Evaluation of Clinical Application and Dosimetric Comparison of Treatment Plans of Gamma Knife and CyberKnife in Treating Arteriovenous Malformations.

PURPOSE: To analyze and compare the characteristics of dose distributions for Leksell Gamma Knife Perfexion (LGK-PFX) and CyberKnife (CK) in treating arteriovenous malformations (AVMs). SUBJECTS AND METHODS: Twenty-four patients with AVMs who received CK radiosurgery at a prescribed dose (PD) of 16-25 Gy in a single fraction were selected. A LGK-PFX treatment plan with the same PD was designed for each patient. Dosimetric values for both systems were compared with respect to the conformity index (CI); selectivity index (SI); gradient index (GI) of 75, 50, and 25% of the PD; heterogeneity index; volume of the brain tissue covered by doses of 10 and 12 Gy; maximum dose delivered to the brainstem; and beam-on time. RESULTS: The CIs of LGK-PFX and CK were 0.744 ± 0.075 and 0.759 ± 0.071 (p = 0.385), respectively. The SIs of LGK-PFX and CK were 0.764 ± 0.081 and 0.780 ± 0.076 (p = 0.424), respectively. The GI75%, GI50%, and GI25% values of LGK-PFX and CK were 1.028 ± 0.123 and 2.439 ± 0.338 (p < 0.001), 3.169 ± 0.265 and 4.972 ± 0.852 (p < 0.001), and 8.650 ± 0.914 and 14.261 ± 2.476 (p < 0.001), respectively. Volumes of the brain tissue covered by 10 Gy and 12 Gy for LGK-PFX and CK (p < 0.001) exhibited a significant difference. CONCLUSIONS: LGK-PFX and CK exhibited similar dose conformity. LGK-PFX showed superior normal tissue sparing.

Forward treatment planning techniques to reduce the normalization effect in Gamma Knife radiosurgery.

In Gamma Knife forward treatment planning, normalization effect may be observed when multiple shots are used for treating large lesions. This effect can reduce the proportion of coverage of high-value isodose lines within targets. The aim of this study was to evaluate the performance of forward treatment planning techniques using the Leksell Gamma Knife for the normalization effect reduction. We adjusted the shot positions and weightings to optimize the dose distribution and reduce the overlap of high-value isodose lines from each shot, thereby mitigating the normalization effect during treatment planning. The new collimation system, Leksell Gamma Knife Perfexion, which contains eight movable sectors, provides an additional means to reduce the normalization effect by using composite shots. We propose different techniques in forward treatment planning that can reduce the normalization effect. Reducing the normalization effect increases the coverage proportion of higher isodose lines within targets, making the high-dose region within targets more uniform and increasing the mean dose to targets. Because of the increase in the mean dose to the target after reducing the normalization effect, we can set the prescribed marginal dose at a higher isodose level and reduce the maximum dose, thereby lowering the risk of complications.

Advancing teeth whitening efficacy via dual-phototherapeutic strategy incorporating molybdenum disulfide embedded in carrageenan hydrogel for dental healthcare.

Teeth discoloration poses a widespread challenge in dental health across various regions. Conventional teeth whitening methods often result in enamel deterioration and soft tissue harm due to the utilization of incompatible whitening agents and continuous intense light exposure. Here, we propose an effective phototherapy technique for teeth whitening, employing pathways of energy transition through intersystem crossing. The integration of MoS2 nanosheets into carrageenan gel (MoS2 NSs@Carr) facilitates both photothermal-hyperthermia and the generation of reactive oxygen species (ROS) through photocatalytic processes. The efficacy of ROS generation by the phototherapeutic MoS2 NSs@Carr on teeth whitening in the scenario. This approach ensures comprehensive teeth whitening by eliminating deep-seated stains on the teeth while preserving structural integrity and avoiding any tissue toxicity. This research highlights the efficacy of the phototherapeutic MoS2 NSs@Carr for dental whitening and underscores the potential of exploring nanostructures based on MoS2 NSs for managing dental healthcare issue.

To Optimize Radiotherapeutic Plans for Superior Tumor Coverage Predicts Malignant Glioma Prognosis and Normal Tissue Complication Probability.

Background: Radiotherapy (RT) provides a modern treatment to enhance the malignant glioma control rate. The purpose of our study was to determine the effect of tumor coverage on disease prognosis and to predict optimal RT plans to achieve a lower normal tissue complication probability (NTCP). Methods: Ten malignant-glioma patients with tumors adjacent to organs at risk (OARs) were collected. The patients were divided into two groups according to adequate coverage or not, and prognosis was analyzed. Then, using intensity-modulated radiation therapy (IMRT), volume-modulated arc therapy (VMAT), and helical tomotherapy (TOMO) to simulate new treatment plans for 10 patients, the advantages of these planning systems were revealed for subsequent prediction of NTCP. Results: The results of clinical analysis indicated that overall survival (p = 0.078) between the adequate and inadequate groups showed no differences, while the adequate group had better recurrence-free survival (p = 0.018) and progression-free survival (p = 0.009). TOMO had better CI (p < 0.001) and also predicted a lower total-irradiated dose to the normal brain (p = 0.001) and a lower NTCP (p = 0.027). Conclusions: The TOMO system provided optimal therapeutic planning, reducing NTCP and achieving better coverage. Combined with the clinical results, our findings suggest that TOMO can make malignant glioma patients close to OARs achieve better disease control.

miR-671-5p Inhibition by MSI1 Promotes Glioblastoma Tumorigenesis via Radioresistance, Tumor Motility and Cancer Stem-like Cell Properties.

MicroRNAs (miRNAs) could be potential biomarkers for glioblastoma multiforme (GBM) prognosis and response to therapeutic agents. We previously demonstrated that the cancer stem cell marker Musashi-1 (MSI1) is an RNA binding protein that promotes radioresistance by increasing downstream RNA stability. To identify that MSI1 interacts with miRNAs and attenuates their function, we also get candidate miRNAs from the mRNA seq by predicting with TargetScan software. miR-671-5p in GBM cells interacts with MSI1 by intersecting the precipitated miRNAs with the predicted miRNAs. Notably, overexpression of MSI1 reversed the inhibitory effect of miR-671-5p. The phenotype of miR-671-5p in GBM cells could affect radiosensitivity by modulating the posttranscriptional activity of STAT3. In addition, miR-671-5p could attenuate tumor migration and cancer stem cell (CSC) characteristics by repressing the posttranscriptional activity of TRAF2. MSI1 may regulate GBM radioresistance, CSCs and tumor motility through miR-671-5p inhibition to increasing STAT3 and TRAF2 presentation. In vivo, the GBM tumor size was inversely correlated with miR-671-5p expression, but tumorigenesis was promoted by STAT3 and TRAF2 activation in the miR-671-5p-positive GBM population. miR-671-5p could be activated as a novel therapeutic target for GBM and has potential application as a predictive biomarker of glioblastoma prognosis.

Gamma Knife Perfexion® radiosurgery and endo diode laser thermotherapy for choroidal melanoma with technical analysis: A case report.

Radiosurgery serves an important function in the treatment of patients with intraocular tumors and preserves visual function via organ conservation. Therefore, it is important to ensure the safety and precision of GK-SRS as a primary treatment for intraocular tumors. The present case study described a 57-year-old female with uveal melanoma treated with GK-SRS. Retrobulbar anesthesia following fixation of the treated eye, via the suture of two of the extraocular muscles to the stereotactic frame, was performed to immobilize the eye during treatment. Computed tomography (CT) scans were performed following eye fixation, immediately prior to and following GK-SRS, to validate the accuracy of the tumor localization. The eye movement analysis revealed that the gravity center point deviations of the tumor and lens during treatment were <0.110 mm. At least 95% of the tumor volume was covered by the prescription dose according to three sets of CT images. The patient underwent a trans pars plana vitrectomy owing to a right eye vitreous hemorrhage. A 37-month follow-up assessment revealed tumor shrinkage, and the disappearance of the serous retinal detachments was noted on the basis of ophthalmoscopy and orbital magnetic resonance imaging. No major complications developed during the follow-up period. Using our treatment protocol, GK-SRS is a non-invasive procedure which is used as a brief single fraction treatment for intraocular tumor. The eye fixation method used in the present study has high accuracy.