Cancer development is a multi-step process that undergoes multiple alterations over time. The tumor microenvironment (TME) contains tumor cells and stroma, including blood cells, fibroblasts, and immune cells, which undergo spatial and temporal changes. These changes contribute to tumor heterogeneity, leading to treatment failure and poor prognosis. As we move toward personalized medicine with the approval of targeted and other therapies, identifying tumor heterogeneity is becoming crucial to management. Positron emission tomography/computed tomography (PET/CT) with various radiopharmaceuticals plays an important role in diagnosing and highlighting heterogeneity non-invasively, guiding treatment decisions, and assessing treatment response. Variability in tracer distribution of ¹⁸F-fluorodeoxyglucose (FDG) and various radiopharmaceuticals when coupled together can target various tumor characteristics and, therefore, play an important role in diagnosing heterogeneity. Some of the commonly paired radiopharmaceuticals include ¹⁸F-FDG with ⁶⁸Gallium DOTA (1,4,7,10-tetraazacyclododecane-tetraacetic acid) peptide for neuroendocrine tumors, 18F-FDG with ⁶⁸Ga-prostate specific membrane antigen for prostate cancers, ¹⁸F-metafluorobenzylguanidine with ¹⁸F-FDG and ⁶⁸Ga-DOTA peptide for neural crest tumors, and ¹⁸F-fluoroestradiol with ¹⁸F-FDG for breast cancers. Many other tracers, including ⁶⁸Ga-fibroblast activation protein inhibitor and labeled integrins, attach to various components on tumor cells and TME and have displayed significantly positive effects in certain tumors. However, their potential role as a biomarker to evaluate tumor heterogeneity and its clinical relevance remains largely uninvestigated.

Malignant tumors continue to pose a significant threat to global health. Emerging evidence suggests that abnormal blood lipid levels may influence tumor incidence, and cancer patients frequently exhibit dysregulated lipid profiles. Radiotherapy, a cornerstone in cancer treatment, has been demonstrated to modulate blood lipid levels in patients. Conversely, blood lipid concentrations can significantly impact the efficacy of radiotherapy and the incidence of associated complications. This comprehensive review delves into cutting-edge research illuminating the intricate bidirectional interplay between blood lipid profiles and radiotherapy efficacy in malignant tumor patients. At the same time, it investigates the promising potential of tailored dietary modulation strategies and novel lipid-lowering therapeutics to enhance treatment efficacy and patient prognosis.

Gastric cancer (GC) is one of the most common malignant tumors in the world and has attracted much attention due to its high incidence and mortality. Early detection and accurate diagnosis of GC is very important to improve the survival rate of patients. Traditional imaging techniques, such as computed tomography (CT), have played an important role in the diagnosis and staging of GC, but their accuracy and predictive power are still limited. Radiomics, as an emerging multidisciplinary field, combines medical imaging, computer technology, and bioinformatics to reveal potential biological information in image data through quantitative extraction of image features. To review the current status and future potential of radiomics in the diagnosis, prognosis, and outcome prediction for patients with GC, related studies with keywords such as “radiomics,” “gastric cancer,” and “predict” were retrieved from PubMed (until October 2022). The clinical value of radiomics in GC research, which encompasses diagnosis, clinical staging, and prognostic prediction, was analyzed and summarized. A total of 52 original articles in radiomics were selected for the prediction of diagnostic classification (n = 9), tumor-node-metastasis stages (n = 19), prognosis and response prediction to treatment (n = 20), and the use of deep learning algorithm (n = 4). Among these, 39 (75%) were single-center studies and 13 (25%) were multicenter studies, with sample sizes ranging from 47 to 1,778. In terms of imaging modalities, 44 studies utilized CT-based radiomics, six used positron emission tomography-CT, and a few employed magnetic resonance imaging. With the continuous improvement and development in radiomics, it has great potential in the diagnosis, post-treatment follow-up, and treatment decision for patients with GC.

This study focuses on upgrading the shielding design of a Co-60 radiotherapy unit to accommodate a linear accelerator operating at 6 and 10 megavoltage, which can function in both flattening filter (FF) and flattening filter-free (FFF) modes. Shielding calculations were performed using analytical methods from the National Council on Radiation Protection and Measurements Report No. 151 and International Atomic Energy Agency Safety Reports Series No. 47, considering standard (40 patients/day) and heavy (60 patients/day) workloads. Barrier thicknesses were determined to ensure the instantaneous dose rate (IDR) behind primary barriers is ≤7.5 μSv/h in FF mode and ≤20 μSv/h in FFF mode, as recommended in the Institute of Physics and Engineering in Medicine Report No. 75. Results showed that workload had no significant effect on the primary barrier thickness. Moreover, strict adherence to the IDR criteria increased shielding demands ranging from 11% to 46% while reducing the personal equivalent dose to 1.2 - 13.4% of the dose constraints. This highlights a potential overdesign that could substantially increase raise construction costs. Therefore, applying the IDR criteria violates the radiation protection principles, namely, “optimization.” An alternative approach has been proposed to optimally use the IDR criteria by including the patient’s transmission factor in the current IDR criteria or by adopting higher values of IDR strictly to verify the shielding efficiency. Higher IDR adoption would result in lower linear accelerator vault costs and more realistic shielding calculations consistent with operating conditions.

Hypercholesterolemia is a major risk factor of atherosclerotic cardiovascular disease. However, current risk stratification models lack consideration of calcium burden. This study aimed to examine the association between calcium burden and inflammatory response in hypercholesterolemia patients. Eighteen participants were prospectively scheduled for 18F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT examination. They were classified into a control group (CL, n=4), a hypercholesteremia group (HC, n=8), and a stable angina group (SA, n=6). Arterial calcium was defined at attenuation ≥130 Hounsfield units in arterial regions of interest (ROIs), and calcium density was divided into four groups based on the Agatston strategy. Calcium area was defined by at least two adjoining pixels and normalized to artery area, forming two groups based on the mean area. The metabolic rate of glucose (MRGlu) was estimated using a two-tissue compartment model. For all ROIs, MRGlu was significantly higher in both HC and SA groups compared to CL (p<0.05). Among no-calcium groups (CL, HC, and SA), no statistical significance was observed (p>0.05). In with-calcium groups, MRGlu in HC was significantly higher than in CL and SA (p<0.05). At the highest calcium density cluster, the difference between CL and HC was also significant (p<0.05). CL and SA showed a similar pattern of decreasing MRGlu with increasing calcium area (p<0.05 when compared with no-calcium), while the HC group showed a marked increase in MRGlu with higher calcium area (p<0.05) compared to CL and AS. Hypercholesterolemia is associated with increased glucose metabolism. Higher calcium area and density in hypercholesterolemia patients appear metabolically active. The results suggest that incorporating calcium burden in hypercholesterolemia risk stratification models may enhance risk assessment.

Dynamic renal scintigraphy is a key imaging technique for assessing renal function using time-activity curves (TACs), which represent radiotracer uptake and clearance. TAC accuracy depends on the region of interest (ROI) selection and the modeling approach used. This study aims to: (i) Reconstruct TACs manually using gray-level values in scintigraphic images and compare them to machine-generated TACs using key kinetic parameters (T_max, T_1/2, and the 30-min min/max ratio); and (ii) evaluate the effectiveness of a one-compartment empirical mathematical model for TAC fitting and its physiological relevance. Twelve clinical cases were analyzed, with TACs reconstructed manually using a rectangular ROI selection method and compared to those automatically generated by the scintigraphy machine. An empirical mathematical fitting function was developed to improve TAC fitting. Manually reconstructed TACs showed better dynamic behavior and physiological accuracy over machine-generated TACs, particularly due to differences in ROI selection and signal processing. Using gray-level values instead of raw radioactive counts enhanced the depiction of kidney dynamics. The proposed mathematical model demonstrated a strong correlation (R² close to 1) and low error metrics, confirming its suitability for renal function assessment. While a free-hand ROI selection may improve accuracy, the rectangular method gives valuable results for the considered cases. This study highlights the importance of ROI selection in TAC reconstruction and demonstrates how manual methods and mathematical modeling can enhance renal functional assessment in clinical practice. Future work should validate these findings in larger datasets and assess the reproducibility of the proposed approach across different patient populations and imaging systems.

The prognosis of patients with muscle-invasive bladder cancer (MIBC) and pelvic nodes remains poor. We developed a novel radiotherapy (RT) protocol using volumetric-modulated arc therapy (VMAT) to treat bladder and locoregional nodes in MIBC. This study explores the safety, efficacy, and development of the VMAT protocol. Between June 2020 and August 2024, a total of 17 patients were treated using the novel VMAT protocol. The treatment regimen consisted of 57.5 Gy in 23 fractions to the bladder and 46 Gy in 23 fractions to the pelvic nodes. The present study reports on various parameters, including patient-related, disease-related, and treatment-related characteristics, along with toxicity profiles and long-term outcomes (response rates, nature of progression, and survival). The RT protocol was well tolerated, with 15 patients (88%) completing treatment as planned. Most acute toxicities were grade 1 or 2. One patient (6%) experienced a grade 3 acute toxicity (pain and local discomfort), while two patients (12%) experienced grade 3 late toxicity (colovesical fistula and severe radiation-induced cystitis). Following treatment, 12 patients (71%) had a response or a stable disease. Two patients (12%) developed local recurrence, six (35%) developed metastatic relapse, and nine patients (53%) showed no progression. The median progression-free survival was 15.8 months (95% confidence interval [CI]: 12.4 - 64.6), while the median overall survival was 23.1 months (95% CI: 13.6 - 64.6). This study has several limitations, primarily due to its retrospective design and small patient cohort. Furthermore, there was considerable variability in histology, fitness scores, and concomitant chemotherapy treatment. Nonetheless, the findings demonstrate the safety and feasibility of the VMAT protocol for treating the bladder and pelvic nodes in locally advanced MIBC, and they provide a rationale for future prospective studies to further evaluate the role of pelvic RT in this population.

This study was carried out to investigate how variations in the beam quality index (QI)-so-called tissue phantom ratio (TPR_20,10) affect tissue inhomogeneity correction factors (ICFs) in external beam radiotherapy treatment plans. A total of 90 three-dimensional conformal radiotherapy (3DCRT) treatment plans for lung, gynecological, and prostate cancers and 15 stereotactic body radiation therapy (SBRT) plans for lung cancer were analyzed. For the 3DCRT plans, ICFs were evaluated across a range of beam QI values. For 6 MV photon beams, the TPR_20,10 values were set at 0.670 ± 3%, while for 15 MV photon beams, the range was 0.760 ± 3%. SBRT plans were generated using two 6 MV photon beam configurations from a Varian TrueBeam accelerator - one employing a flattening filter (6 MV, TPR_20,10 = 0.688) and the other operating in flattening filter-free (FFF) mode (6 MV FFF, TPR_20,10 = 0.632). All dose calculations were performed using the Eclipse treatment planning system with the anisotropic analytical algorithm. For the calculations for 3DCRT plans, a 6.0% variation in the beam QI resulted in maximum differences in ICFs of 16.3% for lung cases with 6 MV beams and 12.5% for 15 MV beams. In gynecological and prostate cases, the ICF differences remained below 2.0% and 1.0%, respectively. In addition, for lung SBRT plans, a 5.6% discrepancy in TPR_20,10 between 6 MV and 6 MV FFF beams led to ICF variations of <3.0%. These findings suggest that while variations in the beam QI significantly influence ICFs in lung cancer 3DCRT plans, their impact is less pronounced in gynecological and prostate treatments. This underscores the necessity of carefully accounting for beam quality variations during radiotherapy treatment planning to ensure accurate dose delivery and optimal patient outcomes.

This study evaluates the impact of target delineation on the dosimetric outcomes and therapeutic efficacy of iodine-125 seed implantation in the treatment of non-small cell lung cancer. A retrospective analysis was conducted on 31 patients who underwent iodine-125 seed implantation at our center. Post-operative dosimetric parameters, including target volume (Vol), minimum peripheral dose received by 90% of the target Vol (D₉₀), as well as the percentage of target Vol covered by 100% (V₁₀₀), 150% (V₁₅₀), and 200% (V₂₀₀) of the prescription dose, were recorded. Patients were divided into two groups based on treatment response: Group A (complete remission [CR]) and Group B (non-CR group). In addition, the gross target Vol (GTV) of both groups was expanded by 5 mm (clinical target volume [CTV]_5mm) and 1 cm (CTV_1mm), and the corresponding dosimetric parameters were obtained. The independent sample t-tests were used to assess differences between the two groups. All patients successfully completed surgery; among them, 15 achieved CR, 12 had partial response, three had stable disease, and one experienced disease progression. Intraoperative complications included pneumothorax (32%), with three cases (10%) requiring pleural drainage, and intrapulmonary hemorrhage (42%), including hemoptysis (13%), all of which recovered after hemostatic treatment. No other adverse reactions occurred. Statistical analysis revealed no significant difference in dosimetric parameters between the two groups immediately after surgery. However, for CTV_5mm, D₉₀ was significantly lower than its immediate post-operative value (p=0.03, <0.05), whereas the other parameters were not significantly different. Expanding the GTV by 5 mm to define the CTV improves treatment outcomes and may enhance local tumor control.