Molecular imaging in oncology: Current impact and future directions

The authors define molecular imaging, according to the Society of Nuclear Medicine and Molecular Imaging, as the visualization, characterization, and measurement of biological processes at the molecular and cellular levels in humans and other living systems. Although practiced for many years clinically in nuclear medicine, expansion to other imaging modalities began roughly 25 years ago and has accelerated since. That acceleration derives from the continual appearance of new and highly relevant animal models of human disease, increasingly sensitive imaging devices, high-throughput methods to discover and optimize affinity agents to key cellular targets, new ways to manipulate genetic material, and expanded use of cloud computing. Greater interest by scientists in allied fields, such as chemistry, biomedical engineering, and immunology, as well as increased attention by the pharmaceutical industry, have likewise contributed to the boom in activity in recent years. Whereas researchers and clinicians have applied molecular imaging to a variety of physiologic processes and disease states, here, the authors focus on oncology, arguably where it has made its greatest impact. The main purpose of imaging in oncology is early detection to enable interception if not prevention of full-blown disease, such as the appearance of metastases. Because biochemical changes occur before changes in anatomy, molecular imaging—particularly when combined with liquid biopsy for screening purposes—promises especially early localization of disease for optimum management. Here, the authors introduce the ways and indications in which molecular imaging can be undertaken, the tools used and under development, and near-term challenges and opportunities in oncology.     

Risk factors of rib metastases in nasopharyngeal carcinoma patients with rib 99mTc- MDP foci on whole-body bone scansCSCD

Objective To investigate the correlation of rib 99mTc-MDP foci on whole-body bone scan with clinical variables and rib metastases in nasopharyngeal carcinoma(NPC) patients, and to screen the risk factors of rib metastases. Methods We retrospectively reviewed 312 NPC patients with rib 99mTc-MDP foci on wholebody bone scan. Chi-square test and logistic regression were performed to evaluate the correlation between clinical variables and rib metastases. Results In all 312 NPC patients, rib metastases were associated with T stage, skull base bone invasion, other bone metastasis, number of rib foci, lateral localization on rib and foci type (P<0.01), and the risk factors of rib metastasis included skull base bone invasion, other bone metastases, lateral localization on rib and foci type (P<0.05). In 176 patients with pure rib foci, rib metastases were closely related to T stage, skull base bone invasion, other bone metastasis, number of rib foci and lateral localization on rib (P<0.05), while only lobar distribution (P=0.029) was the effective risk factor. In 198 patients with single rib focus, rib metastases were affected by skull base bone invasion and foci type (P<0.01), while only foci type (P=0.000) was the effective risk factor. In all 566 rib foci, uptake level and localization on rib were the effective risk factors of rib metastases(P<0.01). Conclusion In NPC patients with rib foci on whole body bone scan, the effective risk factors of rib metastases include skull base bone invasion, other bone metastases, lateral localization on rib, foci type, uptake level and anterior and posterior localization on rib. Follow up should be the main way for the pure rib foci on unilateral ribs. For multiples rib foci on bilateral ribs or single rib focus combined with other bones foci, additional image modalities should be required to exclude bone metastasis. © 2020, CHINA RESEARCH ON PREVENTION AND TREATMENT. All rights reserved.     

Same-Day Yttrium-90 Radioembolization: Feasibility with Resin Microspheres

Purpose

To evaluate the feasibility of a same-day yttrium-90 (⁹⁰Y) radioembolization protocol with resin microspheres (including pretreatment angiography, lung shunt fraction [LSF] determination, and radioembolization) for the treatment of hepatocellular carcinoma (HCC) and liver metastases.

30例消化道肿瘤骨转移患者的定量SPECT/CT显像分析

目的:总结30例消化道肿瘤骨转移患者的临床资料及放射性骨显像的特点，并探讨定量SPECT/CT监测的SUVmax的影响因素。方法:回顾性分析2017年01月至2020年10月之间30例曾经来我院接受定量SPECT/CT检查的消化道肿瘤骨转移患者的临床资料，对消化道肿瘤骨转移的临床特点进行归纳总结，并分析定量SPECT/CT检查结果的SUVmax值与性别、吸烟、饮酒、骨外转移、骨转移灶数量及是否曾经使用双磷酸盐等临床数据的相关性，分析骨转移灶的数目对血钙、血磷、癌胚抗原及碱性磷酸酶等临床指标的影响。结果:患者的性别、是否吸烟饮酒、是否合并其他脏器转移及是否曾经使用双膦酸盐治疗与SUVmax没有明显关系，而骨转移灶数目会影响SUVmax的数值大小，并且骨多发转移患者的血钙水平低于单骨转移患者。结论:骨转移灶的数目是定量SPECT/CT SUVmax的一个影响因素，骨多发转移患者的SUVmax数值高于骨单发转移患者，并且消化道肿瘤骨多发转移患者的血清钙水平低于骨单发转移患者，定量SPECT/CT检查联合血清钙水平测定对消化道肿瘤骨转移具有一定的临床应用价值。     

BDNF levels and nigrostriatal degeneration in “drug naïve” Parkinson's disease patients. An “in vivo” study using I-123-FP-CIT SPECT

IntroductionParkinson's Disease (PD) is a common neurodegenerative disorder, characterized by a progressive loss of dopaminergic neurons and whose cause remains unclear. Brain-Derived Neurotrophic factor (BDNF) is a protein involved in dopaminergic cells survival. Previous studies have shown decreased serum BDNF levels in PD patients.Aim and objectivesThe aim of the study was to evaluate serum BDNF levels in a group of recently diagnosed non-medicated PD patients and its relationship with the nigrostriatal system degeneration using I-123-FP-CIT.Methods30 recently diagnosed, unmedicated PD patients were included in this study. Serum BDNF levels were measured twice using a sandwich enzyme linked immunoabsorbent assay and compared with levels of 27 unrelated Caucasian healthy adults.A I-123-FP-CIT SPECT was performed in all PD Patients in order to assess the association between serum BDNF levels and I-123-FP CIT uptake in several brain areas using a volumetric semi-automatic method.ResultsPD patients showed lower serum BDNF levels (Median = 49.61, IQ range: 43.55 to 61.82) than the controls (Median = 68.82, IQ range: 51.87 to 88.14) (U = 211.00, z = -3.10, p = 0.002). BDNF levels in PD patients correlated with both caudate (Spearman r = 0.58, p = 0.001 for ispilateral and r 0.55, p = 0.002 for contralateral) and putamen (Spearman r = 0.68, p < 0.001 for ipsilateral and r = 0.80, p < 0.001 for contralateral) I-123-FP-CIT uptake ratios.ConclusionsSerum BDNF levels were lower in recently diagnosed, untreated PD patients compared to controls. These lower levels were significantly correlated with the I-123-FP-CIT uptake ratios.     

Comparing calculated and experimental activity and dose values obtained from image-based quantification of 90Y SPECT/CT Data

PurposeSelective internal radiation therapy (SIRT) is a treatment for various kinds of liver tumours by injecting ⁹⁰Y bearing microspheres into the liver vessels. To perform meaningful post-treatment dosimetry, quantitative imaging is performed.MethodsThis work uses a Monte-Carlo based reconstruction software with scatter and attenuation correction and collimator modelling that allows the quantification of ⁹⁰Y bremsstrahlung SPECT/CT data. A dataset comprising 17 patients and measurements on a Jaszczak phantom, a NEMA IEC Body phantom and an anthropomorphic liver phantom are analysed and activities and dose values are acquired. These measured values are compared with applied activities and pre-treatment calculations, allowing to assess the quality of the SPECT reconstruction. A detailed uncertainty budget is presented, including uncertainties of the dose calibrator, the count rate, non-included interactions and other factors.ResultsThe applied method is validated by finding measurements repeatable within the given uncertainty, and it is shown the influence of various parameters on the reconstruction process is negligible. Furthermore, activities and doses measured in the phantoms show good agreement with calculated values, if they are corrected for partial volume effects.ConclusionsThe strict observation of metrological requirements and the creation of an uncertainty budget increase the reliability and traceability of this novel approach to ⁹⁰Y dosimetry. It gives an example of successful voxel-based dosimetry based on quantitative ⁹⁰Y SPECT/CT image data.