Annals of Nuclear Medicine最新文献

Objective

The study aimed to assess the impact of postoperative radioactive iodine (RAI) therapy on parathyroid function in patients who underwent total or subtotal thyroidectomy for differentiated thyroid cancer (DTC).

Methods

Data from 150 patients treated with RAI for DTC and 76 patients with low-risk DTC not receiving RAI were retrospectively analyzed. Clinical characteristics, preoperative and 1-month postoperative biochemical parameters, and adjusted calcium, phosphorus, parathyroid hormone (PTH), and 25-hydroxyvitamin D3 (25-OH-D) levels at 3 months, 1 year, 3 years, and 5 years post-RAI (or in the low-risk group) were recorded.

Results

A total of 226 DTC patients were included in the study (80.5% female, mean age 42.7 ± 13.2 years). Total thyroidectomy was performed in 97.3% (n = 220) of patients, with central lymph node dissection (CLND) in 41.6% (n = 94). No significant preoperative differences in PTH, aCa, P, Mg, or 25-hydroxyvitamin D3 levels were observed. However, patients receiving ≥ 3.7 GBq (or 100 mCi) RAI (n = 70) had lower calcium and PTH levels at the end of the first year following RAI treatment (p = 0.048, p = 0.032). The non-RAI group showed significantly higher calcium levels at one month postoperatively (p = 0.031) and lower rates of CLND and neck dissection. No significant differences in biochemical parameters were found at the five-year follow-up, except for one patient who developed normocalcemic hyperparathyroidism after RAI.

Conclusion

High-dose RAI therapy may lead to transient decreases in calcium and PTH levels in the early post-treatment period. However, long-term parathyroid function appears to remain unaffected in DTC patients, regardless of the RAI dose administered. Nonetheless, close monitoring of calcium and PTH levels is recommended, particularly in the early post-treatment period, to promptly manage any potential transient hypoparathyroidism.

Objective

Diuretic renal scintigraphy is important in diagnosing pelvi-ureteric junction obstruction (PUJO) in antenatally detected hydronephrotic (ANH) kidneys. Early-phase dynamic renal scintigraphy has several pitfalls contributing to the false interpretation of obstructed drainage, especially after pyeloplasty. This study explores the utility of delayed imaging in ^99mTc-L,L-Ethylenedicysteine (EC) diuretic renal scintigraphy to assess post-pyeloplasty renal drainage in ANH.

Methods

Data from May 2019 to January 2024 was retrospectively studied to identify infants with ANH who underwent surgery for PUJO and pre-and post-surgical assessment of renal drainage using ^99mTc-L,L-EC diuretic renal scintigraphy. Dynamic and post-void static images were analyzed to calculate percentage drainage till 3 h. Pre- and post-operative quantitative parameters were compared. Receiver operator curve analysis was done to calculate the threshold drainage to detect renal obstruction on postvoid images.

Results

In a cohort of 104 patients with a mean age of 10.1 ± 6.5 months (range 2–36 months) at surgery, 106 renal units (bilateral involvement in two patients) were analyzed. There was no significant difference in the sum of obstructive and equivocal curve patterns (105 vs 79, p = 0.06) and T_1/2 values (105 vs 82, p = 0.093) before and after surgery. However, there was a significant difference between the pre-and post-surgery median 3-h percentage drainage (26 vs 80%, p < 0.001). A drainage threshold of less than 59% at 3 h had 93.4% sensitivity and 92.5% specificity to detect obstructive drainage.

Conclusion

Delayed images in diuretic renal scintigraphy are crucial in accurately interpreting post-pyeloplasty drainage patterns and help overcome pitfalls of the dynamic study.

The 1st World Congress of Nuclear Medicine and Biology was held from September 30 to October 4 1974 in Japan. This was an epoch-making event in the history of Nuclear Medicine in Japan as well as in the World. The huge success of the meeting contributed a lot to the rapid and remarkable progress of nuclear medicine thereafter. The author served as a secretary of the local organizing committee for the Congress. The author would like to record the event summarizing the publications made by the local organization committee. The author would like to share with nuclear medicine professionals of younger generations the unforgettable experiences which he has kept in memory for the past half a century. The author believes this historical review will help to pave the future way of nuclear medicine by recalling how the World Federation and Congress was started with the great efforts of the excellent minds of predecessors.

Objective

FAPI-PET/CT exhibits high tumor uptake and low background accumulation, enabling high-sensitivity tumor detection. We compared the diagnostic performance of ⁶⁸ Ga-FAPI-46 PET/CT plus contrast-enhanced CT (CE-CT), ¹⁸F-FDG PET/CT plus CE-CT, and standalone CE-CT in patients with various malignancies.

Methods

232 patients underwent ⁶⁸ Ga-FAPI-46 PET/CT,¹⁸F-FDG PET/CT, and CE-CT each within 4 weeks. Detection rates were assessed by a blinded reader, with ≥ 2 weeks between scans of the same patient to avoid recall bias. A sub-analysis of diagnostic performance was performed for 490 histopathologically validated lesions. Detection rates were compared using McNemar’s test.

Results

Lesion-based detection rates in ⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT, ¹⁸F-FDG PET/CT plus CE-CT, and CE-CT alone were 91.2% (1540/1688), 82.5% (1393/1688) and 60.2% (1016/1688). The detection rates were significantly higher for ⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT than for ¹⁸F-FDG PET/CT plus CE-CT (p < 0.02 for primary lesions and p < 0.001 for total, abdominopelvic nodal, liver and other visceral lesions) and CE-CT (p < 0.0001 for total, primary, cervicothoracic nodal, abdominopelvic nodal, liver, other visceral, and bone lesions). In the sub-analysis, sensitivity, specificity, positive and negative predictive value, and accuracy were 61.3%, 96.7%, 81.4%, 91.4% and 90.0% for ⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT, 57.0%, 95.7%, 75.7%, 90.5% and 88.4% for ¹⁸F-FDG PET/CT plus CE-CT, and 51.6%, 97.2%, 81.4%, 89.6% and 88.6% for CECT, respectively.

Conclusions

⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT demonstrates a higher tumor detection rate than ¹⁸F-FDG PET/CT plus CE-CT and CE-CT in a diverse spectrum of malignancies, especially for primary, abdominopelvic nodal, liver, and other visceral lesions. Further studies on which entities draw particular benefit from ⁶⁸ Ga-FAPI-46 PET/CT are warranted to aid appropriate diagnostic workup.

Trial registration

A total of N = 232 patients were analyzed. Of these, N = 50 patients were included in a prospective interventional trial (NCT05160051), and N = 175 in a prospective observational trial (NCT04571086) for correlation and clinical follow-up of PET findings; N = 7 patients were analyzed retrospectively.

Introduction

The aim of this work was to investigate homogeneity and stability of liver SUV in terms of different malignancies considering different body normalization schemes and blood glucose concentrations as well as PET/CT imaging systems.

Methods

The study included 207 patients with four different types of cancers namely breast, lymphoma, lung, and bone-metastasis. Data acquisition was performed with GE Discovery IQ, Biograph mCT, uMI 550, and Ingenuity TF64 after a single intravenous injection of 194 ± 67.5 MBq of 18F-FDG.

Results

In body weight normalization, SUVmax and SUVmean in bone-mets as well as SUVmean in lung patients were not statistically different among scanners especially for data corrected for glucose levels (p = 0.062, 0.121, and 0.150, respectively). In SUVlbm derived from lung patients, there was no significant differences in Philips in comparison to GE and Siemens (both, p > 0.05) for data corrected and not corrected for glucose levels. In SUVbsa, the only non-significant difference revealed among scanners was in the measurements of SUVmean obtained from lung and bone-mets (p = 0.107 and 0.114) both corrected for glucose levels. In SUVbmi, SUVmean of lung and bone-mets as well as SUVmax of bone-mets showed a non-significant differences among the four different scanning systems (p = 0.303, 0.091, and 0.222, respectively) for data corrected for glucose levels.

Conclusion

Liver glucose correction needs further investigations in individual tumors but could be potentially affected by whether measurements are made on SUVmean versus SUVmax, body weight normalization, as well as the imaging system. As such, selection of normalization to body weight method should be carefully selected before clinical adoption and clinically adopted and body surface area would provide the highest correlation. As such, normalization of body weight should be carefully made before clinical adoption. SUVmean proves to be useful and stable metric when liver is corrected for blood glucose levels.

Aim

Conventional imaging techniques and prostate-specific antigen (PSA) values are not useful to follow-up patients during Radium-223 treatment. The study aimed to evaluate the predictive value of prostate-specific membrane antigen PSMA PET/CT-based response in patients with metastatic castration-resistant prostate cancer (mCRPC) receiving Radium-223 dichloride treatment.

Materials and methods

Patients treated with radium-223, having performed two ⁶⁸Ga-PSMA-11 PET/CT scans (baseline 1 month before treatment initiation and follow-up 2 weeks after the third cycle), were retrospectively evaluated. Visual and quantitative PET image analyses were performed, and patients were dichotomized into progressive (PD) and non-PD according to Response Evaluation Criteria in PSMA‑imaging (RECIP1.0) and PSMA-PET Progression criteria (PPP). The primary endpoint was overall survival (OS). Cohen's Kappa (κ) was used to test the agreement between the two criteria. The Cox regression hazard model and Kaplan–Meier method were used for survival analyses.

Results

Twenty-eight mCRPC patients were evaluated. Sixteen (43%) and 18 (64%) patients had PD according to RECIP1.0 and PPP, respectively; κ = 0.85 (95% CI 0.65–1.00). After a median follow-up of 16 months (interquartile IQR 9–33), 20 (71%) patients died. Patients with PSMA PD showed a higher risk of death than non-PD according to RECIP1.0 (HR = 2.9; 95% CI 1.14–7.46; p = 0.029) and PPP (HR = 2.8; 95% CI 1.04–7.64; p = 0.042). For both criteria, the median OS was shorter for PD than non-PD (37 vs. 12 months, Log-rank; p < 0.05). The C-index for RECIP1.0 and PPP were almost equal (0.66 and 0.63; respectively).

Conclusion

This study demonstrated that PSMA-PET/CT imaging is valuable for monitoring radium-223 treatment. Both PSMA PET/CT response criteria (RECIP1.0 and PPP) perform similarly predicting OS at follow-up after three cycles of radium-223. These findings urge further validation in prospective trials.

Objective

Dead-time loss is reported to be non-negligible for some patients with a high tumor burden in Lu-177 radionuclide therapy, even if the administered activity is 7.4 GBq. Hence, we proposed a simple method to shorten the apparent dead time and reduce dead-time loss using a thin lead sheet in previous work. The collimator surface of the gamma camera was covered with a lead sheet in our proposed method. While allowing the detection of 208-keV gamma photons of Lu-177 that penetrate the sheet, photons with energies lower than 208 keV, which cause dead-time loss, were shielded. In this study, we evaluated the usefulness of tungsten functional paper (TFP) for the proposed method using Monte Carlo simulation.

Methods

The count rates in imaging of Lu-177 administered to patients were simulated with the International Commission on Radiological Protection (ICRP) 110 phantom using the GATE Monte Carlo simulation toolkit. The simulated gamma cameras with a 0.5-mm lead sheet, 1.2-mm TFP, or no filter were positioned closely on the anterior and posterior sides of the phantom. The apparent dead times and dead-time losses at 24 h after administration were calculated for an energy window of 208 keV ± 10%. Moreover, the dead-time losses at 24–120 h were analytically assessed using activity excretion data of Lu-177-DOTATATE.

Results

The dead-time loss without a filter was 5% even 120 h after administration in patients with a high tumor burden and slow excretion, while those with a lead sheet and TFP were 0.22 and 0.58 times less than those with no filter, respectively. The count rates with the TFP were 1.3 times higher than those with the lead sheet, and the TFP could maintain primary count rates at 91–94% of those without a filter.

Conclusions

Although the apparent dead time and dead-time loss with the lead sheet were shorter and less than those with TFP, those with TFP were superior to those without a filter. The advantage of TFP over the lead sheet is that the decrease in primary count rates was less.

Background

Brain-dedicated positron emission tomography (PET) systems offer high spatial resolution and sensitivity for accurate clinical assessments. Attenuation correction (AC) is important in PET imaging, particularly in brain studies. This study assessed the reproducibility of attenuation maps (µ-maps) generated by a specialized time-of-flight (TOF) brain-dedicated PET system for imaging using different PET tracers.

Methods

Twelve subjects underwent both ¹⁸F-fluorodeoxyglucose (FDG)-PET and ¹⁸F-flutemetamol (FMM) amyloid-PET scans. Images were reconstructed with µ-maps obtained by a maximum likelihood-based AC method. Voxel-based and region-based analyses were used to compare µ-maps obtained with FDG-PET versus FMM-PET; FDG-PET images reconstructed using an FDG-PET µ-map (FDG × FDG) versus those reconstructed with an FMM-PET µ-map (FDG × FMM); and FMM-PET images reconstructed using an FDG-PET µ-map (FMM × FDG) versus those reconstructed with an FMM-PET µ-map (FMM × FMM).

Results

Small but significant differences in µ-maps were observed between tracers, primarily in bone regions. In the comparison between the µ-maps obtained with FDG-PET and FMM-PET, the µ-maps obtained with FDG-PET had higher µ-values than those obtained with FMM-PET in the parietal regions of the head and skull, in a portion of the cerebellar dentate nucleus and on the surface of the frontal lobe. The comparison between FDG and FDG × FMM values in different regions yielded findings similar to those of the µ-maps comparison. FDG × FMM values were significantly higher than FDG values in the bilateral temporal bones and a small part of the temporal lobe. Similarly, FMM values were significantly higher than FMM × FDG values in the bilateral temporal bones. FMM × FDG values were significantly higher than FMM values in a small area of the right cerebellar hemisphere. However, the relative errors in these µ-maps were within ± 4%, suggesting that they are clinically insignificant. In PET images reconstructed with the original and swapped µ-maps, the relative errors were within ± 7% and the quality was nearly equivalent.

Conclusion

These findings suggest the clinical reliability of the AC method without an external radiation source in TOF brain-dedicated PET systems.

Introduction

Stereotactic ablative body radiotherapy (SABR) is a standard treatment option for patients with malignant pulmonary masses (including primary and metastatic lesions) who are unfit for surgery or who are medically operable but refuse surgery. Flourine-18 flurodeoxyglucose positron emission tomography (¹⁸F-FDG PET) volumetric metabolic parameters, i.e., metabolic tumour volume (MTV) and total lesion glycolysis (TLG) play an important role in assessing the biological characteristics of some tumours and its role as potential prognostic factors has also been introduced.

Objectives

The aim of this retrospective study is to assess the value of baseline metabolic volumetric parameters as prognostic imaging biomarkers in patients with pulmonary masses/nodules treated with SABR.

Methods

70 patients were included in this retrospective study (39 male and 31 female, age range 47–91 years, mean 76 years). Standardized uptake value (SUVmax), SUVmean, MTV and TLG for all the patients were calculated on baseline ¹⁸F-FDG PET/CT. Patient outcome was divided into 3 categories free of disease, stable disease and disease progression.

Results

There was no significant statistical difference in the SUVmax and SUVmean in all the three categories. Mean SUVmax ranges from 7.13 to 8.08 with its highest value in the stable disease and lowest value in the progressive disease categories. Similarly, the average SUVmean was 4.9 in the free of disease category and 4.68 in the progressive disease category. MTV and TLG were low in the free of disease and the highest in progressive disease. MTV increased from 2.25 cm³ in free of disease category to 3.23 cm³ and 7.29 cm³ in stable disease and progressive disease, respectively. TLG has increased from 11.7 in the disease-free survival category to 18.77 and 40.39 in the stable and progressive disease, respectively. Patients with low MTV had longer overall survival (OS) than patients with high MTV (37 months versus 27 months, p value = 0. 0018). In addition, OS was longer in patients with low TLG (36 months versus 24 months, p value = 0.016).

Conclusions

TLG and MTV are more useful than SUVmax and SUVmean for predicting outcome, OS and progression-free survival (PFS) in patients receiving SABR. The TLG and MTV measurement on ¹⁸F-FDG PET imaging may be routinely recommended in baseline ¹⁸F-FDG PET/CT prior to SABR.