Prostate implant dosimetric outcomes and migration patterns between bio-absorbable coated and uncoated brachytherapy seeds

PurposeTo evaluate the lung and pelvic seed migration and intraprostatic dose variability for prostate seed implant (PSI) using bio-absorbable polymer “coated” seeds for intraoperative planning.Methods and MaterialsA total of 100 PSI patients were initially implanted with uncoated I-125 (STM 1251 or I125-SL, N = 85) or Pd-103 (mod 200, N = 15) seeds, and 105 PSI patients were implanted subsequently with coated seeds using inverse optimization with real-time planning. Implant technique, average number of needles, and dose objectives remained identical among the cohorts.ResultsDay 30 postimplant comparison of seed migration demonstrated a significant reduction in overall lung and pelvic seed migration from 25% (uncoated) to 4% (coated) (p < 0.0001). A measurable reduction in intraprostatic dose variability was observed in patients with the coated seeds when comparing 30 days dosimetry results for V₁₀₀, V₁₅₀, and D₉₀ for prostate, and V₁₁₀ for the rectum. A statistically significant reduction in the standard deviation from Day 0 to Day 30 for the above parameters for the prostate as well as for V₁₁₀ of rectum was also observed. A significant improvement in implant quality at Day 30 was demonstrated using Radiation Therapy Oncology Group (RTOG) evaluation criteria range with the coated seeds cohort.ConclusionsPSI using coated seeds shows lower lung and pelvic seed migration compared with those using uncoated seeds and compares favorably to pelvic stranded seed migration reports. A higher concordance was observed with less dose variability in dosimetric parameters on Day 30 dosimetry compared with that on Day 0. Improvement in the implant quality was also observed using the RTOG criteria, suggesting reduced intraprostatic migration.     

Reducing seed migration to near zero with stranded-seed implants: Comparison of seed migration rates to the chest in 1000 permanent prostate brachytherapy patients undergoing implants with loose or stranded seeds

PurposePulmonary seed emboli to the chest may occur after permanent prostate brachytherapy (PPB). The purpose of this study is to analyze factors associated with seed migration to the chest in a large series of PPB patients from a single institution undergoing implant with either loose seeds (LS), mixed loose and stranded seeds (MS), or exclusively stranded seeds in an absorbable vicryl suture (VS).Methods and MaterialsBetween May 1998 and July 2015, a total of 1000 consecutive PPB patients with postoperative diagnostic chest x-rays at 4 months after implant were analyzed for seed migration. Patients were grouped based on seed implant technique: LS = 391 (39.1%), MS = 43 (4.3%), or VS = 566 (56.6%). Univariate and multivariate analysis were performed using Cox proportional hazards regression models to determine predictors of seed migration.ResultsOverall, 18.8% of patients experienced seed migration to the chest. The incidence of seed migration per patient was 45.5%, 11.6%, and 0.9% (p < 0.0001), for patients receiving LS, MS, or VS PPB, respectively. The right and left lower lobes were the most frequent sites of pulmonary seed migration. On multivariable analysis, planimetry volume (p = 0.0002; HR = 0.7 per 10 cc [0.6–0.8]), number of seeds implanted (p < 0.0001, HR = 2.4 per 25 seeds [1.7–3.4]), LS implant (p < 0.0001, HR = 15.9 [5.9–42.1]), and MS implant (p = 0.001, HR = 7.9 [2.3–28.1]) were associated with seed migration to the chest.ConclusionsIn this large series, significantly higher rates of seed migration to the chest are observed in implants using any LS with observed hazard ratios of 15.9 and 7.9 for LS and MS respectively, as compared with implants using solely stranded seeds.     

Seed migration in prostate brachytherapy depends on experience and technique

PurposeTo determine seed loss and pulmonary migration rate over time in permanent seed prostate brachytherapy.Methods and MaterialsWe analyzed the first 495 patients treated in our department. All patients were treated with loose ¹²⁵I seeds with automated seed delivery system and real-time intraoperative planning. Pelvic fluoroscopic imaging was done 30 days after the implant. Patients were divided into five groups of 100 patients according to the order they were treated, and groups were compared using χ² test and one-way analysis of variance.ResultsA total of 22.8% of patients lost at least one seed. The highest percentage of patients losing any number of seeds was in the first 100. Thirty-eight percent lost at least one seed. This number decreased gradually and was only 9% in Patients 400–499. The mean total seed loss rate (number of seeds lost/number seeds implanted) changed significantly over time (p < 0.001). There was a continuous significant (p < 0.001) decline after the first 100 patients (1.25% for the first 100 patients) followed by a rise in Patients 300–399, followed by another decline (0.21% for the last 100 patients). The seed loss rate to the thorax changed significantly over time (p = 0.009). It rose after an initial rate of 0.25–0.42% in Patients 200–299 and 300–399 and declined later to a rate of 0.21% in the last 100 patients.ConclusionsWe found a learning curve for seed migration. Avoiding implanting seeds outside of the capsule and modern transrectal ultrasound imaging can help decrease migration.     

Local seed displacement from Day 0 to Day 30 in I-125 permanent prostate brachytherapy: A detailed,computed tomography-based analysis

PURPOSETo accurately quantify local seed displacement from Day 0 to Day 30 for our brachytherapy procedure. To quantify seed loss/migration and to identify the locations from where seeds are missing.METHODS AND MATERIALSSeed displacements were analyzed in 62 consecutive patients, who received brachytherapy with stranded I-125 seeds. At the start of the procedure, four fiducial gold markers were implanted. At the end of the implantation procedure an in-room 3D CBCT scan (Day 0) was acquired for accurate seed localization. At Day 30 a regular CT scan was acquired. This CT scan was rigidly registered to the CBCT scan using the fiducials. Subsequently, the Hungarian method was used to find pairs of corresponding seeds. Displacements were calculated and missing seeds were identified.RESULTSLocal seed displacements are smaller than 5 mm for 76.3% of the seeds; 2.3% show displacements larger than 10 mm. The largest seed displacements are seen along the inferior-superior axis: on average 1.0 ± 3.2 mm in superior direction with respect to the intraprostatic fiducials. Largest displacements are seen at the inferior-lateral sides of the prostate. On average, the inferior seeds move 1.0 ± 2.8 mm in anterior and 1.8 ± 3.3 mm in superior direction. The percentage of missing seeds is 0.2% (8 out of 3893 seeds for 5 patients). Most of the missing seeds were also originally implanted at the inferior-lateral sides of the prostate.CONCLUSIONSLocal seed displacements and number of missing seeds are small, and predominantly occur around the apex.     

Appropriate timing for postimplant imaging in permanent breast seed implant: Results from a serial CT study

PurposePostimplant analysis in permanent breast seed implant (PBSI) is performed at inconsistent times subsequent to seed implantation across cancer centers, creating challenges in the interpretation of dosimetric data and ultimately the correlation with clinical outcomes. The purpose of this study is to determine the most appropriate time postimplant to perform this analysis.Methods and MaterialsNine patients treated at our institution with PBSI were included in this analysis. Each underwent 4 postimplant CT scans: 0, 15, 30, and 60 days postimplant. A model of the accumulated dose was created by deformably registering the Day 15, 30, and 60 postimplant CT scans and dose matrices to the Day 0 scan, scaling for seed decay. The results from this model were compared to each individual postplan by integral comparison of dose–volume histogram curves for a dose evaluation volume.ResultsThe Day 30 postplan showed the best agreement with the accumulated dose model and the smallest interpatient variability across the patient cohort. The mean (±SD) for the dose evaluation volume V₉₀, V₁₀₀, V₁₅₀, and V₂₀₀ for the accumulated dose model was 90 ± 7%, 86 ± 8%, 66 ± 14%, and 41 ± 16%, respectively.ConclusionsBased on the results of this patient cohort, we recommend that postimplant dosimetric analysis for PBSI be performed approximately 30 days following the implant.     

New approach of ultra-focal brachytherapy for low- and intermediate-risk prostate cancer with custom-linked I-125 seeds: A feasibility study of optimal dose coverage

PurposeTo present the feasibility study of optimal dose coverage in ultra-focal brachytherapy (UFB) with multiparametric MRI for low- and intermediate-risk prostate cancer.Methods and MaterialsUFB provisional dose plans for small target volumes (<7 cc) were calculated on a prostate training phantom to optimize the seeds number and strength. Clinical UFB consisted in a contour-based nonrigid registration (MRI/Ultrasound) to implant a fiducial marker at the location of the tumor focus. Dosimetry was performed with iodine-125 seeds and a prescribed dose of 160 Gy. On CT scans acquired at 1 month, dose coverage of 152 Gy to the ultra-focal gross tumor volume was evaluated. Registrations between magnetic resonance and CT scans were assessed on the first 8 patients with three software solutions: VariSeed, 3D Slicer, and Mirada, and quantitative evaluations of the registrations were performed. Impact of these registrations on the initial dose matrix was performed.ResultsMean differences between simulated dose plans and extrapolated Bard nomogram for UFB volumes were 36.3% (26–56) for the total activity, 18.3% (10–30) for seed strength, and 22.5% (16–38) for number of seeds. Registration method implemented in Mirada performed significantly better than VariSeed and 3D Slicer (p = 0.0117 and p = 0.0357, respectively). For dose plan evaluation between Mirada and VariSeed, D₁₀₀% (Gy) for ultra-focal gross tumor volume had a mean difference of 28.06 Gy, mean values being still above the objective of 152 Gy. D₉₀% for the prostate had a mean difference of 1.17 Gy. For urethra and rectum, dose limits were far below the recommendations.ConclusionsThis UFB study confirmed the possibility to treat with optimal dose coverage target volumes smaller than 7 cc.     

A dosimetric evaluation of using a single treatment plan for multiple treatment fractions within a given applicator insertion in gynecologic brachytherapy

PurposeTo evaluate the dosimetric impact of using one treatment plan for multiple fractions from a single tandem and ring applicator insertion of high-dose-rate brachytherapy for cervical cancer.Methods and MaterialsThirteen cervical cancer patients undergoing high-dose-rate brachytherapy were followed. Patients received the total dose from a single applicator insertion in two fractions, given with at least 6 hours apart within 24 hours. The treatment plan was based on a CT scan taken before the first treatment fraction. A second CT was obtained before the second treatment fraction. The co-registered image series were used to evaluate the dosimetric impact of using a single treatment plan for both fractions. Applicator and catheters were measured to quantify interfraction displacement.ResultsWhen the Day 1 plan was applied to the Day 2 images, high-risk clinical target volume (HR-CTV) coverage was reduced by as much as 17.4 percentage points. The mean decrease was 9.4 ± 5.0 percentage points (p < 0.0001). The rectum V₇₅ increase was significant (p = 0.03), whereas the bladder V₇₅ increase was not significant (p = 0.28). Volume changes in the HR-CTV contour from Day 1 to Day 2 were also observed (p = 0.29). Maximum applicator and catheter displacements of 10–30 mm were seen, from Day 1 to Day 2.ConclusionsWhen the Day 1 plan was used on the Day 2, the HR-CTV coverage decreased significantly (p < 0.0001). Our study establishes the need for institutions to evaluate the necessity for replanning based on imaging obtained before each treatment fraction for their gynecologic brachytherapy techniques.     

Rectal morbidity after permanent interstitial brachytherapy for prostate cancer—Impact of Day 1 vs. Day 30 computed tomography–based postimplant dosimetry

PurposeThe aim of the study was to evaluate bowel quality-of-life changes after prostate brachytherapy and the impact of Day 1 vs. Day 30 postimplant dosimetry.Methods and MaterialsIn 61 patients, computed tomography (CT) scans were performed at Days 1 and 30 after ¹²⁵I brachytherapy. The patients have been surveyed prospectively before (time A), 1 month (time B), and >1 year after treatment (time C) using a validated questionnaire (Expanded Prostate Cancer Index Composite). Different parameters were tested for their predictive value on bowel quality-of-life changes (bowel bother score decrease >20 points at time B = BB20; bowel bother score decrease >10 points at time C = BC10), including seed displacements.ResultsMean bowel function/bother score decreased 13/13 points at time B (p < 0.01) and 1/4 points at time C (change not significant). BB20 and BC10 were found in 25% and 20% of patients, respectively. Bowel bother score declines at time B correlated well with declines at time C (r = 0.53; p < 0.01). Prostate volume before implantation and the number of seeds per cubic centimeters were found to be predictive for BB20 and BC10. Smaller rectal wall volumes covered by the 60–100% isodoses at Day 1 were (paradoxically) found to be significantly predictive for BC10. Larger posterior seed displacements between Days 1 and 30 were significantly associated with BB20.ConclusionsQuality-of-life scores have not been found to change significantly >1 year after brachytherapy. Larger rectal wall volumes within higher isodoses at Day 1 or 30 were not found to be predisposing for adverse quality-of-life changes.     

Comparison between postoperative TRUS-CT fusion with MRI-CT fusion for postimplant quality assurance in prostate LDR permanent seed brachytherapy

PURPOSE/OBJECTIVE Permanent seed Low-Dose-Rate brachytherapy is planned and delivered using transrectal ultrasound (TRUS). Post-implant evaluation for quality assurance is usually performed using Computed Tomography (CT). Registration of the CT images with MRI reduces subjectivity in contouring by improving prostate edge detection. We hypothesized that a set of TRUS images post procedure may provide the same benefit.MATERIAL/METHODS Consecutive patients undergoing Low-Dose-Rate prostate brachytherapy were recruited. TRUS images were recorded under anesthesia at completion of their implant. In addition, all patients underwent standard post-implant quality assurance including prostate CT and MRI at day 30. These were co-registered, contoured and seeds were identified. Three independent observers contoured and registered the post implant TRUS images to the Day 30 CT using seed matching. Prostate volumes and dosimetric parameters were compared through Intraclass Correlation Coefficient (ICC) to evaluate the concordance between MRI and ultrasound (US).RESULTS 26 patients were recruited from 10/17 to 01/18. Mean prostate volume was 34.5 (SD 10.8) cm³ at baseline on planning TRUS images, 37.4 (SD 11.3) cm³ on Day 0 post implant TRUS and 36.7 (SD 11.7) cm³ on Day 30 MRI. D90 was 112.6% (SD 9.3) on CT-MRI and 112.9% (SD 11.1) on CT-US. V100 was 94.6% (SD 3.8) for CT-MRI, 95.1% (SD 4.3) for CT-US. Student t-tests were used to compare groups. No significant differences were noted.CONCLUSION Post implant TRUS may be useful for quality assurance for post-implant dosimetry particularly if access to an MRI is limited.     

A prospective randomized comparison of stranded vs. loose 125I seeds for prostate brachytherapy

PURPOSE: To compare seed loss and dosimetric parameters between stranded and loose 125I seeds (LS) for prostate brachytherapy. METHODS AND MATERIALS: Sixty-four patients with 1997 American Joint Commission on Cancer (AJCC) clinical stage T1c or T2a prostate carcinoma were prospectively randomized to brachytherapy (144Gy) with RAPID Strand 125I seeds (RS) vs. LS (Oncura, Plymouth Meeting, PA) The treatment plan for each patient was devised before randomization, and was not modified based on the randomization. Each patient underwent magnetic resonance, computed tomography, and plain film radiographs on the day of the implant (Day 0) and 30 days later (Day 30). RESULTS: Overall, 21 of 62 patients (30%) experienced seed loss. Seed loss occurred in 15 of 32 of LS patients (47%) vs. 6 of 30 RS patients (23%; p=0.053). Mean seed loss was 1.09 in the LS patient vs. 0.43 in RS patients (p=0.062). Eight LS patients (25%) lost multiple seeds, compared to 3 stranded patients (10%). Despite the lesser degree of seed loss in patients who received stranded seeds, they had a paradoxical trend toward lower V100 and D90 values. CONCLUSION: This prospective randomized trial showed a strong trend toward a decrease in postimplant seed loss with stranded seeds. Improved seed retention may be more advantageous in a setting of less generous periprostatic coverage. The lowered risk seed migration seen with stranded seeds would presumably also decrease the likelihood of lung or cardiac seed embolization.     

First report on the use of a thinner 125I radioactive seed within 20-gauge needles for permanent radioactive seed prostate brachytherapy: Evaluation of postimplant dosimetry and acute toxicity

PurposeTo compare postoperative dosimetry and acute toxicity of new 0.5-mm ¹²⁵I seeds in 20-gauge (20G) diameter prostate brachytherapy (PB) needles with standard 0.8-mm seeds in 18G needles.Methods and MaterialsPostoperative dosimetry was performed on 100 consecutive PB patients treated with ThinSeeds in 20G needles and compared with 100 consecutively treated PB patients using standard-sized seeds and needles (18G). Dosimetry was performed on postoperative Day 1 CT scans. Acute urinary retention was also compared between these two groups. Acute toxicity was evaluated in 22 consecutively treated patients with thinner seeds/needles and compared with 22 consecutive concurrent patients treated with standard seeds and needles. All patients were evaluated by pre- and post-PB self-administered surveys, physical examinations on post-PB Day 1, and telephone surveys on Day 7. Endpoints included dysuria, acute urinary retention, hematuria, perineal pain/bruising, and International Prostate Symptom Score.ResultsPost-PB dosimetric comparison demonstrated that the V₁₀₀ (95% vs. 91%), D₉₀ (161 Gy vs.149 Gy), V₁₅₀ (55% vs. 45%), and RV₁₀₀ (0.43 cc vs. 0.30 cc) were significantly (p < 0.0004) higher in the 20G group. Urinary retention rates were 8% and 7% and median catheter-dependent durations were 7 and 14 days for the 20G and 18G groups, respectively. No significant differences were found for dysuria, hematuria, or International Prostate Symptom Score. Post-PB Day 1 perineal bruising and pain scores on Days 1 and 7 were significantly less (p < 0.04) in 20G cohort.ConclusionsSmaller diameter needles and seeds resulted in improved post-PB Day 1 V₁₀₀ and D₉₀ dosimetry, and significantly less acute perineal pain and bruising.     

Placement of empty catheters for an HDR-Emulating LDR Prostate Brachytherapy technique: Comparison to standard intraoperative planning

PurposeWe sought to determine whether placing empty catheters within the prostate and then inverse planning iodine-125 seed locations within those catheters (High Dose Rate-Emulating Low Dose Rate Prostate Brachytherapy [HELP] technique) would improve concordance between planned and achieved dosimetry compared with a standard intraoperative technique.Methods and MaterialsWe examined 30 consecutive low dose rate prostate cases performed by standard intraoperative technique of planning followed by needle placement/seed deposition and compared them to 30 consecutive low dose rate prostate cases performed by the HELP technique. The primary endpoint was concordance between planned percentage of the clinical target volume that receives at least 100% of the prescribed dose/dose that covers 90% of the volume of the clinical target volume (V₁₀₀/D₉₀) and the actual V₁₀₀/D₉₀ achieved at Postoperative Day 1.ResultsThe HELP technique had superior concordance between the planned target dosimetry and what was actually achieved at Day 1 and Day 30. Specifically, target D₉₀ at Day 1 was on average 33.7 Gy less than planned for the standard intraoperative technique but was only 10.5 Gy less than planned for the HELP technique (p < 0.001). Day 30 values were 16.6 Gy less vs. 2.2 Gy more than planned, respectively (p = 0.028). Day 1 target V₁₀₀ was 6.3% less than planned with standard vs. 2.8% less for HELP (p < 0.001). There was no significant difference between the urethral and rectal concordance (all p > 0.05).ConclusionsPlacing empty needles first and optimizing the plan to the known positions of the needles resulted in improved concordance between the planned and the achieved dosimetry to the target, possibly because of elimination of errors in needle placement.     

A comparison of preplan transrectal ultrasound with preplan-CT in assessing volume and number of seeds needed for real-time ultrasound-based intra-operative planning in prostate 125I seed implantation

PurposeIntra-operative (real-time) treatment planning has been adapted by many institutions for low–dose rate prostate brachytherapy. Although this allows dosimetric planning to be done during the procedure, preplan imaging to obtain a prostate volume is essential to identify the number of seeds to ensure adequate volume coverage. Currently, there is no consensus regarding the most appropriate imaging to obtain this information. We conducted a retrospective study to compare how volumes obtained from preplan CT (p-CT) scans or preplan transrectal ultrasound (p-TRUS) correlated with real-time ultrasound and postimplant CT volumes and the difference in accuracy of seed estimation between these techniques.Methods and MaterialsNinety-two patients underwent ¹²⁵I permanent seed implants at Thomas Jefferson University Hospital between February 2002 and August 2008. Fifty-one patients underwent p-TRUS before intra-operative planning and 41 patients were evaluated by p-CT.ResultsThe median difference in volume between preimplant imaging and the intra-operative planning ultrasound was 3.59 and 5.2 cc for patients who underwent p-TRUS and p-CT, respectively. p-TRUS volumes more closely correlated with real-time intra-operative volumes (R = 0.84 in all patients and R = 0.91 in hormone-naïve patients) vs. p-CT (R = 0.82). The median number of seeds wasted using p-CT was 18 vs. 7 using volumes derived from p-TRUS.ConclusionsThe number of seeds ordered could be more accurately obtained from p-TRUS volumes, and this translated into less seed wastage. Our findings indicate that p-TRUS is a more accurate and an economically superior alternative to p-CT imaging in the era of real-time ultrasound planning.     

Inferring postimplant dose distribution of salvage permanent prostate implant (PPI) after primary PPI on CT images

PurposeTo evaluate the dose distribution of additional radioactive seeds implanted during salvage permanent prostate implant (sPPI) after a primary permanent prostate implant (pPPI).Methods and MaterialsPatients with localized prostate cancer were primarily implanted with iodine-125 seeds and had a dosimetric assessment based on day 30 postimplant CT (CT1). After an average of 6 years, these patients underwent sPPI followed by the same CT-based evaluation of dosimetry (CT2). Radioactive seeds on each CT were detected. The detected primary seeds on CT1 and CT2 were registered and then removed from CT2 referred as a modified CT2 (mCT2). Dosimetry evaluations (D₉₀ and V₁₀₀) of sPPI were performed with dedicated planning software on CT2 and mCT2. Indeed, prostate volume, D₉₀, and V₁₀₀ differences between CT2 and either CT1 or mCT2 were calculated, and values were expressed as mean (standard deviation).ResultsThe mean prostate volume difference between sPPI and pPPI over the 6 patients was 9.85 (7.32) cm³. The average D₉₀ and V₁₀₀ assessed on CT2 were 486.5 Gy (58.9) and 100.0% (0.0), respectively, whereas it was 161.3 Gy (47.5) and 77.3% (25.2) on mCT2 (p = 0.031 each time). The average D₉₀ the day of sPPI [145.4 Gy (11.2)] was not significantly different from that observed on mCT2 (p = 0.56).ConclusionPostimplant D₉₀ and V₁₀₀ of sPPI after pPPI can be estimated on CT images after removing the primary seeds.     

Gait stability improvement after fusion surgery for adolescent idiopathic scoliosis is influenced by corrective measures in coronal and sagittal planes

To achieve optimal results after fusion for adolescent idiopathic scoliosis (AIS), radiographic parameters must be aligned with motion and performance. The effects of fusion on balance are poorly understood. Center of mass (COM) excursion and instantaneous interaction with center of pressure (COP) provides information about patients’ balancing ability during gait. This study investigates the interaction between COM and COP (COM–COP) in AIS patients before and one year after spine fusion and determines what radiographic goals predict restoration of harmonious COM–COP. This was a prospective study that investigated sixteen adolescents with AIS curvature >30˚ requiring surgical correction. Clinical outcomes measures, X-rays, and 3D motion-capture gait analysis were collected. Sagittal and coronal COM and COP offsets and inclination angles were calculated from positional data. COM excursion was calculated as peak COM displacement based on mediolateral and vertical deviation from a line fitted to the patient’s path. Radiographic parameters were measured to determine variables predictive of change in COM excursion. Post-operatively, average COM peak displacement decreased (42.6 to 13.1 mm, p = 0.001) and COM peak vertical displacement remained unchanged (17.0 to 16.3mm, p = 0.472). COM–COP inclination angles reduced in the coronal, but not sagittal plane. Coronal lower extremity peak inclination angles reduced (8.8˚ to 7.5˚, p = 0.025), correlating with C7 plumb-line offset (R = 0.581, p = 0.018). Thoracic Cobb, thoracic kyphosis, and C7 plumb-line were predictors of change in COM excursion. Mediolateral COM excursion post-surgery may reflect an attempt to reduce kinetic demands with improved spinal alignment. Although AIS correction has historically focused on the coronal plane, sagittal parameters may be more important for motion than previously theorized.     

Gait stability improvement after fusion surgery for adolescent idiopathic scoliosis is influenced by corrective measures in coronal and sagittal planes

To achieve optimal results after fusion for adolescent idiopathic scoliosis (AIS), radiographic parameters must be aligned with motion and performance. The effects of fusion on balance are poorly understood. Center of mass (COM) excursion and instantaneous interaction with center of pressure (COP) provides information about patients’ balancing ability during gait. This study investigates the interaction between COM and COP (COM–COP) in AIS patients before and one year after spine fusion and determines what radiographic goals predict restoration of harmonious COM–COP. This was a prospective study that investigated sixteen adolescents with AIS curvature >30˚ requiring surgical correction. Clinical outcomes measures, X-rays, and 3D motion-capture gait analysis were collected. Sagittal and coronal COM and COP offsets and inclination angles were calculated from positional data. COM excursion was calculated as peak COM displacement based on mediolateral and vertical deviation from a line fitted to the patient’s path. Radiographic parameters were measured to determine variables predictive of change in COM excursion. Post-operatively, average COM peak displacement decreased (42.6 to 13.1 mm, p = 0.001) and COM peak vertical displacement remained unchanged (17.0 to 16.3mm, p = 0.472). COM–COP inclination angles reduced in the coronal, but not sagittal plane. Coronal lower extremity peak inclination angles reduced (8.8˚ to 7.5˚, p = 0.025), correlating with C7 plumb-line offset (R = 0.581, p = 0.018). Thoracic Cobb, thoracic kyphosis, and C7 plumb-line were predictors of change in COM excursion. Mediolateral COM excursion post-surgery may reflect an attempt to reduce kinetic demands with improved spinal alignment. Although AIS correction has historically focused on the coronal plane, sagittal parameters may be more important for motion than previously theorized.     

Comparison of intraoperative ultrasound with postimplant computed tomography--dosimetric values at Day 1 and Day 30 after prostate brachytherapy

PurposeTo compare the results of intraoperative dosimetry with those of postimplant computed tomography (CT)-based dosimetry after ¹²⁵I prostate brachytherapy.Methods and materialsWe treated 412 prostate cancer patients with ¹²⁵I prostate brachytherapy, with or without external beam radiotherapy at our institution. Neoadjuvant hormone therapy was administered to 331 patients (80.3%). Implantation was performed using an intraoperative interactive technique. Postimplant dosimetry was performed on Day 1 and Day 30 using CT imaging. The dosimetric results for the prostate, urethra, and rectum were compared among intraoperative ultrasound, and CT scans of Day 1 and Day 30.ResultsThe mean intraoperative minimal dose received by 90% of the prostate volume (D₉₀) was 118.8% of the prescribed dose vs. 106.4% for Day 1 (p < 0.01) and 119.2% for Day 30 (p = 0.25). There were no significant correlations between the intraoperative D₉₀ and the postimplant D₉₀ values (intraclass correlation coefficients = 0.42 and 0.33 for Day 1 and Day 30, respectively). Prostatic edema at Day 1 had the largest effect on the Day 1 D₉₀ (p < 0.01). The factor significantly affecting the Day 30 D₉₀ was neoadjuvant hormone therapy (p < 0.01). The mean Day 30 D₉₀ for the hormone-treated patients was 117.9%, compared with 124.6% for those who remained hormone naïve. The intraoperative and postimplant dosimetric values differed significantly for the urethra and rectum.ConclusionsOur results demonstrate that there are no significant differences between the D₉₀ assessments obtained intraoperatively and at Day 30 postoperatively. Furthermore, there are no definite correlations between intra- and postimplantation dosimetric values. Other D₉₀ values differed significantly between the intraoperative and postimplant dosimetry. This study suggests that dosimetry has negligible clinical utility for informing patients, at discharge, of whether or not their implants are adequate.     

Choroidal thickness changes in healthcare professionals wearing surgical masks or FFP2 masks: Pilot study

PurposeTo evaluate the choroidal thickness (CT) with enhanced depth-imaging optical coherence tomography (EDI-OCT) in healthcare professionals using surgical masks or FFP2 (N95) masks.MethodsWe included the 120 eyes of 120 healthy volunteers who were using a surgical mask (Group 1) or FFP2 mask (Group 2) in the study. Spectral domain (SD) OCT was used to measure CT. EDI-OCT was used to measure subfoveal and perifoveal CT. Points 1500 μm nasal (C_N1500) and temporal (C_T1500) to the foveal center were used to measure perifoveal CT. Oxygen saturation and heart rate were measured with a pulse oximeter. All measurements were performed at 8:30, before wearing the mask, and at 12:30, when the mask was removed for the lunch break.ResultsOf a total of 120 subjects, Group 1 consisted of 60 subjects (mean age 38.50±8.60 (range 24–44) years) and Group 2 also consisted of 60 subjects (mean age 36.60±6.53 (range 26–45) years). Although not statistically significant, CT was seen to have increased at 3 measurement points in Group 1 after using the mask for 4 h: subfoveal CT (C_SF) (p = 0.545), C_T1500 (p = 0.080), and C_N1500 (p = 0.251)). In Group 2, the increase in C_SF (p = 0.001) was statistically significant while the increases in C_N1500 and C_T1500 were not (p = 0.162 and p = 0.058, respectively) after using the mask for 4 h.ConclusionWe found CT to increase after 4 h of mask use, and this increase was more marked in Group 2. The increase in subfoveal CT in particular was statistically significant in Group 2.