Medical imaging and nuclear medicine: a Lancet Oncology Commission

Dynamic nanoassembly-based drug delivery systems on the horizon

Self-assembly in nature creates matter with complex structures and unpredictable designs; disordered building blocks spontaneously organize into ordered structures to achieve specific functions. Self-assembly begins to play an important role in the design of advanced drug delivery as well. Though, the behavior of 'dynamic nanoassembly-based drug delivery systems' (DNDDS) in biological media and cells remains poorly understood, while this is highly critical for controlling spatiotemporal drug release from DNDDS in vivo. To deepen the understanding of tailor-made DNDDS, this contribution in the Oration - New Horizons section of the Journal of controlled Release aims to highlight nature-inspired designs, construction principles, and controllable functionalities of DNDDS and how they are triggered by endogenous and exogenous stimuli. Furthermore, biomedical applications of tailor-made DNDDS for accurate diagnosis and precise treatment of diseases, including tumors, neurological diseases, injuries and infections are discussed. Finally, current challenges and future perspectives of DNDDS are briefly outlined.

A Predictive Clinical-Radiomics Nomogram for Survival Prediction of Glioblastoma Using MRI

Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adult patients with a median survival of around one year. Prediction of survival outcomes in GBM patients could represent a huge step in treatment personalization. The objective of this study was to develop machine learning (ML) algorithms for survival prediction of GBM patient. We identified a radiomic signature on a training-set composed of data from the 2019 BraTS challenge (210 patients) from MRI retrieved at diagnosis. Then, using this signature along with the age of the patients for training classification models, we obtained on test-sets AUCs of 0.85, 0.74 and 0.58 (0.92, 0.88 and 0.75 on the training-sets) for survival at 9-, 12- and 15-months, respectively. This signature was then validated on an independent cohort of 116 GBM patients with confirmed disease relapse for the prediction of patients surviving less or more than the median OS of 22 months. Our model insured an AUC of 0.71 (0.65 on train). The Kaplan–Meier method showed significant OS difference between groups (log-rank p = 0.05). These results suggest that radiomic signatures may improve survival outcome predictions in GBM thus creating a solid clinical tool for tailoring therapy in this population.

Salvage therapy for prostate cancer after radical prostatectomy

More than 40% of men with intermediate-risk or high-risk prostate cancer will experience a biochemical recurrence after radical prostatectomy. Clinical guidelines for the management of these patients largely focus on the use of salvage radiotherapy with or without systemic therapy. However, not all patients with biochemical recurrence will go on to develop metastases or die from their disease. The optimal pre-salvage therapy investigational workup for patients who experience biochemical recurrence should, therefore, include novel techniques such as PET imaging and genomic analysis of radical prostatectomy specimen tissue, as well as consideration of more traditional clinical variables such as PSA value, PSA kinetics, Gleason score and pathological stage of disease. In patients without metastatic disease, the only known curative intervention is salvage radiotherapy but, given the therapeutic burden of this treatment, importance must be placed on accurate timing of treatment, radiation dose, fractionation and field size. Systemic therapy also has a role in the salvage setting, both concurrently with radiotherapy and as salvage monotherapy.

Estimating Catchment Populations of Global Health Radiology Outreach Using Geographic Information Systems Analysis

PURPOSE

The purpose of this study was to design, develop, and test geographic information systems (GIS) analytic methods for quantifying and characterizing catchment populations across all sites served by a radiology global health organization.

METHODS

The analysis included populations served by 78 low-resource medical facilities in 32 countries partnered with radiology nonprofit organization, RAD-AID International. Three constraints were used to approximate patient catchment areas: (1) 1-hour driving time, (2) 1-hour walking time, and (3) 10-mile circular radius. GIS calculated populations within each constraint using publicly available geospatial input databases, including a global digital elevation model, population and land cover data, and road locations from OpenStreetMap. Demographic and health data from the World Health Organization were incorporated to provide further characteristics of covered populations.

RESULTS

The total populations served by all RAD-AID sites as measured by driving time, walking time, and 10-mile radius were 189,241,193 (47.8% female), 26,190,117 (48.7% female), and 110,884,095 (48.1% female), respectively. For individual locations, median population within 1-hour driving time was 1,795,977 (range: 8,742-30,630,800), with an average life expectancy of 68.4 ± 5.8 years. Median child mortality before age 5 was 3.8% (range: 0.9%-8.3%), and median prevalence of human immunodeficiency virus infection was 3.1% (range: 0.7%-10.9%).

CONCLUSION

In this study, GIS provided a robust multisite analysis for estimating the potential global population reached by an international radiology outreach organization with targeted individual site measurements. Given heightened needs to accurately characterize global outreach populations, this GIS-based approach may be useful for analysis, outreach planning, and resource allocation among global health organizations.

Medical Imaging: The Missing Element of National Health Plans

Purpose: Radiology global outreach programs have increased in recent years but progressed more slowly than other specialties. Establishing radiology services is increasingly recognized as a priority in resource-limited settings. Myanmar has a tremendous disease burden that is treatable with interventional radiology (IR) techniques, and aims to grow and effectively integrate this service into its public healthcare sector. Through collaborations between Asia Pacific Society of Cardiovascular and Interventional Radiology (APSCVIR) and Myanmar Radiological Society (MRS), the field of IR has grown exponentially over recent years. This study aims to provide a Myanmar national IR report on the current trends and future challenges. Methods and materials: Descriptive variables across five domains (facility and equipment, workforce, supplies, infrastructure, and casemix) from the four public sector hospitals with IR capability were obtained between 2016-2019. The four hospitals were Yangon General Hospital (YGH), Yangon Specialty Hospital (YSH), Mandalay General Hospital (MGH), and Defense Services General Hospital (DSGH). Data were analyzed to demonstrate progress in IR and the differing casemix. Results: There are currently four IR-capable hospitals and nine interventional radiologists across Myanmar’s public healthcare sector. IR case volumes tripled from 514 cases in 2016 to more than 1,500 cases in 2019. The three most common procedures performed were trans-arterial chemoembolization (TACE, 63%), bronchial arterial embolization (BAE, 7.7%), and drainages (7.7%). Significant challenges to the growth and adoption of IR services span the domains of infrastructure, equipment and supplies, workforce, and IR awareness, among other clinical specialties. Conclusion: Myanmar’s healthcare priorities, coupled with international radiological outreach programs, have led to rapid growth of IR. The exponential growth in case volumes is promising for Myanmar and other developing countries. But to widen the scope of practice and integrate the service within local clinical workflows, a holistic effort that addresses multiple domains is needed in the future.

Optimizing integrated imaging service delivery by tier in low-resource health systems

Access to imaging diagnostics has been shown to result in accurate treatment, management, and optimal outcomes. Particularly in low-income and low-middle-income countries (LICs, LMICs), access is limited due to a lack of adequate resources. To achieve Sustainable Development Goal (SDG) 3, access to imaging services is critical at every tier of the health system. Optimizing imaging services in low-resource settings is best accomplished by prescriptive, integrated, and coordinated tiered service delivery that takes contextual factors into consideration. To our knowledge, this is the first recommendation for optimized, specific imaging care delivery by tier. A model for tier-based essential imaging services informs and guides policymakers as they set priorities and make budgetary decisions. In this paper, we recommend a framework for tiered imaging services essential to reduce the global burden of disease and attain universal health coverage (UHC). A lack of access to basic imaging services, even at the lowest tier of the health system, can no longer be justified by cost. Worldwide, affordable modalities of modern ultrasound and X-ray are becoming an accessible mainstay for the investigation of common conditions such as pregnancy, pneumonia, and fractures, and are safely performed and interpreted by qualified professionals. Finally, given the vast gap in access to imaging resources between LMICs and high-income countries (HICs), a scale-up of tiered imaging services in low-resource settings has the potential to reduce health disparities between, and within countries. As the access to appropriately integrated imaging services improves, UHC may be achieved.

The UK's contribution to cancer control in low-income and middle-income countries

Cancer mortality rates in low-income and middle-income countries (LMICs) are unacceptably high, requiring both collaborative global effort and in-country solutions. Experience has shown that working together in policy, clinical practice, education, training, and research leads to bidirectional benefit for LMICs and high-income countries. For over 60 years, the UK National Health Service has benefited from recruitment from LMICs, providing the UK with a rich diaspora of trained health-care professionals with links to LMICs. A grassroots drive to engage with partners in LMICs within the UK has grown from the National Health Service, UK academia, and other organisations. This drive has generated a model that rests on two structures: London Global Cancer Week and the UK Global Cancer Network, providing a high-value foundation for international discussion and collaboration. Starting with a historical perspective, this Series paper describes the UK landscape and offers a potential plan for the future UK's contribution to global cancer control. We also discuss the opportunities and challenges facing UK partnerships with LMICs in cancer control. The UK should harness the skills, insights, and political will from all partners to make real progress.

Responsible Radionuclide Cancer Care

The landscape of nuclear oncology is rapidly changing. The advent of molecular radionuclide theranostics, multidisciplinary tumor board decision making, artificial intelligence and radiomics interpretation of diagnostic imaging, evolution of pharmacogenomics prediction of tumor response, and regulatory requirements for prospective individual dosimetry are just some of the elements which are broadening the essence of physician responsibility. The burgeoning knowledge base essential for mastering the emergent technologies, and their profound effect on moral philosophic aspects of provision of cancer care, are challenging. The new relationship of the theranostic nuclear physician with respect to shared care of the individual patient, particularly with regard to transparency, accountability, and responsibility for targeted radionuclide diagnosis and therapy of cancer, will be explored in this update.

How to improve access to medical imaging in low- and middle-income countries ?

Imaging has become key in the care pathway of communicable and non-communicable diseases. Yet, there are major shortages of imaging equipment and workforce in low- and middle-income countries (LMICs). The International Society of Radiology outlines a plan to upscale the role of imaging in the global health agenda and proposes a holistic approach for LMICs. A generic model for organising imaging services in LMICs via regional Centres of Reference is presented. The need to better exploit IT and the potential of artificial intelligence for imaging, also in the LMIC setting, is highlighted. To implement the proposed plan, involvement of professional and international organisations is considered crucial. The establishment of an International Commission on Medical Imaging under the umbrella of international organisations is suggested and collaboration with other diagnostic disciplines is encouraged to raise awareness of the importance to upscale diagnostics at large and to foster its integration into the care pathway globally.

Radiation protection perspective to recurrent medical imaging: what is known and what more is needed?

This review summarises the current knowledge about recurrent radiological imaging and associated cumulative doses to patients. The recent conservative estimates are for around 0.9 million patients globally who cumulate radiation doses above 100 mSv, where evidence exists for cancer risk elevation. Around one in five is estimated to be under the age of 50. Recurrent imaging is used for managing various health conditions and chronic diseases such as malignancies, trauma, end-stage kidney disease, cardiovascular diseases, Crohn's disease, urolithiasis, cystic pulmonary disease. More studies are needed from different parts of the world to understand the magnitude and appropriateness. The analysis identified areas of future work to improve radiation protection of individuals who are submitted to frequent imaging. These include access to dose saving imaging technologies; improved imaging strategies and appropriateness process; specific optimisation tailored to the clinical condition and patient habitus; wider utilisation of the automatic exposure monitoring systems with an integrated option for individual exposure tracking in standardised patient-specific risk metrics; improved training and communication. The integration of the clinical and exposure history data will support improved knowledge about radiation risks from low doses and individual radiosensitivity. The radiation protection framework will need to respond to the challenge of recurrent imaging and high individual doses. The radiation protection perspective complements the clinical perspective, and the risk to benefit analysis must account holistically for all incidental and long-term benefits and risks for patients, their clinical history and specific needs. This is a step toward the patient-centric health care.

PET Molecular Imaging: A Holistic Review of Current Practice and Emerging Perspectives for Diagnosis, Therapeutic Evaluation and Prognosis in Clinical Oncology

PET/CT molecular imaging has been imposed in clinical oncological practice over the past 20 years, driven by its two well-grounded foundations: quantification and radiolabeled molecular probe vectorization. From basic visual interpretation to more sophisticated full kinetic modeling, PET technology provides a unique opportunity to characterize various biological processes with different levels of analysis. In clinical practice, many efforts have been made during the last two decades to standardize image analyses at the international level, but advanced metrics are still under use in practice. In parallel, the integration of PET imaging with radionuclide therapy, also known as radiolabeled theranostics, has paved the way towards highly sensitive radionuclide-based precision medicine, with major breakthroughs emerging in neuroendocrine tumors and prostate cancer. PET imaging of tumor immunity and beyond is also emerging, emphasizing the unique capabilities of PET molecular imaging to constantly adapt to emerging oncological challenges. However, these new horizons face the growing complexity of multidimensional data. In the era of precision medicine, statistical and computer sciences are currently revolutionizing image-based decision making, paving the way for more holistic cancer molecular imaging analyses at the whole-body level.