Yttrium-90 (90Y) microsphere radioembolization (RE) has become an important locoregional therapy for unresectable primary and metastatic liver tumors, supported by advances in catheter-based delivery and quantitative nuclear medicine imaging. Successful treatment requires coordinated multidisciplinary collaboration, with nuclear medicine playing a central role from initial patient selection through post-treatment verification and follow-up assessment. Pre-treatment imaging—particularly 18F-FDG positron emission tomography/computed tomography (PET/CT) and pathology-specific non-FDG tracers—supports staging, characterization of tumor biology, and prognostic stratification. In parallel, 99mTc macroaggregated albumin or Single Photon Emission Computed Tomography (SPECT) mapping enables identification of extrahepatic shunting, lung dose estimation, and predictive intrahepatic dose modeling, thereby guiding treatment feasibility and personalized dosimetry. Following microsphere administration, post-therapy imaging with 90Y PET/CT, Bremsstrahlung SPECT/CT, or hybrid PET/magnetic resonance imaging provides essential confirmation of microsphere distribution and supports voxel-based dose-response evaluation. Emerging quantitative metrics, including metabolic tumor volume, total lesion glycolysis, and radiomics-derived features, offer additional prognostic insight and may refine individualized treatment planning. This review synthesizes current evidence on the clinical utility, technical considerations, and evolving applications of nuclear medicine imaging throughout the 90Y-RE workflow. It highlights practical decision-making principles relevant to nuclear medicine physicians, interventional radiologists, oncologists, and medical physicists, with the objective of supporting optimized patient selection, improving dosimetric accuracy, and enhancing post-therapy response evaluation in liver-directed radionuclide therapy.
Yttrium-90 selective internal radiation therapy (90Y-SIRT) has emerged as a transformative locoregional modality for primary hepatocellular carcinoma (HCC) with distinct radiobiological advantages and favorable safety profiles. 90Y-SIRT is expected to break through the limitations of conventional treatment by combining it with other systemic therapies in the treatment of liver cancer at all stages. This review systematically examines: (i) The four mechanistic foundations of SIRT’s therapeutic efficacy, including precise arterial delivery of microspheres, sustained low-dose-rate β-irradiation, tumor-selective high-dose escalation, and modulation of the tumor immune microenvironment; (ii) clinical evidence supporting its dual role in downstaging advanced HCC with portal vein tumor thrombus and enhancing systemic therapy efficacy in intermediate-stage disease; and (iii) comparative studies demonstrating its superiority over transarterial chemoembolization in terms of tumor response, resectability or transplant conversion, and treatment tolerability. In addition, we discuss emerging directions, including the development of cost-effective domestically manufactured microspheres and the integration of biomarker-guided combination regimens to potentiate immunogenic synergy. By integrating mechanistic insights with clinical validation, this review positions 90Y-SIRT as a central pillar in the evolving landscape of precision medicine for primary HCC.
Conformal dose delivery in external beam radiotherapy often requires a tissue‐equivalent bolus to compensate for surface irregularities and increase skin dose. However, traditional bolus fabrication methods are time‐consuming, imprecise, and poorly adaptable to patient anatomy. This study presents an alternative, innovative workflow that integrates three-dimensional (3D) structured-light scanning (SLS), computer-aided design, and 3D printing to rapidly and accurately fabricate patient‐specific boluses. First, a chin bolus was generated within the treatment planning system using a Rando anthropomorphic phantom as a reference. The generated bolus was then processed, 3D-printed, and tested. To avoid additional computed tomography scans and unnecessary X-ray exposure, a high‐resolution, inoffensive SLS scanner was used to capture the treatment surface. The resulting point‐cloud data were imported into 3D modeling software to design a custom bolus geometry that conforms exactly to the patient’s skin contour. The workflow also incorporated a rapid rescanning and reprinting loop, enabling intra‐fractional and inter‐fractional modifications in response to anatomical changes. The 3D‐printed bolus demonstrated excellent conformity to the phantom surface. The entire process, from scanning to bolus deployment, was completed within a reasonable timeframe, substantially reducing patient waiting time compared with conventional methods. Overall, the proposed 3D printing-based workflow offers a rapid, accurate, and patient-specific alternative to conventional bolus fabrication. By leveraging SLS and digital modeling, this approach enhances conformity, improves dosimetric accuracy, and allows agile modifications to accommodate anatomical changes, thereby optimizing radiotherapy treatment delivery.
Pediatric nephroblastoma is a rare kidney cancer occurring in children. This study investigates the impact of kidney shielding using a multileaf collimator compared with individual block techniques on dose-volume histograms (DVHs) of organs at risk (OARs) and on planning target volume (PTV) coverage during whole-abdominal irradiation with 6 MV beams in children with nephroblastoma. A computed tomography scan was performed in the supine position for five children with nephroblastoma. Treatment plans for both techniques—the conformal block technique (CFBT) and the conventional block technique (CVBT)—were created using the three-dimensional treatment planning system XIO version 4.8. Plans were compared based on dose conformity, homogeneity, and DVHs of OARs. Statistical analysis was performed using the t-test. The mean PTV conformity and homogeneity indices were 0.99 and 1.13 for CFBT, and 0.95 and 1.08 for CVBT, respectively. CFBT demonstrated superior target coverage, achieving 95% of the prescribed dose on 99.2% of the PTV compared to 95.0% for CVBT, which showed greater dose heterogeneity due to conventional kidney shielding and underdosing of adjacent abdominal regions. The average mean dose to the healthy kidney was 11.65 Gy (11.27-12.05) for CFBT and 11.44 Gy (11.09-11.75) for CVBT, with no significant differences in other OARs (p>0.05). CFBT represents an important advancement in three-dimensional conformal radiotherapy for children in developing countries, providing improved PTV homogeneity, enhanced treatment quality assurance, and a reduced potential for human error compared to CVBT. After the initial 10.5 Gy, the abdominal cavity was treated uniformly with CFBT.
The proper functioning of mitochondria requires preserving the membrane potential (ΔΨm) within a narrow window. Significant deviation from the membrane potential of mitochondria is a well-established indicator of mitochondrial dysfunction. Various pathological conditions, such as cancer, diabetes, and cardiotoxicity, have been linked to mitochondrial dysfunction, highlighting the need for reliable methods to assess membrane potential in vivo. Hence, there is a need to explore radiolabeled lipophilic cations that accumulate within mitochondria in proportion to the potential gradient. The lipophilic organic cation triphenylphosphonium (TPP) has gained attention as a promising tracer for non-invasive imaging of mitochondrial function. It has been labeled with various radioisotopes, such as F-18, for imaging mitochondrial membrane potential in cancer through positron emission tomography (PET). The first attempt to quantify membrane potential in living organisms by examining the biodistribution of the 11C-labeled TPP derivative was reported more than 30 years ago. Herein, a series of TPP derivatives, together with TPP, have been radiolabeled with 64Cu for imaging gliomas, which are characterized by high mitochondrial content. 2-(diphenylphosphoryl)-ethyldiphenylphosphonium (TPEP) has demonstrated superior tumor uptake and favorable tumor-to-background ratios, leading to its selection for further assessment as a magnetic resonance imaging contrast agent. Building on these findings, we developed 68Ga-labeled TPP and TPEP as novel PET tracers for rhabdomyosarcoma. To assess how the choice of targeting moiety and bifunctional chelator influences tracer performance, biodistribution studies were conducted in mitochondrial-rich rhabdomyosarcoma patient-derived xenografts. These results support further development of 68Ga-TPP-based agents for mitochondrial-targeted oncologic imaging applications.
Palliative patients receiving radiotherapy often experience significant pain. Nevertheless, they must be transported for a planning computed tomography (CT) scan and endure additional waiting times because treatment planning is time-consuming. New artificial intelligence (AI)-assisted radiotherapy devices enable simplified workflows. Using cone-beam CT data, an adaptive treatment plan based on the current patient anatomy can be generated within minutes. This study examines how technical innovations can shorten radiation treatment planning using diagnostic images instead of planning CT (pCT) scans. The entire treatment planning chain was evaluated using an Alderson phantom in an end-to-end test with dose measurements for an AI-supported adaptive workflow. Different diagnostic CT acquisitions were used, and the resulting dose calculations were compared with those obtained from a pCT calibrated for radiotherapy. In Report 24, the International Commission on Radiation Units and Measurements (ICRU) specifies a tolerance for radiotherapy dose delivery of ±5% relative to the prescribed dose. To evaluate if an adaptive workflow with diagnostic images on the Varian’s Ethos system (v1.1) meets these requirements, ionization chamber measurements in a phantom were compared to planned doses. Comparison of the results showed that the requirements of ICRU Report 24 were met. When diagnostic CT images were used instead of a dedicated treatment pCT, increased dose deviations of up to 2% were observed, although these remained within the ICRU tolerance. The end-to-end test presented here provides a practical approach to assessing the impact of using diagnostic CT data in adaptive treatment planning. The findings indicate that the observed dose deviations remain within the 5% limit defined by ICRU Report 24.
Thyroid cancer is rare in children but often presents at an advanced stage with aggressive features. Following the Chernobyl accident (CA), a marked increase in pediatric papillary thyroid carcinoma (PTC) was reported in contaminated areas, coinciding with the initiation of mass screening and heightened diagnostic scrutiny. This review summarizes prior publications on thyroid lesions related to the CA and examines potential biases in associated epidemiological research. Based on the linear no-threshold theory, an increase in the incidence of various malignancies was predicted after the accident. In reality, however, no elevation in cancer frequency has been conclusively linked to Chernobyl-related radiation exposure, except for PTC in residents exposed at a young age. It remains plausible that a considerable proportion of these thyroid cancers were indeed caused by ionizing radiation from the accident. Before the CA, pediatric thyroid cancer was infrequently diagnosed in Belarus and Ukraine. It is well established that screening can significantly increase the detection rate of thyroid tumors. Post-accident screening efforts identified not only small lesions but also previously undiagnosed cancers - some of which were labeled as aggressive radiogenic carcinomas. This labeling contributed to the perception of exceptional tumor aggressiveness. Such interpretations influenced clinical practice: certain experts recommended more radical approaches for thyroid nodules diagnosed as radiogenic carcinoma, diverging from standard international guidelines. Overestimations of the medical and environmental consequences of low-dose ionizing radiation have played a role in constraining the development of nuclear energy. Several studies on Chernobyl-related thyroid malignancies warrant reassessments. Lifelong animal studies represent a promising approach for elucidating dose-response relationships.
A neutron beam system (NBS) based on an electrostatic proton accelerator designed for accelerator-based boron neutron capture therapy has been installed in Xiamen Humanity Hospital in China. The NBS has been used for patient treatments since October 2023, after more than a year of preliminary studies. By the end of 2024, more than 50 treatments had been executed. NBS uptime during 2024 was above 96%. Repeatability of the beam parameters was well within 2%. At present, configuration with only one treatment room operational, the overall machine usage, including clinical use, physics and dosimetry measurements, and biological experiments, has reached 27% of its capacity.
Adult ovarian granulosa cell tumors (AGCTs) are among the most common types of gonadal sex cord-stromal tumors. This pathological entity is generally associated with a favorable prognosis but only accounts for about 2-5% of all malignant ovarian tumors. Disease stage is the most important prognostic factor, with patients diagnosed at an early stage exhibiting a good prognosis. Surgery remains the cornerstone of treatment, both for primary and recurrent cases, while chemotherapy is typically reserved for inoperable or advanced progressive situations. Despite treatment, about one-third of patients experience relapse or progression within 4-7 years, and approximately 50% of these cases result in mortality. We report a case of recurrent AGCT occurring three years after initial surgery and chemotherapy. The patient underwent secondary cytoreductive surgery for recurrent lesions, with postoperative recovery achieved. Further chemotherapy will be administered based on clinical condition and treatment response.