Rectus sheath block added to parasternal block may improve postoperative pain control and respiratory performance after cardiac surgery: a superiority single-blinded randomized controlled clinical trial.

BACKGROUND: The population undergoing cardiac surgery confronts challenges from uncontrolled post-sternotomy pain, with possible adverse effects on outcome. While the parasternal block can improve analgesia, its coverage may be insufficient to cover epigastric area. In this non-blinded randomized controlled study, we evaluated the analgesic and respiratory effect of adding a rectus sheath block to a parasternal block. METHODS: 58 patients undergoing cardiac surgery via median sternotomy were randomly assigned to receive parasternal block with rectus sheath block (experimental) or parasternal block with epigastric exit sites of chest drains receiving surgical infiltration of local anesthetic (control). The primary outcome of this study was pain at rest at extubation. We also assessed pain scores at rest and during respiratory exercises, opiate consumption and respiratory performance during the first 24 hours after extubation. RESULTS: The median (IQR) maximum pain scores (on a 0-10 Numeric Rate Scale (NRS)) at extubation were 4 (4, 4) in the rectus sheath group and 5 (4, 5) in the control group (difference 1, p value=0.03). Rectus sheath block reduced opioid utilization by 2 mg over 24 hours (IC 95% 0.0 to 2.0; p<0.01), reduced NRS scores at other time points, and improved respiratory performance at 6, 12, and 24 hours after extubation. CONCLUSION: The addition of a rectus sheath block with a parasternal block improves analgesia for cardiac surgery requiring chest drains emerging in the epigastric area. TRIAL REGISTRATION NUMBER: NCT05764616.

Laparoscopic-Guided Transversus Abdominis Plane (TAP) Block Combined with Port-Site Infiltration (PSI) for Laparoscopic Sleeve Gastrectomy in an ERABS Pathway: A Randomized, Prospective, Double-Blind, Placebo-Controlled Trial.

PURPOSE: Patients undergoing laparoscopic sleeve gastrectomy (LSG) commonly experience moderate to severe postoperative pain. We conducted a randomized, prospective double-blind placebo-controlled study to evaluate the analgesic effect of laparoscopic-guided TAP (LG-TAP) block after LSG in a high-volume bariatric center, applying an enhanced recovery after bariatric surgery (ERABS) pathway. MATERIAL AND METHODS: One hundred ten patients were randomly allocated to receive LG-TAP block with local anesthetic (LA) or saline solution (placebo), both combined with port-site infiltration with LA (LA-PSI). Primary outcome was pain score measured in post-anesthesia care unit (PACU) and at 6, 12, and 24 h after surgery. Secondary outcomes included postoperative nausea and/or vomiting (PONV), analgesic requirement, time to walking, time to flatus, length of hospital stay (LOS), and surgical complications. RESULTS: No significant differences were observed between LG-TAP and placebo groups in postoperative analgesia, with a median (IQR) NRS of 2 (4.75-0) vs. 2 (5.25-0) in PACU, 5.5 (7-3) vs. 6 (7-4) at 6 h, 2 (6-0) vs. 3 (5.25-1.75) at 12 h, and 2 (3.75-0) vs. 1 (2-0) at 24 h; all p > 0.05. A significant difference was found in PONV in PACU (LG-TAP, 46%; placebo, 25%, p-value, 0.019) and at 6 h postoperatively (LG-TAP, 69%, placebo, 41%, p-value, 0.003). No differences were observed as regards other secondary outcomes. CONCLUSION: Our results suggest that LG-TAP block is not related to more effective postoperative analgesia compared to placebo when LA-PSI is performed.

Lateral Femoral Cutaneous Nerve Block or Wound Infiltration Combined with Pericapsular Nerve Group (PENG) Block for Postoperative Analgesia following Total Hip Arthroplasty through Posterior Approach: A Randomized Controlled Trial.

Background: Pericapsular nerve group (PENG) block, although effective for pain management following total hip arthroplasty (THA), does not cover skin analgesia. In this randomized controlled trial, we compared the effectiveness of PENG block combined with lateral femoral cutaneous nerve (LFCN) block or wound infiltration (WI) on postoperative analgesia and functional outcomes. Methods: Fifty patients undergoing posterior-approached THA under spinal anesthesia were randomly allocated to receive LFCN block with 10 mL of 0.5% ropivacaine or WI with 20 mL of 0.5% ropivacaine. In both groups, PENG block was performed by injecting 20 mL of 0.5% ropivacaine. Primary outcomes were static and dynamic pain scores (0-10 numeric rating scale) measured in the first 24 h after surgery. Secondary outcomes included postoperative opioid consumption, functional assessment and length of hospital stay. Results: Postoperative static NRS of patients receiving LFCN was higher than that of patients receiving WI at 6 h but lower at 24 h, with a median (IQR) of 3 (2-4) vs. 2 (1-2) (p < 0.001) and 2 (2-3) vs. 3 (3-4) (p = 0.02), respectively. Static pain scores at 12 h did not show significant differences, with an NRS of 3 (2-4) for WI vs. 3 (3-4) for LFCN (p = 0.94). Dynamic pain and range of movement followed a similar trend. No significant differences were detected in other outcomes. Conclusions: LFCN block was not inferior to WI for postoperative analgesia and functional recovery in association with PENG block during the first postoperative day, although it had worse short-term pain scores. Based on these results, it is reasonable to consider LFCN block as a valid alternative to WI or even a complementary technique added to WI to enhance skin analgesia during the first 24 h after THA. Future studies are expected to confirm this hypothesis and find the best combination between PENG block and other techniques to enhance analgesia after THA.

Stress-strain and fatigue life numerical evaluation of two different dental implants considering isotropic and anisotropic human jaw.

Dental prostheses are currently a valid solution for replacing potential missing tooth or edentulism clinical condition. Nevertheless, the oral cavity is a dynamic and complex system: occlusal loads, external agents, or other unpleasant events can impact on implants functionality and stability causing a future revision surgery. One of the failure origins is certainly the dynamic loading originated from daily oral activities like eating, chewing, and so on. The aim of this paper was to evaluate, by a numerical analysis based on Finite Elements Method (FEM), and to discuss in a comparative way, firstly, the stress-strain of two different adopted dental implants and, subsequently, their fatigue life according to common standard of calculations. For this investigation, the jawbone was modeled accounting for either isotropic or anisotropic behavior. It was composed of cortical and cancellous regions, considering it completely osseointegrated with the implants. The impact of implants' fixture design, loading conditions, and their effect on the mandible bone was finally investigated, on the basis of the achieved numerical results. Lastly, the life cycle of the investigated implants was estimated according to the well-established theories of Goodman, Soderberg, and Gerber by exploiting the outcomes obtained by the numerical simulations, providing interesting conclusions useful in the dental practice.

Natural history of chronic thromboembolic pulmonary disease with no or mild pulmonary hypertension.

BACKGROUND: We describe baseline characteristics, disease progression and mortality in chronic thromboembolic pulmonary disease patients as a function of mean pulmonary artery pressure (mPAP) according to new and previous definitions of pulmonary hypertension. METHODS: All patients diagnosed with chronic thromboembolic pulmonary disease between January, 2015 and December, 2019 were dichotomized according to initial mPAP: ≤ 20 mmHg ('normal') vs 21-24 mmHg ('mildly-elevated'). Baseline features were compared between the groups, and pairwise analysis performed to determine changes in clinical endpoints at 1-year, excluding those who underwent pulmonary endarterectomy or did not attend follow-up. Mortality was assessed for the whole cohort over the entire study period. RESULTS: One hundred thirteen patients were included; 57 had mPAP ≤ 20 mmHg and 56 had mPAP 21-24 mmHg. Normal mPAP patients had lower pulmonary vascular resistance (1.6 vs 2.5WU, p < 0.01) and right ventricular end-diastolic pressure (5.9 vs 7.8 mmHg, p < 0.01) at presentation. At 3 years, no major deterioration was seen in either group. No patients were treated with pulmonary artery vasodilators. Eight had undergone pulmonary endarterectomy. Over 37 months median follow-up, mortality was 7.0% in the normal mPAP group and 8.9% in the mildly-elevated mPAP group. Cause of death was malignancy in 62.5% of cases. CONCLUSIONS: Chronic thromboembolic pulmonary disease patients with mild pulmonary hypertension have statistically higher right ventricular end-diastolic pressure and pulmonary vascular resistance than those with mPAP ≤ 20 mmHg. Baseline characteristics were otherwise similar. Neither group displayed disease progression on non-invasive tests up to 3 years. Mortality over 37 months follow-up is 8%, and mainly attributable to malignancy. Further prospective study is required to validate these findings.

Mandibular Reconstruction after Resection of Ameloblastoma by Custom-Made CAD/CAM Mandibular Titanium Prosthesis: Two Case Reports, Finite Element Analysis and Discussion of the Technique.

Virtual surgical planning for CAD/CAM mandibular reconstruction by titanium prosthesis was recently reported for resected cases. Even if some advantages are evident, difficulties that may arise for TMJ function after reconstruction originate from prosthesis contamination through oral mucosa dehiscence. In these two cases reported of mandibular reconstruction after resection of ameloblastoma by custom-made CAD/CAM titanium prosthesis, the procedures were aimed to preserve the TMJ glenoid cavity and articular disc avoiding functional problems for hemi-mandibular resections that included the condyle (as in case #1) or with condylar preservation (as in case #2) and avoiding intraoral incisions in both cases. The entire surgical planning and prosthetic fabrication were explained with specifications and the sequence of the surgical procedure. Finite elements analysis (FEA) was performed to check the force distribution and efficacy of the prosthetic device (case 1 with hemi-mandibular resection and rehabilitation). Although successful in these two cases, surgical reconstruction of the mandibular defect after resection by a CAD-CAM custom-made prosthesis still shows some drawbacks and failure risks. Several advantages of this technique and the surgical success in these two cases were presented, but limitations and side effects must be considered when cases are selected.

Ultrasound predictors of difficult spinal anesthesia: a prospective single-blind observational study.

BACKGROUND: Ultrasound showed to improve the precision and efficacy of spinal anesthesia (SA) through the identification of specific structures surrounding the intrathecal space, such as the anterior and posterior complex of dura mater (DM). The aim of this study was to verify the efficacy of ultrasonography in predicting difficult SA trough the analysis of different ultrasound patterns. METHODS: This prospective single-blind observational study involved 100 patients undergoing orthopedic or urological surgery. A first operator chose by landmarks the intervertebral space where he wanted to perform SA. Then a second operator recorded the visibility of DM complexes at ultrasound. Subsequently, the first operator, blinded to the ultrasound evaluation, performed SA, defined as "difficult" in case of failure, change of intervertebral space, operator exchange, duration >400 seconds or more than 10 needle passes. RESULTS: The ultrasound visualization of only posterior complex or the failure in visualization of both complexes showed a positive predictive value of 76% and 100%, respectively, towards difficult SA vs. 6% when both complexes were visible; P<0.001. A negative correlation was found between the number of visible complexes and both patients' age and BMI. Landmark-guided evaluation underestimated the intervertebral level in 30% of cases. CONCLUSIONS: Ultrasound showed a high accuracy in detecting difficult spinal anesthesia and its use should be recommended in the daily clinical practice in order to increase success rate and minimize patient discomfort. The absence of both DM complexes at ultrasound should lead the anesthetist to evaluate other intervertebral levels or consider alternative techniques.

Tribo-corrosive behavior of additive manufactured parts for orthopaedic applications.

Background: Additive manufacturing (AM) being an integral component of the production offers a wide variety of applications in the production of different components. The medical industry after the introduction of Additive Manufacturing has resulted in several advancements. The production of intricate patient-specific implants is one of such advancements which greatly assist a surgeon during a surgery. Orthopedic implants apart from possessing good mechanical strength are also expected to exhibit good tribological and corrosion behavior. As a result, the development of various orthopaedic implants and tools has become simple with the use of additive manufacturing. Objectives and Rationale: In the current paper an effort has been made to discuss actual scientific knowledge on the tribo-corrosive behavior of additive manufactured parts for orthopedic applications. Different studies dealing with the mechanisms of lubrication and friction in synovial joints have also been considered. A special focus has also been laid down to study the corrosive effect of implants on the human body. A section dedicated to texturing of orthopedic implants has also been provided. The paper further elaborates the different research challenges and issues related to the use of additive manufacturing for the production of optimized orthopedic implants. Conclusion: The study revealed that additive manufacturing has greatly aided in the manufacture of different orthopaedic implants with enhanced properties. However, a detailed study of the effect of processes like friction, wear, lubrication and corrosion in these implants needs to be done. The performance of these implants in the presence of various synovial fluids also needs to be addressed. However, the lack of more biocompatible materials, scalability and cost issues hinder the widespread use of AM in the different orthopaedic applications.

Prognostic significance of CTNNB1 mutation in early stage endometrial carcinoma: a systematic review and meta-analysis.

BACKGROUND: In the last years, mutations in the exon 3 of CTNNB1 have emerged as a possible prognostic factor for recurrence in early stage endometrioid endometrial carcinoma, especially in cases with no specific molecular profile (NSMP). OBJECTIVE: To define the prognostic value of CTNNB1 mutations in early stage endometrioid endometrial carcinoma, through a systematic review and meta-analysis. METHODS: Electronic databases were searched from their inception to November 2020 for all studies assessing the prognostic value of CTNNB1 mutation in early stage (FIGO I-II) endometrioid endometrial carcinoma. Odds ratio (OR) for tumor recurrence and hazard ratio (HR) for disease-free survival (DFS) were calculated with a significant p value < 0.05. RESULTS: Seven studies with 1031 patients were included. Four studies were suitable for meta-analysis of OR and showed significant association between CTNNB1 mutation and the absolute number of recurrence (OR = 3.000; p = 0.019); the association became stronger after excluding patients with known molecular status other than NSMP (HR = 5.953; p = 0.012). Three studies were suitable for meta-analysis of HR and showed no significant association between CTNNB1 mutation and decreased DFS (HR = 1.847; p = 0.303); the association became significant after excluding patients with known molecular status other than NSMP (HR = 2.831; p = 0.026). CONCLUSION: CTNNB1 mutation is significantly associated with recurrence in early stage endometrioid endometrial carcinomas, especially in the NSMP, appearing potentially useful in directing adjuvant treatment.

Computed Tomography and Magnetic Resonance Imaging.

Imaging in Oncology is rapidly moving from the detection and size measurement of a lesion to the quantitative assessment of metabolic processes and cellular and molecular interactions. Increasing insights into cancer as a complex disease with involvement of the tumor stroma in tumor pathobiological processes have made it clear that for successful control of cancer, treatment strategies should not only be directed at the cancer cells but should also take aspects of the tumor microenvironment into account. This requires an understanding of the complex molecular and cellular interactions in cancer tissue. Recent developments in imaging technology have increased the possibility to image various pathobiological processes in cancer development and response to treatment. For computed tomography (CT) and magnetic resonance imaging (MRI) various improvements in hardware, software, and imaging probes have lifted these modalities from classical anatomical imaging techniques to techniques suitable to image and quantify various physiological processes and molecular and cellular interactions. Next to a more general overview of possible imaging targets in oncology, this chapter provides an overview of the various developments in CT and MRI technology and some specific applications.

Vascular Targeted Radioimmunotherapy for the Treatment of Glioblastoma.

Glioblastoma is characterized by an aggressive and aberrant vascular network that promotes tumor progression and hinders effective treatment; the median survival is 16 mo despite standard-of-care therapies. There is a need to improve therapeutic options for this disease. We hypothesized that antibody targeting of the vascular endothelium of glioblastoma with cytotoxic short-range, high-energy α-particles would be an effective therapeutic approach. METHODS: E4G10, an antibody directed at an epitope of monomeric vascular endothelium cadherin that is expressed in tumor neovasculature and on endothelial progenitor cells in the bone marrow, was labeled with α-particle-emitting 225Ac. Pharmacokinetic studies investigated the tissue distribution and blood clearance of the 225Ac-E4G10 radioimmunoconstruct in a transgenic Nestin-tumor virus A (Ntva) mouse model of high-grade glioblastoma. Histologic analysis was used to demonstrate local therapeutic effects in treated brain tumor sections. Radioimmunotherapy with 225Ac-E4G10 was performed in Ntva mice to assess overall survival alone and in combination with temozolomide, the standard-of-care chemotherapeutic agent. RESULTS: 225Ac-E4G10 was found to accumulate in tissues expressing the target antigen. Antivascular α-particle therapy of glioblastoma in the transgenic Ntva model resulted in significantly improved survival compared with controls and potent control of tumor growth. Adding the chemotherapeutic temozolomide to the treatment increased survival to 30 d (vs. 9 d for vehicle-treated animals). Histologic analyses showed a remodeled glioblastoma vascular microenvironment. CONCLUSION: Targeted α-particle antivascular therapy is shown for the first time to be effective in increasing overall survival in a solid tumor in a clinically relevant transgenic glioblastoma mouse model.

The effect of baseline morphology and its change during treatment on the accuracy of Response Evaluation Criteria in Solid Tumours in assessment of liver metastases.

PURPOSE: Tumour response assessment to therapy is crucial in oncology. We analysed the morphology of liver metastases (LM) in gastrointestinal stromal tumour (GIST) patients to determine whether uni-dimensional measurement of lesions by Response Evaluation Criteria in Solid Tumours (RECIST), accurately reflects lesion volume. MATERIALS AND METHODS: The volumes of LM (n=139) from a GIST patient cohort were measured using computed tomography (CT) at baseline, 3, 6 and 12 months after commencement of imatinib therapy. Baseline measurements were obtained by two independent investigators and inter-observer agreement assessed using Bland-Altman plots. Actual lesion volumes (V(ACTUAL)) were measured and compared with volumes based on the RECIST measure (V(RECIST)), and with volumes based on three orthogonal measures (V(ELLIPSOID)) at several time-points. RESULTS: At baseline, the inter-observer bias for V(ACTUAL) was just 1.8%. V(RECIST) and V(ELLIPSOID) overestimated V(ACTUAL) by a mean of 35% and only 9% respectively (P<0.0001 for both). At baseline, 44% (61/139) of LM were classified as spheroidal and 56% (78/139) as ellipsoidal. During treatment, only 42% of LM retained their original morphology. The remainder demonstrated significant changes in morphology (from spheroidal to ellipsoidal and vice versa) over time, while the RECIST measure did not reflect such changes. CONCLUSIONS: The morphology of LM in GIST is rarely spherical (an underlying assumption for RECIST) and can change considerably during imatinib therapy. In this setting, measurements using RECIST do not reflect changes in size and morphology. Additionally, whilst V(ELLIPSOID) is a more suitable surrogate for volume estimation, it is still somewhat limited by the morphology and orientation of such lesions. Studies are warranted to further explore the clinical impact of these findings.

In vivo quantitative assessment of cell viability of gadolinium or iron-labeled cells using MRI and bioluminescence imaging.

In cell therapy, noninvasive monitoring of in vivo cell fate is challenging. In this study we investigated possible differences in R1, R2 or R2* relaxation rate as a measure of overall cell viability for mesenchymal stem cells labeled with Gd-liposomes (Gd-MSCs) or iron oxide nanoparticles (SPIO-MSCs). Cells were also transduced with a luciferase vector, facilitating a correlation between MRI findings and cell viability using bioluminescence imaging (BLI). Viable Gd-MSCs were clearly distinguishable from nonviable Gd-MSCs under both in vitro and in vivo conditions, clearly differing quantitatively (ΔR1 and ΔR2) as well as by visual appearance (hypo- or hyperintense contrast). Immediately post-injection,viable Gd-MSCs caused a substantially larger ΔR2 and lower ΔR1 effect compared with nonviable MSCs. With time, the ΔR1 and ΔR2 relaxation rate showed a good negative correlation with increasing cell number following proliferation. Upon injection, no substantial quantitative or visual differences between viable and nonviable SPIO-MSCs were detected. Moreover, nonviable SPIO-MSCs caused a persisting signal void in vivo, compromising the specificity of this contrast agent. In vivo persistence of SPIO particles was confirmed by histological staining. A large difference was found between SPIO- and Gd-labeled cells in the accuracy of MR relaxometry in assessing the cell viability status. Gd-liposomes provide a more accurate and specific assessment of cell viability than SPIO particles. Viable Gd cells can be differentiated from nonviable Gd cells even by visual interpretation. These findings clearly indicate Gd to be the favourable contrast agent in qualitative and quantitative evaluation of labeled cell fate in future cell therapy experiments.

Computed tomography and magnetic resonance imaging.

Imaging in Oncology is rapidly moving from the detection and size measurement of a lesion to the quantitative assessment of metabolic processes and cellular and molecular interactions. Increasing insights into cancer as a complex disease with involvement of the tumor stroma in tumor pathobiological processes have made it clear that for successful control of cancer, treatment strategies should not only be directed at the tumor cells but also targeted at the tumor microenvironment. This requires understanding of the complex molecular and cellular interactions in cancer tissue. Recent developments in imaging technology have increased the possibility to image various pathobiological processes in cancer development and response to treatment. For computed tomography (CT) and magnetic resonance imaging (MRI) various improvements in hardware, software, and imaging probes have lifted these modalities from classical anatomical imaging techniques to techniques suitable to image and quantify various physiological processes and molecular and cellular interactions. Next to a more general overview of possible imaging targets in oncology this chapter provides an overview of the various developments in CT and MRI technology and some specific applications.

Tumor volume as an alternative response measurement for imatinib treated GIST patients.

BACKGROUND: Assessment of tumor size changes is crucial in clinical trials and patient care. We compared imatinib-induced volume changes of liver metastases (LM) from gastro-intestinal stromal tumors (GIST) to RECIST and Choi criteria and their association with overall survival (OS). METHODS: LM from 84 GIST patients (training and validation set) were evaluated using manual and semi-automated Computed Tomography measurements at baseline, after 3, 6 and 12 months of imatinib. The ability of uni-dimensional (1D) and three-dimensional (3D) measurements to detect size changes (increase/decrease) ≥20% was evaluated. Volumetric response cut-offs were derived from minimally relevant changes (+20/-30%) by RECIST, considering lesions as spherical or ellipsoidal. RESULTS: 3D measurements detected size changes ≥20% more frequently than 1D at every time-point (P≤0.008). 3D and Choi criteria registered more responses than RECIST at 3 and 6 months for 3D-spheres (P≤0.03) and at all time-points for 3D-ellipsoids and Choi criteria (P<0.001). Progressive disease by 3D criteria seems to better correlate to OS at late time-points than other criteria. CONCLUSION: Volume criteria (especially ellipsoids) classify a higher number of patients as imatinib-responders than RECIST. Volume discriminates size changes better than diameter in GIST and constitutes a feasible and robust method to evaluate response and predict patient benefit.

Cell tracking in cardiac repair: what to image and how to image.

Stem cell therapies hold the great promise and interest for cardiac regeneration among scientists, clinicians and patients. However, advancement and distillation of a standard treatment regimen are not yet finalised. Into this breach step recent developments in the imaging biosciences. Thus far, these technical and protocol refinements have played a critical role not only in the evaluation of the recovery of cardiac function but also in providing important insights into the mechanism of action of stem cells. Molecular imaging, in its many forms, has rapidly become a necessary tool for the validation and optimisation of stem cell engrafting strategies in preclinical studies. These include a suite of radionuclide, magnetic resonance and optical imaging strategies to evaluate non-invasively the fate of transplanted cells. In this review, we highlight the state-of-the-art of the various imaging techniques for cardiac stem cell presenting the strengths and limitations of each approach, with a particular focus on clinical applicability.

Targeting the internal epitope of prostate-specific membrane antigen with 89Zr-7E11 immuno-PET.

UNLABELLED: The potential of the positron-emitting (89)Zr has been recently investigated for the design of radioimmunoconjugates for immuno-PET. In this study, we report the preparation and in vivo evaluation of (89)Zr-desferrioxamine B (DFO)-7E11, a novel (89)Zr-labeled monoclonal antibody (mAb) construct for targeted imaging of prostate-specific membrane antigen (PSMA), a prototypical cell surface marker highly overexpressed in prostate cancer. The ability of (89)Zr-DFO-7E11 to delineate tumor response to therapy was also investigated, because it binds to the intracellular epitope of PSMA, which becomes available only on membrane disruption in dead or dying cells. METHODS: 7E11 as a marker of dying cells was studied by flow cytometry and microscopy of cells after antiandrogen-, radio-, and chemotherapy in LNCaP and PC3 PSMA-positive cells. The in vivo behavior of (89)Zr-DFO-7E11 was characterized in mice bearing subcutaneous LNCaP (PSMA-positive) tumors by biodistribution studies and immuno-PET. The potential of assessing tumor response was evaluated in vivo after radiotherapy. RESULTS: In vitro studies correlated 7E11 binding with markers of apoptosis (7-amino-actinomycin-D and caspase-3). In vivo biodistribution experiments revealed high, target-specific uptake of (89)Zr-DFO-7E11 in LNCaP tumors after 24 h (20.35 ± 7.50 percentage injected dose per gram [%ID/g]), 48 h (22.82 ± 3.58 %ID/g), 96 h (36.94 ± 6.27 %ID/g), and 120 h (25.23 ± 4.82 %ID/g). Excellent image contrast was observed with immuno-PET. 7E11 uptake was statistically increased in irradiated versus control tumor as measured by immuno-PET and biodistribution studies. Binding specificity was assessed by effective blocking studies at 48 h. CONCLUSION: These findings suggest that (89)Zr-DFO-7E11 displays high tumor-to-background tissue contrast in immuno-PET and can be used as a tool to monitor and quantify, with high specificity, tumor response in PSMA-positive prostate cancer.