The persistent threat of cancer necessitates the development of improved and more efficient therapeutic strategies that limit damage to healthy tissues. Targeted alpha therapy (TαT), a novel form of radioimmuno-therapy (RIT), utilizes a targeting vehicle, commonly antibodies, to deliver high-energy, but short-range, alpha-emitting particles specifically to cancer cells, thereby reducing toxicity to surrounding normal tissues. Although full-length antibodies are often employed as targeting vehicles for TαT, their high molecular weight and the presence of an Fc-region lead to a long blood half-life, increased bone marrow toxicity, and accumulation in other tissues such as the kidney, liver, and spleen. The discovery of single-domain antibodies (sdAbs), or nanobodies, naturally occurring in camelids and sharks, has introduced a novel antigen-specific vehicle for molecular imaging and TαT. Given that nanobodies are the smallest naturally occurring antigen-binding fragments, they exhibit shorter relative blood half-lives, enhanced tumor uptake, and equivalent or superior binding affinity and specificity. Nanobody technology could provide a viable solution for the off-target toxicity observed with full-length antibody-based TαT. Notably, the pharmacokinetic properties of nanobodies align better with the decay characteristics of many short-lived α-emitting radionuclides. This review aims to encapsulate recent advancements in the use of nanobodies as a vehicle for TαT.

Background: Seizures are common neurological events in children, with neuroimaging playing a crucial role in evaluating new-onset seizures. While magnetic resonance imaging (MRI) is often preferred over computed tomography (CT) for pediatric seizure imaging due to higher sensitivity and lack of ionizing radiation, practices regarding imaging protocols and sedation use vary. Currently, there are no published Canada-wide guidelines describing the practices for workup of pediatric seizures. Methods: A cross-sectional survey was conducted among radiologists at 16 Canadian tertiary pediatric centers to assess neuroimaging practices for children with new-onset seizures. The survey explored the presence and content of dedicated seizure MRI protocols, sedation use, and strategies to facilitate non-sedated MRI. Results: Fifteen centers (94%) responded. Only 2 (13%) reported using dedicated new-onset seizure protocols, while 10 (67%) used epilepsy-specific MRI protocols, and the others used different approaches, including variations of routine brain MRI. MRI sequences varied across institutions. Sedation use also varied, with a median sedation age range of 3 months to 6 years. Non-sedated MRI techniques such as feed-and-swaddle (93%) and natural sleep (27%) were commonly used for infants. Video goggles (67%) and child life specialist support (53%) were often used for older children. Only 2 institutions (13%) had fast MRI protocols, and virtual reality preparation was uncommon (13%). Conclusion: Considerable variability exists in MRI protocols and sedation practices across Canadian pediatric centers evaluating new-onset seizures. Our findings emphasize the need for national consensus guidelines to standardize imaging protocols, reduce sedation use, and optimize care for pediatric seizure patients.

Brain magnetic resonance imaging (MRI) is recommended to rule out structural abnormalities in children presenting with new-onset unprovoked seizures. Although non-pharmacologic methods enable successful non-sedated MRIs in neonates and older children, monitored anesthesia care (MAC) remains the standard approach for those aged 1 month to 3 years. However, anesthesia exposure may be associated with adverse neurodevelopmental outcomes, increased health care costs, and longer wait times. We evaluated the feasibility, clinical utility, and family experiences of non-sedated MRI in 31 children aged 1 month to 3 years requiring brain MRI following new-onset seizures. Image quality was assessed by a neuroradiologist, and caregivers completed experience surveys. Completed MRI images were obtained in 27 of 31 participants (87%), and 26 of those 27 participants (96%) had diagnostic-quality images. Ninety percent of caregivers were satisfied and willing to repeat non-sedated MRI. These findings support non-sedated MRI as a feasible and caregiver-accepted alternative to anesthesia in young children.