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AimDescribe the results of brachytherapy in the prevention of recurrences in conjunctival melanoma (CM) and describe a dosimetric protocol.MethodsRetrospective and descriptive case report. Eleven consecutive patients with a confirmed histopathological diagnosis of CM treated with brachytherapy between 1992 and 2023 were reviewed. Demographic, clinical, and dosimetric characteristics as well as recurrences were recorded. Quantitative variables were represented by the mean, median, and standard deviation, and qualitative variables by frequency of distribution.ResultsOf a total of 27 patients diagnosed with CM, 11 who were treated with brachytherapy were included in the study (7 female; mean age at time of treatment: 59.4 years). Mean follow-up was 58.82 months (range 11–141 months). Of a total of 11 patients, 8 were treated with ruthenium-106 and 3 with iodine-125. Brachytherapy was performed in 6 patients as adjuvant therapy after biopsy-proven CM on histopathology and in the other 5 patients after recurrence. The mean dose was 85 Gy in all cases. Recurrences outside of the previously irradiated area were observed in 3 patients, metastases were diagnosed in 2 patients, and one case of an ocular adverse event was reported.ConclusionBrachytherapy is an adjuvant treatment option in invasive conjunctival melanoma. In our case report, only one patient had an adverse effect. However, this topic requires further research. Furthermore, each case is unique and should be evaluated by experts in a multidisciplinary approach involving ophthalmologists, radiation oncologists, and physicists.

Recurrent and metastatic tumors of the head and neck pose significant treatment challenges due to their proximity to critical structures and prior radiation exposure. This study aimed to evaluate the consistency between preoperative and postoperative dosimetric parameters in CT-guided 3D-printed noncoplanar template (3DPNCT)-assisted radioactive iodine-125 seed implantation (RISI). Twenty-six patients with recurrent or metastatic head and neck cancer were retrospectively analyzed. Gross tumor volume (GTV) coverage and dosimetric parameters such as D90 (dose covering 90% of the GTV), conformity index (CI), and homogeneity index (HI) were compared before and after implantation. The Shapiro-Wilk test was used to assess data normality. There were no significant differences between pre- and postoperative D90, V100, V150, or CI values (P > 0.05). Bland-Altman analysis showed high agreement for key metrics. 3DPNCT-assisted RISI demonstrated accurate dose delivery and high reproducibility. This approach may enhance local control while minimizing radiation to organs at risk in complex head and neck anatomies. These results suggest that this technique has promising clinical applicability in complex head and neck cases; however, further validation through larger prospective studies is warranted to confirm long-term efficacy and safety.

Cancer screening and surveillance programmes and the use of sophisticated imaging tools such as positron emission tomography‐computed tomography (PET‐CT) have increased the detection of impalpable lesions requiring imaging guidance for excision. A new technique involves intra‐lesional insertion of a low‐activity iodine‐125 (125I) seed and detection of the radioactive signal in theatre using a hand‐held gamma probe to guide surgery. Whilst several studies describe using this method to guide the removal of impalpable breast lesions, only a handful of publications report its use to guide excision of lesions outside the breast. We describe a case in which radio‐guided occult lesion localisation using an iodine 125 seed was used to guide excision of an impalpable posterior chest wall metastasis detected on PET‐CT. Use of a new technique involving intra‐lesional insertion of a low‐activity iodine 125 seed to guide excision of an impalpable chest wall metastasis.

Lung cancer, a leading cause of death, sees variable outcomes with iodine-125 seed implantation. Predictive tools are lacking, complicating clinical decisions. This study integrates radiomics and clinical features to develop a predictive model, advancing personalized treatment. To construct a nomogram model combining enhanced CT image features and general clinical characteristics to evaluate the efficacy of radioactive iodine-125 seed implantation in lung cancer treatment. Patients who underwent lung iodine-125 seed implantation at the Nuclear Medicine Department of Xiling Campus, Yichang Central People's Hospital from January 1, 2018, to January 31, 2024, were randomly divided into a training set (73 cases) and a test set (31 cases). Radiomic features were extracted from the enhanced CT images, and optimal clinical factors were analyzed to construct clinical, radiomics, and combined models. The best model was selected and validated for its role in assessing the efficacy of iodine-125 seed implantation in lung cancer patients. Three clinical features and five significant radiomic features were successfully selected, and a combined nomogram model was constructed to evaluate the efficacy of iodine-125 seed implantation in lung cancer patients. The AUC values of the model in the training and test sets were 0.95 (95% CI: 0.91-0.99) and 0.83 (95% CI: 0.69-0.98), respectively. The calibration curve demonstrated good agreement between predicted and observed values, and the decision curve indicated that the combined model outperformed the clinical or radiomics model across the majority of threshold ranges. A combined nomogram model was successfully developed to assess the efficacy of iodine-125 seed implantation in lung cancer patients, demonstrating good clinical predictive performance and high clinical value.

Purpose We have developed probes for multiradionuclides radiotheranostics using RGD peptide ([ 67 Ga]Ga-DOTA-c[RGDf(4-I)K] ([ 67 Ga] 1 ) and Ga-DOTA-[ 211 At]c[RGDf(4-At)K] ([ 211 At] 2 )) for clinical applications. The introduction of an albumin binding moiety (ABM), such as 4-(4-iodophenyl)-butyric acid (IPBA), that has high affinity with the blood albumin and prolongs the circulation half-life can improve the pharmacokinetics of drugs. To perform more effective targeted alpha therapy (TAT), we designed and synthesized Ga-DOTA-K([ 211 At]APBA)-c(RGDfK) ([ 211 At] 5 ) with 4-(4-astatophenyl)-butyric acid (APBA), which has an astato group instead of an iodo group in IPBA. We evaluated whether APBA functions as ABM and [ 211 At] 5 is effective for TAT. In addition, we prepared 67 Ga-labeled RGD peptide without ABM, [ 67 Ga]Ga-DOTA-K-c(RGDfK) ([ 67 Ga] 3 ), and 125 I-labeled RGD peptide with ABM, Ga-DOTA-K([ 125 I]IPBA)-c(RGDfK) ([ 125 I] 4 ), to compare with [ 211 At] 5 . Methods Biodistribution experiments of [ 67 Ga] 3 without ABM, [ 125 I] 4 and [ 211 At] 5 with ABM were conducted in normal mice and U-87 MG tumor-bearing mice. In addition, two doses of [ 211 At] 5 (370 or 925 kBq) were administered to U-87 MG tumor-bearing mice to confirm the therapeutic effects. Results The blood retention of [ 125 I] 4 and [ 211 At] 5 was remarkably increased compared to [ 67 Ga] 3 . Also, [ 125 I] 4 and [ 211 At] 5 showed similar biodistribution and significantly greater tumor accumulation and retention compared to [ 67 Ga] 3 . In addition, [ 211 At] 5 inhibited tumor growth in a dose-dependent manner. Conclusion The functionality of APBA as ABM like IPBA, and the usefulness of [ 211 At] 5 as the radionuclide therapy agent for TAT was revealed.

Objectives To evaluate the role of sequential therapy with percutaneous biliary stenting and CT-guided iodine-125 seed implantation for locally advanced pancreatic carcinoma with concomitant obstructive jaundice. Methods Between January 2016 and December 2018, 42 patients diagnosed with locally advanced pancreatic carcinoma with concomitant obstructive jaundice were enrolled retrospectively. All patients received biliary stenting via percutaneous transhepatic biliary drainage (PTBD) to alleviate obstructive jaundice. Thereafter, twenty-two patients underwent CT-guided iodine-125 seed implantation (treatment group), and 20 did not (control group). The prescribed dose in the treatment group was 110–130 Gy. The clinical data, duration of biliary stent patency, and overall survival (OS) were evaluated. Results Overall, the total bilirubin level decreased from 275.89 ± 115.44 to 43.08 ± 43.35 μmol/L ( p < 0.001) 1 month after percutaneous biliary stenting. In the treatment group, the postoperative median dose covering 90% of the target volume was 129.71 Gy. Compared with the control group, the treatment group had a long mean duration of biliary stent patency and median OS (11.42 vs. 8.57 months, p < 0.01; 11.67 vs. 9.40 months, p < 0.01, respectively). The overall positive response rates 6 months post-treatment in the treatment and control groups were 72.7% (16/22) and 30% (6/20), respectively. Adverse events of more than grade 3 were not observed during the follow-up. Conclusion Sequential therapy with percutaneous biliary stenting and CT-guided iodine-125 seed implantation is an effective and safe treatment alternative for locally advanced pancreatic carcinoma with concomitant obstructive jaundice, which is worthy of clinical application. Key Points • Obstructive jaundice was alleviated after biliary stent placement in all patients, and the total bilirubin level decreased. • The overall positive response rates at 6 months post-treatment were higher in the treatment group than in the control group, and adverse events of more than grade 3 were not observed during the follow-up period. • Sequential therapy with percutaneous biliary stenting and CT-guided iodine-125 seed implantation can prolong biliary stent patency and improve survival.

Background Auger electrons (AEs) are very low energy electrons that are emitted by radionuclides that decay by electron capture (e.g. 111 In, 67 Ga, 99m Tc, 195m Pt, 125 I and 123 I). This energy is deposited over nanometre-micrometre distances, resulting in high linear energy transfer (LET) that is potent for causing lethal damage in cancer cells. Thus, AE-emitting radiotherapeutic agents have great potential for treatment of cancer. In this review, we describe the radiobiological properties of AEs, their radiation dosimetry, radiolabelling methods, and preclinical and clinical studies that have been performed to investigate AEs for cancer treatment. Results AEs are most lethal to cancer cells when emitted near the cell nucleus and especially when incorporated into DNA (e.g. 125 I-IUdR). AEs cause DNA damage both directly and indirectly via water radiolysis. AEs can also kill targeted cancer cells by damaging the cell membrane, and kill non-targeted cells through a cross-dose or bystander effect. The radiation dosimetry of AEs considers both organ doses and cellular doses. The Medical Internal Radiation Dose (MIRD) schema may be applied. Radiolabelling methods for complexing AE-emitters to biomolecules (antibodies and peptides) and nanoparticles include radioiodination ( 125 I and 123 I) or radiometal chelation ( 111 In, 67 Ga, 99m Tc). Cancer cells exposed in vitro to AE-emitting radiotherapeutic agents exhibit decreased clonogenic survival correlated at least in part with unrepaired DNA double-strand breaks (DSBs) detected by immunofluorescence for γH2AX, and chromosomal aberrations. Preclinical studies of AE-emitting radiotherapeutic agents have shown strong tumour growth inhibition in vivo in tumour xenograft mouse models. Minimal normal tissue toxicity was found due to the restricted toxicity of AEs mostly on tumour cells targeted by the radiotherapeutic agents. Clinical studies of AEs for cancer treatment have been limited but some encouraging results were obtained in early studies using 111 In-DTPA-octreotide and 125 I-IUdR, in which tumour remissions were achieved in several patients at administered amounts that caused low normal tissue toxicity, as well as promising improvements in the survival of glioblastoma patients with 125 I-mAb 425, with minimal normal tissue toxicity. Conclusions Proof-of-principle for AE radiotherapy of cancer has been shown preclinically, and clinically in a limited number of studies. The recent introduction of many biologically-targeted therapies for cancer creates new opportunities to design novel AE-emitting agents for cancer treatment. Pierre Auger did not conceive of the application of AEs for targeted cancer treatment, but this is a tremendously exciting future that we and many other scientists in this field envision.

Objectives To determine if dynamic CT can differentiate local progression from radioactive seed-induced peritumoral reaction (RSIPR) after brachytherapy with iodine-125 radioactive seeds (BIRS) for advanced hepatic malignancies. Methods Enhanced CT images of seed-implanted lesions between 2006 and 2018 were retrospectively evaluated. Hounsfield units of peritumoral parenchyma were measured and assessed quantitatively. The classification, conversion, consequences, and serological indicators during follow-up were recorded and quantified. Statistical differences were analyzed using a Pearson χ 2 test. Results RSIPR was observed in 201 of 290 (69.3%) lesions (161 patients; median age, 55 years; range, 26–79 years), while local progression occurred in 53 lesions. The low density of local progression was much lower than that of RSIPR ( p < 0.001), and the former did not exhibit iso-/high density in the portal or equilibrium phase. Ring-like enhancement in progressive lesions was also quite different from RSIPR. Local progression rate was lower for lesions with RSIPR than for those without RSIPR (14.9% vs 25.8%; p = 0.03), and their doses were different (397.2 Gy vs 120.3 Gy, p < 0.001). Conclusions Radioactive seed-induced peritumoral reaction has characteristic manifestations on CT images, which is associated with a higher dose of lesions and lower local progression rate. Notably, the enhancement pattern of local progression was distinct from RSIPR and was clearly distinguishable on dynamic-enhanced CT. Key Points • Radioactive seed-induced peritumoral reaction after brachytherapy with 125 I seeds for liver malignancies has characteristic manifestations on CT images, which is associated with a higher dose of lesions (397.2 Gy vs 120.3 Gy, p < 0.001), as a focal radiation injury. • Lesions with RSIPR were less likely to develop local progression, while those without RSIPR had a higher rate of local progression (14.9% vs 25.8%; p = 0.03). • The enhancement pattern of local progression after brachytherapy was distinct from radioactive seed-induced peritumoral reaction and was clearly distinguishable on dynamic-enhanced CT.

Background Radiotherapy (RT) is one of the four pillars of cancer treatment. Plesiotherapy, or contact brachytherapy, involves irradiating a tumor by placing small radioactive sources directly on the skin’s surface above the tumor. In this study, we evaluated the efficacy of a novel local external radiation technique using iodine-125 seeds enclosed within a 3D-printed case, positioned externally on the tumor surface. Methods First, the protocol was tested on the skin of NodRag1 mice with doses up to 10 Gy (at the skin), and the results demonstrated no signs of skin toxicity. Subsequently, this protocol was used to locally irradiate subcutaneous MDA-MB-231 triple-negative breast cancer and MCA-205 fibrosarcoma tumors via a single 10 Gy dose at the tumor center. Results RT significantly hindered tumor growth, with irradiated tumors being approximately half the size of nonirradiated tumors on the same day. Importantly, the irradiated mice exhibited no apparent systemic side effects, as evidenced by stable body weight and unaffected behavior, including alertness, appearance, and activity levels. Moreover, no instances of skin toxicity were observed. Conclusions This in vivo plesiotherapy protocol offers a straightforward and cost-effective means of advancing research on RT in a variety of laboratory settings.

PURPOSEWe aimed to evaluate the clinical benefit of 125I seed brachytherapy under DynaCT guidance for palliative local treatment of bone metastases.METHODSFrom December 2014 to September 2017, 82 patients with painful bone metastases, who experienced treatment failure using standard strategies or rejected treatment were enrolled in this retrospective study. All patients underwent 125I seed brachytherapy under DynaCT guidance. Technical success, visual analogue scale (VAS), numerical rating scale (NRS), verbal rating scale (VRS), Karnofsky performance status (KPS) and complications were analyzed.RESULTSThe success rate of 125I seed implantation was 100%. The VAS and NRS scores for the most severe pain were 7.0 (5.0–9.0) and 8.0 (6.0–9.0) before brachytherapy. The pain scores assessed every 2 hours gradually decreased within 12 hours (p < 0.001). A comparison of KPS scores showed that patients had significantly better quality of life on weeks 1, 4, and 8 than on week 0 (p < 0.001). The associated complications were mild subcutaneous hemorrhage 25.6% (21/82), fever 7.3% (6/82), minor displacement of radioactive seeds 5.0% (4/82), pathologic fracture 2.4% (2/82), and local skin reaction 2.4% (2/82). After symptomatic treatment, all complications were relieved. Minor displacement of radioactive seeds did not cause damage to adjacent tissues. No serious life-threatening complications occurred in the study group.CONCLUSIONDynaCT-guided 125I seed implantation is a safe and effective method for palliation of painful bone metastases from cancer after failure or rejection of conventional treatments.