Radiation Oncology最新文献

Background: Carbon-ion radiotherapy (CIRT) for head and neck tumors is typically delivered in the supine posture using fixed beam lines, which limits beam angle selection. Combining upright posture with fixed beam lines offers expanded angular access and potential dosimetric advantages, yet optimal angle configurations remain unclear. This study identifies optimal beam angles in head and neck CIRT by comparing dosimetry and robustness of upright and supine plans for fixed-beam systems, thereby supporting beam angle optimization and clinical implementation of upright treatment in fixed-beam systems.

Methods: Twenty patients with head and neck cancer were retrospectively robustly optimized using four beam configurations: horizontal beams at 0° (S0) and with a 15° superior-oblique tilt (S15) in the supine posture, anterior beams at 15° (U15) and 45° (U45) in the upright posture. Plans were generated in RayStation (v10B) accounting for ± 3 mm setup and ± 3.5% range uncertainties. Target coverage (D_95%, D_2%, V_95%, conformity index [CI], homogeneity index [HI]), plan robustness (DVH bands, worst-case scenario), and organ-at-risk (OAR) dosimetry (mean dose to cochleae and parotid glands, and brainstem D_1cc) were compared. Statistical analyses used paired t-tests or Wilcoxon signed-rank tests.

Results: All plans achieved comparable nominal target coverage and similar CI values. S15 showed significantly improved robustness (DVH band ΔD_95% = 0.5 Gy(RBE), ΔV_95% = 1.4%; worst-case ΔD_95% = 0.3 Gy(RBE), ΔHI = 0.01, ΔCI = 0.02, all p < 0.05) and lower OAR doses versus S0 (cochlea: 28.4 vs. 30.6 Gy(RBE), parotid: 13.5 vs. 18.5 Gy(RBE), brainstem D_1cc: 40.1 vs. 41.7 Gy(RBE), all p < 0.001). U15 exhibited comparable robustness to S15 with further reductions in cochlea (18.5 vs. 28.4 Gy(RBE), p < 0.001) and parotid sparing (11.9 vs. 13.5 Gy(RBE), p < 0.05). U45 showed the highest robustness and OAR sparing, except for the brainstem, where D_1cc was significantly increased (50.9 Gy(RBE), p < 0.05).

Conclusions: The anterior beams at 15°in the upright setup (U15) showed the best balance of robustness and OAR sparing, making it the preferred option. The 15°-angled supine setup (S15) is a practical alternative. S0 and U45 are not recommended due to inferior robustness and higher brainstem dose, respectively.

Background: Tumor heterogeneity is a significant factor contributing to the marked differences in survival rates among glioblastoma multiforme (GBM) patients, who face a poor prognosis. To improve personalized treatment, it is essential to identify specific tumor characteristics that capture this variability and aid in predicting survival. This study aimed to evaluate the utility of dosiomics and radiomics in predicting overall survival (OS). The central hypothesis was that integrating dosiomics and radiomics could improve survival outcome predictions.

Methods: A total of 74 GBM patients from The Cancer Imaging Archive were retrospectively included. Dosiomic features from the gross tumor volume (GTV) of planned dose distributions, along with radiomic features from the contrast-enhanced tumor (CET) and edema/non-contrast-enhanced tumor (ED/nCET) subregions across various pre-radiation MRI modalities, were extracted and optimized using L1-based feature selection. Logistic Regression (LR) models were built utilizing different feature configurations to assess the discriminative power of dosiomic and radiomic features, considering the impact of heterogeneous subregions. Model performance was assessed through stratified 10-fold cross-validation (CV).

Results: The dosiomic model exhibited a mean area under the receiver operating characteristic (ROC) curve (AUC) of 0.80 ± 0.12. The subregion-based models demonstrated mean AUC values of 0.90 ± 0.09 for the CET subregion and 0.76 ± 0.10 for the ED/nCET subregion, indicating that the CET subregion significantly outperformed the ED/nCET subregion (p-value < 0.05). The mean AUC values for modality-based models were as follows: 0.86 ± 0.12 for T1-weighted contrast-enhanced (T1CE), 0.84 ± 0.18 for T1-weighted (T1), 0.85 ± 0.14 for T2-weighted (T2), and 0.76 ± 0.21 for fluid-attenuated inversion recovery (FLAIR) sequences. There was no significant difference in discrimination power among the four modalities (p-value > 0.05). The combined dosiomic and CET model improved performance to 0.96 ± 0.07 (p < 0.05).

Conclusions: Dosiomic and pre-radiotherapy MRI-derived radiomic features are capable of stratifying GBM patients into two long-term and short-term groups. Notably, the integration of dosiomics and radiomics significantly enhances survival prediction in GBM patients.

Purpose: Leveraging the distinct properties of X-rays and γ-rays, a novel radiation therapy platform integrating both modalities has been implemented in clinical practice (NMPA: 20223050973; FDA: K210921). This study investigates the application of this integrated approach in spatially fractionated radiotherapy, systematically evaluating its feasibility and therapeutic potential.

Methods: In this retrospective study, lattice radiotherapy (LRT) was designed for 10 NSCLC cases with gross tumor volumes (GTV) ranging from 572 to 1367 cm³ (mean 862.9 ± 285.4 cm³), incorporating the number of high-dose vertices per case ranged from 6 to 13, with a median of 8.5, respectively. Each LRT plan consisted of a single 12 Gy dose to the intratumoral vertices, followed by conventional external beam radiotherapy (cEBRT) delivering 25 daily fractions of 1.8 Gy to the Planning Target Volume (PTV). Treatment plans were developed using the Varian Eclipse 13.5 Treatment Planning System (TPS) for Linac plans, while TaiChiB system plans were generated using the RT PRO TPS: a focused gamma plan was created to target the vertices, and a Linac plan was optimized to cover the PTV. A comparative analysis of D0.5 cc, D10/D90, EQD2, and Dmean was performed to evaluate the ability of dual-modality to optimize high-dose vertices while reducing doses to GTV margins and organs at risk (OARs).

Results: The LRT plan involved the placement of a median of 8.5 high-dose vertices (range, 6 to13), each with a diameter of 1.5 cm and spaced 3-3.5 cm apart within the GTV. The average vertices volume was 17.2 ± 4.5 cm³, corresponding to 2.05% ± 0.34% of the GTV. Compared to the Linac plans, the TaiChiB system plans demonstrated significantly increased D0.5 cc, Dmean, and EQD2 within the GTV (P < 0.01), improved peak/valley dose ratio (PVDR, D10/D90, P < 0.01), and reduced marginal GTV dose. Additionally, the TaiChiB system plans significantly reduced doses to OARs, including right lung Dmean (P = 0.031), heart Dmean (P = 0.024), esophagus Dmax (P < 0.01), and spinal cord Dmax (P = 0.042). All plans complied with the OARs dose constraints, thereby ensuring clinical feasibility and patient safety.

Conclusion: By integrating X-ray and γ-ray technologies, this platform enhances the vertex dose within the GTV while reducing doses to the GTV margins and OARs, offering a promising and feasible approach for the treatment of LRT in patients with large-volume lung tumors.

Background: It is not clear how frailty may affect the outcomes of stereotactic radiosurgery (SRS) for brain metastasis. This study aimed to evaluate the impact of frailty on clinical outcomes in patients ≥ 60 years old who underwent SRS for brain metastasis from a population-based perspective.

Materials and methods: Data were extracted from the National Readmission Database (NRD), 2016 to 2020. Inclusion criteria were ≥ 60 years old with brain metastasis who underwent SRS. Frailty was assessed using the modified Frailty Index (mFI), derived from 11 clinical conditions. The primary outcomes were in-hospital mortality, length of hospital stay (LOS), total hospital costs, and 30-day and 90-day readmission rates. Logistic and linear regression models were used to assess the association between frailty and outcomes.

Results: A total of 904 patients (mean age: 71 years, 53% male) were included, of which 17.5% were defined as frail. After adjusting for demographic, clinical, and hospital-related factors, frailty was significantly associated with increased in-hospital mortality (adjusted odds ratio [aOR] = 2.39, 95% confidence interval [CI]: 1.16-4.92), longer LOS (adjusted Beta [aBeta] = 2.61 days, 95% CI: 1.95-3.28), higher total costs (aBeta = $36.04 thousand USD, 95% CI: 28.84-43.23), and higher 30-day readmission rate (aOR = 1.47, 95% CI: 1.02-2.11).

Conclusion: Frailty independently predicts poorer outcomes in older adults undergoing SRS for brain metastasis, including higher mortality, longer hospital stays, increased hospital costs, and increased 30-day readmission rate. These findings highlight the importance of incorporating frailty-informed risk stratification and perioperative care planning to optimize patient outcomes.

Trial registration number: Not applicable.

Background: The aim of this study is to investigate the potential mechanisms underlying the protective effects of high-energy X-ray FLASH radiotherapy (FLASH-RT) on intestine through multi-omics analysis.

Methods: This study utilized syngeneic colon carcinoma mouse models of CT26 and MC38 to evaluate the therapeutic efficacy of FLASH-RT versus conventional dose rate radiotherapy (CONV-RT) by monitoring survival, tumor size, and body weight. Furthermore, healthy C57BL/6 female mice received whole-abdominal irradiation with either FLASH-RT, CONV-RT, or sham irradiation to compare differences in normal tissue protection. 72 h post-irradiation, intestinal contents from mice were collected for metagenomic analysis, and intestinal tissue was harvested for non-targeted metabolic and single-cell sequencing analyses.

Results: In CT26 and MC38 models, both CONV-RT and FLASH-RT have demonstrated similar anti-tumor efficacy. Compared with CONV-RT, whole-abdominal FLASH-RT significantly alleviated acute intestinal injury in mice, as evidenced by better preservation of crypt numbers and villus architecture in the FLASH group. Metagenomic analysis revealed that the relative abundance of the gut-protective bacterium Ligilactobacillus ruminis was significantly higher in the FLASH group than in the CONVgroup. Non-targeted metabolomic profiling identified 34 differential metabolites, of which 29 were upregulated and 5 were downregulated in the FLASH group. Notably, the abundance of 2-hydroxyglutarate, a metabolite associated with the butyrate metabolism pathway, was significantly elevated in the FLASH group compared with the CONV group (p < 0.05). Single-cell sequencing data revealed notable differences in cell distribution and proportions between the groups, with a higher proportion of fibroblasts, proliferative cells, macrophages, and CD4 + T cells in the FLASH group compared to the CONV and control groups. Immunofluorescence analysis revealed a significantly greater number of Lgr5⁺ intestinal stem cells in the FLASH group compared to the CONV group. Conversely, immunohistochemical analysis demonstrated stronger p50/p65 staining intensity in the CONV group relative to the FLASH group.

Conclusions: This study confirms that FLASH-RT, compared to CONV-RT, maintains equivalent antitumor efficacy while mitigating damage to normal intestinal tissues. Moreover, it preliminarily reveals that the protective mechanism of FLASH-RT is multifaceted, involving remodeling of the microbiota-metabolite axis, attenuation of inflammatory responses, and enhanced preservation of stem cells.

Background: The Fred Hutchinson Cancer Center (FHCC) has developed a novel in-house method for ocular proton therapy by adapting a pencil beam scanning (PBS) beamline and using a commercial treatment planning system. This manuscript outlines the workflow from simulation to treatment delivery and presents our experiences with the initial 40 patients.

Methods: Key innovations of our treatment approach include in-house developed treatment chair and gaze localization systems, CT imaging for planning, and a Monte Carlo algorithm for dose calculation. We gathered data on patient characteristics, dose volume statistics, and total treatment time. Additionally, we examined the distances patients traveled to access ocular proton therapy. An example illustrating our treatment technique is also presented.

Results: The average patient age at the time of treatment was 63.9 years. Tumor apical height ranged from 0.7 to 11.9 mm, and the largest basal diameter from 2.8 to 15.5 mm. GTV volumes ranged from 0.02 to 0.89 cc, while PTV volumes ranged from 0.17 to 2.27 cc. The D99% dose to GTV ranged from 5041 to 5242 cGy (RBE). The median mean dose to the lacrimal gland was 1570 cGy (RBE), while the median D2% doses to the optic nerve, macula, and optic disc were 4188 cGy (RBE), 5024 cGy (RBE), and 5133 cGy (RBE), respectively. Out of the 40 patients, 16 successfully met all treatment planning goals. The remaining patients did not meet some goals due to the target either abutting or being close (< 2 mm) laterally or distally to the OARs. The total treatment duration per fraction was approximately 25 min. Nearly one-third of the patients traveled around 900 miles to receive ocular treatment.

Conclusions: The approach at FHCC demonstrates that ocular proton therapy can be effectively delivered using a general-purpose PBS beamline, providing a solution for centers without dedicated ocular beamlines.