Relationship between Day 0 dosimetric parameters and biochemical relapse-free survival in patients treated with transperineal permanent prostate interstitial brachytherapy with 125I seeds

ObjectivesTo determine the relationship between dosimetric parameters obtained on postimplantation Day 0 and biochemical relapse-free survival (bRFS) in patients treated with ¹²⁵I transperineal interstitial permanent prostate brachytherapy (TIPPB).MethodsTwo-hundred twenty men with low-risk (n = 155, 70.4%), low-volume intermediate-risk (n = 63, 28.7%), or high-risk (n = 2, 0.9%) prostate cancer were treated with TIPPB between December 2000 and June 2006. Seventy-four (33.6%) patients received short-term (3–6 months) androgen suppression therapy before TIPPB. The median followup for patients free of biochemical failure was of 37.9 months (range, 24.0–84.5 months).ResultsThe receiver operating characteristic (ROC) analysis established a best-fit cutoff value for the quantifiers D₉₀ and V₁₀₀ of 147 Gy and 92%, respectively. The Kaplan–Meier analysis of bRFS at the cutoff value of D₉₀ = 147 Gy using the ASTRO, nadir + 2, and combined (ASTRO and nadir + 2) definitions showed a trend toward statistical significance for the ASTRO (p = 0.076) and nadir + 2 (p = 0.064) definitions and a statistically significant correlation for the combined definition (p = 0.033). The corresponding 7-year bRFS for the D₉₀ >147 Gy and D₉₀ ≤147 Gy subsets using the ASTRO, nadir + 2, and combined definitions were 96.5% vs. 89.7% (ASTRO, p = 0.076); 93.7% vs. 70.5% (nadir + 2, p = 0.064); and 94.4 vs. 75.5% (combined, p = 0.033). The V₁₀₀ (%) cutoff value of 92% predicted by the ROC analysis was not significant. Among other cutoff values, only D₉₀ = 140 Gy (p = 0.050) and D₉₀ = 160 Gy (p = 0.098) showed a trend toward statistical significance when the nadir + 2 and the ASTRO definitions were used. The rest of dosimetric, tumor, and patient parameters did not show statistical correlation with bRFS in the Kaplan–Meier analysis.ConclusionsThe cutoff value of D₉₀ = 147 Gy obtained on postimplantation Day 0 showed a trend toward significant correlation with bRFS when the standard ASTRO and nadir + 2 definitions were used and a weak but statistically significant correlation with bRFS as per the nonstandard combined definition in a series of patients with predominantly low-risk disease (70.4%) treated at high radiation doses (median D₉₀ = 152.9 Gy, median V₁₀₀ = 92.5%).     

Correlation between intravoxel incoherent motion MR parameters and MR nodular grade of parotid glands in patients with Sjögren’s syndrome: A pilot study

PurposeTo explore the correlation between intravoxel incoherent motion (IVIM) magnetic resonance (MR) parameters and MR nodular grade of parotid glands in patients with Sjögren’s syndrome (SS).Materials and methodsA total of 31 consecutive patients with SS and 28 gender- and age-matched healthy volunteers underwent bilateral parotid 3.0T MR examination including the IVIM sequence (9 b values, 0–800 s/mm²). The apparent diffusion coefficient (ADC), diffusion coefficient D, pseudo-diffusion coefficient D^*, and perfusion fraction f of bilateral parotid glands were obtained, and the nodular grade of each parotid gland was evaluated according to the MR morphological appearance.ResultsSixty-two parotid glands in 31 patients with SS consisted of 32, 14, 8, and 8 parotid glands at MR nodular grades 0, 1, 2, and 3, respectively. In parotid glands of grade 0, 1, 2, 3 and healthy volunteers, the ADC values were (1.13 ± 0.25, 1.11 ± 0.17, 1.05 ± 0.24, 0.89 ± 0.04 and 1.00 ± 0.21) × 10⁻³ mm²/s, D values were (0.92 ± 0.13, 0.90 ± 0.19, 0.90 ± 0.03, 0.67 ± 0.03, 0.81 ± 0.03) × 10⁻³ mm²/s, f values were 0.20 ± 0.04, 0.18 ± 0.02, 0.15 ± 0.01, 0.11 ± 0.01, 0.15 ± 0.06, and D^*values were (53.89 ± 28.26, 41.78 ± 16.35, 51.24 ± 18.69, 31.83 ± 18.03, 36.83 ± 16.14) × 10⁻³ mm²/s respectively. The ADC, D, f, and D^* values of parotid glands in patients with SS at grade 0 were significantly higher than those in healthy volunteers (all P < 0.05). Significant differences were observed in the D and f values of parotid glands in patients with SS among different grades (P = 0.003, < 0.001, respectively). The IVIM parameters (D, f) of parotid glands at early (grades 0–1) and advanced (grades 2–3) stages in patients with SS were significantly higher and lower, respectively, than those in healthy volunteers (all P < 0.05). The D and f values inversely correlated with MR nodular grades significantly (r = − 0.297, P = 0.019; r = − 0.653, P < 0.001, respectively)ConclusionThe parotid glands with different MR nodular grades in patients with SS showed different IVIM parameters, reflecting different pathophysiological characteristics of parotid glands at different stages.     

Stature estimation from scapular measurements by CT scan evaluation in an Italian population

This study evaluated the correlation between scapula size and stature and developed standard equations in order to estimate stature by CT scan evaluation.A total of 200 healthy Italian subjects (100 men and 100 women, mean age 64.2 ± 12.8 years) underwent thoracic CT scan evaluation during pulmonary screening in our department; we measured the stature of each patient with standard anthropometric instruments and then analyzed images to calculate the longitudinal scapular length (LSL) and the transverse scapular length (TSL). The correlation between stature and each parameter measured was analyzed by dividing the population into two groups, males and females, and was examined by simple regression analysis using Pearson’s correlation coefficient (r).Each anthropometric variable showed a significant difference between males and females (p value <0.001). The correlation coefficients (r-values) were LSL = 0.74 and TSL = 0.51 in males and LSL = 0.70 and TSL = 0.48 in females. In both sexes the r-values showed a significant correlation between stature and LSL.Our study demonstrates that scapulae can be used for stature estimation; in our sample LSL was found to have a better correlation with stature then TSL. h_m = 4.247 * LSL + 93.74 and h_f = 4.031 * LSL + 92.38 are the formulae that provide the most accurate stature assessment in males and females respectively.     

The prediction of the treatment response of cervical nodes using intravoxel incoherent motion diffusion-weighted imaging

PurposeTo investigate the predictive role of Intravoxel Incoherent Motion Diffusion-Weighted Imaging (IVIM-DWI) parameters on cervical nodal response to chemo-radiotherapy (CRT) of head and neck squamous cell carcinoma (HNSCC).Materials and methodsPatients with pathologically confirmed HNSCC were included in the present prospective study, having at least one positive cervical lymph node (LN). They received concomitant CRT and underwent three serial IVIM-DWI investigations: before, at mid-treatment and after treatment completion. Tissue diffusion coefficient D, perfusion-related diffusion coefficient D* and perfusion fraction f were calculated by a bi-exponential fit. The two-sided Mann–Whitney rank test was used to compare the imaging parameters of patients with regional failure (RF) and regional control (RC). A p value lower than 0.05 was considered to be statistically significant.ResultsThirty-four patients were accrued. Twenty-four out of 34 LN (70.6%) showed persistent RC after a median follow-up time of 27.6 months (range: 12.0–50.2 months), while ten cases of RF (29.4%) were confirmed with a median time of 6.8 months (range: 1.5–19.5 months). Patients with RC showed significantly lower pre-treatment D values compared to the RF patients (p = 0.038). At mid-treatment, the patients with RF showed significantly higher D values (p = 0.025), and exhibited larger percent reductions in f and the product D* × f from the baseline (p = 0.008 and <0.001, respectively). No additional information was provided by the examination at the end of treatment.ConclusionPre-treatment and mid-treatment IVIM-DWI showed potential for prediction of treatment response of cervical LN in HNSCC patients.     

Body mass index,dose to organs at risk during vaginal brachytherapy,and the role of three-dimensional CT-based treatment planning

PurposeTo assess the effect of body mass index (BMI) on dose to organs at risk (OARs) during high-dose-rate vaginal brachytherapy and evaluate the role of three-dimensional dose evaluation during treatment planning.Methods and MaterialsThree-dimensional dosimetric data for rectum, bladder, sigmoid colon, and small bowel for 125 high-dose-rate vaginal brachytherapy fractions were analyzed. Dose–volume histograms were generated for D_{0.1 cc} and D_{2 cc} of each OAR. Contributing factors including the use of urinary catheter and cylinder size were also recorded. As different dose fractionations were used, the OAR doses were tabulated as a percent dose prescribed to 0.5 cm. All patients were treated to 4 cm of the vaginal length.ResultsMedian BMI in this cohort was 31.7 kg/m². The BMI values had a weak inverse correlation with D_{0.1 cc} to sigmoid colon (r_s = −0.18, p = 0.047) and D_{0.1 cc} to bladder (r_s = −0.19, p = 0.038). There was a strong inverse correlation of D_{2 cc} and increasing BMI (r_s = −0.64, p = 0.003). The median D_{2 cc} was 25.1% for BMI higher than 31 and 61.9% for BMI of 31 or lower. For D_{0.1 cc}, there was also a strong inverse correlation with increasing BMI (r_s = −0.57, p < 0.001). Median D_{1 cc} was 33.5% for BMI >31 and 84.4% for BMI ≤ 31. On multivariate analysis higher BMI remained a significant predictor of lower small bowel D_{2 cc} (p < 0.001) and D_{0.1 cc} (p < 0.001).ConclusionsWomen with a lower BMI receive higher doses to the bladder and small bowel compared with those with a higher BMI. Three-dimensional dose evaluation should be considered in patients with low BMI, particularly when combined with external beam radiation.     

A comparative dosimetric analysis of virtual stereotactic body radiotherapy to high-dose-rate monotherapy for intermediate-risk prostate cancer

PurposeStereotactic body radiotherapy (SBRT) is being used with increasing frequency as definitive treatment of early stage prostate cancer. Much of the justification for its adoption was derived from earlier clinical results using high-dose-rate (HDR) brachytherapy. We determine whether HDR's dosimetry can be achieved by virtual SBRT.Methods and MaterialsPatients with intermediate-risk prostate cancer on a prospective trial evaluating the efficacy of HDR monotherapy treated to dose of 9.5 Gy × 4 fractions were used for this study. A total of 5 patients were used in this analysis. Virtual SBRT plans were developed to reproduce the planning target volume (PTV) HDR dose distributions. Both normal tissue– and PTV-prioritized plans were generated.ResultsFrom the normal tissue–prioritized plan, HDR and virtual SBRT achieved similar PTV V₁₀₀ (93.8% vs. 93.1%, p = 0.20) and V₁₅₀ (40.3% vs. 42.9%, p = 0.69) coverage. However, the PTV V₂₀₀ was not attainable with SBRT (15.2% vs. 0.0%, p < 0.001). The rectal D_max was significantly lower with HDR (94.2% vs. 99.42%, p = 0.05). The rectal D_{2 cc} was also lower (60.8% vs. 71.1%, p = 0.07). Difference in D_{1 cc} urethral dose was not significantly different (87.7% vs. 75.2%, p = 0.33). Comparing the PTV-prioritized plans, the rectal D_max (94.2% vs. 111.1%, p = 0.05) and mean dose (27.1% vs. 33.3%, p = 0.03) were significantly higher using SBRT, and the rectal D_{2 cc} was higher using SBRT (60.8% vs. 81.8%, p = 0.07).ConclusionsHDR achieves significantly higher intraprostatic doses while achieving a lower maximum rectal dose compared with our virtual SBRT treatment planning. Future studies should compare clinical outcomes and toxicity between these modalities.     

Interstitial brachytherapy vs. intensity-modulated radiation therapy for patients with cervical carcinoma not suitable for intracavitary radiation therapy

PurposeInterstitial brachytherapy (IBT) is the standard alternative treatment for patients with cervical carcinoma not suitable for intracavitary radiotherapy. There is an emerging belief that intensity-modulated radiotherapy (IMRT) has the potential to replace IBT. We aimed to compare the dosimetry achieved by IBT and IMRT in such patients.Methods and MaterialsThe CT imaging data, previously used for IBT planning of 12 patients with cervical carcinoma, were transferred to IMRT planning system to generate parallel IMRT plans. Prescribed dose to the planning target volume (PTV) was 20 Gy delivered in 2-weekly high-dose-rate fractions of 10 Gy each with IBT (biologically equivalent dose [BED₁₀] 40 Gy) and 33 Gy/13 fractions/2.5 wk with IMRT (BED₁₀ 41 Gy). For comparison, dose–volume parameters for target and organs at risk were recorded and expressed in terms of BED₁₀ and BED₃, respectively.ResultsFor PTV, the mean D₉₅ (dose received by 95% of PTV) was better with IBT (57.16 Gy vs. 41.47 Gy, p = 0.003). The mean conformity index was 0.94 and 0.90 with IBT and IMRT, respectively (p = 0.034). IBT delivered significantly reduced doses to 1.0 cc (D_max), 5.0 cc (D_{5 cc}), 50% (D₅₀), and 75% (D₇₅) of bladder volume as compared with IMRT. The mean rectal D_max was significantly better with IBT as compared with IMRT (54.64 Gy vs. 62.63 Gy, p = 0.02).ConclusionsIBT provides superior PTV coverage and organs at risk sparing to IMRT. Thus, IBT remains the standard treatment for patients with cervical carcinoma unsuitable for intracavitary radiotherapy.     

Accelerometer detected lateral sway during a submaximal running test correlates with endurance exercise performance in elite Australian male cricket players

ObjectiveTo identify whether movement patterns during a standardized submaximal running test (SSRT), assessed by accelerometry, were associated with improvements in endurance exercise performance.DesignA retrospective analysis of data collected from the 2018–2019 Australian cricket preseason.MethodsThirty-nine high-performance male cricket players were studied (25 ± 3 years, 82 ± 6 kg, 183 ± 6 cm). SSRT was performed monthly prior to a two kilometre (km) running time trial (2 kmTT). SSRT involved running between markers, positioned twenty metres apart, for three minutes. Foot strikes were timed to a metronome (154 beats/min) to elicit a running speed of ˜eight km/h. Triaxial accelerometers were worn in vests on the upper back and used to assess PlayerLoad medio-lateral vector (PL1D_side%), vertical vector (PL1D_up%) and anterior-posterior vector (PL1D_fwd%) were assessed.Results2 kmTT performance improved over the study period (p < 0.05). PlayerLoad vectors during the first minute of SSRT were not related to 2 kmTT performance (p > 0.23). During the second and third minutes there were positive associations between 2 kmTT (run time) and PL1D_side% (SSRT_2min, β 2.12, p < 0.03, 95% CI: 0.22–4.01; SSRT3_min, β 2.30, p < 0.03, 95% CI:0.32–4.29), but not PL1D_up% (SSRT_2min, β −0.15, p = 0.77, 95% CI: −1.13–0.83; SSRT_3min, β −0.15, p = 0.77, 95% CI: −1.11–0.87) or PL1D_fwd% (SSRT_2min, β −0.45, p = 0.42, 95% CI: −1.49–0.62; SSRT_3min, B−0.45, p = 0.40, 95% CI: −1.51–0.60).ConclusionAssessment of PL1D_side% during the second or third minutes of SSRT may inform how an athlete’s endurance exercise performance is responding to changes in training load.     

Computed diffusion-weighted MR imaging for visualization of pancreatic adenocarcinoma: Comparison with acquired diffusion-weighted imaging

ObjectiveTo assess the feasibility of computed diffusion-weighted imaging (cDWI) in comparison with directly acquired DWI for visualizing pancreatic adenocarcinomas.Materials and methodsPatients with pancreatic adenocarcinoma underwent DWI at b-values of 0, 1000 (DWI₁₀₀₀), 1500 (DWI₁₅₀₀) and 2000 (DWI₂₀₀₀) s/mm². From DWIs at b-values of 0 and 1000 s/mm², we generated cDWIs at b-values of 1500 (cDWI₁₅₀₀) and 2000 (cDWI₂₀₀₀) s/mm². DWI findings of pancreatic adenocarcinomas (clear hyperintensity; hyperintensity with an unclear distal border; and isointensity), the image quality and the tumor to pancreas contrast ratio (CR) were compared between directly acquired DWI and cDWI.ResultsAmong the 63 included patients, clear hyperintense tumors were seen in 35 on DWI₁₀₀₀, 50 on DWI₁₅₀₀, 50 on cDWI₁₅₀₀, 53 on DWI₂₀₀₀ and 44 on cDWI₂₀₀₀. Incidence of clear hyperintense tumors was significantly higher on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P = 0.013). There was no significant difference in the incidence of clear hyperintense tumors between DWI₁₅₀₀ and cDWI₁₅₀₀ (P > 0.999), but a lower incidence was seen on cDWI₂₀₀₀ than on DWI₂₀₀₀ (P = 0.028). Image quality was lower on cDWI than on DWI at b-values of 1500 (P = 0.002) and 2000 s/mm² (P < 0.001). The tumor to distal pancreas CR was significantly higher on cDWI₂₀₀₀ than on cDWI₁₅₀₀ (P < 0.001), and on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P < 0.001). The cDWI showed a significantly higher tumor to distal pancreas CR than DWI at b-values of 1500 (P = 0.004) and 2000 s/mm² (P < 0.001).ConclusionscDWI₁₅₀₀ generated from b-values of 0 and 1000 s/mm² should be considered more effective than DWI₁₀₀₀ and at least as effective as DWI₁₅₀₀.     

Correlation between enhancement characteristics of MR mammography and capillary density of breast lesions

ObjectiveTo correlate capillary density of breast lesions using the markers D2-40, CD31, and CD34 with early and late enhancement of magnetic resonance mammography (MRM).Materials and methodsThe local ethics committee approved this study, and informed consent was available from all patients. The study included 64 women with 66 histologically proven breast lesions (41 malignant, 25 benign). MR-enhancement 1 min after contrast medium administration was determined in the tumor (I_t1/I_t0 ratio) and in comparison to the surrounding tissue (I_t1/I_t1-fat ratio). Capillary density was quantified based on immunohistological staining with D2-40, CD31, and CD34 in breast tumors and surrounding breast tissue. Mean capillary densities were correlated with contrast enhancement in the tumor and surrounding breast tissue. The Kruskal–Wallis test was used to test whether lesions with different MR enhancement patterns differed in terms of capillary density.ResultsFor CD34, there was statistically significant correlation between capillary density and tumor enhancement (r = 0.329, p = 0.012), however not for the malignant or benign groups separately. Mean vessel number identified by staining with D2-40 and CD31 did not correlate significantly with tumor enhancement (D2-40: r = −0.188, p = 0.130; CD31: r = 0.095, p = 0.448). There were no statistically significant differences in capillary density between breast lesions with delayed enhancement or a plateau and lesions showing washout (Kruskal–Wallis test. D2-40: p = 0.173; CD31: p = 0.647; CD34: p = 0.515).ConclusionOf the three markers tested, CD34 showed best correlation between early contrast enhancement on MRM and capillary density. Further studies are necessary to clearly demonstrate an association between capillary density and contrast enhancement in breast tumors and surrounding tissue.     

Does providing real-time augmented feedback affect the performance of repeated lower limb loading to exhaustion?

IntroductionThis study aimed to determine whether real-time augmented feedback influenced performance of single-leg hopping to volitional exhaustion.MethodsTwenty-seven healthy, male participants performed single-leg hopping (2.2 Hz) with (visual and tactile feedback for a target hop height) or without feedback on a force plate. Repeated measures ANOVA were used to determine differences in vertical stiffness (k), duration of flight (t_f) and loading (t_l) and vertical height displacement during flight (z_f) and loading (z_l). A Friedman 2-way ANOVA was performed to compare the percentage of trials between conditions that were maintained at 2.2 Hz ± 5%. Correlations were performed to determine if the effects were similar when providing tactile or visual feedback synchronously with the audible cue.ResultsAugmented feedback resulted in maintenance of the t_f, z_f and z_l between the start and end of the trials compared to hopping with no feedback (p < 0.01). With or without feedback there was no change in t_l and k from start to end. Without feedback, 21 of 27 participants maintained >70% of total hops at 2.2 ± 5% Hz and this was significantly lower (p = 0.01) with tactile (13/27) and visual (15/27) feedback. There was a strong correlation between tactile and visual feedback for duration of hopping cycle (Spearman's r = 0.74, p ≤ 0.01).ConclusionFeedback was detrimental to being able to maintain hopping cadence in some participants while other participants were able to achieve the cadence and target hop height. This indicates variability in the ability to use real-time augmented feedback effectively.     

Improving prostate brachytherapy quality assurance with MRI–CT fusion–based sector analysis in a phase II prospective trial of men with intermediate-risk prostate cancer

PurposeWe combined sector analysis with MRI–CT fusion to comprehensively assess postimplant dosimetry after prostate brachytherapy.Methods and MaterialsSubjects were 50 men with intermediate-risk prostate cancer treated with ¹²⁵I brachytherapy in a prospective phase II clinical trial. On Day 30 after the implantation, dosimetry was evaluated in the prostate base, midgland, and apex regions on fused MRI–CT scans and CT scans. Volumes of each sector receiving 100% of the prescribed dose (V₁₀₀) and doses to 90% of each sector (D₉₀) were also calculated on the ultrasonogram used for treatment planning and compared with values derived from CT and fused MRI–CT scans.ResultsFused MRI–CT scans revealed lower-than-expected doses for the whole prostate (V₁₀₀ = 91.3%, D₉₀ = 152.9 Gy) compared with CT scans (98.5% and 183.6 Gy, p < 0.0001) and lower doses to the prostate base (V₁₀₀ = 79%, D₉₀ = 130 Gy) vs. CT (96% and 170 Gy, p < 0.0001). However, lower doses to the prostate base did not adversely affect biochemical outcomes in men with biopsy-proven disease at the base. At a median followup time of 42 months, the mean prostate-specific antigen level for all patients was 0.3 ng/mL, and no patient had experienced biochemical or clinical progression or recurrence.ConclusionsMRI–CT fusion–based sector analysis was feasible and revealed significantly lower doses to the prostate base than doses estimated from CT alone, although this did not affect biochemical outcomes. MRI–CT fusion–based sector analysis may be useful for developing MRI-based dosimetric markers to predict disease outcomes and treatment-related morbidity.     

Toxicity and early treatment outcomes in low- and intermediate-risk prostate cancer managed by high-dose-rate brachytherapy as a monotherapy

PurposeTo determine the acute and late genitourinary (GU) and gastrointestinal (GI) toxicity and present short-term biochemical no evidence of disease (bNED) rates after high-dose-rate brachytherapy (HDR-B) monotherapy.Methods and MaterialsBetween October 2003 and June 2006, 36 patients with low (28) and intermediate (8) risk prostate cancer (PCA) were treated by HDR-B monotherapy. All patients received one implant and four fractions of 9.5 Gy within 48 h for a total prescribed dose (PD) of 38 Gy. Five patients received hormonal therapy (HT). Median age was 63.5 years and median followup was 3 years (range, 0.4–4 years). Toxicity was scored according to the CTCAE version 3.0. Biochemical failure was defined according to the Phoenix criteria.ResultsAcute and late Grade 3 GU toxicity was observed in 1 (3%) and 4 (11%) patients, respectively. Grade 3 GI toxicity was absent. The three- year bNED survival rate was 100%. The sexual preservation rate in patients without HT was 75%. Late Grade 3 GU toxicity was associated with the planning target volume (PTV) V₁₀₀ (% PTV receiving ≥100% of the PD; p = 0.036), D₉₀ (dose delivered to 90% of the PTV; p = 0.02), and the urethral V₁₂₀ (urethral volume receiving ≥120% of the PD; p = 0.043). The urethral V₁₂₀ was associated with increased PTV V₁₀₀ (p < 0.001) and D₉₀ (p = 0.003).ConclusionsAfter HDR-B monotherapy, late Grade 3 GU toxicity is associated with the urethral V₁₂₀ and the V₁₀₀ and D₉₀ of the PTV. Decrease of the irradiated urethral volume may reduce the GU toxicity and potentially improve the therapeutic ratio of this treatment.     

Lymph node metastasis in head and neck squamous carcinoma: Efficacy of intravoxel incoherent motion magnetic resonance imaging for the differential diagnosis

PurposeTo evaluate the value of pure molecular diffusion(D), perfusion-related diffusion (D*), perfusion fraction (f) and apparent diffusion coefficient (ADC) based on intravoxel incoherent motion (IVIM) theory for differential diagnosis of metastatic lymph nodes (LNs) in head and neck squamous cell carcinoma(HNSCC).Materials and methods29 patients with HNSCC and 20 patients with lymph node hyperplasia (LNH) were enrolled in this retrospective study, underwent magnetic resonance (MR) examination. IVIM Diffusion-weighted imaging (IVIM-DWI) was performed with 13 b values. D, D*, f and ADC values were compared between two groups. The diagnostic value of ADC, D, D* and D·D* value were evaluated by Receiver operating characteristic (ROC) curve. Two radiologists measured D, D*, f and ADC values independently.Results33 malignant LNs in HNSCC group and 22 benign LNs in LNH group (minimum diameter, ≥5 mm) were successfully examined, ADC(P < 0.05), D (P < 0.01) and f (P < 0.01) were significantly lower in malignant LNs than that in benign LNs, whereas D* was significantly higher (P < 0.01). The area under the ROC curve (AUC) for D·D* was 0.983 and was larger than that for D* (0.952), D (0.78) and ADC (0.67).ConclusionOur results indicate that IVIM DWI is feasible in the diagnosis of LN metastasis. D was significantly decreased in malignant LNs reflected increased nuclear-to-cytoplasmic ratio tissue, and D* was significantly increased reflected increased blood vessel generation and parenchymal perfusion in malignant LNs.     

Optimization for high-dose-rate brachytherapy of cervical cancer with adaptive simulated annealing and gradient descent

PurposeTo validate an in-house optimization program that uses adaptive simulated annealing (ASA) and gradient descent (GD) algorithms and investigate features of physical dose and generalized equivalent uniform dose (gEUD)–based objective functions in high-dose-rate (HDR) brachytherapy for cervical cancer.MethodsEight Syed/Neblett template-based cervical cancer HDR interstitial brachytherapy cases were used for this study. Brachytherapy treatment plans were first generated using inverse planning simulated annealing (IPSA). Using the same dwell positions designated in IPSA, plans were then optimized with both physical dose and gEUD-based objective functions, using both ASA and GD algorithms. Comparisons were made between plans both qualitatively and based on dose–volume parameters, evaluating each optimization method and objective function. A hybrid objective function was also designed and implemented in the in-house program.ResultsThe ASA plans are higher on bladder V_75% and D_2cc (p = 0.034) and lower on rectum V_75% and D_2cc (p = 0.034) than the IPSA plans. The ASA and GD plans are not significantly different. The gEUD-based plans have higher homogeneity index (p = 0.034), lower overdose index (p = 0.005), and lower rectum gEUD and normal tissue complication probability (p = 0.005) than the physical dose-based plans. The hybrid function can produce a plan with dosimetric parameters between the physical dose-based and gEUD-based plans. The optimized plans with the same objective value and dose–volume histogram could have different dose distributions.ConclusionsOur optimization program based on ASA and GD algorithms is flexible on objective functions, optimization parameters, and can generate optimized plans comparable with IPSA.     

Impact of small prostate size on postimplant prostate dosimetry: Analysis of a large community database

PurposeAchieving high-quality permanent interstitial brachytherapy in smaller prostates is thought to be more difficult than in larger glands. This study evaluates 4547 implants in a large community database to test this hypothesis.Methods and MaterialsFrom January 2003 to October 2010, 4547 prostate brachytherapy implants from a large community database were analyzed. The cohort was divided into three groups based on size, namely smaller (<30 cm³, n = 1301), medium (30–40 cm³, n = 1861), and large (>40 cm³, n = 1385). Postimplant dosimetry, including D₉₀, V₁₀₀, and V₁₀₀ by prostate sector, was performed for each implant. Comparison of mean V₁₀₀ among small, medium, and larger prostate volume cohorts was performed using a one-way analysis of variance test.ResultsFor the overall cohort, the D₉₀ was 105% and 104% for monotherapy and boost, respectively. Mean D₉₀ for small prostates was 106% and 104% for monotherapy and boost, respectively. Mean V₁₀₀ for small prostates was 91.1% and 90.0%, respectively. Coverage for small prostates was as good or slightly better than larger glands. V₁₀₀ by prostate sector revealed that there were no sectors for which smaller glands had significantly inferior coverage compared with larger glands.ConclusionAlthough smaller prostates may in some respects be more technically difficult to implant than larger glands, a review of community-based brachytherapists reveals that with current implant techniques, good quality implants are readily achievable in men with smaller glands.     

Stride length–cadence relationship is disrupted in below-knee prosthesis users

The aim of this study was to evaluate the linearity of the relationship between stride length and cadence (STRIDE_LC) over three self-selected speeds (normal, slow, fast) in below-knee prosthesis users (n = 14, 11 men, mean age 43 ± 12 years, mean time since amputation 9.2 ± 6.9 years) in comparison to controls (n = 20, 11 men, mean age 43 ± 17 years). The step length–cadence relationship (STEP_LC) was also calculated for the prosthetic and intact legs in prosthesis users and compared to the dominant leg of controls. The goodness of linear fit (R²) and slope over 3 speeds were used as outcome measures. Prosthesis users walked significantly slower than controls (slow-fast speed means 82–131 vs. 97–169 cm/s, respectively, ANOVA p < 0.0001) due to both lower cadence (42–53 vs. 47–63 strides/min, p < 0.0001) and shorter stride length (116–149 vs. 123–161 cm, p < 0.0001). The R² of STRIDE_LC relationship in below-knee prosthesis users (0.76 ± 0.13) was significantly lower than in controls (0.91 ± 0.03, p < 0.001). The R² values of STEP_LC relationship between the prosthetic and intact legs in prosthesis users were correlated (r = 0.85, p < 0.001) and both (0.67 ± 0.19, 0.58 ± 0.21, respectively) were significantly smaller than in the dominant leg of controls (0.86 ± 0.04, p < 0.01). The slopes of STRIDE_LC and STEP_LC were not different. The R² of 0.84 for STRIDE_LC best discriminated prosthesis users from controls with high sensitivity (71%) and specificity (95%). The results indicate that coupling between stride/step length and cadence is disturbed in prosthesis users. Upon further investigation, the goodness of linear fit may prove to be useful in assessing prosthetic design, optimizing prosthetic fit, and predicting clinical outcomes.     

Large prostate gland size is not a contraindication to low-dose-rate brachytherapy for prostate adenocarcinoma

PurposeProstate volume greater than 50 cc is traditionally a relative contraindication to prostate seed implantation (PSI), but there is little consensus regarding prostate size and clinical outcomes. We report biochemical control and toxicity after low-dose-rate PSI and compare outcomes according to the prostate size.Methods and MaterialsA total of 429 men who underwent low-dose-rate PSI between 1998 and 2009 were evaluated. Median followup was 38.7 months. Patients were classified by prostate volume into small, medium, and large subgroups. Differences were analyzed using the Mann–Whitney and Pearson's χ² tests for continuous and categorical variables, respectively. Cox proportional hazards regression models were used to evaluate effect of prostate size on outcomes.ResultsPatient pretreatment factors were balanced between groups except for age (p = 0.001). The 10-year actuarial freedom from biochemical failure for all patients treated with PSI was 96.3% with no statistically significant difference between large vs. small/medium prostate size (90% vs. 96.6%, p = 0.47). In a multivariate analysis, plan type (hazard ratio [HR] = 0.25, p = 0.03), dose to 90% of the gland (D₉₀: HR = 0.98, p = 0.02), volume receiving 200 Gy (V₂₀₀: HR = 0.98, p = 0.026), and biologic effective dose (HR = 0.99, p = 0.045), but not prostate size (HR = 2.27, p = 0.17) were significantly associated with freedom from biochemical failure. Prostate size was not significantly associated with time to maximum American Urologic Association score.ConclusionIn men with large prostates, the PSI provides biochemical control and temporal changes in genitourinary toxicity that are comparable with men having smaller glands. Accurate dose optimization and delivery of PSI provides the best clinical outcomes regardless of gland size.     

Analysis of brain and spinal cord lesions to occult brain damage in seropositive and seronegative neuromyelitis optica

ObjectivesAccording to aquaporin-4 antibody (AQP4-Ab), neuromyelitis optica (NMO) can be divided into seropositive and seronegative subgroups. The purpose of this study was to a) compare the distribution of spinal cord and brain magnetic resonance imaging (MRI) lesions between seropositive and seronegative NMO patients; b) explore occult brain damage in seropositive and seronegative NMO patients; and c) explore the contribution of visible lesions to occult grey and white matter damage in seropositive and seronegative NMO patients.Materials and methodsTwenty-two AQP4-Ab seropositive and 14 seronegative NMO patients and 30 healthy controls were included in the study. Two neuroradiologists independently measured the brain lesion volume (BLV) and the length of spinal cord lesion (LSCL) and recorded the region of brain lesions. The normal-appearing grey matter volume (NAGM-GMV) and white matter fractional anisotropy (NAWM-FA) were calculated for each subject to evaluate occult brain damage.ResultsThe seropositive patients displayed more extensive damage in the spinal cord than the seronegative patients, and the seronegative group had a higher proportion of patients with brainstem lesions (28.57%) than the seropositive group (4.55%, P = 0.064). Both NMO subgroups exhibited reduced NAGM-GMV and NAWM-FA compared with the healthy controls. NAGM-GMV was negatively correlated with LSCL in the seropositive group (r_s = −0.444, P = 0.044) and with BLV in the seronegative group (r_s = −0.768, P = 0.002). NAWM-FA was also negatively correlated with BLV in the seropositive group (r_s = −0.682, P < 0.001).ConclusionOur findings suggest that the occult brain damage in these two NMO subgroups may be due to different mechanisms, which need to be further clarified.