A novel radioguided surgery technique exploiting β(-) decays

First-in-human validation of a DROP-IN β-probe for robotic radioguided surgery: defining optimal signal-to-background discrimination algorithm

PURPOSE

In radioguided surgery (RGS), radiopharmaceuticals are used to generate preoperative roadmaps (e.g., PET/CT) and to facilitate intraoperative tracing of tracer avid lesions. Within RGS, there is a push toward the use of receptor-targeted radiopharmaceuticals, a trend that also has to align with the surgical move toward minimal invasive robotic surgery. Building on our initial ex vivo evaluation, this study investigates the clinical translation of a DROP-IN β probe in robotic PSMA-guided prostate cancer surgery.

METHODS

A clinical-grade DROP-IN β probe was developed to support the detection of PET radioisotopes (e.g., 68 Ga). The prototype was evaluated in 7 primary prostate cancer patients, having at least 1 lymph node metastases visible on PSMA-PET. Patients were scheduled for radical prostatectomy combined with extended pelvic lymph node dissection. At the beginning of surgery, patients were injected with 1.1 MBq/kg of [68Ga]Ga-PSMA. The β probe was used to trace PSMA-expressing lymph nodes in vivo. To support intraoperative decision-making, a statistical software algorithm was defined and optimized on this dataset to help the surgeon discriminate between probe signals coming from tumors and healthy tissue.

RESULTS

The DROP-IN β probe helped provide the surgeon with autonomous and highly maneuverable tracer detection. A total of 66 samples (i.e., lymph node specimens) were analyzed in vivo, of which 31 (47%) were found to be malignant. After optimization of the signal cutoff algorithm, we found a probe detection rate of 78% of the PSMA-PET-positive samples, a sensitivity of 76%, and a specificity of 93%, as compared to pathologic evaluation.

CONCLUSION

This study shows the first-in-human use of a DROP-IN β probe, supporting the integration of β radio guidance and robotic surgery. The achieved competitive sensitivity and specificity help open the world of robotic RGS to a whole new range of radiopharmaceuticals.

Surgical radioguidance with beta-emitting radionuclides; challenges and possibilities: A position paper by the EANM

Radioguidance that makes use of β-emitting radionuclides is gaining in popularity and could have potential to strengthen the range of existing radioguidance techniques. While there is a strong tendency to develop new PET radiotracers, due to favorable imaging characteristics and the success of theranostics research, there are practical challenges that need to be overcome when considering use of β-emitters for surgical radioguidance. In this position paper, the EANM identifies the possibilities and challenges that relate to the successful implementation of β-emitters in surgical guidance, covering aspects related to instrumentation, radiation protection, and modes of implementation.

Radioguided surgery with β decay: A feasibility study in cervical cancer

PURPOSE

Radioguided surgery (RGS) is a technique that helps the surgeon to achieve a tumour resection as complete as possible, by means of the intraoperative detection of particles emitted by a radiotracer that bounds to tumoural cells. This study aimed to investigate the applicability of β-RGS for tumour resection and margin assessment in cervical cancer patients preoperatively injected with [18F]FDG, by means of Monte Carlo simulations.

METHODS

Patients were retrospectively included if they had a recurrent or persistent cervical cancer, underwent preoperative PET/CT to exclude distant metastases and received radical surgery. All PET/CT images were analysed extracting tumour SUVmax, background SUVmean and tumour-to-non-tumour ratio. These values were used to obtain the expected count rate in a realistic surgical scenario by means of a Monte Carlo simulation of the β probe, assuming the injection of 2 MBq/kg of [18F]FDG 60 min before surgery.

RESULTS

Thirty-eight patients were included. A measuring time of ∼2-3 s is expected to be sufficient for discriminating the tumour from background in a given lesion, being this the time the probe has to be over the sample in order to be able to discriminate tumour from healthy tissue with a sensitivity of ∼99% and a specificity of at least 95%.

CONCLUSION

This study presents the first step towards a possible application of our β-RGS technique in cervical cancer. Results suggest that this approach to β-RGS could help surgeons distinguish tumour margins from surrounding healthy tissue, even in a setting of high radiotracer background activity.

67 Ga-PSMA I&T for Radioguided Surgery of Lymph Node Metastases in Patients With Biochemical Recurrence of Prostate Cancer

PURPOSE

Radioguided lymph node dissection in patients with prostate cancer, and suffering from biochemical recurrence has been described thoroughly during the past few years. Several prostate-specific membrane antigen (PSMA)-directed ligands labeled with 111 In, 99m Tc, and 68 Ga have been published; however, limitations regarding availability, short half-life, high costs, and unfavorable high energy might restrict frequent use. This study aims at introducing 67 Ga as a promising radionuclide for radioguided surgery.

METHODS

Retrospective analysis was performed on 6 patients with 7 PSMA-positive lymph node metastases. 67 Ga-PSMA I&T (imaging and therapy) was synthesized in-house and intravenously applied according to §13 2b of the German Medicinal Products Act. Radioguided surgery was performed 24 hours after injection of 67 Ga-PSMA I&T using a gamma probe. Patient urine samples were collected. Occupational and waste dosimetry was performed to describe hazards arising from radiation.

RESULTS

67 Ga-PSMA application was tolerated without adverse effects. Five of 7 lymph nodes were detected on 22-hour SPECT/CT in 4 of 6 patients. During surgery, all 7 lymph node metastases were identified by positive gamma probe signal. Relevant accumulation of 67 Ga was observed in lymph node metastases (32.1 ± 15.1 kBq). Histology analysis of near-field lymph node dissection revealed more lymph node metastases than PET/CT (and gamma probe measurements) identified. Waste produced during inpatient stay required decay time of up to 11 days before reaching exemption limits according to German regulations.

CONCLUSIONS

Radioguided surgery using 67 Ga-PSMA I&T is a safe and feasible option for patients suffering from biochemical recurrence of prostate cancer. 67 Ga-PSMA I&T was successfully synthesized according to Good Manufacturing Practice guidelines. Radioguided surgery with 67 Ga-PSMA I&T does not lead to relevant radiation burden to urology surgeons and represents a novel interdisciplinary approach in nuclear medicine and urology.

Characterization and optimization of a β detector for 18F radio-guided surgery

Radio-Guided Surgery (RGS) is a nuclear medicine technique to support the surgeon during surgery towards a complete tumor resection. It is based on intraoperative detection of radiation emitted by a radio-pharmaceutical that bounds selectively to tumoral cells. In the past years, an approach that exploits β^- emitting radiotracers has been pursued to overtake some limitations of the traditional RGS based on γ emission. A particle detector dedicated to this application, demonstrating very high efficiency to β^- particles and remarkable transparency to photons, has been thus developed. As a by-product, its characteristics suggested the possibility to utilize it with β⁺ emitting sources, more commonly in use in nuclear medicine. In this paper, performances of such detector on ¹⁸F liquid sources are estimated by means of Monte Carlo simulations (MC) and laboratory measurements. The experimental setup with a ¹⁸F saline solution comprised a "positron signal" spot (a 7 × 10 mm cylinder representing the tumor residual), and a surrounding "far background" volume, that represented for the detector an almost isotropic source of annihilation photons. Experimental results show good agreement with MC predictions, thus confirming the expected performances of the detector with ¹⁸F, and the validity of the developed MC simulation as a tool to predict the gamma background determined by a diffuse source of annihilation photons.

Current use and potential role of radioguided surgery in brain tumours

Purpose

The aim of this mini-review is to discuss the possible role of radioguided surgery in brain tumours and, in particular, in gliomas.

Methods

A research in the PubMed/Medline database was carried out to identify relevant studies evaluating radioguided surgery in brain tumours.

Results

Radioguided surgery results using gamma (γ)-emitting tracers and γ-detection probes were summarised. Most importantly, the review included preliminary findings with novel approaches, particularly those relying on the use of beta (β)−emitting isotopes and a dedicated β probe.

Conclusion

Although few data are available in the current literature, the use of β probes could be useful to accurately identify surgical margins in brain tumours. Nevertheless, further in vivo studies are required.

Nuclear‐medicine probes: where we are and where we are going

Nuclear medicine probes turned into the key for the identification and precise location of sentinel lymph nodes and other occult lesions (i.e., tumors) by using the systemic administration of radiotracers. Intraoperative nuclear probes are key in the surgical management of some malignancies as well as in the determination of positive surgical margins, thus reducing the extent and potential surgery morbidity.

Depending on their application, nuclear probes are classified into two main categories, namely, counting and imaging. Although counting probes present a simple design, are handheld (to be moved rapidly), and provide only acoustic signals when detecting radiation, imaging probes, also known as cameras, are more hardware‐complex and also able to provide images but at the cost of an increased intervention time as displacing the camera has to be done slowly.

This review article begins with an introductory section to highlight the relevance of nuclear‐based probes and their components as well as the main differences between ionization‐ (semiconductor) and scintillation‐based probes. Then, the most significant performance parameters of the probe are reviewed (i.e., sensitivity, contrast, count rate capabilities, shielding, energy, and spatial resolution), as well as the different types of probes based on the target radiation nature, namely: gamma (γ), beta (β) (positron and electron), and Cherenkov. Various available intraoperative nuclear probes are finally compared in terms of performance to discuss the state‐of‐the‐art of nuclear medicine probes.

The manuscript concludes by discussing the ideal probe design and the aspects to be considered when selecting nuclear‐medicine probes.

Implementation of radioguided surgery in prostate cancer

With the development of new imaging technologies and tracers, the applications of radioguided surgery for prostate cancer are growing rapidly. The current paper aims to give an overview of the recent advances of radioguided surgery in the management of prostate cancer. We performed a literature search to give an overview of the current status of radioguided surgery for prostate cancer. Three modalities of radioguided surgery, the sentinel node procedure, Cerenkov Luminescence / beta-radio-guided surgery and radio-guided salvage surgery in recurrent prostate cancer, were reviewed in detail. Radioguided surgery for prostate cancer has shown promising value in the treatment of primary diagnosed prostate cancer and recurrent loco-regional lymph node positive prostate cancer. Advances have been made into minimal invasive (robot-assisted) laparoscopic surgery. The sentinel node procedure for prostate cancer has been further developed and is currently performed with high diagnostic sensitivity. Cerenkov luminescence imaging is a feasible and encouraging technique for intraoperative margin assessment in prostate cancer. Radioguided surgery in recurrent prostate cancer has shown to be feasible, yielding high sensitivity and specificity for detecting small local recurrences and metastases. With the availability of different new tracers, the road has been paved towards clinically feasible radioguided surgery for prostate cancer. Novel technologies now being developed for minimal invasive surgery are speeding up clinical research. Currently, none of the radioguided surgery techniques mentioned have been accepted as standard of care.

Beta radioguided surgery: towards routine implementation?

INTRODUCTION

In locally or locally advanced solid tumors, surgery still remains a fundamental treatment method. However, conservative resection is associated with high collateral damage and functional limitations of the patient. Furthermore, the presence of residual tumor tissue following conservative surgical treatment is currently a common cause of locally recurrent cancer or of distant metastases. Reliable intraoperative detection of small cancerous tissue would allow surgeons to selectively resect malignant areas: this task can be achieved by means of image-guided surgery, such as beta radioguided surgery (RGS).

EVIDENCE ACQUISITION

In this paper, a comprehensive review of beta RGS is given, starting from the physical principles that differentiate beta from gamma radiation, that has already its place in nuclear medicine current practice. Also, the recent clinical feasibility of using Cerenkov radiation is discussed.

EVIDENCE SYNTHESIS

Despite being first proposed several decades ago, only in the last years a remarkable interest in beta RGS has been observed, probably driven by the diffusion of PET radio tracers. Today several different approaches are being pursued to assess the effectiveness of such a technique, including both beta+ and beta- emitting radiopharmaceuticals.

CONCLUSIONS

Beta RGS shows some peculiarities that can present it as a very promising complementary technique to standard procedures. Good results are being obtained in several tests, both ex vivo and in vivo. This might however be the time to initiate the trials to demonstrate the real clinical value of these technologies with seemingly clear potential.

Contemporary update of SPECT tracers and novelties in radioguided surgery: a perspective based on urology

Recent technical advances and implementation of novel radiotracers have further increased the potential of radioguided surgery for a broad variety of malignancies. Indeed, the possibilities for future applications of novel radiotracers in diverse oncological strategies has become more promising than ever. This literature review aims to provide a contemporary update on a selected group of radiotracers and evaluates the usability of radioguided surgery and sentinel node procedures, focusing on most promising advances. For example, the impact of targeted radiotracers on prostate specific membrane antigen (PSMA), CD206 receptor-targeted agents (^99mTc-tilmanocept), and hybrid tracers adding fluorescence to radioguidance (ICG-^99mTc-nanocolloid) as well as targeting hypoxia-induced carbonic anhydrase IX (CAIX) will be covered. Furthermore, future outlooks on the implementation of gold nanoparticles (AuNP's), but also technical advances in improved radiotracer detection by hybrid gamma devices will be discussed.

First Ex Vivo Results of β--Radioguided Surgery in Small Intestine Neuroendocrine Tumors with 90Y-DOTATOC

Background: In neuroendocrine tumor (NET), complete surgery could better the prognosis. Radioguided surgery (RGS) with β^--radioisotopes is a novel approach focused on developing a new probe that, detecting electrons and operating with low background, provides a clearer delineation of the lesions with low radiation exposition for surgeons. As a first step to validate this procedure, ex vivo specimens of tumors expressing somatostatin receptors, as small intestine neuroendocrine tumor (SI-NET), were tested. Materials and Methods: SI-NET presents a high uptake of a beta-emitting radiotracer, ⁹⁰Y-DOTATOC. Five SI-NET patients were enrolled after performing a ⁶⁸Ga-DOTATOC positron emission tomography/computed tomography (CT) and a CT enterography; 24 h before surgery, they received 5 mCi of ⁹⁰Y-DOTATOC. Results: Surgery was performed as routine. Tumors and surrounding tissue were sectioned in different samples and examined ex vivo with the beta-detecting probe. All the tumor samples showed high counts of radioactivity that was up to a factor of 18 times higher than the corresponding cutoff value, with a sensitivity of 96% and a specificity of 100%. Conclusions: These first ex vivo RGS tests showed that this probe can discriminate very effectively between tumor and healthy tissues by the administration of low activities of ⁹⁰Y-DOTATOC, allowing more precise surgery.

Interventional nuclear medicine: a focus on radioguided intervention and surgery

Within interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of clinical indications (e.g. lymphatic mapping, local tumor demarcation and/or tumor receptor targeted applications) have been adopted into routine care. The clinical integration is further strengthened by technical innovations in chemistry and engineering that enhance the translational potential of radioguided procedures in iNM. Together, these features not only ensure ongoing expansion of iNM but also warrant a lasting clinical impact for the sub-discipline of radioguided surgery.

A DROP-IN beta probe for robot-assisted 68Ga-PSMA radioguided surgery: first ex vivo technology evaluation using prostate cancer specimens

BACKGROUND

Recently, a flexible DROP-IN gamma-probe was introduced for robot-assisted radioguided surgery, using traditional low-energy SPECT-isotopes. In parallel, a novel approach to achieve sensitive radioguidance using beta-emitting PET isotopes has been proposed. Integration of these two concepts would allow to exploit the use of PET tracers during robot-assisted tumor-receptor-targeted. In this study, we have engineered and validated the performance of a novel DROP-IN beta particle (DROP-INβ) detector.

METHODS

Seven prostate cancer patients with PSMA-PET positive tumors received an additional intraoperative injection of ~ 70 MBq 68Ga-PSMA-11, followed by robot-assisted prostatectomy and extended pelvic lymph node dissection. The surgical specimens from these procedures were used to validate the performance of our DROP-INβ probe prototype, which merged a scintillating detector with a housing optimized for a 12-mm trocar and prograsp instruments.

RESULTS

After optimization of the detector and probe housing via Monte Carlo simulations, the resulting DROP-INβ probe prototype was tested in a robotic setting. In the ex vivo setting, the probe-positioned by the robot-was able to identify 68Ga-PSMA-11 containing hot-spots in the surgical specimens: signal-to-background (S/B) was > 5 when pathology confirmed that the tumor was located < 1 mm below the specimen surface. 68Ga-PSMA-11 containing (and PET positive) lymph nodes, as found in two patients, were also confirmed with the DROP-INβ probe (S/B > 3). The rotational freedom of the DROP-IN design and the ability to manipulate the probe with the prograsp tool allowed the surgeon to perform autonomous beta-tracing.

CONCLUSIONS

This study demonstrates the feasibility of beta-radioguided surgery in a robotic context by means of a DROP-INβ detector. When translated to an in vivo setting in the future, this technique could provide a valuable tool in detecting tumor remnants on the prostate surface and in confirmation of PSMA-PET positive lymph nodes.

Extending the Hybrid Surgical Guidance Concept With Freehand Fluorescence Tomography

Within image-guided surgery, 'hybrid' guidance technologies have been used to integrate the complementary features of radioactive guidance and fluorescence guidance. Here, we explore how the generation of a novel freehand fluorescence (fhFluo) imaging approach complements freehand SPECT (fhSPECT) in a hybrid setup. Near-infrared optical tracking was used to register the position and the orientation of a hybrid opto-nuclear detection probe while recording its readings. Dedicated look-up table models were used for 3D reconstruction. In phantom and excised tissue settings (i.e., flat-surface human skin explants), fhSPECT and fhFluo were investigated for image resolution and in-tissue signal penetration. Finally, the combined potential of these freehand technologies was evaluated on prostate and lymph node specimens of prostate cancer patients receiving prostatectomy and sentinel lymph node dissection (tracers: indocyanine green (ICG) +^99m Tc-nanocolloid or ICG-^99mTc-nanocolloid). After hardware and software integration, the hybrid setup created 3D nuclear and fluorescence tomography scans. The imaging resolution of fhFluo (1 mm) was superior to that of fhSPECT (6 mm). Fluorescence modalities were confined to a maximum depth of 0.5 cm, while nuclear modalities were usable at all evaluated depths (<2 cm). Both fhSPECT and fhFluo enabled augmented- and virtual-reality navigation toward segmented image hotspots, including relative hotspot quantification with an accuracy of 3.9% and 4.1%. Imaging in surgical specimens confirmed these trends (fhSPECT: in-depth detectability, low resolution, and fhFluo: superior resolution, superficial detectability). Overall, when radioactive and fluorescent tracer signatures are used, fhFluo has complementary value to fhSPECT. Combined the freehand technologies render a unique hybrid imaging and navigation modality.

Recent advances in nuclear and hybrid detection modalities for image-guided surgery

Introduction: Radioguided surgery is an ever-evolving part of nuclear medicine. In fact, this nuclear medicine sub-discipline actively bridges non-invasive molecular imaging with surgical care. Next to relying on the availability of radio- and bimodal-tracers, the success of radioguided surgery is for a large part dependent on the imaging modalities and imaging concepts available for the surgical setting. With this review, we have aimed to provide a comprehensive update of the most recent advances in the field. Areas covered: We have made an attempt to cover all aspects of radioguided surgery: 1) the use of radioisotopes that emit γ, β⁺, and/or β^- radiation, 2) hardware developments ranging from probes to 2D cameras and even the use of advanced 3D interventional imaging solutions, and 3) multiplexing solutions such as dual-isotope detection or combined radionuclear and optical detection. Expert opinion: Technical refinements in the field of radioguided surgery should continue to focus on supporting its implementation in the increasingly complex minimally invasive surgical setting, e.g. by accommodating robot-assisted laparoscopic surgery. In addition, hybrid concepts that integrate the use of radioisotopes with other image-guided surgery modalities such as fluorescence or ultrasound are likely to expand in the future.

Radioguided surgery with β radiation: a novel application with Ga68

Radio Guided Surgery is a technique helping the surgeon in the resection of tumors: a radiolabeled tracer is administered to the patient before surgery and then the surgeon evaluates the completeness of the resection with a handheld detector sensitive to emitted radiation. Established methods rely on γ emitting tracers coupled with γ detecting probes. The efficacy of this technique is however hindered by the high penetration of γ radiation, limiting its applicability to low background conditions. To overtake such limitations, a novel approach to RGS has been proposed, relying on β⁻ emitting isotopes together with a dedicated β probe. This technique has been proved to be effective in first ex-vivo trials. We discuss in this paper the possibility to extend its application cases to ⁶⁸Ga, a β⁺ emitting isotope widely used today in nuclear medicine. To this aim, a retrospective study on 45 prostatic cancer patients was performed, analysing their ⁶⁸Ga-PSMA PET images to asses if the molecule uptake is enough to apply this technique. Despite the expected variability both in terms of SUV (median 4.1, IQR 3.0–6.1) and TNR (median 9.4, IQR 5.2–14.6), the majority of cases have been found to be compatible with β-RGS with reasonable injected activity and probing time (5 s).

From interventionist imaging to intraoperative guidance: New perspectives by combining advanced tools and navigation with radio-guided surgery

The integration of medical imaging technologies into diagnostic and therapeutic approaches can provide a preoperative insight into both anatomical (e.g. using computed tomography, magnetic resonance imaging, or ultrasound), as well as functional aspects (e.g. using single photon emission computed tomography, positron emission tomography, lymphoscintigraphy, or optical imaging). Moreover, some imaging modalities are also used in an interventional setting (e.g. computed tomography, ultrasound, gamma or optical imaging) where they provide the surgeon with real-time information during the procedure. Various tools and approaches for image-guided navigation in cancer surgery are becoming feasible today. With the development of new tracers and portable imaging devices, these advances will reinforce the role of interventional molecular imaging.

Feasibility of beta-particle radioguided surgery for a variety of "nuclear medicine" radionuclides

PURPOSE

Beta-particle radioguided tumor resection may potentially overcome the limitations of conventional gamma-ray guided surgery by eliminating, or at least minimizing, the confounding effect of counts contributed by activity in adjacent normal tissues. The current study evaluates the clinical feasibility of this approach for a variety of radionuclides. Nowadays, the only β^- radioisotope suited to radioguided surgery is ⁹⁰Y. Here, we study the β^- probe prototype capability to different radionuclides chosen among those used in nuclear medicine.

METHODS

The counting efficiency of our probe prototype was evaluated for sources of electrons and photons of different energies. Such measurements were used to benchmark the Monte Carlo (MC) simulation of the probe behavior, especially the parameters related to the simulation of the optical photon propagation in the scintillation crystal. Then, the MC simulation was used to derive the signal and the background we would measure from a small tumor embedded in the patient body if one of the selected radionuclides is used.

RESULTS

Based on the criterion of detectability of a 0.1 ml tumor for a counting interval of 1 s and an administered activity of 3 MBq/kg, the current probe yields a detectable signal over a wide range of Standard Uptake Values (SUVs) and tumor-to-non-tumor activity-concentration ratios (TNRs) for ³¹Si, ³²P, ⁹⁷Zr, and ¹⁸⁸Re. Although efficient counting of ⁸³Br, ¹³³I, and ¹⁵³Sm proved somewhat more problematic, the foregoing criterion can be satisfied for these isotopes as well for sufficiently high SUVs and TNRs.

Multiplexed imaging for diagnosis and therapy

Complex molecular and metabolic phenotypes depict cancers as a constellation of different diseases with common themes. Precision imaging of such phenotypes requires flexible and tunable modalities capable of identifying phenotypic fingerprints by using a restricted number of parameters while ensuring sensitivity to dynamic biological regulation. Common phenotypes can be detected by in vivo imaging technologies, and effectively define the emerging standards for disease classification and patient stratification in radiology. However, for the imaging data to accurately represent a complex fingerprint, the individual imaging parameters need to be measured and analysed in relation to their wider spatial and molecular context. In this respect, targeted palettes of molecular imaging probes facilitate the detection of heterogeneity in oncogene-driven alterations and their response to treatment, and lead to the expansion of rational-design elements for the combination of imaging experiments. In this Review, we evaluate criteria for conducting multiplexed imaging, and discuss its opportunities for improving patient diagnosis and the monitoring of therapy.

Endoscopic detection of cancer with lensless radioluminescence imaging and machine vision

Complete removal of residual tumor tissue during surgical resection improves patient outcomes. However, it is often difficult for surgeons to delineate the tumor beyond its visible boundary. This has led to the development of intraoperative detectors that can image radiotracers accumulated within tumors, thus facilitating the removal of residual tumor tissue during surgical procedures. We introduce a beta imaging system that converts the beta radiation from the radiotracer into photons close to the decay origin through a CdWO₄ scintillator and does not use any optical elements. The signal is relayed onto an EMCCD chip through a wound imaging fiber. The sensitivity of the device allows imaging of activity down to 100 nCi and the system has a resolution of at least 500 μm with a field of view of 4.80 × 6.51 mm. Advances in handheld beta cameras have focused on hardware improvements, but we apply machine vision to the recorded images to extract more information. We automatically classify sample regions in human renal cancer tissue ex-vivo into tumor or benign tissue based on image features. Machine vision boosts the ability of our system to distinguish tumor from healthy tissue by a factor of 9 ± 3 and can be applied to other beta imaging probes.