Dedicated Breast Gamma Camera Imaging and Breast PET: Current Status and Future Directions

Breast Imaging: what women & healthcare professionals need to know

Women in Radiology should be aware of the importance of early detection of breast cancer, the most common cancer in women. This knowledge is essential to advocate for high quality breast imaging for women, including themselves and their patients. The imaging modalities used in breast imaging have dramatically changed the way in which breast cancer may be diagnosed, and their use affects the stage at which it is diagnosed. Breast cancer may be screen-detected, either with mammography, digital breast tomosynthesis, breast ultrasound, breast MRI or contrast-enhanced mammography, and is typically diagnosed at stage 1. Incidental detection with Chest CT, abdominal CT or MRI or by PET CT may also lead to a diagnosis of breast cancer. When detected because of symptoms in women who have not undergone routine screening or as an interval cancer in women after a normal screen typically because of the masking effect of dense breast tissue, breast cancer is typically diagnosed at a more advanced stage, stage IIA or greater. A review of the imaging modalities currently used to diagnose breast cancer is provided and includes the advantages and limitations of each modality and the ways to optimize the imaging quality for detection of breast cancer. Up-to-date recommendations aimed to minimize the harms of delayed diagnosis of breast cancer are summarized to improve the health of women in Radiology and their patients.

Current Concepts in Molecular Breast Imaging

Molecular breast imaging (MBI) is a functional imaging modality that utilizes technetium 99m sestamibi radiotracer uptake to evaluate the biology of breast tumors. Molecular breast imaging can be a useful tool for supplemental screening of women with dense breasts, for breast cancer diagnosis and staging, and for evaluation of treatment response in patients with breast cancer undergoing neoadjuvant systemic therapy. In addition, MBI is useful in problem-solving when mammography and US imaging are insufficient to arrive at a definite diagnosis and for patients who cannot undergo breast MRI. Based on the BI-RADS lexicon, a standardized lexicon has been developed to aid radiologists in MBI reporting. In this article, we review MBI equipment, procedures, and lexicon; clinical indications for MBI; and the radiation dose associated with MBI.

Breast cancer epidemiology, diagnostic barriers, and contemporary trends in breast nanotheranostics and mechanisms of targeting

INTRODUCTION

Breast cancer is one of the main causes of mortality in women globally. Early and accurate diagnosis represents a milestone in cancer management. Several breast cancer diagnostic agents are available. Many chemotherapeutic agents in conventional dosage forms are approved; nevertheless, they lack cancer cell specificity, resulting in improper treatment and undesirable side effects. Recently, nanotheranostics has emerged as a new paradigm to achieve safe and effective cancer diagnosis and management.

AREA COVERED

This review provides insight into breast cancer epidemiology, barriers hindering the early diagnosis, and effective delivery of chemotherapeutics. Also, conventional diagnostic agents and recent nanotheranostic platforms have been used in breast cancer. In addition, mechanisms of cancer cell targeting and nano-carrier surface functionalization as an effective approach for chemotherapeutic targeting were reviewed along with future perspectives.

EXPERT OPINION

We proposed that modified nano-carriers may provide an efficacious approach for breast cancer drug targeting. These nanotheranostics need more clinical evaluations to confirm their efficacy in cancer management. In addition, we recommend the use of artificial intelligence (AI) as a promising approach for early and efficient assessment of breast lesions. AI allows better interpretation and analysis of nanotheranostic data, which minimizes misdiagnosis and avoids the belated intervention of health care providers.

Case report: Possible role of low-dose PEM for avoiding unneeded procedures associated with false-positive or equivocal breast MRI results

Contrast-enhanced breast magnetic resonance imaging (MRI) is currently recommended as a screening tool for high-risk women and has been advocated for women with radiologically dense breast tissue. While breast MRI is acknowledged for its high sensitivity (with an exception for lower-grade ductal carcinoma in situ (DCIS) where emerging techniques like diffusion-weighted imaging offer improvement), its limitations include sensitivity to hormonal changes and a relatively high false-positive rate, potentially leading to overdiagnosis, increased imaging uncertainty, and unnecessary biopsies. These factors can exacerbate patient anxiety and impose additional costs. Molecular imaging with breast-targeted Positron Emission Tomography (PET) has shown the capability to detect malignancy independent of breast density and hormonal changes. Furthermore, breast-targeted PET has shown higher specificity when compared with MRI. However, traditional PET technology is associated with high radiation dose, which can limit its widespread use particularly in repeated studies or for undiagnosed patients. In this case report, we present a clinical application of low-dose breast imaging utilizing a breast-targeted PET camera (Radialis PET imager, Radialis Inc). The case involves a 33-year-old female patient who had multiple enhanced lesions detected on breast MRI after surgical removal of a malignant phyllodes tumor from the right breast. A benign core biopsy was obtained from the largest lesion seen in the left breast. One month after the MRI, 18F-fluorodeoxyglucose (18F-FDG) PET imaging session was performed using the Radialis PET Imager. Although the Radialis PET Imager has proven high count sensitivity and the capability to detect breast lesions with low metabolic activity (at a dose similar to mammography), no areas of increased 18F-FDG uptake were visualized in this particular case. The patient underwent a right-sided nipple-sparing mastectomy and left-sided lumpectomy, with bilateral reconstruction. The excised left breast tissue was completely benign, as suggested by both core biopsy and the PET results. The case presented highlights a promising clinical application of low-dose breast-targeted PET imaging to mitigate the uncertainty associated with MRI while keeping radiation doses within the safe range typically used in X-ray mammography.

Quarter-Century Transformation of Oncology: Positron Emission Tomography for Patients with Breast Cancer

PET radiotracers have become indispensable in the care of patients with breast cancer. 18F-fluorodeoxyglucose has become the preferred method of many oncologists for systemic staging of breast cancer at initial diagnosis, detecting recurrent disease, and for measuring treatment response after therapy. 18F-Sodium Fluoride is valuable for detection of osseous metastases. 18F-fluoroestradiol is now FDA-approved with multiple appropriate clinical uses. There are multiple PET radiotracers in clinical trials, which may add utility of PET imaging for patients with breast cancer in the future. This article will describe the advances during the last quarter century in PET for patients with breast cancer.

Mammography with deep learning for breast cancer detection

X-ray mammography is currently considered the golden standard method for breast cancer screening, however, it has limitations in terms of sensitivity and specificity. With the rapid advancements in deep learning techniques, it is possible to customize mammography for each patient, providing more accurate information for risk assessment, prognosis, and treatment planning. This paper aims to study the recent achievements of deep learning-based mammography for breast cancer detection and classification. This review paper highlights the potential of deep learning-assisted X-ray mammography in improving the accuracy of breast cancer screening. While the potential benefits are clear, it is essential to address the challenges associated with implementing this technology in clinical settings. Future research should focus on refining deep learning algorithms, ensuring data privacy, improving model interpretability, and establishing generalizability to successfully integrate deep learning-assisted mammography into routine breast cancer screening programs. It is hoped that the research findings will assist investigators, engineers, and clinicians in developing more effective breast imaging tools that provide accurate diagnosis, sensitivity, and specificity for breast cancer.

Clinical Applications of Dedicated Breast Positron Emission Tomography

Breast-specific positron imaging systems provide higher sensitivity than whole-body PET for breast cancer detection. The clinical applications for breast-specific positron imaging are similar to breast MRI including preoperative local staging and neoadjuvant therapy response assessment. Breast-specific positron imaging may be an alternative for patients who cannot undergo breast MRI. Further research is needed in expanding the field-of-view for posterior breast lesions, increasing biopsy capability, and reducing radiation dose. Efforts are also necessary for developing appropriate use criteria, increasing availability, and advancing insurance coverage.

Role of Positron Emission Tomography/Computed Tomography in Epithelial Ovarian Cancer

Ovarian cancer (OC) is the most lethal gynecological malignancy with majority of cases diagnosed in advanced stages and associated with high morbidity and mortality. Positron emission tomography/computed tomography (PET/CT) has emerged as an integral part of the management of several nongynecological cancers. We used PubMed search engine using MeSH words "ovarian cancer" and "PET/CT" and reviewed the current status of PET/CT in epithelial OC. Its application related to ovarian tumor including adnexal mass evaluation, baseline staging, as a triaging tool for upfront surgery or neoadjuvant chemotherapy, for response assessment and prognostication, and for relapse detection and treatment planning has been highlighted. we highlight the current guidelines and newer upcoming PET modalities and radiotracers.

What radiolabeled FAPI pet can add in breast cancer? A systematic review from literature

To provide an overview of the current available data about FAPI PET in breast cancer patients, with a perspective point of view. A literature search for studies about FAPI PET in the last 5 years (from 2017 to January 2023) was carried out on MEDLINE databases, such as PubMed, EMBASE, Web of Science and Google Scholar using the following keywords: "PET" AND "FAPI" AND "Breast Cancer" AND "Fibroblast imaging". The Critical Appraisal Skills Program (CASP) checklist for diagnostic test studies was used for testing the quality of selected papers. 13 articles were selected, including 172 patients affected by breast cancer who underwent FAPI-based PET images. CASP checklist was used in 5/13 papers, demonstrating a general low quality. Different types of FAPI-based tracers were used. No difference in terms of FAPI uptake was reported based on the histopathological characteristics, such as immunohistochemistry and grading of breast cancer. FAPI demonstrated more lesions and yielded much higher tumor-to-background ratios than 2-[18F]FDG. Preliminary experiences with FAPI PET in breast cancer showed some advantages than the current available 2-[18F]FDG, although prospective trials are needed to further evaluate its diagnostic utility in clinical practice.

Deep learning for differentiating benign from malignant tumors on breast-specific gamma image

BACKGROUND

Breast diseases are a significant health threat for women. With the fast-growing BSGI data, it is becoming increasingly critical for physicians to accurately diagnose benign as well as malignant breast tumors.

OBJECTIVE

The purpose of this study is to diagnose benign and malignant breast tumors utilizing the deep learning model, with the input of breast-specific gamma imaging (BSGI).

METHODS

A benchmark dataset including 144 patients with benign tumors and 87 patients with malignant tumors was collected and divided into a training dataset and a test dataset according to the ratio of 8:2. The convolutional neural network ResNet18 was employed to develop a new deep learning model. The model proposed was compared with neural network and autoencoder models. Accuracy, specificity, sensitivity and ROC were used to evaluate the performance of different models.

RESULTS

The accuracy, specificity and sensitivity of the model proposed are 99.1%, 98.8% and 99.3% respectively, which achieves the best performance among all methods. Additionally, the Grad-CAM method is used to analyze the interpretability of the diagnostic results based on the deep learning model.

CONCLUSION

This study demonstrates that the proposed deep learning method could help physicians diagnose benign and malignant breast tumors quickly as well as reliably.

Prediction of pathological response after neoadjuvant chemotherapy using baseline FDG PET heterogeneity features in breast cancer

Complete pathological response to neoadjuvant systemic treatment (NAST) in some subtypes of breast cancer (BC) has been used as a surrogate of long-term outcome. The possibility of predicting BC pathological response to NAST based on the baseline 18F-Fluorodeoxyglucose positron emission tomography (FDG PET), without the need of an interim study, is a focus of recent discussion. This review summarises the characteristics and results of the available studies regarding the potential impact of heterogeneity features of the primary tumour burden on baseline FDG PET in predicting pathological response to NAST in BC patients. Literature search was conducted on PubMed database and relevant data from each selected study were collected. A total of 13 studies were eligible for inclusion, all of them published over the last 5 years. Eight out of 13 analysed studies indicated an association between FDG PET-based tumour uptake heterogeneity features and prediction of response to NAST. When features associated with predicting response to NAST were derived, these varied between studies. Therefore, definitive reproducible findings across series were difficult to establish. This lack of consensus may reflect the heterogeneity and low number of included series. The clinical relevance of this topic justifies further investigation about the predictive role of baseline FDG PET.

The role of medical physicists in clinical trials across Europe

INTRODUCTION

The roles and responsibilities of medical physicists (MPs) are growing together with the evolving science and technology. The complexity of today's clinical trials requires the skills and knowledge of MPs for their safe and efficient implementation. However, it is unclear to what extent the skillsets offered by MPs are being exploited in clinical trials across Europe.

METHODS

The EFOMP Working Group on the role of Medical Physics Experts in Clinical Trials has designed a survey that targeted all 36 current National Member Organisations, receiving a response from 31 countries. The survey included both quantitative and qualitative queries regarding the involvement of MPs in trial design, setup, and coordination, either as trial team members or principal investigators.

RESULTS

The extent of MPs involvement in clinical trials greatly varies across European countries. The results showed disparities between the roles played by MPs in trial design, conduct or data processing. Similarly, differences among the 31 European countries that responded to the survey were found regarding the existence of national bodies responsible for trials or the available training offered to MPs. The role of principal investigator or co-investigator was reported by 12 countries (39%), a sign of efficient collaboration with medical doctors in designing and implementing clinical studies.

CONCLUSION

Organisation of specific training courses and guideline development for clinical trial design and conduct would encourage the involvement of a larger number of MPs in all stages of trials across Europe, leading to a better standardisation of clinical practice.

Recent Development in Metallic Nanoparticles for Breast Cancer Therapy and Diagnosis

Metal-based nanoparticles are very promising for their applications in cancer diagnosis, drug delivery and therapy. Breast cancer is the major reason of death in woman especially in developed countries including EU and USA. Due to the heterogeneity of cancer cells, nanoparticles are effective as therapeutics and diagnostics. Anti-cancer therapy of breast tumors is challenging because of highly metastatic progression of the disease to brain, bone, lung, and liver. Magnetic nanoparticles are crucial for metastatic breast cancer detection and protection. This review comprehensively discusses the application of nanomaterials as breast cancer therapy, therapeutics, and diagnostics.

Simultaneous FAPI PET/MRI Targeting the Fibroblast-Activation Protein for Breast Cancer

Background Integrated PET/MRI is a promising modality for breast assessment. The most frequently used tracer, fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG), is applied for whole-body staging in advanced breast cancer but has limited accuracy in evaluating primary breast lesions. The fibroblast-activation protein (FAP) is abundantly expressed in invasive breast cancer. FAP-directed PET tracers have recently become available, but results in primary breast tumors remain lacking. Purpose To evaluate the use of FAP inhibitor (FAPI) breast PET/MRI in assessing breast lesions and of FAPI whole-body scanning for lymph node (LN) and distant staging using the ligand gallium 68 (⁶⁸Ga)-FAPI-46. Materials and Methods In women with histologically confirmed invasive breast cancer, all primary ⁶⁸Ga-FAPI-46 breast and whole-body PET/MRI and PET/CT examinations conducted at the authors' center between October 2019 and December 2020 were retrospectively analyzed. MRI lesion characteristics and standardized uptake values (SUVs) were quantified with dedicated software. Mann-Whitney U tests were used to compare tumor SUVs across different tumor types. The Pearson correlation coefficient was calculated between SUV and measures of MRI morphologic characteristics. Results Nineteen women (mean age, 49 years ± 9 [standard deviation]) were evaluated-18 to complement initial staging and one for restaging after therapy for distant metastases. Strong tracer accumulation was observed in all 18 untreated primary breast malignancies (mean maximum SUV [SUV_max] = 13.9 [range, 7.9-29.9]; median lesion diameter = 26 mm [range, 9-155 mm]), resulting in clear tumor delineation across different gradings, receptors, and histologic types. All preoperatively verified LN metastases in 13 women showed strong tracer accumulation (mean SUV_max= 12.2 [range, 3.3-22.4]; mean diameter = 21 mm [range, 14-35 mm]). Tracer uptake established or supported extra-axillary LN involvement in seven women and affected therapy decisions in three women. Conclusion This retrospective analysis indicates use of ⁶⁸Ga fibroblast-activation protein inhibitor tracers for breast cancer diagnosis and staging. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Mankoff and Sellmyer in this issue.

PET Imaging for Breast Cancer

Imaging plays an integral role in the clinical care of patients with breast cancer. This review article focuses on the use of PET imaging for breast cancer, highlighting the clinical indications and limitations of 2-deoxy-2-[¹⁸F]fluoro-d-glucose (FDG) PET/CT, the potential use of PET/MRI, and 16α-[¹⁸F]fluoroestradiol (FES), a newly approved radiopharmaceutical for estrogen receptor imaging.

Molecular Breast Imaging: A Scientific Review

Molecular breast imaging (MBI) is a nuclear medicine technique that has evolved considerably over the past two decades. Technical advances have allowed reductions in administered doses to the point that they are now acceptable for screening. The most common radiotracer used in MBI, 99mTc-sestamibi, has a long history of safe use. Biopsy capability has become available in recent years, with early clinical experience demonstrating technically successful biopsies of MBI-detected lesions. MBI has been shown to be an effective supplemental screening tool in women with dense breasts and is also utilized for breast cancer staging, assessment of response to neoadjuvant chemotherapy, problem solving, and as an alternative to breast MRI in women who have a contraindication to MRI. The degree of background parenchymal uptake on MBI shows promise as a tool for breast cancer risk stratification. Radiologist interpretation is guided by a validated MBI lexicon that mirrors the BI-RADS lexicon. With short interpretation times, a fast learning curve for radiologists, and a substantially lower cost than breast MRI, MBI provides many benefits in the practices in which it is utilized. This review will discuss the current state of MBI technology, clinical applications of MBI, MBI interpretation, radiation dose associated with MBI, and the future of MBI.

Current State of Breast Cancer Diagnosis, Treatment, and Theranostics

Breast cancer is one of the leading causes of cancer-related morbidity and mortality in women worldwide. Early diagnosis and effective treatment of all types of cancers are crucial for a positive prognosis. Patients with small tumor sizes at the time of their diagnosis have a significantly higher survival rate and a significantly reduced probability of the cancer being fatal. Therefore, many novel technologies are being developed for early detection of primary tumors, as well as distant metastases and recurrent disease, for effective breast cancer management. Theranostics has emerged as a new paradigm for the simultaneous diagnosis, imaging, and treatment of cancers. It has the potential to provide timely and improved patient care via personalized therapy. In nanotheranostics, cell-specific targeting moieties, imaging agents, and therapeutic agents can be embedded within a single formulation for effective treatment. In this review, we will highlight the different diagnosis techniques and treatment strategies for breast cancer management and explore recent advances in breast cancer theranostics. Our main focus will be to summarize recent trends and technologies in breast cancer diagnosis and treatment as reported in recent research papers and patents and discuss future perspectives for effective breast cancer therapy.

Application-specific nuclear medicalin vivoimaging devices

Nuclear medical imaging devices, such as those enabling photon emission imaging (gamma camera, single photon emission computed tomography, or positron emission imaging), that are typically used in today's clinics are optimized for assessing large portions of the human body, and are classified as whole-body imaging systems. These systems have known limitations for organ imaging, therefore application-specific devices have been designed, constructed and evaluated. These devices, given their compact nature and superior technical characteristics, such as their higher detection sensitivity and spatial resolution for organ imaging compared to whole-body imaging systems, have shown promise for niche applications. Several of these devices have further been integrated with complementary anatomical imaging devices. The objectives of this review article are to (1) provide an overview of such application-specific nuclear imaging devices that were developed over the past two decades (in the twenty-first century), with emphasis on brain, cardiac, breast, and prostate imaging; and (2) discuss the rationale, advantages and challenges associated with the translation of these devices for routine clinical imaging. Finally, a perspective on the future prospects for application-specific devices is provided, which is that sustained effort is required both to overcome design limitations which impact their utility (where these exist) and to collect the data required to define their clinical value.

[99mTc]Tc-Sestamibi Bioaccumulation Can Induce Apoptosis in Breast Cancer Cells: Molecular and Clinical Perspectives

The aim of this study was to investigate the possible role of [99mTc]Tc-Sestamibi in the regulation of cancer cell proliferation and apoptosis. To this end, the in vivo values of [99mTc]Tc-Sestamibi uptake have been associated with the in-situ expression of both Ki67 and caspase-3. For in vitro investigations, BT-474 cells were incubated with three different concentrations of [99mTc]Tc-Sestamibi: 10 µg/mL, 1 µg/mL, and 0.1 µg/mL. Expression of caspase-3 and Ki67, as well as the ultrastructure of cancer cells, was evaluated at T0 and after 24, 48, 72, and 120 h after [99mTc]Tc-Sestamibi incubation. Ex vivo data strengthened the known association between sestamibi uptake and Ki67 expression. Linear regression analysis showed a significant association between sestamibi uptake and the number of apoptotic cells evaluated as caspase-3-positive breast cancer cells. As concerning the in vitro data, a significant decrease of the proliferation index was observed in breast cancer cells incubated with a high concentration of [99mTc]Tc-Sestamibi (10 µg/mL). Amazingly, a significant increase in caspase-3-positive cells in cultures incubated with 10 µg/mL [99mTc]Tc-Sestamibi was observed. This study suggested the possible role of sestamibi in the regulation of pathophysiological processes involved in breast cancer.

A layered single-side readout depth of interaction time-of-flight-PET detector

We are exploring a scintillator-based PET detector with potential of high sensitivity, depth of interaction (DOI) capability, and timing resolution, with single-side readout. Our design combines two previous concepts: (1) multiple scintillator arrays stacked with relative offset, yielding inherent DOI information, but good timing performance has not been demonstrated with conventional light sharing readout. (2) Single crystal array with one-to-one coupling to the photodetector, showing superior timing performance compared to its light sharing counterparts, but lacks DOI. The combination, where the first layer of a staggered design is coupled one-to-one to a photodetector array, may provide both DOI and timing resolution and this concept is here evaluated through light transport simulations. Results show that: (1) unpolished crystal pixels in the staggered configuration yield better performance across all metrics compared to polished pixels, regardless of readout scheme. (2) One-to-one readout of the first layer allows for accurate DOI extraction using a single threshold. The number of multi pixel photon counter (MPPC) pixels with signal amplitudes exceeding the threshold corresponds to the interaction layer. This approach was not possible with conventional light sharing readout. (3) With a threshold of 2 optical photons, the layered approach with one-to-one coupled first layer improves timing close to the MPPC compared to the conventional one-to-one coupling non-DOI detector, due to effectively reduced crystal thickness. Single detector timing resolution values of 91, 127, 151 and 164 ps were observed per layer in the 4-layer design, to be compared to 148 ps for the single array with one-to-one coupling. (4) For the layered design with light sharing readout, timing improves with increased MPPC pixel size due to higher signal per channel. In conclusion, the combination of straightforward DOI determination, good timing performance, and relatively simple design makes the proposed concept promising for DOI-Time-of-Flight PET detectors.

Modelling and Simulation of Compton Scatter Image Formation in Positron Emission Tomography

We present the comparative study of the analytical forward model and the statistical simulation of the Compton single scatter in the Positron Emission Tomography. The formula of the forward model has been obtained using the Single Scatter Simulation approximation under simplified assumptions and therefore we calculate scatter projections using independent Monte Carlo simulation mimicking the scatter physics. The numerical comparative study has been performed using a digital cylindrical phantom filled in with water and containing spherical sources of emission activity located at the central and several displaced positions. Good fits of the formula-based and statistically generated profiles of scatter projections are observed in the presented numerical results.

Advanced and futuristic approaches for breast cancer diagnosis

Background

Breast cancer is the most frequent cancer and one of the most common causes of death in women, impacting almost 2 million women each year. Tenacity or perseverance of breast cancer in women is very high these days with an extensive increasing rate of 3 to 5% every year. Along with hurdles faced during treatment of breast tumor, one of the crucial causes of delay in treatment is invasive and poor diagnostic techniques for breast cancer hence the early diagnosis of breast tumors will help us to improve its management and treatment in the initial stage.

Main body

Present review aims to explore diagnostic techniques for breast cancer that are currently being used, recent advancements that aids in prior detection and evaluation and are extensively focused on techniques that are going to be future of breast cancer detection with better efficiency and lesser pain to patients so that it helps to a physician to prevent delay in treatment of cancer. Here, we have discussed mammography and its advanced forms that are the need of current era, techniques involving radiation such as radionuclide methods, the potential of nanotechnology by using nanoparticle in breast cancer, and how the new inventions such as breath biopsy, and X-ray diffraction of hair can simply use as a prominent method in breast cancer early and easy detection tool.

Conclusion

It is observed significantly that advancement in detection techniques is helping in early diagnosis of breast cancer; however, we have to also focus on techniques that will improve the future of cancer diagnosis in like optical imaging and HER2 testing.

Novel Approaches to Screening for Breast Cancer

Screening for breast cancer reduces breast cancer-related mortality and earlier detection facilitates less aggressive treatment. Unfortunately, current screening modalities are imperfect, suffering from limited sensitivity and high false-positive rates. Novel techniques in the field of breast imaging may soon play a role in breast cancer screening: digital breast tomosynthesis, contrast material-enhanced spectral mammography, US (automated three-dimensional breast US, transmission tomography, elastography, optoacoustic imaging), MRI (abbreviated and ultrafast, diffusion-weighted imaging), and molecular breast imaging. Artificial intelligence and radiomics have the potential to further improve screening strategies. Furthermore, nonimaging-based screening tests such as liquid biopsy and breathing tests may transform the screening landscape. © RSNA, 2020 Online supplemental material is available for this article.

Breast-Specific Gamma Imaging with [99mTc]Tc-Sestamibi: An In Vivo Analysis for Early Identification of Breast Cancer Lesions Expressing Bone Biomarkers

The main purpose of this pilot investigation was to evaluate the possible relationship among [⁹⁹mTc]Tc-Sestamibi uptake, the presence of breast osteoblast-like cells, and the expression of molecules involved in bone metabolism, such as estrogen receptor, bone morphogenetic proteins-2, and PTX3. To this end, forty consecutive breast cancer patients who underwent both breast-specific gamma imaging with [^99mTc]Tc-Sestamibi and breast bioptic procedure were retrospectively enrolled. From each diagnostic paraffin block collected in the study, histological diagnosis, immunohistochemical investigations, and energy dispersive X-ray microanalysis were performed. Our data highlight the possible use of breast-specific gamma imaging with [⁹⁹mTc]Tc-Sestamibi for the early detection of breast cancer lesions expressing bone biomarkers in the presence of breast osteoblast-like cells. Specifically, we show a linear association among sestamibi uptake, the presence of breast osteoblast-like cells, and the expression of estrogen receptor, bone morphogenetics proteins-2, and PTX3. Notably, we also observed an increase of [⁹⁹mTc]Tc-Sestamibi in breast cancer lesions with magnesium-substituted hydroxyapatite. In conclusion, in this pilot study we evaluated data from the nuclear medicine unit and anatomic pathology department on breast cancer osteotropism, identifying a new possible interpretation of Breast Specific Gamma Imaging with [⁹⁹mTc]Tc-Sestamibi analysis.

99mTC-sestamibi breast imaging: Current status, new ideas and future perspectives

Here we proposed the most recent innovations in the use of Breast Specific Gamma Imaging with ⁹⁹mTc-sestamibi for the management of breast cancer patients. To this end, we reported the recent discoveries concerning: a) the implementation of both instrumental devices and software, b) the biological mechanisms involved in the ⁹⁹mTc-sestamibi uptake in breast cancer cells, c) the evaluation of Breast Specific Gamma Imaging with ⁹⁹mTc-sestamibi as predictive markers of metastatic diseases. In this last case, we also reported preliminary data about the capability of Breast Specific Gamma Imaging with ⁹⁹mTc-sestamibi to identify breast cancer lesions with high propensity to form bone metastatic lesions due to the presence of Breast Osteoblast-Like Cells.