Imaging

Diagnostic medical imaging

One of the domains in healthcare that has witnessed significant changes over the years is diagnostic medical imaging. With the introduction of new imaging modalities and image acquisition techniques, it became possible to non-invasively characterize tissues in vivo with high precision. These developments, together with the increased availability of imaging technology at lower cost prices per examination, resulted in a widespread adoption of medical imaging in almost any clinical workflow. Furthermore, the digital revolution in medical imaging inspired the development of digital innovations for extracting more and more quantitative information from medical images.

Medical imaging relies on a series of interconnected activities also known as the radiology value chain. The radiology value chain can be described in the following steps: (1) imaging request and patient scheduling, (2) image acquisition and reconstruction, and (3) image analysis and reporting. There are many technological innovations that support each step of the radiology value chain to make the acquisition of high-quality images as efficient and effective as possible. In the following sections, the role of the technical physician in diagnostic medical imaging will be further highlighted related to each step of the radiology value chain.

Imaging request and patient scheduling

The radiology value chain begins with patient referral and preparation, where physicians order imaging studies and patients are prepared accordingly. Such patient preparation ensures that optimal conditions for imaging are met. One of the primary contributions of the technical physician is educating and guiding referring physicians on the most appropriate imaging modalities and protocols, ensuring that each imaging request is tailored to the patient’s specific needs and clinical indications. This education is typically done together with radiologists and nuclear medicine physicians and helps to reduce unnecessary imaging and enhances the diagnostic yield of studies performed. The combination of the medical and technical expertise ensures a more effective communication about the possibilities and limitations of different imaging techniques. Furthermore, technical physicians are instrumental in implementing advanced technologies, such as software relying on artificial intelligence (AI), to improve scheduling efficiency and decision support. By integrating these software applications, they can streamline patient scheduling, predict and manage workflow bottlenecks, and ensure optimal utilization of imaging resources. This not only enhances operational efficiency but also minimizes patient wait times and improves overall patient experience.

Image acquisition and reconstruction

In image acquisition and reconstruction, technical physicians play a pivotal role in developing new imaging protocols and optimizing existing ones. The key role of technical physicians in optimizing procedures surrounding image acquisition and reconstruction is their ability to work in collaboration among radiologists, radiographers, nuclear medicine physicians, and medical physicists. By acting as intermediaries among these stakeholders, technical physicians facilitate effective communication and coordination, ensuring that imaging protocols meet the specific needs of each patient population. This multidisciplinary approach leads to the development of tailored protocols that maximize image quality and diagnostic utility. Technical physicians also focus on optimizing patient preparation schedules and automating various aspects of image acquisition, such as patient positioning, protocol selection, artifact correction, and quality control, leveraging technologies like AI to streamline these processes and reduce human error.

Image analysis and reporting

This step includes both visual assessment and advanced image analysis, where quantitative features such as size, shape, density, and texture of anatomical structures are measured and analyzed using sophisticated software tools. Such comprehensive analyses help to identify subtle abnormalities, staging diseases, and monitoring treatment responses, thereby providing useful insights that guide clinical decision-making.

Technical physicians can contribute to the interpretation of images and consequently to radiological reporting. Although most technical physicians do not engage in full-time reporting duties, after sufficient training technical physicians can enrich reports with relevant information and insights from their own knowledge, while at the same time gain deeper clinical insights into underlying theories and policies. This enhances their ability to engage effectively with medical specialists and identify potential improvements in clinical workflows.

For many clinical indications, the use of quantitative imaging information is essential for downstream patient management. This includes the measurement of different physical, physiological and biological properties of tissues and organs. However, appropriate image quantification is a complex and tedious process where usually different software packages are to be used. Due to the combined understanding of anatomy, imaging physics and software by the technical physician, they are able to oversee different factors influencing image quantification and estimate the accuracy of obtained results. Furthermore, with their understanding of advanced software, they can train radiographers, radiologists, nuclear medicine physicians, and medical physicists on the use of these tools, ensuring effective implementation and utilization.

In addition to utilization of software, technical physicians are also involved in the adoption of different types of digital innovations, such as the purchase and implementation of software packages and AI applications. Their expertise allows them to select appropriate software applications and AI technologies as well as validating their added value in a clinical scenario. They design and configure the necessary infrastructure to integrate software applications seamlessly into clinical workflows, by continuously re-evaluating and modifying processes to maximize the benefits of these innovations. Technical physicians conduct regular audits and quality control checks, ensuring that the highest standards are maintained. This ensures that these innovations are fully embedded in clinical practice, enhancing diagnostic accuracy and efficiency.

Case: Artificial intelligence tool for fracture detection

Accurate fracture detection is a critical aspect of emergency care, where timely diagnosis ensures appropriate treatment and improves patient outcomes. However, the fast-paced environment of emergency departments (EDs), combined with varying levels of expertise among clinicians and the complexity of certain cases, can lead to missed fractures. Recent advancements in artificial intelligence (AI) have introduced computer-assisted detection (CAD) systems as valuable tools to support clinicians, offering a reliable second opinion for interpreting radiographs.

Through deep learning, models are trained that can detect fractures in radiographs, providing outputs that classify each image as either fractured or not fractured. For images identified as fractured, most models generate a bounding box that localizes the predicted fracture. Current AI models for fracture detection achieve performance metrics such as area under the curve (AUC), sensitivity and specificity in the range of 90% to 95%, demonstrating their reliability across various fracture types and clinical scenarios, even in the presence of comorbid conditions such as arthritis and osteosarcoma. Figure 1 shows several clinical example cases and illustrates the capabilities and limitations of these AI systems.

Radiotherapy

Radiotherapy is a cancer treatment that uses high-energy radiation to kill cancer cells and shrink tumors. Over the past decades, advancements in radiotherapy have dramatically improved treatment accuracy and have reduced associated side effects. Technological developments continue at a high pace. However, it is crucial to consider the implications for the patient alongside these developments. The technical physician is ideally suited for work in radiotherapy. The technical physician can easily adapt in this dynamical environment, which combines innovative techniques, close patient interaction, and collaboration with physicians, physicists, and radiation therapists. In this section, the role of the technical physician in radiotherapy will be highlighted, particularly in treatment planning, dealing with motion, proton therapy, and hyperthermia.

Treatment planning

The goal of treatment planning in radiotherapy is to create a treatment plan that gives a high dose to the target while sparing healthy tissue surrounding the target. To achieve this balance, knowledge on the patient anatomy, tumor characteristics and technical possibilities is required. Treatment plans are therefore made with the input from a multidisciplinary team, including radiation oncologists, medical physicists, radiation therapists, and technical physicians. Treatment planning is a complex and time-consuming task and automation of this process is therefore desirable, especially in times of skilled staff shortages.

Technical physicians help to implement automated treatment planning algorithms to streamline and speed up the treatment planning process. These automated planning algorithms can rapidly generate high-quality treatment plans and reduce the number of manual changes. The technical physician’s role includes programming, validating, and clinical implementation of knowledge-based treatment planning models. In addition, technical physicians have the necessary expertise and clinical judgment to assess the quality and feasibility of the automatically generated treatment plans, to make necessary adjustments, and to monitor the entire treatment process in clinical practice.

Dealing with motion

Motion between fractions

The total dose that will be delivered to the tumor is divided into small doses, called fractions. Patients are therefore irradiated with multiple fractions over the course of days or weeks. In between these fractions, the patient’s anatomy may change, which might result in a different position of the tumor and that the treatment plan does not fit optimally. Conventionally, when radiotherapy technicians at the treatment machine see large anatomical changes on the daily imaging, the treatment plans will be adjusted before the next fraction(s). This is called offline adaptive radiotherapy. Over the last decade, online adaptive radiotherapy has emerged, in which a treatment plan can be optimized directly at the treatment machine. Offline adaptive radiotherapy demands quite some time from trained clinicians but should be performed fast, to have a new treatment plan ready at the next fraction(s) of the patient. Furthermore, online adaptive radiotherapy is a new workflow in radiotherapy that requires proper implementation.

Technical physicians work on strategies to automatically identify when offline treatment plan adaptation is necessary and to prevent offline treatment plan adaptations by making treatment plan libraries so that multiple treatment plans are available when anatomical changes occur. In online adaptive radiotherapy, the technical physician can approve optimized plans where normally both a radiation oncologist and a medical physicist are required. Together with radiation oncologists, technical physicians can train radiotherapy technicians to safely perform the new online adaptive workflow. The technical physician helps at the treatment machine if problems arise regarding tumor and healthy tissue delineation, treatment plan selection, or any software-related technical problems. Moreover, for new tumor sites and medically or technically challenging cases, technical physicians are always present at the treatment machine. Technical physicians are also actively exploring the application of online adaptive radiotherapy for other cancer types and leading its implementation in collaboration with a multidisciplinary team.

Clinical case of a locally advanced rectal carcinoma treated with online adaptive radiotherapy

A 70-year-old man presented with rectal bleeding and diagnosed with a distal rectum carcinoma (T3cN0Mx). The patient was treated with online adaptive radiotherapy combined with chemotherapy. Compared with the conventional treatment plan, online adaptive radiotherapy allowed a planning target volume (PTV) margin (which surrounds the tumor and accounts for motion and other uncertainties) reduction from 8 mm isotropic to 5 mm in the lateral and dorsal direction. Given a mean clinical target volume of 434 cc, this allowed for a reduction in PTV from 970 to 877 cc, thereby improving sparing of surrounding healthy tissue. As shown in Figure 1, the online adapted plan resulted in decreased bladder and bowel dose as compared to the conventional plan. Additionally, the online adaptive radiotherapy corrected for the substantial daily bowel movement of this patient. The technical physician was involved in the selection, preparation, and daily treatment by supervising the radiotherapy technicians to adjust the target volume. The understanding of both the clinical implications of decisions as well as the technical knowledge makes the technical physician suitable for this complex treatment. Eventually, this patient showed complete tumor regression on MRI (T1N0Mx), opting for a watch-and-wait approach regarding surgery, and no complications such as diarrhea from radiotherapy.

Motion during fractions

The delivery of a fraction, when the patient is treated on the treatment machine, can take up to 20 minutes. In this time, the patient and tumor can move. As a result, the dose cannot be delivered accurately. There are varying strategies to monitor, minimize, and adjust for motion. These motion management strategies, however, can be challenging as knowledge on margins, 4D imaging, gating, tracking, and breath-hold is required. Additionally, there are tumor sites with challenging motion patterns, such as respiratory and cardiac motion in the thoracic and abdominal regions.

Technical physicians can specialize in motion management strategies and are actively engaged in the clinical implementation of monitoring methods. Additionally, there is an increasing interest in novel techniques in which patients have to hold their breath or receive oxygen or respiratory support to control breathing. Technical physicians contribute to the safe application of these motion management strategies by investigating and evaluating the different technologies, analyzing patient-specific tumor motion, evaluating patient’s experiences, and implementing these techniques into clinical practice.

Proton therapy

Proton therapy is a relatively new radiotherapeutic technique in which protons instead of photons are used for radiotherapy. Protons have the unique ability to deliver a high dose to the tumor while minimizing the dose to surrounding healthy tissue. However, protons are more sensitive to changes in the patient’s anatomy than photons. It is therefore most important to carefully prepare and monitor proton therapy treatment. Numerous studies have been initiated to implement proton therapy and to compare this technique with photon therapy, as proton therapy is more expensive.

The technical physician can prepare the complex proton therapy treatment, as discussed in the section ‘Treatment planning’. Secondly, technical physicians can identify the impact of anatomical variation on the accuracy of the proton therapy and can assist at the treatment machine to identify when treatment plans should be adapted. By understanding both the clinical and technical aspects of the treatment, the technical physician can facilitate the implementation of proton therapy for new tumor types, such as cervical and liver cancer. Lastly, technical physicians can create models that predict the risk of side effects for an individual patient and therefore identify patients that benefit most from the more expensive proton therapy.

Hyperthermia

Hyperthermia is a treatment modality for cancer and is often used in conjunction with radiotherapy and chemotherapy. The goal of hyperthermia is to increase the temperature in the tumor for one hour, which leads to increased tissue oxygenation and thereby enhances the effect of radiotherapy and chemotherapy. It also stimulates the immune system and temporarily inhibits DNA repair pathways, so that tumors are more effectively treated. For instance recurrent breast cancer, cervical cancer, and non-muscle invasive bladder cancer are treated with hyperthermia. Several methods are clinically accepted to induce hyperthermia in tumors and selecting the best suiting method can be challenging. Additionally, treatment success relies on controlling temperatures, with low temperatures decreasing the treatment effectiveness and high temperatures causing damage to healthy tissue and patient discomfort.

Depending on the tumor location and size the technical physician will decide which technique is best for the patient. The technical physician can place interstitial temperature probes in the tumor or surrounding tissue to monitor the temperature and is responsible for achieving the most optimal temperatures by preparing a personalized treatment plan, continually optimizing settings during treatment, and training staff. The technical physician can contribute to future technological developments, including the development of devices to achieve homogeneously high tumor temperatures, improved non-invasive temperature monitoring, and optimized treatment planning. Another interesting field of research for the technical physician is to combine hyperthermia with immunotherapy and targeted therapies. Finally, the technical physician plays a key role in patient selection and identification of new treatment (combinations) using both clinical and technical knowledge.

Nuclear medicine therapy

Nuclear medicine uses radioactive tracers (radiopharmaceuticals) to assess body functions and to diagnose and treat diseases. Like radiotherapy, nuclear medicine therapy highly depends on imaging. Not only for the diagnosis and treatment selection prior to starting treatment, but also for pretreatment dosimetry and posttreatment effect monitoring. Therefore, technical physicians can play important roles in this technologically advanced and multidisciplinary field.

Targeted radionuclide therapy

Nuclear medicine therapy, also known as targeted radionuclide therapy (TRT), has gained increasing interest regarding cancer treatment in patients presenting with advanced stages of the disease who are not eligible for conventional therapies such as surgery, chemotherapy, and radiotherapy. TRT uses radiolabeled cancer cell-specific molecules to deliver a cytotoxic dose of radiation to the tumor. It can personalize treatment of cancer, because both the cell-specific molecule as well as the radionuclide can be tailored to the individual patient.

Currently, the guidelines for TRT prescribe a standard “one-size-fits-all” treatment approach. Additionally, TRT is mostly applied in late and advanced disease stages but may also prove effective earlier in the patient care pathway.

Technical physicians can play an important role in optimization of TRT treatments, for example using advanced methods to personalize the dose delivered to the target lesion. In order to do so, technical physicians can help in the selection of patients that could qualify for TRT, inform and prepare these patients during their hospital visits, prepare the personalized dose plan, and guide the treatment. In addition, technical physicians are well equipped to evaluate treatment effects, for example using nuclear imaging and post-therapeutic dosimetry.

Selective internal radiation therapy (SIRT)

For patients with liver malignancies who are not eligible for surgical treatments, a minimally invasive treatment called SIRT is available. During this treatment, an interventional radiologist places a catheter in the hepatic artery after which radioactive microspheres with holmium-166 or yttrium-90 are administered, which get stuck in the microvasculature of the liver and irradiate the surrounding cells by means of β-radiation. The SIRT procedure consists of several consecutive steps involving the patient selection, scout procedure, pre-therapy assessment, radioembolization procedure, and post-therapy verification. Dosimetry can be performed as part of the pre-therapy assessment as well as the post-therapy verification. Imaging is an essential part in the workflow of this therapy. When placing the catheter (CT), but also for therapy planning and evaluation (SPECT/PET). An effective high tumor dose and a limited dose to the healthy liver tissue is crucial for the outcome of the patient.

The entire SIRT procedure is performed in a multi-disciplinary team involving physicians, radiographers, radiopharmacists, medical physicists, and technical physicians. The technical physicians form a synergistic role within this multidisciplinary team mainly between the nuclear medicine physician and medical physicist, contributing with specific expertise in all consecutive steps of the SIRT workflow, from the administration of the radioactive scout and therapy doses to the creation and evaluation of a personalized dose plan. SIRT continues to develop in order to work towards the optimal outcome for each individual patient. Technical physicians can bring together the needed expertise to improve and implement personalized radioembolization.

MRI dosimetry is an important tool for this treatment. The patient lies in the MRI during the administration of holmium-166 microspheres, and a holmium-sensitive MRI can be made at any desired moment to map the dose distribution. Based on this MRI dosimetry, the dose administration is determined during the procedure in order to achieve the most optimal dose distribution. This is currently used in a research setting, where insight into MRI acquisition, the creation of MRI dosimetry and the consequences of absorbed dose for the individual patient are important.

Radiopharmacy

Introduction

Nuclear medicine imaging- and therapy would not be possible without radiopharmaceuticals.

Identify the gap

The development and implementation of the production of new radiopharmaceuticals requires knowledge on the developments in the clinical field, radiopharmaceutical chemistry, regulations on radiation safety and protection, pharmaceutical legislation, and complex equipment.

Role for the technical physician

In order for a radiopharmaceutical to be introduced into the clinic, many steps need to be performed, which can be summarized as follows: (1) identification of the most suitable pharmaceutical and radionuclide for the clinical question, (2) assessment of pharmaceutical- and radiation safety considerations, (3) acquisition of suitable starting materials, (4) optimization of labeling parameters, (5) automation of the labeling with a labeling robot, (6) development and validation of quality control procedures, (7) validation of the labeling, (8) training of staff and introduction into the clinic. Although this entire process is done within the radiopharmacy, many technical aspects come into play, such as calculation of radiation exposure of staff, calibration of equipment for each radionuclide, and programming of a labeling robot.

An excellent example of the integration of technology and pharmacy is the use of HPLC (used for separation of components in a mixture) coupled to a radiodetector. This requires knowledge of the chemicals and separation processes (liquid and solid phases), but also knowledge on the photomultiplier tube and collimator in the radiodetector and its sensitivity, linear range, and dead time.

Industry

Technical physicians in industry play an integral role in the journey from a product idea to its market launch. Their in-depth understanding of medical technology and the integration into the medical field enables them to navigate the process of bringing innovative products into the healthcare environment. In industry, technical physicians often work closely with healthcare institutions, start-ups, and established medical technology companies to align cutting-edge imaging technologies with strategic objectives.

For example, technical physicians in industry are responsible for developing comprehensive clinical strategies, clinical evaluation plans and reports. They set up clinical investigations to validate new products prior to launch, carefully considering the correct claims to make and the scope and scale of studies required to substantiate those claims. This thorough process greatly enhances the product’s credibility and success in the market.

The strategic insight of technical physicians facilitates collaborations between healthcare institutions and, for example, technology start-ups. They use their in-depth knowledge of hospital workflows and clinical environments to improve the development of new technologies with (practical) user insights. By involving end-users in the design process, using frameworks such as Voice of the Customer, and understanding how the product will be used in clinical practice, they guide companies in balancing technological innovation with realistic application. This ensures that the solutions developed are not only groundbreaking, but also practical and easily to adopt.

In addition, technical physicians recognize the differences between academic research (with prototypes) and bringing a product to the clinical market. They help companies navigate through complex medical regulations, such as the Medical Device Directive (MDR), to ensure that products meet stringent safety standards, and receive the necessary approvals. By translating clinical needs into clear product requirements and regulatory strategies, they enable companies to operate more smoothly in the healthcare market.

Technical physicians are key players in strategic decision-making. They analyze clinical data and evaluate emerging technologies, to help companies identify opportunities and threats in the healthcare market. By keeping an eye on trends, they can advise companies on where to invest in research and development. They may oversee the integration of advanced imaging systems into diagnostic workflows or advise healthcare professionals on their use. Their multidisciplinary knowledge enables them to translate complex technical concepts into practical business strategies.

Technical physicians in industry, not limited to those who once specialized in medical imaging, work in a variety of roles across the medical technology industry, including clinical scientist, clinical expert, clinical consultant, project manager medical device development, medical affairs manager, clinical evaluation specialist and program officer. Their expertise enables them to work effectively as both independent experts and in-house specialists.