Fast and Accurate Thoracic SPECT Image Reconstruction

In Single-Photon Emission Computed Tomography(SPECT),the reconstructed image has insufficient contrast,poor resolution and inaccurate volume of the tumor size due to physical degradation factors.Generally,nonstationary filtering of the projection or the slice is one of the strategies for correcting the resolution and therefore improving the quality of the reconstructed SPECT images.This paper presents a new 3D algorithm that enhances the quality of reconstructed thoracic SPECT images and reduces the noise level with the best degree of accuracy.The suggested algorithm is composed of three steps.The first one consists of denoising the acquired projections using the benefits of the complementary properties of both the Curvelet transformand theWavelet transforms to provide the best noise reduction.The second step is a simultaneous reconstruction of the axial slices using the 3D Ordered Subset Expectation Maximization(OSEM)algorithm.The last step is post-processing of the reconstructed axial slices using one of the newest anisotropic diffusion models named Partial Differential Equation(PDE).The method is tested on two digital phantoms and clinical bone SPECT images.A comparative study with four algorithms reviewed on state of the art proves the significance of the proposed method.In simulated data,experimental results show that the plot profile of the proposed model keeps close to the original one compared to the other algorithms.Furthermore,it presents a notable gain in terms of contrast to noise ratio(CNR)and execution time.The proposed model shows better results in the computation of contrast metric with a value of 0.68±7.2 and the highest signal to noise ratio(SNR)with a value of 78.56±6.4 in real data.The experimental results prove that the proposed algorithm is more accurate and robust in reconstructing SPECT images than the other algorithms.It could be considered a valuable candidate to correct the resolution of bone in the SPECT images.

In vivo SPECT imaging of an 131I-labeled PM 2.5 mimic substitute

The health effects of ambient PM 2.5 and its potential mechanisms have generated considerable interest.In vitro cell studies and ex vivo animal experiments may not accurately determine the characteristics of PM 2.5 particles.To better understand their detailed mechanisms,we performed an in vivo study using single photon emission tomography(SPECT)imaging.To mimic the PM 2.5 particles,SiO2 nanoparticles modified by ethylene carbonate or polyvinyl pyrrolidone were labeled with 131I.After administration via inhalation,in vivo SPECT imaging of the radiolabeled particles in sprague dawley rats was performed.It was found that radioactivity accumulated in the lungs and trachea 6 and 24 h after administration.In addition,significant radioactivity was observed in the abdomen,including the liver and kidneys.The results were also confirmed by ex vivo autoradiography.This study revealed that in vivo SPECT imaging could be an effective method for investigating the properties of PM 2.5 particles.

EFFECT OF ACUPUNCTURE ON CEREBRAL IMAGES IN AUTISM CHILDREN

Objective: To observe the effect of acupuncture on images in autism children. Methods; A total of 27 cases of autism children were subjected into this study. By using a SPECT, the cerebral images were collected before and after acupuncture treatment and analyzed according to the recommended methods in 《Clinical Nuclear Medicine》 for assessing the state of blood flow, radioactivity quantity distribution and radioactivity count in bilateral hemispheres. 'JIN's three-needling' was employed. The acupuncture treatment was given once every other day, with 4 months being a therapeutic course and an interval of one month between two courses. Results: After acupuncture treatment, of the 22 cases, 20 had remarkable improvement and 2 had improvement in cerebral blood flow, with the total effective rate being 90.8%. Before the treatment there were significant differences between the left and right cerebrum (P<0. 001), and between the left and right frontal lobes in radioactive areas (P<0.01); however, after treatment, no differences were found between them (P>0.05). After treatment, the radioactivity count in the whole brain decreased significantly in comparison with that of pretreatment (P<0.01). It indicates the improvement of cerebral blood flow and cellular metabolism after the treatment. Conclusion: Acupuncture can significantly improve cerebral blood flow in autism children.

Application of SPECT Combined with CT and MRI in Malignant Tumors Clinical Value in the Diagnosis of Bone Metastasis

Introduction: Bone is the most common site of hematogenous metastasis of malignant tumors. Patients with bone metastasis can have a series of bone related adverse events, which seriously affect the quality of life and survival time of patients. Imaging examination is the main means of clinical diagnosis and evaluation of bone metastasis. Aim of the Work: To evaluate the value of single-photon emission computerized tomography (SPECT) combined with CT and MRI in the diagnosis of bone metastasis of malignant tumors. Subjects and Methods: Eighty patients with bone metastasis from malignant tumors who were admitted to Affiliated Hospital of Chengde Medical College were selected from March 2019 to June 2021. They underwent bone scan with SPECT imaging, CT and MRI separately. The distribution of bone metastasis from primary tumors as well as efficacy of the above three detection methods for bone metastasis was analyzed. Results: A total of 464 lesions were detected by SPECT and CT in the same scanning field, with SPECT detection rate of 92.5% (429/464) and CT detection rate of 77.8% (361/464) (P P P P Conclusion: SPECT may be the preferred screening modality for uspected bone metastases, and when combined with CT and MRI, it can clarify the regional distribution of bone metastasis from malignant tumors and improve the sensitivity, specificity and accuracy of diagnosis with high clinical significance.

Creating Knowledge-Based Diagnostic Models by Mining Textual Diagnostic Reports of SPECT Scans

Mining rich semantic information hidden in heterogeneous information network is one of the important tasks of data mining. Generally, a nuclear medicine text consists of the description of disease (i.e., lesions) and diagnostic results. However, how to construct a computer-aided diagnostic model with a large number of medical texts is a challenging task. To automatically diagnose diseases with SPECT imaging, in this work, we create a knowledge-based diagnostic model by exploring the association between a disease and its properties. Firstly, an overview of nuclear medicine and data mining is presented. Second, the method of preprocessing textual nuclear medicine diagnostic reports is proposed. Last, the created diagnostic modes based on random forest and SVM are proposed. Experimental evaluation conducted real-world data of diagnostic reports of SPECT imaging demonstrates that our diagnostic models are workable and effective to automatically identify diseases with textual diagnostic reports.

APPLICATION OF SINGLE PHOTON EMMISSION COMPUTED TOMOGRAPHY TO CLINICAL STUDY ON THE THERAPEUTIC EFFECT OF ACUPUNCTURE IN TREATMENT OF CHILD CEREBRAL PARALYSIS

Subjective To identify the practicability and clinical values of acupuncture in the treatment of child cerebral paralysis, try to provide visualized evidence and mechanisms for acupuncture treatment of this disease. Meth- ods: 13 cerebral palsy children including 9 cases of spasmodic type, 2 cases of ataxia type and 2 cases of mixed type, 9 males and 4 females were subjected into this study. Acupoints used were Hegu (LI 4), Quchi (LI 11), Zusanli (ST 36) and Sanyinjiao (SP 6) that were punctured and stimulated electrically with parameters of frequency 2/15 Hz, elec- tric current 5 mA, and duration of stimulation 30 min. Under monitoring of Siemens ECAM/ICON SPECT System, blood flow volumes of different brain regions were observed before, during and after elctroacupuncture (EA) stimulation of the above-mentioned acupoints. Results: SPECT revealed that in these 13 infantile patients, 18 regions of the brain in- cluding 12 in tbe frontal lobe and 6 in the temporal lobe presented insufficiency of blood perfusion and hypofunction; during EA, these cerebral regions and parietal lobe, visual cortex, thalamus, basal ganglion and cerebellum showed improvement in blood perfusion and function in different degrees. Results of the quantitative analysis on blood flow func- tion changing rate (BFCR) % showed a significant increase in 83.3% of the focal regions during EA. Conclusion: Acupuncture therapy can effectively improve cerebral blood perfusion of the focus and is of clinical value in treatment of infantile cerebral paralysis.

Diagnosis Performance of 99mTc-MIBI and Multimodality Imaging for Hyperparathyroidism

This study aimed to examine the diagnosis performance of^（99m）Tc-methoxyisobutylisonitrisonitrile （^（99m）Tc-MIBI） and multimodality imaging [ultrasound, single-photon emission computed tomography/computed tomography（SPECT/CT）] for hyperparathyroidism（HPT）. From Nov. 2009 to Dec. 2015, clinical data of a total of 43 HPT patients（16 males and 27 females; 26–70 years old, average age： 51.60±10.66 years old） were retrospectively analyzed. Among them, 19 patients with primary hyperparathyroidism（PHPT） underwent ^（99m）Tc-MIBI planar imaging, 24 [15 with PHPT and 9 with secondary hyperparathyroidism（SHPT）] underwent SPECT/CT hybrid imaging, and 41（33 with PHPT and 8 with SHPT） had neck ultrasound imaging. Final diagnosis was determined by pathological examination after surgery. The positive rate was compared between different imaging modalities, and the correlation analysis was conducted between imaging results and lesion size or serum parathyroid hormone（PTH） level. The results showed that the total positive rates of^（99m）Tc-MIBI imaging, ultrasound, and the two combined imaging in the 43 HPT cases were 90.70%（39/43）, 58.54%（24/41）, and 100%（41/41）, respectively. According to lesion numbers, the positive rates were 79.10%（53/67）, 53.23%（33/62）, and 88.71%（55/62）, respectively. SPECT/CT hybrid images were positive in all the 24 patients who underwent this examination. The mean maximum diameters of the lesions in ^（99m）Tc-MIBI positive and negative patients were 1.96±0.95 cm and 1.36±0.67 cm respectively, with statistically significant difference noted（P=0.03）. The T/NT of ^（99m）Tc-MIBI imaging at the early phase was correlated positively with serum PTH level（r=0.40, P=0.01）. The T/NT of ^（99m）Tc-MIBI imaging at both the early phase and the delay phase was correlated positively with lesion size（r=0.51, and r=0.45, respectively; P〈0.01 for both）. It was concluded that ^（99m）Tc-MIBI imaging presents significant value for location diagnosis of HPT, especially when combined with SPECT/CT hybrid imaging or ultrasound. The ^（99m）Tc-MIBI uptake correlates positively with serum PTH level and lesion size.

A novel peptide-based probe^(99m)Tc-PEG_(6)-RD-PDP2 for the molecular imaging of tumor PD-L2 expression

Tumor-related PD-L2 expression is associated with the clinical efficacy of PD-1/PD-L1 blockade therapy.PD-L2-specific imaging can help selecting patients for appropriate immunotherapy.In this study,a PD-L2-targeting peptide(PDP2)was screened by the one-bead one-compound combinatorial library approach.Using the retro-inverso D-peptide of PDP2(RD-PDP2)and PEGylation strategies,we developed a novel Tc-99m-labeled PD-L2-targeting peptide as a SPECT tracer(^(99m)Tc-PEG_(6)-RD-PDP2)for imaging of tumor PD-L2 expression.The radiolabeling yield of ^(99m)Tc-PEG_(6)-RD-PDP2 was greater than 95%by the standard HYNIC/tricine/TPPTS labeling procedure.^(99m)Tc-PEG_(6)-RD-PDP2 displayed high PD-L2-binding specificity both in vitro and in vivo.SPECT/CT imaging with^(99m)Tc-PEG_(6)-RD-PDP2 showed that the A549-PD-L2tumors were clearly visualized,whereas the signals in PD-L2-negative A549 tumors were much lower.In vivo blocking study suggested that the tumor uptake of^(99m)Tc-PEG_(6)-RD-PDP2 was PD-L2 specifically mediated.^(99m)Tc-PEG_(6)-RD-PDP2 is a promising SPECT probe for the non-invasive imaging of tumor PD-L2expression and has a great potential in guiding the anti-PD-1 or anti-PD-L1 immunotherapy of cancer.