Stereotactic body radiotherapy for medically unfit patients with cancers to the head and neck.

BACKGROUND: A single institutional experience of stereotactic body radiation therapy (SBRT) to medically unfit patients with unresectable head and neck cancers (HNCs). METHODS: A retrospective review of HNC patients undergoing SBRT was undertaken from 2011 to 2016 for fractionation ranges between 35 and 50 Gy in 4 to 6 fractions. RESULTS: One hundred and fourteen patients with 117 SBRT courses were included with mean follow-up of 10.5 months. The cohort consisted of previously untreated primary HNC (n = 48), recurrent never irradiated HNC (n = 19), oligometastatic (n = 17) non-HNC primaries and previously irradiated HNC (n = 33). Local control (LC) at 12 months and median progression free survival was 85.8%, 78.2%, 85%, 78.9% (P = .86) and 23.7, 14.8, 10.5 and 7.8 months (P = .04) respectively. Only one patient had an acute grade 4 toxicity, two patients had grade 4 late toxicities. CONCLUSIONS: HNC SBRT is an effective treatment for frail patients where longer LC is relevant but are unable to tolerate protracted radiation schedules.

Reliability, Validity, and Sensitivity of a Novel Smartphone-Based Eccentric Hamstring Strength Test in Professional Football Players.

PURPOSE: To evaluate the test-retest reliability, sensitivity, and concurrent validity of a smartphone-based method for assessing eccentric hamstring strength among male professional football players. METHODS: A total of 25 healthy male professional football players performed the Chinese University of Hong Kong (CUHK) Nordic break-point test, hamstring fatigue protocol, and isokinetic hamstring strength test. The CUHK Nordic break-point test is based on a Nordic hamstring exercise. The Nordic break-point angle was defined as the maximum point where the participant could no longer support the weight of his body against gravity. The criterion for the sensitivity test was the presprinting and postsprinting difference of the Nordic break-point angle with a hamstring fatigue protocol. The hamstring fatigue protocol consists of 12 repetitions of the 30-m sprint with 30-s recoveries between sprints. Hamstring peak torque of the isokinetic hamstring strength test was used as the criterion for validity. RESULTS: A high test-retest reliability (intraclass correlation coefficient = .94; 95% confidence interval, .82-.98) was found in the Nordic break-point angle measurements. The Nordic break-point angle significantly correlated with isokinetic hamstring peak torques at eccentric action of 30°/s (r = .88, r2 = .77, P < .001). The minimal detectable difference was 8.03°. The sensitivity of the measure was good enough that a significance difference (effect size = 0.70, P < .001) was found between presprinting and postsprinting values. CONCLUSION: The CUHK Nordic break-point test is a simple, portable, quick smartphone-based method to provide reliable and accurate eccentric hamstring strength measures among male professional football players.

Eccentric hamstring strength deficit and poor hamstring-to-quadriceps ratio are risk factors for hamstring strain injury in football: A prospective study of 146 professional players.

OBJECTIVES: The purpose of this study was to investigate whether preseason isokinetic strength measures were predictive of future HSI among professional football players. DESIGN: Prospective cohort study, Level of evidence 2. METHODS: A total of 169 professional players participated in a preseason isokinetic strength screening, followed by a 10-month competitive season. Testing protocol included the concentric performance of both knee flexion and extension at 60degs-1 and 240degs-1 and the eccentric performance of the knee flexor at 30degs-1. Strength deficits, bilateral differences, and hamstring to quadriceps strength ratios were computed. Univariate and multivariate logistic regressions were used to identify potential risk factors of HSI. Receiver operating characteristic (ROC) curves were used to investigate the sensitivity and specificity of the strength measures. RESULTS: Forty-one acute HSIs were sustained, and 12% (n=5) reoccurred within the study period. In the multivariate analysis, we have shown an association between the injury risk and eccentric hamstring peak torque below 2.4Nmkg-1 (OR=5.59; 95% CI, 2.20-12.92); concentric H/Q ratio below 50.5% (OR=3.14; 95% CI, 1.37-2.22); players with previous injury of HSI (OR=3.57; 95% CI, 3.13-8.62). ROC analysis displayed an area under curve (AUC) of 0.77, indicating fair combined sensitivity and specificity of the overall predicting model. CONCLUSIONS: Professional football players with significant lower isokinetic hamstring strength, lower hamstring-to-quadriceps strength ratio, and a previous injury of HSI were linked to an increased risk of acute HSI.

The reliability and validity of a video-based method for assessing hamstring strength in football players.

BACKGROUND/OBJECTIVE: Evaluating hamstring strength by isokinetic dynamometry is limited by various practical issues such as time and cost. A video-based Nordic hamstring exercise is introduced as an alternative option. The aims of this study are to evaluate 1.) the between-session reliability and 2.) concurrent validity of the testing method compared to a standardized isokinetic dynamometry. METHODS: Thirty male elite footballers were recruited for the study. From the Nordic hamstring exercise, the video-analysis-determined Nordic break-point angles where the participant could no longer withstand the force of the fall (eccentric mode) and the number of seconds that the player could hold at 30° forward flexion angle (isometric mode) were measured. Intra-class correlation coefficients for between-session reliability, Pearson r correlations between the current method and isokinetic dynamometry were calculated. RESULTS: The reliability of the eccentric mode was moderate (ICC (2,1) = 0.82) while that of isometric mode was poor (ICC (2,1) = 0.57). The Nordic break-point angle of the eccentric mode significantly correlated with the concentric and eccentric hamstring peak torque (r = 0.48 and 0.58, p < 0.001), while the isometric was not (r = 0.02 - 0.07, p > 0.05). CONCLUSION: The eccentric mode of the video-based hamstring strength test was a moderately reliable and valid method to measure the eccentric hamstring strength in elite football players.

Tumor radiation response enhancement by acoustical stimulation of the vasculature.

We have discovered that ultrasound-mediated microbubble vascular disruption can enhance tumor responses to radiation in vivo. We demonstrate this effect using a human PC3 prostate cancer xenograft model. Results indicate a synergistic effect in vivo with combined single treatments of ultrasound-stimulated microbubble vascular perturbation and radiation inducing an over 10-fold greater cell kill with combined treatments. We further demonstrate with experiments in vivo that induction of ceramide-related endothelial cell apoptosis, leading to vascular disruption, is a causative mechanism. In vivo experiments with ultrasound and bubbles permit radiation doses to be decreased significantly for comparable effect. We envisage this unique combined ultrasound-based vascular perturbation and radiation treatment method being used to enhance the effects of radiation in a tumor, leading to greater tumor eradication.

Volumetric changes of the anterolateral thigh free flap following adjuvant radiotherapy in total parotidectomy reconstruction.

OBJECTIVES/HYPOTHESIS: The aim of this study was to prospectively evaluate volume change in anterolateral thigh free flaps pre- and postradiotherapy and to compare computed tomography (CT) volumetric analysis with intraoperative water displacement calculation. STUDY DESIGN: Matched pair cohort study. METHODS: Thirteen patients with advanced carcinoma of the parotid gland underwent anterolateral thigh free flap reconstruction following total parotidectomy resections and neck dissection. Before the initiation of external beam radiation, routine CT planning scans were done on all patients. A minimum of 6 months after surgery, a CT scan of the head and neck was carried out, and a detailed volumetric assessment was performed. RESULTS: The mean preradiotherapy flap volume was 94.3 mL, and the postradiotherapy volume was 84.8 mL. The mean volume reduction in all 13 patients was 8.12%. CONCLUSIONS: In this prospective study we observed an 8% volume loss in anterolateral thigh free flaps 6 months postradiotherapy. This loss of volume should be taken into account when reconstructing large defects of the face and lateral skull base. Intraoperative water displacement measurement is a useful adjunctive tool for shaping free tissue transfers that are to be used for volume replacement and soft-tissue fill-in.

Scanning-free compressive holography for object localization with subpixel accuracy.

We propose quantitative localization measurement of a known object with subpixel accuracy using compressive holography. We analyze the theoretical optimal solution in the compressive sampling framework and experimentally demonstrate localization accuracy of 1/45 pixel, in good agreement with the analysis.