Objective:To explore the optimization potential of clinical target volume (CTV) delineation proposed in the guidelines of the Oncology Group (RTOG), the Francophone Group of Urological Radiotherapy (GFRU), and the European Society for Radiotherapy and Oncology (ESTRO) based on prostate bed local occurrence patterns after radical prostatectomy identified using prostate-specific membrane antigen positron emission tomography (PSMA PET).Methods:A retrospective analysis was conducted on patients with local prostate bed recurrence after radical prostatectomy who underwent PSMA PET at the Department of Nuclear Medicine, Peking University First Hospital from September 2021 to February 2024. The central point of each recurrence was marked. A six-zone method was established based on prostate bed anatomy and the characteristics of cross-sectional imaging. Then, the positional relationships (within or outside) were recorded with respect to recurrences and CTV defined by the RTOG, GFRU, and ESTRO (CTV RTOG, CTV GFRU, and CTV ESTRO), followed the analysis of the recurrence rates and distribution characteristics of various zones. Results:A total of 63 patients with prostate bed recurrence after radical prostatectomy were enrolled in this study, including 97 recurrences. The recurrence rates in the six zones were as follows: 10% of zone 1, 22% of zone 2, 29% of zone 3, 2% of zone 4, 12% of zone 5a, 18% of zone 5b, and 7% of zone 6. Among these zones, zones 2 and 3 showed the highest and second-highest recurrence rates, respectively. CTV GFRU and CTV ESTRO completely covered zones 2 and 3, while CTV RTOG covered zone 2 completely and zone 3 partially. Zone 4, characterized by a low recurrence rate, was not covered by CTV GFRU and CTV ESTRO but was entirely covered by CTV RTOG. Zone 5a, with a recurrence rate of 12%, was completely covered by CTV RTOG but was partially covered by CTV GFRU and CTV ESTRO. The range of 1.3 cm in front of the posterior wall of the bladder covered all recurrences in zone 5a. Conclusions:For CTV delineation of the prostate cancer surgical bed, zone 4, the anterior half of the bladder above the pubic symphysis midpoint, should be contracted due to the low recurrence rate in this zone. In contrast, the anterior boundary above the pubic symphysis midpoint should extend to 1.3 cm in front of the posterior wall of the bladder to completely cover the recurrence zones.

Undifferentiated spindle cell sarcoma of the prostate is clinically rare. This article reports a case of a 29-year-old male who presented on February 7，2022，with a two-week history of localized pain in the perineal area and spermatic cord. The diagnosis of prostatic undifferentiated spindle cell sarcoma was confirmed by imaging studies and prostate needle biopsy pathology. After consultation by the urologic oncology multidisciplinary team and considering the patient's preference，a treatment plan of radical radiotherapy combined with chemotherapy，immunotherapy，and targeted therapy was adopted，Partial stereotactic body radiotherapy（P-SBRT）was delivered to the tumor center with a total dose of 74.4 Gy，combined with cisplatin and pembrolizumab. Lung metastasis progression occurred 1.5 months after radiotherapy，and treatment was switched to a combination of pirarubicin，ifosfamide，pembrolizumab，and bevacizumab. After 39 months of follow-up，the disease remained well-controlled with preserved organ function and long-term survival. This case，utilizing a multidisciplinary comprehensive diagnosis and treatment model，provides a reference for organ-preserving non-surgical management in patients with prostate soft tissue sarcoma.

Objective:To explore the optimization potential of clinical target volume (CTV) delineation proposed in the guidelines of the Oncology Group (RTOG), the Francophone Group of Urological Radiotherapy (GFRU), and the European Society for Radiotherapy and Oncology (ESTRO) based on prostate bed local occurrence patterns after radical prostatectomy identified using prostate-specific membrane antigen positron emission tomography (PSMA PET).Methods:A retrospective analysis was conducted on patients with local prostate bed recurrence after radical prostatectomy who underwent PSMA PET at the Department of Nuclear Medicine, Peking University First Hospital from September 2021 to February 2024. The central point of each recurrence was marked. A six-zone method was established based on prostate bed anatomy and the characteristics of cross-sectional imaging. Then, the positional relationships (within or outside) were recorded with respect to recurrences and CTV defined by the RTOG, GFRU, and ESTRO (CTV RTOG, CTV GFRU, and CTV ESTRO), followed the analysis of the recurrence rates and distribution characteristics of various zones. Results:A total of 63 patients with prostate bed recurrence after radical prostatectomy were enrolled in this study, including 97 recurrences. The recurrence rates in the six zones were as follows: 10% of zone 1, 22% of zone 2, 29% of zone 3, 2% of zone 4, 12% of zone 5a, 18% of zone 5b, and 7% of zone 6. Among these zones, zones 2 and 3 showed the highest and second-highest recurrence rates, respectively. CTV GFRU and CTV ESTRO completely covered zones 2 and 3, while CTV RTOG covered zone 2 completely and zone 3 partially. Zone 4, characterized by a low recurrence rate, was not covered by CTV GFRU and CTV ESTRO but was entirely covered by CTV RTOG. Zone 5a, with a recurrence rate of 12%, was completely covered by CTV RTOG but was partially covered by CTV GFRU and CTV ESTRO. The range of 1.3 cm in front of the posterior wall of the bladder covered all recurrences in zone 5a. Conclusions:For CTV delineation of the prostate cancer surgical bed, zone 4, the anterior half of the bladder above the pubic symphysis midpoint, should be contracted due to the low recurrence rate in this zone. In contrast, the anterior boundary above the pubic symphysis midpoint should extend to 1.3 cm in front of the posterior wall of the bladder to completely cover the recurrence zones.

Undifferentiated spindle cell sarcoma of the prostate is clinically rare. This article reports a case of a 29-year-old male who presented on February 7，2022，with a two-week history of localized pain in the perineal area and spermatic cord. The diagnosis of prostatic undifferentiated spindle cell sarcoma was confirmed by imaging studies and prostate needle biopsy pathology. After consultation by the urologic oncology multidisciplinary team and considering the patient's preference，a treatment plan of radical radiotherapy combined with chemotherapy，immunotherapy，and targeted therapy was adopted，Partial stereotactic body radiotherapy（P-SBRT）was delivered to the tumor center with a total dose of 74.4 Gy，combined with cisplatin and pembrolizumab. Lung metastasis progression occurred 1.5 months after radiotherapy，and treatment was switched to a combination of pirarubicin，ifosfamide，pembrolizumab，and bevacizumab. After 39 months of follow-up，the disease remained well-controlled with preserved organ function and long-term survival. This case，utilizing a multidisciplinary comprehensive diagnosis and treatment model，provides a reference for organ-preserving non-surgical management in patients with prostate soft tissue sarcoma.

Objective:To investigate the effects of different labeling conditions on the yield of Al 18F-labeled 1, 4, 7-triazacylononane-1, 4, 7-triaceticacid (NOTA)-prostate specific membrane antigen (PSMA)-137, and to determine the experimental condition for obtaining Al 18F-PSMA-137 probe in high yield. Methods:The effects of different pH values, buffer systems (acetic acid-sodium acetate buffer system and potassium hydrogen phthalate (KHP) buffer system), AlCl 3-ligand ratios, ligand amounts, ethanol volumes and reaction temperatures on the labeling rate were investigated in detail. Results:The pH value of the reaction solution had a significant effect on the labeling rate, and the optimal range was 4.0-4.5. When the pH value was higher than 4.5, the labeling rate decreased significantly. Both the acetic acid-sodium acetate buffer system and the KHP buffer system could be used to label NOTA-PSMA-137 with Al 18F, and the KHP buffer system obtained higher labeling rate. The ratio of AlCl 3-ligand affected the labeling rate, and the highest labeling rate could be obtained when the ratio of AlCl 3-ligand was 0.54-0.62. When the ratio of AlCl 3-ligand was fixed, increasing the amount of ligand could improve the labeling yield. Adding hydrophilic organic solvent ethanol to the reaction system could significantly increase yield, with the highest labeling rate being achieved at a volume of 100 μl ethanol. The most suitable reaction temperature was 100 ℃, and when the temperature raised to 110 ℃, the labeling rate decreased significantly. The most suitable labeling conditions for NOTA-PSMA-137 were as following: 25 μl KHP buffer (0.50 mol/L, pH=4.0), 7.0 μl AlCl 3 solution (20 mmol/L), 200 μl Na 18F solution (74-80 MBq) and 230 μg ligand NOTA-PSMA-137 were mixed in a vial, then stood for 5 min and 100 μl ethanol was added, and all reagents were heated at 100 ℃ for 10 min. The yield of Al 18F-PSMA-137 under above conditions were 85.7%-88.5%. Conclusion:Optimization of labeling condition can improve the yield of Al 18F-PSMA-137 and the stability of the labeling.

Objective: To explore the relationships of 18F-FDG standardized uptake value (SUV)-derived parameters and mutation subtypes (deletions in exon 19 and a mutation in exon 21) in lung adenocarcinoma patients with mutant epidermal growth factor receptor (EGFR) gene. Methods Data of 64 lung adenocarcinoma patients who underwent 18F-FDG PET/CT scans and EGFR gene mutation test were collected. The relationships of subtype mutation of EGFR gene with four parameters (maximum standardized uptake value [SUVmax], average of standardized uptake value [SUVmean], metabolic tumor volume [MTV] and total lesion glycolysis [TLG]) of primary lesion based on 18F-FDG PET/CT and clinical characteristics were evaluated with univariate and multivariate Logistic regression, respectively. Results The mutant ratio of exon 19 and exon 21 was 23:41. When the parameters were continuous variables, univariate Logistic regression showed exon 21 mutations were found more frequently in the EGFR-positive patients with shorter maximum diameter of primary lesion (OR=0.942, 95%CI [0.890,0.998]) and low level of MTV of primary lesion (pMTV) (OR=0.957, 95%CI [0.923,0.991]). As dichotomous variables, in univariate regression shorter maximum diameter of primary lesion (<26.5 mm: OR=3.759, 95%CI [1.284,11.005]), high level SUVmean (≥4.35: OR=4.267, 95%CI [1.088,16.726]), low level pMTV (<11.2 cm3: OR=7.000, 95%CI [1.798,27.253]) would be significantly related to mutant exon 21. The multivariate Logistic regression displayed that low level of pMTV were found more frequently in exon 21 mutations (OR=8.093, P=0.041). Conclusion: The primary-lesion SUV-derived parameters from 18F-FDG PET/CT of lung adenocarcinoma patients with EGFR-gene mutation associate with the mutant subtypes (exon 19 and 21 mutation) to some extent, but this correlation might be limited.

Objective To investigate the clinical value of 18 F?FDG PET/CT in staging multiple myeloma ( MM) and evaluating the glucose metabolic activity of MM. Methods A total of 25 MM patients ( 13 males, 12 females, age:39-67 years) from May 2010 to April 2015 were enrolled in this retrospective study. The SUVmax of each patient was recorded. D?S plus staging according to 18 F?FDG PET/CT was com?pared with the traditional D?S staging. The SUVmax and the percentage of plasmacytes of bone marrow of phase Ⅲ and non?phase Ⅲ ( phaseⅠand Ⅱ) according to D?S plus staging were compared. Two?sample t test and Wilcoxon rank sum test were used to analyze the data. Results In 25 MM patients, the range of SUVmax of lesions was 1.8-12?0 and the mean value was 5.15±2.74. According to D?S staging, the numbers of patients with phase Ⅰ,Ⅱ andⅢwere 7, 4 and 14, respectively. While the numbers were 3, 1 and 21 by D?S plus staging. Based on the D?S plus staging system, stages of 7 patients ( 28%, 7/25 ) were changed. According to the D?S plus staging system, the SUVmax between phaseⅢand non?phaseⅢpatients was significantly different (5.75±2.54 vs 3.00±0?70; t=2.12, P<0.05), while the percentage of plasma?cytes of bone marrow between the 2 groups had no significant difference ( 17. 50%( 4. 25%-41. 75%) vs 11?15%(10.25%-36.57%);z=0.05, P>0.05). Conclusion 18F?FDG PET/CT is of clinical importance for MM staging and metabolic activity assessment of MM.