis that, for a given biologically effective dose, the efficacy of the combination therapy and the synergy between the two therapies are favoured by the administration of radiotherapy in a hypofractionated regime. Furthermore, for a double-fraction irradiation regimen, the synergy is favoured by a short time interval between the treatment fractions. Conclusion: It was concluded that the model could be fitted to reproduce the experimental data well within its uncertainties. It was also demonstrated that the fitted model can be used to form hypotheses to be validated by further pre-clinical experiments. Advances in knowledge: The results of this work support the hypothesis that the synergetic action of combined radiotherapy and immunotherapy is favoured by using a hypofractionated radiation treatment regimen, given over a short time interval.
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Edvardsson A, Nordström F, Ceberg C, Ceberg S. Motion induced interplay effects for VMAT radiotherapy. ACTA ACUST UNITED AC 2018; 63:085012. [DOI: 10.1088/1361-6560/aab957] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Adrian G, Ceberg C, Carneiro A, Ekblad L. Rescue Effect Inherited in Colony Formation Assays Affects Radiation Response. Radiat Res 2017; 189:44-52. [PMID: 29136392 DOI: 10.1667/rr14842.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
It is well known that nonirradiated cells can exhibit radiation damage (bystander effect), and recent findings have shown that nonirradiated cells may help protect irradiated cells (rescue effect). These findings call into question the traditional view of radiation response: cells cannot be envisioned as isolated units. Here, we investigated traditional colony formation assays to determine if they also comprise cellular communication affecting the radiation response, using colony formation assays with varying numbers of cells, modulated beam irradiation and media transfer. Our findings showed that surviving fraction gradually increased with increasing number of irradiated cells. Specifically, for DU-145 human prostate cancer cells, surviving fraction increased 1.9-to-4.1-fold after 5-12 Gy irradiation; and for MM576 human melanoma cells, surviving fraction increased 1.9-fold after 5 Gy irradiation. Furthermore, increased surviving fraction was evident after modulated beam irradiation, where irradiated cells could communicate with nonirradiated cells. Media from dense cell culture also increased surviving fraction. The results suggest that traditional colony formation assays comprise unavoidable cellular communication affecting radiation outcome and the shape of the survival curve. We also propose that the increased in-field surviving fraction after modulated beam irradiation is due to the same effect.
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Ahlstedt J, Ceberg C, Salford LG, Redebrandt HN. IMMU-27. OPTIMIZING THE COMBINATORY TREATMENT OF LOW-DOSE RADIATION AND INDOLEAMINE-2,3-DEOXYGENASE INHIBITION FOR GLIOBLASTOMA. Neuro Oncol 2017. [DOI: 10.1093/neuonc/nox168.485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Said M, Nilsson P, Ceberg C. Analysis of dose heterogeneity using a subvolume-DVH. Phys Med Biol 2017; 62:N517-N524. [DOI: 10.1088/1361-6560/aa8b0a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Benedek H, Ahlström M, Nilsson P, Engström P, Knöös T, Ceberg C. The Dosimetric Effect of Prostate Motion in Flattening Filter Free VMAT Treatments Using Extreme Hypofractionation. Int J Radiat Oncol Biol Phys 2017. [DOI: 10.1016/j.ijrobp.2017.06.2141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Day L, Smyth L, Holm M, Rogers P, Engström P, Ceberg C, Poole C, Crosbie J, Senthi S, Woodford K. EP-1563: Treatment planning for synchrotron microbeam radiotherapy. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)31998-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Ceberg C, Ahlstedt J, Redebrant Nittby H. EP-1599: Mathematical modeling of the synergistic combination of cancer immunotherapy and radiotherapy. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)32034-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Edvardsson A, Nordstrom F, Ceberg C, Ceberg S. Motion-Induced Interplay Effects for Hypofractionated Volumetric Modulated Arc Therapy Treatment of Liver Tumors—Dependence on Breathing Pattern, Dose Rate, and Plan Modulation Complexity. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.2283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Persson E, Nordström F, Siversson C, Ceberg C. OC-0156: MRI only prostate radiotherapy using synthetic CT images. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)31405-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ahlström M, Benedek H, Nilsson P, Knöös T, Ceberg C. PO-0855: Flattening Filter Free VMAT for extreme hypofractionation of prostate cancer. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)32105-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Edvardsson A, Nordström F, Ceberg C, Ceberg S. OC-0462: Motion induced interplay effects for hypo-fractionated FFF VMAT treatment of liver tumours. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)31711-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Dalaryd M, Knöös T, Ceberg C. EP-1597: Investigation of in-air output ratios in FFF beams. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)32847-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Petersson K, Nilsson P, Engström P, Knöös T, Ceberg C. Evaluation of dual-arc VMAT radiotherapy treatment plans automatically generated via dose mimicking. Acta Oncol 2015; 55:523-5. [PMID: 26361238 DOI: 10.3109/0284186x.2015.1080855] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Petersson K, Nilsson P, Engström P, Knöös T, Ceberg C. Multi-modality optimisation in radiotherapy treatment planning using composite objective values. Acta Oncol 2015; 54:552-6. [PMID: 25178091 DOI: 10.3109/0284186x.2014.953255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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