Breast implant surface topography triggers a chronic-like inflammatory response

Breast implants are extensively employed for both reconstructive and esthetic purposes. However, the safety of breast implants with textured surfaces has been questioned, owing to a potential correlation with anaplastic large-cell lymphoma and the recurrence of breast cancer. This study investigates the immune response elicited by different prosthetic surfaces, focusing on the comparison between macrotextured and microtextured breast implants. Through the analysis of intraoperatively harvested periprosthetic fluids and cell culture experiments on surface replicas, we demonstrate that macrotextured surfaces elicit a more pronounced chronic-like activation of leucocytes and an increased release of inflammatory cytokines, in contrast to microtextured surfaces. In addition, in vitro fluorescent imaging of leucocytes revealed an accumulation of lymphocytes within the cavities of the macrotextured surfaces, indicating that the physical entrapment of these cells may contribute to their activation. These findings suggest that the topography of implant surfaces plays a significant role in promoting a chronic-like inflammatory environment, which could be a contributing factor in the development of lymphomas associated with a wide range of implantable devices.

Microbial composition associated with biliary stents in patients undergoing pancreatic resection for cancer

Malignant bile duct obstruction is typically treated by biliary stenting, which however increases the risk of bacterial infections. Here, we analyzed the microbial content of the biliary stents from 56 patients finding widespread microbial colonization. Seventeen of 36 prevalent stent species are common oral microbiome members, associate with disease conditions when present in the gut, and include dozens of biofilm- and antimicrobial resistance-related genes. This work provides an overview of the microbial communities populating the stents.

Clinical Implementation and Evaluation of Automated Contouring for Breast Malignancies

PURPOSE/OBJECTIVE(S)

As breast radiotherapy becomes more conformal, precise target delineation is increasingly important. Multiple atlases are available to provide uniformity, but contouring remains resource intensive and prone to variation. Automated contouring has been investigated to reduce planning time and standardize contouring practices. Herein, we investigate a model trained to autocontour RADCOMP breast regional nodal targets using a small, highly curated set of manual contours.

MATERIALS/METHODS

The contours for 15 patients previously treated on the RADCOMP study were edited per the RADCOMP atlas guidelines including bilateral supraclavicular region (SCR), posterior triangle, axilla, breast, and internal mammary nodes (IMN). A 3D U-Net architecture was trained on these volumes to autocontour each structure. For validation, 20 new cases were autocontoured with this model. The autocontours were independently scored for accuracy by three physicians on a 5-point modified Likert scale. A score of 3 indicated that there were edits that the reviewer judged as clinically important, but it was more efficient to edit the automatically generated contours than start without an autocontour. A score of 4 indicated differences were stylistic and not clinically significant. A score of 5 indicated that contours were clinically acceptable without stylistic changes. To evaluate time saved, a breast specialist radiation oncologist first edited the autocontours, then manually contoured bilateral target regions of interest on 5 cases. Finally, these edited contours were objectively compared with unedited autocontours for similarity using Dice Similarity Coefficient (DSC) and Mean Surface Distance (MSD).

RESULTS

Twenty retrospectively autocontoured cases were evaluated by 3 physicians for clinical appropriateness. Mean Likert scores for each OAR were as follows: L Breast: 3.6, R Breast: 3.4, L Axilla: 4.0, R Axilla: 3.9, L IMN: 3.6, R IMN: 3.6, L Posterior Triangle: 4.0, R Posterior Triangle: 3.9, L SCR: 3.8, and R SCR: 3.8. For the timed portion of the study, the mean time spent editing autocontours for clinical appropriateness was 5 minutes and 43 seconds ± 64.4 seconds, while the mean contouring time when manually contouring was 11 minutes and 36 seconds ± 50.1 seconds (p<0.001; paired t-test). Average DSC and MSD values measuring differences between pre and post clinical edits were 0.99 and 0.3mm, 0.99 and 0.2mm, 0.93 and 0.3mm, 0.97 and 0.2mm and 0.92 and 0.3mm for Breast, Axilla, IMN, SCR, and posterior triangle, respectively.

CONCLUSION

This study demonstrates that a small and carefully curated dataset can train an autocontouring model that is subjectively useful, time efficient, and objectively accurate. Future studies using the RADCOMP Atlas may benefit from autocontouring to standardize treatment or streamline central verification of treatment planning.

kV-CBCT-Guided Daily Adaptation Improves Target Coverage and Spares Normal Tissue for Accelerated Partial Breast Irradiation

PURPOSE/OBJECTIVE(S)

Linear accelerator based accelerated partial breast irradiation (APBI) in early-stage breast cancer necessitates a reduction in non-target breast tissue to decrease long term toxicity and adverse cosmetic outcome. In particular, lumpectomy cavity seromas may decrease in size and deform in shape during the course of short course APBI. Online adaptive RT (oART) offers considerable prospect for treating mobile targets through pendulous breast anatomy. However, there are limited studies outlining the methods and outcomes of CBCT-based oART for APBI. Here we present a retrospective, single institutional study analyzing the treatment process for patients receiving stereotactic kV-CBCT guided oART APBI.

MATERIALS/METHODS

Fourteen patients were treated to 30 Gy in 5 fractions for a total of 70 fractions. Time between simulation and treatment, change in gross tumor volume (GTV), and differences in DVH metrics with adaption were analyzed. The Wilcoxon paired, non-parametric test was utilized to test for DVH metric differences between the scheduled plans (initial plans recalculated on daily CBCT anatomy) and treated plans, which were either the scheduled or adapted plan (initial plans re-optimized using daily anatomy), depending on the preference of the treating physician or physicist.

RESULTS

Median (inter-quartile range) time from simulation to first treatment was 28 days (21-33 days). During this same time, GTV volume reduced to 72.5% (57.8-87.3%) of the simulation lumpectomy cavity volume. Adaptive treatments required 31.1 min (27.2-37.1 min) from start of CBCT to treatment session end. Table 1 summarizes differences between scheduled and treated plan metrics for 70 fractions, 62 (89%) of which were treated adaptively and 8 (11%) of which were treated using the scheduled plan. Significant improvement in prescription planning target volume coverage (p = 0.003), significant reduction in 5/6 organ-at-risk metrics evaluated (p ≤ 0.003), and significant improvement in conformity index and high dose spillage (p ≤ 0.001) were realized with adaption. Table 1: Scheduled versus treated plan metrics.

CONCLUSION

APBI using oART decreased most organs at risk DVH metrics, improved plan quality metrics, and increased target coverage, justifying the use of kV-CBCT-guided oART for APBI.

Cobalt Compensator-Based IMRT for Gynecologic Cancer Treatment in Low- and Middle-Income Countries: Equivalence to LINAC-Based IMRT

PURPOSE/OBJECTIVE(S)

Cobalt intensity modulated radiation therapy (IMRT) has the potential to impact global oncology by improving access to precision radiation therapy, particularly in low- and middle-income countries, and a novel compensator-based machine has been developed. Previously, cobalt compensator-based IMRT and LINAC-based IMRT were shown to achieve similar target goals and dose constraints for head and neck clinical cases. Additionally, the fidelity of those calculations was supported by Monte Carlo simulations and gamma analysis. The current study investigates the use of cobalt compensator IMRT for another application - gynecologic cancer patients.

MATERIALS/METHODS

A commercial treatment planning system was previously commissioned for the cobalt compensator-based device using Monte Carlo simulations from a simulation toolkit. Patient-specific compensators were modeled. Clinical gynecologic cancer cases were planned and compared to clinical plans with a 6MV LINAC using IMRT. The prescribed dose was 45 Gy in 25 fractions. Dosimetric plan quality endpoints for the planning target volume (PTV) and organs-at-risk (OARs) were compared. Parametric t-testing was used for statistical analysis, and criteria for significance was p<0.05.

RESULTS

Dose statistics of 10 cases showed similar target coverage and normal tissue sparing between IMRT plans using a 6 MV LINAC and using a cobalt compensator-based device. Greater than 95% of the dose to greater than 95% of the PTV was achieved for all 10 cases using both the LINAC-based and cobalt compensator-based plans. There was no significant difference in the mean percentage of the PTV receiving 95% of the dose between LINAC-based and cobalt compensator-based plans (98.0 ± 1.88% vs 97.1 ± 1.90%, respectively, p = 0.313). Additionally, both the LINAC-based and cobalt compensator-based plans, for all 10 cases, met dose constraints for the OARs, including Spinal Cord Dmax < 4500 cGy, Kidney Dmean < 1800 cGy, Bladder Dmax < 5750 cGy, Rectum Dmax < 5500 cGy, Small Bowel Dmax < 5400 cGy, Bone Marrow V4000 < 37%, and Femoral Heads Dmax < 5000 cGy.

CONCLUSION

Cobalt compensator-based IMRT may provide comparable quality treatment plans to LINAC-based IMRT for gynecologic cancer patients. Physical development of the cobalt compensator device has been completed and will be commissioned for further research to assess clinical outcomes.

Early Experience with CBCT-Guided Online Adaptive Radiotherapy for Muscle Invasive Bladder Cancer

PURPOSE/OBJECTIVE(S)

Radiation therapy for muscle-invasive bladder cancer (MIBC) requires substantial planning target volume (PTV) margins to account for variability in bladder filling as well as other anatomic changes. We hypothesized that CBCT-guided online adaptive RT (oART) may both improve target coverage and reduce normal tissue exposure as compared to non-adaptive RT. The purpose of this study is to report the dosimetric results of our initial experience utilizing oART for treatment of MIBC.

MATERIALS/METHODS

Seven patients with MIBC were treated with oART over a 1-year period. Patients were simulated with an empty bladder and were asked to void prior to each treatment. Five patients received 55 Gy in 20 fractions to a clinical target volume (CTV) expanded from the TURBT bed and 46 Gy simultaneously to the remaining bladder and for 2 patients the high dose CTV was the entire bladder. PTVs consisted of a 7mm isometric expansion of the CTV. The oART delivery process initially coregisters the daily CBCT to the treatment planning CBCT using skeletal alignment. Target volumes and organs-at-risk (OARs) were modified at each treatment session and the plan re-optimized to meet prespecified clinical goals. Target coverage and OAR dosimetric parameters for the adaptive were compared non-adaptive (scheduled) plan for each fraction using the Wilcoxon paired test of means.

RESULTS

The adapted plan was selected for delivery for all fractions across all patients. Daily bladder volumes differed from the bladder volume at simulation by a mean of 60cc ± 66cc. At least 95% of the high dose CTV was covered by the prescription dose for 139 (99.3%) fractions with the oART plan as compared to 70 (50%) fractions with scheduled. A portion of the high dose CTV was outside of the 80% isodose line for 13 (9.3%) of scheduled fractions and was outside of the 50% isodose line for 2 (0.01%) of scheduled fractions. There were no cases of oART plans where any portion of the high dose CTV was outside of the 90% isodose line. A comparison of selected target and OAR dosimetric parameters is shown in the Table. oART treatment plans were associated with greater target coverage and less OAR exposure for all metrics.

CONCLUSION

In this initial experience, oART resulted in acceptable delivered dosimetry to target volumes with a reduced PTV margin of 7mm despite considerable daily variation in bladder volume. As expected, oART plans were associated with improved target coverage and OAR dosimetry. Future patient-centered studies should explore the clinical impact of reduced margin oART for patients with MIBC.

Artificial Intelligence-Assisted Automated Applicator Digitization for Fully-Automated Gynecological High-Dose Rate Brachytherapy Treatment Planning

PURPOSE/OBJECTIVE(S)

To automate the digitization of plastic and titanium applicators used in interstitial and hybrid gynecological (GYN) computed tomography (CT)-based high-dose-rate (HDR) brachytherapy procedures to accelerate the planning and reduce the potential for planning errors. Our hypothesis is that artificial intelligence can accurately automate the identification and digitization of plastic and titanium applicators used in HDR brachytherapy.

MATERIALS/METHODS

Forty-eight patients who had received GYN procedures (7 tandem/ring: plastic applicators, 41 interstitial: titanium needles) were selected retrospectively. Patients were randomly split into training (n = 40) and test (n = 8) sets for this study. DICOM images and digitized needles from delivered plans were converted to 3D binary format. The points from each needle were transformed to individual contours and combined into a single binary mask using custom software. Using nnU-Net, a self-configuring deep convolutional neural network, 2D and 3D U-Net architectures were trained and ensembled. With the CT image as input, the nnU-Net model learned features to automatically segment the needle contours. Lastly, a 3D U-Net model was trained using 5 of the 7 tandem/ring cases (plastic applicators), with two reserved to evaluate this automated digitization. The models' performance was evaluated using the Dice Similarity Coefficient (DSC) and identification rate for individual needles.

RESULTS

The model trained on 40 patients performed well on titanium needle cases [mean (+/- std. dev.) DSC = 0.738+/-0.034], but did not perform well on the tandem/ring cases [DSC = 0.408] in the test set. This model automatically identified 100% (54 out of 54) titanium needles but missed all plastic applicators from tandem/ring cases. Training a model with only a limited number of tandem/ring (plastic applicators) cases greatly improved segmentation accuracy [mean DSC = 0.646] for tandem/ring test cases. This model which was trained using only tandem/ring cases, automatically identified 7 out of 7 needles (100% vs 0% with previous model) from cases in the test set.

CONCLUSION

The nnU-Net can automatically detect HDR needles with high confidence. Using applicator-specific identification models may improve digitization accuracy. Further evaluation of these tools on larger datasets will confirm the findings of this study.

Offline Verification of Daily Adaptive Therapy for Locally Advanced Lung Cancer

PURPOSE/OBJECTIVE(S)

Daily adaptive therapy (AdaptT) for locally advanced lung cancer has been an intriguing field with the adoption of cone beam CT (CBCT). We have utilized AdaptT for lung cancer. In this workflow, contours for targets and organs at risk from the original CT simulation dataset are deformed and registered to the CBCT for each fraction. A physicist reviews and edits the deformed contours online without MD presence and a new plan is treated daily. Treating physicians are required to attend 1 fraction per week. We sought to evaluate the accuracy of these contours for targets and OARs in comparison to a thoracic physician contouring offline with the same CBCT dataset. The impetus of this study was to evaluate the model of physics directed contouring and ensure that gross tumor volume (GTV) misses are not occurring during treatment, defined as Planning Target Volumes (PTV's) derived from AdaptT failing to encompass the GTV redrawn offline by the physician.

MATERIALS/METHODS

Six consecutive patients were treated from 2021-2022 with AdaptT utilizing processes as described above. One CBCT per week was re-contoured by a physician for 5-6 CBCT's per case. The GTVs, heart, and lungs were redrawn without registration. The physician was blinded to the structures approved for that fraction and from clinical information outside of the CT simulation data. The clinical target volume expansions were 5 mm shaved from normal tissue barriers and a uniform 5 mm expansion to form the PTV. The Dice Similarity Coefficient (DSE), mean surface distance (MSD), 95th percentile Hausdorff distance (95HD) for contours were calculated and the True Positive Fraction (TPF) of the redrawn GTVs within the treated PTVs were calculated.

RESULTS

Thirty CBCTs from 6 patients were contoured. The TPF was 1 for each redrawn GTV, indicating each GTV drawn by the physician offline would have been encompassed within the PTV for treatment. The median 95HF for the targets was below 5 mm (Table 1) and the MSD for targets was close to 1.07 mm. The DSC for Heart and Lungs approached 1.0, indicating close similarity. The average time the physician spent on contouring was 9.8 minutes compared to 9.6 minutes with AdaptT.

CONCLUSION

All redrawn GTVs were within the treated PTV and there was close agreement of normal structures. We evaluated the current model employing daily physics overview with weekly physician input and it appears safe and feasible. Further prospective study is needed to standardize comparison of contour quality and validate clinical outcomes of this approach.

Evaluation of HKUST-1 as Volatile Organic Compound Adsorbents for Respiratory Filters

Cyclohexane is a representative of volatile organic compounds (VOCs). VOCs can cause serious health problems in case of continuous exposure; therefore, it is essential to develop efficient personal protective equipment. Historically, activated carbons are used as VOC adsorbents. However, the emergence of promising novel adsorbents, such as metal-organic frameworks, has pushed the research to study their behavior under the same conditions. In this work, the use of the well-known HKUST-1 MOF of different particle sizes (20 μm, 300-600 μm, and 1-1.18 mm) for the adsorption of low-grade (5000 ppm) cyclohexane combined with different water concentrations (dry, 27 and 80% RH) in a fixed bed is proposed. The results were compared under the same conditions for a typically used activated carbon, PICACTIF TA 60. HKUST-1 has higher affinity to cyclohexane than PICACTIF for the whole pressure range studied, especially at low partial pressures. It begins to adsorb much earlier (0.0025 kPa) than the activated carbon (0.01 kPa). However, a different adsorption behavior is evidenced for both materials in the presence of water vapor since HKUST-1 is very hydrophilic in the zone near to the copper open metal sites, whereas PICACTIF is hydrophobic. After three consecutive cycles, good stability results were obtained for the MOF, comparable to activated carbon, even in the presence of water. As the main finding, although the unstability of HKUST-1 is well established under high humid conditions, the kinetic of degradation has not been established so far. Here, it is shown that the time usage of HKUST-1 as the adsorbent for respiratory mask (single pass) is not affected by the degradation of the structure, which may occur on a longer time scale. Finally, shaping by tableting provides good results since it is possible to increase the MOF density by around 69% with minor loss of adsorption capacity. The best fraction is 300-600 μm, reaching cyclohexane breakthrough times around 85 min/cm³ at 80% RH, comparable with PICACTIF-activated carbon and promising for practical applications.

Lung water assessment in isolated lung perfusion model via reactance monitoring

The aim of this work was to build up a new monitoring technique for the lung preservation. The medical aside problem is to measure the integrity and functionality of the lung tissue, specifically at cellular preservation level in order to improve the survival time until it is grafted. The Impedance monitoring technique for diagnosis edema development is the key in this new technique. The hypothesis was that lung edema formation is highly correlated with the reactance changes so that a rat lung perfusion model was considered as a good model to produce edema in vitro. To prove that pulmonary edema can be induced increasing the venous pressure and the perfusion time, the reactance and hemodynamic parameters were recorder in 16 pulmonary blocks of Wistar rats as methodology. Results showed statistical changes in each pulmonary block weight as a consequence to apply 7.5 ± 1.2 and 10.2 ± 1.7 mmHg venous pressure (multiple samples, Anova, p<0.05). These edema weights were correlated with the reactance changes giving 0.6 (p<0.05, Pearson). Also, data analysis showed significant differences in reactance with the time of perfusion at 16, 30, and 50 min when venous pressure level were intermittent switched from 7.5 to 10.2 mmHg. The conclusion was this preliminary evidence sustains that reactance measurement is a good technique for monitoring the lung edema level in rats. However, more research should be continuing in bigger animal models in order to prove the validity and application of this monitoring technique in human lungs.

The effect of virtual reality and training on liver operation planning

OBJECTIVE

The three-dimensional relation of a liver tumour to the intrahepatic vascular trees is basis of operation planning in liver surgery. Yet it has not been proven whether 3D reconstruction and further computerised processing will enhance precision of operation planning in liver surgery which has been based on the liver segment classification of Couinaud up to now.

DESIGN

Our interdisciplinary group (department of Surgery, German Cancer Research Center and Department of Radiology) has developed a new interactive computer-based quantitative 3D operation planning system for liver surgery which is being introduced into the clinical routine. The system quantifies the organ structures semiautomatically, defines resection planes depending on safety margins and the vascular trees, and presents the data in digital movies as well as in quantitative reports. We conducted a clinical trial to evaluate whether 3D reconstruction will lead to an improved operation planning. Data of 7 virtual patients were presented to a total of 81 surgeons in different levels of training. The tumours had to be assigned to a liver segment and subsequently drawn together with the operation proposals into a liver model. The precision of both was measured quantitatively for each surgeon and stratified concerning 2D and different types of 3D presentations.

RESULTS

The 3D anatomy can be visualised in high quality which results in good perception of the third dimension (depth). Tumour assignment to liver segments was significantly correlated to the level of training (p < 0.05). There was a significant increase (p < 0.001) in the precision of tumour localisation by 51% and resection proposal from 2D through 3D reconstructions by 13%-21%. Quantitative differences of the simplified Couinaud's classification of the liver segments compared to the true vascular anatomy of up to 40% were found.

CONCLUSION

The impact of individual 3D-reconstruction on surgical planning has been proven to be significant and increases precision quantitatively. The merit of Couinaud's classification may be enhanced by individualisation of the segment borders in future.

Plasmodium falciparum AMA-1 erythrocyte binding peptides implicate AMA-1 as erythrocyte binding protein

The role of AMA-1 during merozoite invasion has not yet been determined. However, reported experimental evidence suggests that this protein can be used, in particular as erythrocyte-binding protein, since, Fab fragments against this protein are able to block merozoite invasion. Using a previously described methodology, eight peptides with high binding activity to human erythrocyte, scattered along the different domains and having around 130 nM affinity constants, were identified in the Plasmodium falciparum AMA-1 protein. Their binding activity was sialic acid independent. Some of these peptides showed homology with the erythrocyte binding domains of one of the apical organelle protein family, MAEBL, identified in rodent malarial parasites. One of these peptides shares amino acid sequence with a previously reported B-cell epitope which induces antibodies to block parasite growth. The critical residues were identified for erythrocyte binding conserved peptides 4313 (DAEVAGTQYRLPSGKCPVFG), 4321 (VVDNWEKVCPRKNLQNAKFG), 4325 (MIKSAFLPTGAFKADRYKSH) and 4337 (WGEEKRASHTTPVLMEKPYY). All conserved peptides were able to block merozoite invasion of new RBC and development, suggesting that these peptides are involved in P. falciparum invasion.

[Virtual surgical planning in liver surgery]

The operability of a liver tumour depends on its three-dimensional relation to the intrahepatic vascular trees which define autonomously functioning liver (sub-)segments. The aim of our study was to establish a computer-based three-dimensional volumetric operation planning system for the liver.

METHODS

Using data from routine helical CT scans the three tissue subclasses of liver parenchyma, liver vessels and liver tumour were segmented semiautomatically. A dedicated segmenting tool was established using region growing algorithms in combination with an "intelligent" border finder. Visualisation is performed by the "Heidelberg Raytracer". The vascular trees are visualised as 3D graphs. Pseudoconnections between portal and hepatic venous trees are separated automatically. Security margins are calculated and the system presents a virtual resection proposal.

RESULTS

The 3D anatomy of the liver can be visualised in high quality resulting in good depth perception. Security margins are demonstrated. Dependent liver parenchyma can be recognized automatically on the basis of the vascular trees. The system offers a individualised resection proposal including the tumour, security margin and dependent liver parenchyma.

CONCLUSION

Three-dimensional presentation of the individual liver anatomy of a given patient facilitates the perception of the pathology. Virtual reality combined with artificial intelligence allows calculation of complete resection protocols, which can be quantified and modified interactively. This will make operation planning more objective; patient selection may be improved, and in cases of difficult tumour localisation different resection strategies may be tested. Thus virtual reality in liver surgery will improve teaching, surgical training and planning. It may lead to improved surgical care.

Case report 650: Grade II chondrosarcoma of the proximal end of the right femur

A case is presented in which the conventional radiograph was suggestive of avascular necrosis. This impression remained unchanged inspite of an MRI examination that was more suggestive or replacement of marrow. The diagnosis of ischemic necrosis was strongly supported by the patient having previously established avascular necrosis in the opposite hip. The gross pathologic specimen showed only necrotic tumor, which mimicked avascular necrosis on the plain film. The importance of placing proper confidence in the MRI findings is thus emphasized. A classification and brief description of the various types of chondrosarcoma are included in the Discussion.

Tardive dyskinesia in psychiatric outpatients: a study of prevalence and association with demographic, clinical, and drug history variables

We examined 153 psychiatric outpatients, on a maintenance regimen of neuroleptics, for tardive dyskinesia (TD) and parkinsonism. Demographic, clinical, and drug history data were collected to assess whether any of these factors were significantly associated with TD. After initial univariate screening, significant variables were analyzed by multivariate statistical methods. Tardive dyskinesia was significantly associated with the use of high-potency or high-dosage neuroleptics and depot fluphenazine, whereas low-potency neuroleptics were negatively correlated with moderate TD. Age, but not sex, correlated significantly with TD, as did histories of incoherence, grandiose delusions, and teeth or denture problems. Parkinsonism and TD were strongly associated. Although the prevalence of TD was quite high, there were no severe involvements of any of the Abnormal Involuntary Movement Scale body areas.