Normal Tissue Complication Probability Model for Radiation-induced Temporal Lobe Injury after Intensity-modulated Radiation Therapy for Nasopharyngeal Carcinoma

Zeng, Lei; Huang, Shao Min; Tian, Yun; Sun, Xue Ming; Han, Fei; Lu, Tai Xiang; Deng, Xiao Wu

doi:10.1148/radiol.14141721

Cited by 49 publications

(50 citation statements)

References 11 publications

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“…We were, however, able to extract a TD 50 parameter because our model is based on the probit function, which facilitates comparison of results with the more traditional models and analyses. Published values for TD 50 of necrosis/infarction in the brain (the most closely related normal tissue effect for which large amounts of data are reported) for photons are in the range of 60–75 Gy [15,34–36]. Our own analysis indicates that, for this set of patients, the TD 50 for voxel image change spans a similar range for typical low proton LET values of 0–2 keV µm −1 .…”

Section: Discussionmentioning

confidence: 62%

Clinical evidence of variable proton biological effectiveness in pediatric patients treated for ependymoma

Peeler

Mirković

Titt

et al. 2016

Radiotherapy and Oncology

225

230

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Background and Purpose A constant relative biological effectiveness (RBE) is used for clinical proton therapy; however, experimental evidence indicates that RBE can vary. We analyzed pediatric ependymoma patients who received proton therapy to determine if areas of normal tissue damage indicated by post-treatment image changes were associated with increased biological dose effectiveness. Material and Methods Fourteen of 34 children showed T2-FLAIR hyperintensity on post-treatment magnetic resonance (MR) images. We delineated regions of treatment-related change and calculated dose and linear energy transfer (LET) distributions with Monte Carlo. Voxel-level image change data were fit to a generalized linear model incorporating dose and LET. Cross-validation was used to determine model parameters and for receiver operating characteristic curve analysis. Tolerance dose (TD50; dose at which 50% of patients would experience toxicity) was interpolated from the model. Results Image changes showed dependence on increasing LET and dose. TD50 decreased with increasing LET, indicating an increase in biological dose effectiveness. The cross-validated area under the curve for the model was 0.91 (95% confidence interval 0.88–0.94). Conclusions Our correlation of changes on MR images after proton therapy with increased LET constitutes the first clinical evidence of variable proton biological effectiveness.

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Section: Discussionmentioning

confidence: 62%

Clinical evidence of variable proton biological effectiveness in pediatric patients treated for ependymoma

Peeler

Mirković

Titt

et al. 2016

Radiotherapy and Oncology

225

230

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“…Radiation-induced brain injury, including structural and functional deficits, is a severe complication for patients with nasopharyngeal carcinoma (NPC) after radiotherapy (RT) (Zeng, et al, 2015). Based on the onset time of RT, three phases of the pathophysiological reaction to irradiation in normal brain tissue can be classified, acute reaction period (few days to few weeks), early delayed radiation period (1–6 months), and late delayed radiation period (6 months to few years) (Lell, 2015).…”

Section: Introductionmentioning

confidence: 99%

Radiation-induced abnormal cortical thickness in patients with nasopharyngeal carcinoma after radiotherapy

Lin

Niu

et al. 2017

NeuroImage: Clinical

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Conventional MRI studies showed that radiation-induced brain necrosis in patients with nasopharyngeal carcinoma (NPC) in years after radiotherapy (RT) could involve brain gray matter (GM) and impair brain function. However, it is still unclear the radiation-induced brain morphological changes in NPC patients with normal-appearing GM in the early period after RT. In this study, we acquired high-resolution brain structural MRI data from three groups of patients, 22 before radiotherapy (pre-RT) NPC patients with newly diagnosed but not yet medically treated, 22 NPC patients in the early-delayed stage after radiotherapy (post-RT-ED), and 20 NPC patients in the late-delayed stage after radiotherapy (post-RT-LD), and then analyzed the radiation-induced cortical thickness alteration in NPC patients after RT. Using a vertex-wise surface-based morphometry (SBM) approach, we detected significantly decreased cortical thickness in the precentral gyrus (PreCG) in the post-RT-ED group compared to the pre-RT group. And the post-RT-LD group showed significantly increased cortical thickness in widespread brain regions, including the bilateral inferior parietal, left isthmus of the cingulate, left bank of the superior temporal sulcus and left lateral occipital regions, compared to the pre-RT group, and in the bilateral PreCG compared to the post-RT-ED group. Similar analysis with ROI-wise SBM method also found the consistent results. These results indicated that radiation-induced brain injury mainly occurred in the post-RT-LD group and the cortical thickness alterations after RT were dynamic in different periods. Our findings may reflect the pathogenesis of radiation-induced brain injury in NPC patients with normal-appearing GM and an early intervention is necessary for protecting GM during RT.

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“…In NPC, many important OARs are adjacent to the edges of the target volumes in the longitudinal direction. Zeng et al (10) established a clinical dose association model and performed an analysis using the equivalent dose in 2-Gy fractions (EQD2), reporting a biologically-equivalent tolerance dose of D 1cc for the development of temporal lobe injury of 62.83 Gy. Hsiao et al (9) reported that patients with NPC showed significant cognitive decline after receiving radiotherapy when the D mean of the temporal lobe was >36 Gy.…”

Section: Discussionmentioning

confidence: 99%

“…The hippocampus is an important organ for memory and cognitive function in humans. The control and reduction of radiation dose received by the hippocampus are critical for the quality of long-term survival in patients with NPC who achieve satisfactory therapeutic effects (8)(9)(10). Therefore, to ensure better protection of OARs, clinical planning of HT for NPC often involves using a jaw width of 2.5cm and partly sacrifices the delivery efficiency when using the conventional fixed jaw mode.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Different Combinations of Irradiation Mode and Jaw Width in Helical Tomotherapy for Nasopharyngeal Carcinoma

et al. 2020

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Purpose: To aid in the selection of a suitable combination of irradiation mode and jaw width in helical tomotherapy (HT) for the treatment of nasopharyngeal carcinoma (NPC). Materials and Methods:Twenty patients with NPC who underwent radiotherapy were retrospectively selected. Four plans using a jaw width of 2.5 or 5-cm in dynamic jaw (DJ) or fix jaw (FJ) modes for irradiation were designed (2.5DJ, 2.5FJ, 5.0DJ, and 5.0FJ). The dose parameters of planning target volume (PTV) and organs at risk (OARs) of the plans were compared and analyzed, as well as the beam on time (BOT) and monitor unit (MU). The plans in each group were ranked by scoring the doses received by the OARs and the superity was assessed in combination with the planned BOT and MU. Results:The prescribed dose coverage of PTV met the clinical requirements for all plans in the four groups. The groups using a 2.5-cm jaw width or a DJ mode provided better protection to most OARs, particularly for those at the longitudinal edges of the PTV (P < 0.05). The 2.5DJ group had the best ranking for OAR-dose, followed by the 2.5FJ and 5.0DJ groups with a same score. The BOT and MU of the groups using a 5.0-cm jaw width reduced nearly 45% comparing to those of the 2.5-cm jaw groups.Conclusion: 2.5DJ has the best dose distribution, while 5.0DJ has satisfactory dose distribution and less BOT and MU that related to the leakage dose. Both 2.5DJ or 5DJ were recommended for HT treatment plan for NPC based on the center workload.

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Normal Tissue Complication Probability Model for Radiation-induced Temporal Lobe Injury after Intensity-modulated Radiation Therapy for Nasopharyngeal Carcinoma

Abstract: D1cc is predictive for radiation-induced TLI, suggesting that delivery of a high dose of radiation to a small volume of the temporal lobe is unsafe. A D1cc of 62.83 Gy by using a correction formula for varying fraction size may be the dose tolerance of the temporal lobe.

Cited by 49 publications

References 11 publications

Clinical evidence of variable proton biological effectiveness in pediatric patients treated for ependymoma

Clinical evidence of variable proton biological effectiveness in pediatric patients treated for ependymoma

Radiation-induced abnormal cortical thickness in patients with nasopharyngeal carcinoma after radiotherapy

Comparison of Different Combinations of Irradiation Mode and Jaw Width in Helical Tomotherapy for Nasopharyngeal Carcinoma

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