CT-Guided 125I Seed Interstitial Brachytherapy as a Salvage Treatment for Recurrent Spinal Metastases after External Beam Radiotherapy

Clinical outcomes of radioactive seed brachytherapy and microwave ablation in inoperable stage I non-small cell lung cancer

This study assessed the efficacy and safety of radioactive iodine-125 seed ablation brachytherapy (RSABT) in comparison to microwave ablation therapy (MWAT) for treating inoperable stage I non-small cell lung cancer (NSCLC). We conducted a retrospective analysis of data from stage I NSCLC patients who underwent CT-guided RSABT or MWAT. The primary outcomes measured were progression-free survival (PFS), overall survival (OS), and the occurrence of adverse events. Of the patients included in the study, 71 underwent RSABT and 105 received MWAT. The median follow-up time for these groups was 47.4 months and 60 months, respectively. The PFS rates at 1-year, 3-year, and 5-year for the RSABT group were 87.3%, 72.6%, and 65.8%, while for the MWAT group, they were 89.5%, 69.3%, and 43.7%, respectively (P = 0.011). The OS rates at 1-year, 3-year, and 5-year for the RSABT group were 97.2%, 78.1%, and 66.1%, and for the MWAT group, they were 99%, 75.8%, and 55%, respectively (P = 0.112). Upon multivariate analysis, the treatment modality was identified as an independent predictor of PFS (P = 0.008). Additionally, both sex and T stage were found to be independent predictors of both PFS and OS (P < 0.05). Adverse events, such as pneumothorax, occurred in 50% of the MWAT group and 39% of the RSABT group (P = 0.313). The incidence of pleural effusion was 44% in the MWAT group compared to 14% in the RSABT group (P < 0.001). Needle bleeding was observed in 32% of the RSABT group and 5% of the MWAT group (P < 0.001). We conclude RSABT demonstrates promising efficacy and safety in the treatment of stage I NSCLC. However, further studies are essential to validate these preliminary findings.

Multimodal locoregional procedures for cancer pain management: a literature review

Pain is the most common and fearsome symptom in cancer patients, particularly in the advanced stage of disease. In cancer pain management, the first option is represented by analgesic drugs, whereas surgery is rarely used. Prior to considering surgical intervention, less invasive locoregional procedures are available from the wide pain management arsenal. In this review article, comprehensive information about the most commonly used locoregional options available for treating cancer pain focusing on interventional radiology (neurolysis, augmentation techniques, and embolization) and interventional radiotherapy were provided, also highlighting the potential ways to increase the effectiveness of treatments.

Safety and efficacy of stereotactic ablative brachytherapy as a salvage therapy for recurrent chest wall cancer: A retrospective, multicenter study

Purpose

To evaluate the safety and efficacy of stereotactic ablative brachytherapy (SABT) as a salvage therapy for patients with recurrent chest wall cancer (rCWC) who have previously received external beam radiotherapy (EBRT) or surgery.

Materials and methods

Between November 2013 and October 2020, a total of 130 patients (including 75 men with a median age of 63 years) with rCWC treated with SABT were enrolled in this multicenter retrospective study. There were 97 cases of non-small-cell lung carcinoma, 24 cases of breast cancer, and 9 cases of thymic cancer. Of the patients included, 102 patients previously received surgery and 58 patients received EBRT, with systemic treatment progressing after recurrence. None of them were suitable or refused to undergo salvage EBRT or surgery again.

Results

During the 22 (4-70)-month median patient follow-up, 59 patients died. The local control (LC) rates at 6, 12, 24, and 36 months were 88.3%, 74.3%, 50.4%, and 36.7%, respectively. The 1-, 2- and 3-year survival rates were 85%, 56%, and 42%, respectively. The median overall survival was 26 months (95% CI, 18.9-33.1 months). The pain relief rate was 81%, and the median to remission time was 10 days. Univariate and multivariate analyses showed that independent prognostic factors for LC included tumor size and postoperative D90. On the other hand, independent prognostic factors for survival include the Karnofsky performance status (KPS) score, tumor size, and D90 19 patients (14.6%) developed grade I/II skin reaction complications. No grade III or severer complications occurred.

Conclusion

SABT is safe and effective as a salvage therapy for rCWC following EBRT/surgery. For patients with a KPS score greater than 80, prescribed dose greater than 130 Gy, and tumor size less than 4 cm may bring better results.

Efficacy and safety of CT-guided 125I seed implantation by coplanar template as a salvage therapy for vertebral metastases after failure of external beam radiation therapy: a retrospective study

Purpose

To evaluate the efficacy safety of computed tomography (CT)-guided ¹²⁵I seed implantation by coplanar template for vertebral metastases after failure of external beam radiation therapy (EBRT).

Material and methods

Retrospective analysis of the clinical outcomes of 58 patients with vertebral metastases after failure of EBRT, who underwent ¹²⁵I seed implantation as a salvage treatment with a CT-guided coplanar template-assisted technique from January 2015 to January 2017.

Results

The mean post-operative NRS score decreased significantly at T_4w (3.5 ± 0.9, p<0.01), T_8w (2.1 ± 0.9, p<0.01), T_12w (1.5 ± 0.7, p< 0.01) and T_6m (1.2 ± 0.6, p< 0.01) respectively. The local control rates after 3, 6, 9 and 12 months were 100% (58/58), 93.1% (54/58), 87.9% (51/58), and 81% (47/58), respectively. The median overall survival time was 18.52months (95% CI, 16.24-20.8), and 1- and 2-year survival rates were 81% (47/58) and 34.5% (20/58), respectively. By performing a paired t-test analysis, there was no significant difference in D90, V90, D100, V100, V150, V200, GTV volume, CI, EI and HI between preoperative and postoperative (p>0.05).

Conclusions

¹²⁵I seed implantation can be used as a salvage treatment for patients with vertebral metastases after failure of EBRT.

125I brachytherapy: a useful treatment to control painful osteoblastic bone metastases

Backgrounds

125I brachytherapy is effective in relieving cancer pain due to osteolytic bone metastases. However, fewer studies focused on painful osteoblastic bone metastases (OBMs), we conducted a retrospective study to evaluate the efficacy of 125I brachytherapy for the treatment of painful OBMs.

Methods

From April 2017 to April 2019, clinical data of a total of 65 patients with OBMs who underwent CT/cone beam CT -guided 125I brachytherapy were collected and analyzed. The primary study endpoints were technical success, relief of pain (RoP), and quality of life (QoL). The secondary study endpoints were treatment-related complications, local tumor control (LCR), and overall survival (OS). The logistic regression analysis was performed to predict RoP.

Results

Technical success rate was 100%. Visual analog scale scores and daily morphine consumption continuously decreased significantly at 2 weeks, 6 weeks, and 10 weeks (all P < 0.05). The RoP at 6 weeks was 84.62%. QoL presented improvement at 6 and 10 weeks. Only minor complications occurred in 12 patients (18.46%). LCR was 93.85% at 10 weeks. The OS was 29.80 months. Two factors were significantly associated with the RoP: max diameter (MD, < 3 cm vs. ≥ 3 cm, P = 0.019) and serum levels of bone alkaline phosphatase (B-ALP, ≥ 100 U/L vs. < 100 U/L, P = 0.016).

Conclusions

125I brachytherapy is an effective treatment in relieving painful OBMs and improving patients’ QoL.

Systematic review of brachytherapy for symptom palliation

PURPOSE

Brachytherapy is most often applied in the curative or salvage setting, but many forms of brachytherapy can be helpful for symptom palliation. Declining utilization is seen, for multiple reasons, such as lack of awareness, insufficient expertise, or poor access to equipment. High level evidence for many types of palliative brachytherapy has been lacking. The objective of the current study was to review the evidence for utilization and efficacy of brachytherapy to palliate symptoms from cancer.

MATERIALS AND METHODS

We performed a systematic search in EMBASE and MEDLINE for English-language articles published from January 1980 to May 2022 that described brachytherapy used for a palliative indication in adults with a diagnosis of cancer (any subtype) and at least one symptom related outcome. Individual case reports and conference abstracts were excluded. All publications were independently screened by two investigators for eligibility.

RESULTS

The initial search identified 3637 abstracts of which 129 were selected for in-depth review. The number of studies (total number of patients) included in the final analysis varied widely by tumor site with the majority (68.2%) involving either lung or esophageal cancer. Despite a limited number of prospective trials that assessed the efficacy of brachytherapy for symptom management, there was a positive effect on palliation of symptoms across all tumor types. There was no clear trend in the number of publications over time. The most commonly cited symptom indications for palliation by brachytherapy were dysphagia, dyspnea, pain and bleeding.

CONCLUSIONS

Brachytherapy can provide palliation for patients with advanced cancer, across different tumor sites and clinical scenarios. However, high level evidence in the literature to support palliative applications of brachytherapy is lacking or limited for many tumor sites. There appears to be a strong publication bias towards positive studies in favor of brachytherapy. Beyond anecdotal reports and individual practices, outcomes research can further our understanding of the role of brachytherapy in palliating advanced cancers of all types, and should be encouraged.

Small-scale spatiotemporal epidemiology of notifiable infectious diseases in China: a systematic review

Background

The prevalence of infectious diseases remains one of the major challenges faced by the Chinese health sector. Policymakers have a tremendous interest in investigating the spatiotemporal epidemiology of infectious diseases. We aimed to review the small-scale (city level, county level, or below) spatiotemporal epidemiology of notifiable infectious diseases in China through a systematic review, thus summarizing the evidence to facilitate more effective prevention and control of the diseases.

Methods

We searched four English language databases (PubMed, EMBASE, Cochrane Library, and Web of Science) and three Chinese databases (CNKI, WanFang, and SinoMed), for studies published between January 1, 2004 (the year in which China’s Internet-based disease reporting system was established) and December 31, 2021. Eligible works were small-scale spatial or spatiotemporal studies focusing on at least one notifiable infectious disease, with the entire territory of mainland China as the study area. Two independent reviewers completed the review process based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

A total of 18,195 articles were identified, with 71 eligible for inclusion, focusing on 22 diseases. Thirty-one studies (43.66%) were analyzed using city-level data, 34 (47.89%) were analyzed using county-level data, and six (8.45%) used community or individual data. Approximately four-fifths (80.28%) of the studies visualized incidence using rate maps. Of these, 76.06% employed various spatial clustering methods to explore the spatial variations in the burden, with Moran’s I statistic being the most common. Of the studies, 40.85% explored risk factors, in which the geographically weighted regression model was the most commonly used method. Climate, socioeconomic factors, and population density were the three most considered factors.

Conclusions

Small-scale spatiotemporal epidemiology has been applied in studies on notifiable infectious diseases in China, involving spatiotemporal distribution and risk factors. Health authorities should improve prevention strategies and clarify the direction of future work in the field of infectious disease research in China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07669-9.

Interstitial 125I Brachytherapy as a Salvage Treatment for Refractory Cervical Lymph Node Metastasis of Thoracic Esophageal Squamous Cell Carcinoma After External Irradiation With a CT-Guided Coplanar Template-Assisted Technique: A Retrospective Study

Purpose: To analyze the outcome and prognosis of patients with refractory cervical lymph node metastasis of thoracic esophageal squamous cell carcinoma after external irradiation, who underwent interstitial ¹²⁵I brachytherapy as a salvage treatment with a CT-guided coplanar template-assisted technique. We also want to compare the dosimetry of 3D printed coplanar template-assisted interstitial ¹²⁵I brachytherapy preoperative and postoperative, and to explore the accuracy of this technology. Material and methods: We retrospectively collected and analyzed the results of 32 patients with refractory cervical lymph node metastasis of thoracic esophageal squamous cell carcinoma after external irradiation, who underwent interstitial ¹²⁵I brachytherapy as a salvage treatment with a CT-guided coplanar template-assisted technique from January 2012 to December 2017. Results: The actual D90 were 114 to 240 Gy, and the median postoperative dosimetry assessment was 177.5 Gy. The local control rates at 3, 6, 9, and 12 months were 87.5%, 59.38%, 40.63%, and 31.25%, respectively. The median local control time was 7.5 months. The median overall survival time was 10.5 months (95% CI, 8.9-13.4), and the survival rates of 1- and 2-year, respectively, were 43.75% and 9.38%. There were 36 lesions in 32 patients. By performing a paired t-test analysis, there was no significant difference in D90, D100, V100, V150, V200, GTV volume, CI, EI, and HI between preoperative and postoperative (P > .05). Conclusions: Interstitial ¹²⁵I brachytherapy can be used as a salvage treatment for patients with refractory cervical lymph node metastasis of thoracic esophageal squamous cell carcinoma after external irradiation. With the auxiliary function of 3D printed coplanar template, the main dosimetry parameters verified after the operation can meet the requirements of the preoperative plan with good treatment accuracy.

Radioactive Iodine-125 in Tumor Therapy: Advances and Future Directions

Radioactive iodine-125 (I-125) is the most widely used radioactive sealed source for interstitial permanent brachytherapy (BT). BT has the exceptional ability to deliver extremely high doses that external beam radiotherapy (EBRT) could never achieve within treated lesions, with the added benefit that doses drop off rapidly outside the target lesion by minimizing the exposure of uninvolved surrounding normal tissue. Spurred by multiple biological and technological advances, BT application has experienced substantial alteration over the past few decades. The procedure of I-125 radioactive seed implantation evolved from ultrasound guidance to computed tomography guidance. Compellingly, the creative introduction of 3D-printed individual templates, BT treatment planning systems, and artificial intelligence navigator systems remarkably increased the accuracy of I-125 BT and individualized I-125 ablative radiotherapy. Of note, utilizing I-125 to treat carcinoma in hollow cavity organs was enabled by the utility of self-expandable metal stents (SEMSs). Initially, I-125 BT was only used in the treatment of rare tumors. However, an increasing number of clinical trials upheld the efficacy and safety of I-125 BT in almost all tumors. Therefore, this study aims to summarize the recent advances of I-125 BT in cancer therapy, which cover experimental research to clinical investigations, including the development of novel techniques. This review also raises unanswered questions that may prompt future clinical trials and experimental work.

Aortoesophageal fistula involving the central aortic arch salvaged with emergent percutaneous TEVAR, great vessel coverage and in vivo graft fenestration

Immediate intervention is needed for aortoesophageal fistulas (AEF), a rare but highly lethal cause of massive gastrointestinal hemorrhage. Emergent thoracic endovascular aortic repair (TEVAR) is considered first-line treatment for massive bleeding from AEFs. We describe an unusual and challenging case of TEVAR coverage of an AEF involving the central aortic arch immediately followed by in vivo endograft fenestration to regain arch vessel perfusion. In vivo fenestration, currently a procedure for emergency or investigational purposes only, was shown to be life saving in our case. The main complications associated with the procedure included stroke and infection, requiring esophagectomy and cervical diversion as well as ongoing antibiotic treatment.

Iodine-125 radioactive seed brachytherapy as a treatment for spine and bone metastases: A systematic review and meta-analysis

AIM

To evaluate the analgesic efficacy, safety, and local tumor control of iodine-125 (¹²⁵I) seed brachytherapy (BT) for the management of spine and bone metastases.

METHODS

A systematic literature search was conducted using PubMed, the Cochrane Library, and Scopus databases. Data regarding patient demographics, tumor characteristics, procedural parameters, and clinical outcomes were extracted and analyzed.

RESULTS

Fourteen studies (7 prospective, 7 retrospective) were included, accounting for 689 patients, in our review. Analgesic efficacy was assessed at baseline and various postoperative time points. Significant improvement in pain was noted at 4- and 24-week follow-ups (p < 0.01). Interestingly, all studies that combined ¹²⁵I seed BT with cement augmentation reported relatively higher levels of pain reduction (mean pain reduction ≥4 points) as compared to the studies which applied ¹²⁵I seed BT as a stand-alone therapy (mean pain reduction ≥2 points), at the last follow-up. Local tumor control rates ranged widely from 14% to 100% at varying follow-ups. Median overall survival ranged between 10 months and 25 months. The overall complication rate was 19% (130/689) and mainly included minor subcutaneous hemorrhage, fever, myelosuppression, and seed displacement. Metrics assessing performance and quality of life demonstrated significant improvements from baseline to posttreatment.

CONCLUSION

¹²⁵I seed BT, alone or in conjunction with cement augmentation, may be a viable salvage therapy in appropriately selected patients. However, further studies are needed to analyze the long-term efficacy of this intervention as a palliative and curative modality.

Clinical Therapy of Metastatic Spinal Tumors

Metastatic spinal tumors (MST) have high rates of morbidity and mortality. MST can destroy the vertebral body or compress the nerve roots, resulting in an increased risk of pathological fractures and intractable pain. Here, we elaborately reviewed the currently available therapeutic options for MST according to the following four aspects: surgical management, minimally invasive therapy (MIT), radiation therapy, and systemic therapy. In particular, these aspects were classified and introduced to show their developmental process, clinical effects, advantages, and current limitations. Furthermore, with the improvement of treatment concepts and techniques, we discovered the prevalent trend toward the use of radiation therapy and MIT in clinic therapies. Finally, the future directions of these treatment options were discussed. We hoped that along with future advances and study will lead to the improvement of living standard and present status of treatment in patients with MST.

Electron beam intraoperative radiotherapy for metastatic epidural spinal cord compression: a prospective observational study

To assess the additional effects of intraoperative radiotherapy (IORT) with decompression surgery and adjuvant external beam radiotherapy (EBRT) for metastatic epidural spinal cord compression (MESCC). This single-arm institutional prospective observational study recruited patients between June 2017 and March 2020 and included those with symptoms of spinal cord compression owing to metastases, who were diagnosed using MRI. Patients with radiation-sensitive primary tumors and those who could not tolerate surgery were excluded. The treatment protocol comprised decompression surgery and electron beam IORT of 20 Gy in a single fraction followed by EBRT of 30 Gy in 10 fractions. The primary endpoints included the 1-year local failure rate and ambulatory functions. The study was closed in May 2019 owing to changes in treatment policies at our institution. Twenty patients were registered between June 2017 and May 2019. Although all patients completed surgery and IORT, 2 did not receive postoperative EBRT. Patients most commonly had colorectal cancer (4 patients), followed by thyroid cancer, renal cell carcinoma, lung cancer, breast cancer, sarcomas, and other cancers (3, 3, 2, 2, 2, and 4 patients, respectively). The median follow-up duration was 16 months (range 2-30 months); the 1-year local failure rate was 16%. On comparing ambulatory functions pre-treatment and at 1 year after treatment, improvement, no change, and worsening were observed in 3, 9, and 0 patients, respectively. This study's findings suggest that decompression surgery and IORT followed by EBRT are effective in achieving local control and maintaining ambulation in patients with MESCC.

Accuracy and dosimetric parameters comparison of 3D-printed non-coplanar template-assisted computed tomography-guided iodine-125 seed ablative brachytherapy in pelvic lateral recurrence of gynecological carcinomas

Purpose

To investigate the accuracy of needle distribution and dosimetric parameter differences of 3D-printing non-coplanar template (3D-PNCT)-assisted computed tomography (CT)-guided iodine-125 seed ablative brachytherapy (¹²⁵I-SAB) in gynecological cancer patients with non-central pelvic recurrence between pre-operative plan and post-operative plan.

Material and methods

Thirty-eight patients with forty-one non-central pelvic recurrent gynecological carcinomas after radiotherapy were enrolled in this study. All patients received 3D-PNCT-assisted CT-guided ¹²⁵I-SAB from January 2016 to January 2019. The position, angle, and depth of seed needles were measured in both pre-operative plan and intra-operative real-time plan in brachytherapy treatment planning system (B-TPS). Dosimetric parameters of D₉₀, D₁₀₀, V₁₀₀, V₁₅₀, and V₂₀₀ as well as quality parameters of conformal index (CI), external index (EI), and homogeneity index (HI) were compared between pre-operative plan and post-operative plan. Peri-operation complications and radiation-related toxicity were assessed.

Results

Median follow-up time was 12 months (range, 5-34 months). Prescribed dose was 100-170 Gy (median, 120 Gy). Radioactivity of ¹²⁵I seed was 0.4-0.7 mCi (median, 0.55 mCi). Mean depth deviation for 499 needles was 0.8 ±1.0 cm. Mean angular deviation was 2.2 ±2.1 degrees. Mean tip distance deviation of needles was 0.4 ±0.3 cm. There were significant differences between pre-operative and post-operative plans in CI (p = 0.001) and EI (p = 0.005). No significant differences were shown in D₉₀, D₁₀₀, V₁₀₀, V₁₅₀, V₂₀₀, and HI between pre-operative and post-operative plans. Only few patients suffered from ≤ grade 2 toxicities.

Conclusions

3D-PNCT-assisted CT-guided ¹²⁵I-SAB is safe and feasible for non-central pelvic recurrence of gynecological cancer. All complications are tolerable and mild.

CT-guided 125I brachytherapy combined with chemotherapy for the treatment of unresectable or locally advanced pancreatic carcinoma

PURPOSE

We aimed to explore the feasibility and clinical effectiveness of percutaneous CT-guided iodine-125 (¹²⁵I) brachytherapy combined with chemotherapy for the treatment of patients with unresectable or locally advanced pancreatic carcinoma (PC).

METHODS

We retrospectively reviewed 66 patients with Stage III and IV PC who had received chemotherapy. A total of 35 (53%) patients receiving 125I brachytherapy and chemotherapy (gemcitabine + cisplatin, GP) were classified as Group A, and 31 (47%) patients who received GP chemotherapy alone were categorized as Group B. The evaluated indications were local control rate (LCR), local progression-free survival (LPFS), overall survival (OS), treatment-related complications, and the degree of symptom relief. Kaplan-Meier curves, log-rank test and Cox regression models were generated and used for further analysis to identify predictors of outcomes.

RESULTS

The median follow-up time was 6.00±0.84 months. The 1-, 3-, 6-, 12- and 18-month LCRs for Group A were 100% (35/35), 89.3% (25/28), 71.4% (15/21), 37.5% (3/8) and 33.3% (1/3), respectively; and those for Group B were 87.1% (27/31), 69.6% (16/23), 41.2% (7/17), 14.3% (1/7) and 0% (0/3), respectively. The LCR differed at 1-, 3- and 6-months (P = 0.032; P = 0.009; P = 0.030; respectively). The median LPFS was 7.00±0.30 months and 5.00±0.75 months for Groups A and B (P = 0.023), respectively; however, the median OS of the groups were not significantly different (8.00±0.77 months vs. 6.00±1.04 months. P = 0.917). No life-threatening complications occurred during or after the procedures. Patients in Group A experienced better pain control and relief of abdominal distension than those in Group B.

CONCLUSION

CT-guided 125I brachytherapy is a feasible, safe, and valuable treatment for patients with unresectable PC.

MR-guided 125I seed implantation treatment for maxillofacial malignant tumor

PURPOSE

This study assessed the therapeutic efficacy of postoperative magnetic resonance (MR)-guided interstitial 125 I seed implantation for treatment of oral and maxillofacial malignant tumors.

METHODS AND MATERIALS

A total of 127 patients with oral or maxillofacial malignant tumors were included in this study who received interstitial 125 I treatment after the surgery resection. Before implantation, all the patients received MR scans to assess the lesion scope, extent, and nature. 125 I implantation target regions were based on the pre-operative imaging. 125 I seeds were delivered to target regions via puncture needles under the real-time guidance of MR. Computed tomography (CT)or MR was performed immediately after implantation and again every 3 months later.

RESULTS

After successful 125 I implantation, all patients were also examined regularly to detect tumor recurrence, lymphatic, and distant metastases. To date, CT or MR verification showed that 13/127 patients experienced tumor recurrence or lymphatic metastasis or distant metastasis. No seeds migration was observed, no serious treatment-related complications affected patient quality of life, and no important organ (such as major cervical vessels, spinal cord, etc.) injuries were observed.

CONCLUSION

Our results show that MR-guided 125 I implantation is an effective approach to site-specific treatment for oral and maxillofacial tumor, which could potentially reduce postoperative complications and tumor recurrence rates, increase patient survival, and improve quality of life.

Monte Carlo study on the gold and gadolinium nanoparticles radio-sensitizer effect in the prostate 125I seeds radiotherapy

Monte Carlo and TL dosimetry applied to the characterization of 125I brachytherapy with a different design with other 125I seeds. In a water phantom, lattice configuration simulated with 125I seed in the center and 10 nm gold and gadolinium nan-particle filed voxels. This simulation conducted to the characterization of the nano-particles DEF in low energy and prostate tissue. To study of the prostate brachytherapy, a humanoid computational phantom developed by CT slices applied. KTMAN-2 computational phantom contains 29 organs and 19 skeletal regions and was produced from cross-sectional x-ray computed tomography (CT slices) images. The simulated seed was 125I seed having an average energy of 28.4 keV for photons, a half-life of 59.4 days. DEF factor in the seed radiation energy (28.4 keV) DEF factor was found to be two times higher for the gold nano-particles. It was revealed than gold-nano-particles posing Z about 1.24 times higher than gadolinium led to around 200% DEF increasing in the same conditions and the nano-particles size. It was concluded that in low energy sources brachytherapy, photoelectric is dominant in the presence of relative high element nanoparticles. This leads to a high dose increasing in some micro-meters and causes a dramatic dose gradient in the vicinity of a nano-particle. This dose gradient effectively kills the tumor cells in continuous low energy irradiation in the presence of a high Z material nano-scaled particle. Application of gold nano-particles in low energy brachytherapy is recommended.

DTI and pathological changes in a rabbit model of radiation injury to the spinal cord after 125I radioactive seed implantation

Excessive radiation exposure may lead to edema of the spinal cord and deterioration of the nervous system. Magnetic resonance imaging can be used to judge and assess the extent of edema and to evaluate pathological changes and thus may be used for the evaluation of spinal cord injuries caused by radiation therapy. Radioactive ¹²⁵I seeds to irradiate 90% of the spinal cord tissue at doses of 40–100 Gy (D90) were implanted in rabbits at T₁₀ to induce radiation injury, and we evaluated their safety for use in the spinal cord. Diffusion tensor imaging showed that with increased D90, the apparent diffusion coefficient and fractional anisotropy values were increased. Moreover, pathological damage of neurons and microvessels in the gray matter and white matter was aggravated. At 2 months after implantation, obvious pathological injury was visible in the spinal cords of each group. Magnetic resonance diffusion tensor imaging revealed the radiation injury to the spinal cord, and we quantified the degree of spinal cord injury through apparent diffusion coefficient and fractional anisotropy.

Surgical decompression for recurrent cord compression in cancer: a case series and review of the literature

Spine metastases affect a significant number of cancer patients each year, with the spine being the third most common location for cancer spread. As patients live longer with improved treatments, the opportunity for recurrence at previously treated sites increases. Here, we describe seven patients with recurrent, compressive, metastatic spine tumors at previously surgically treated sites that required additional surgical intervention with manipulation of at least one rod. Five of the patients had recurrence including adjacent levels while two had recurrence solely at the previously decompressed level. The patients remained ambulatory for an average of 31.2 months after the initial surgery. We also discuss the role of adjuvant treatment in these patients and review the literature.

[Repair and time-dose factor: The example of spinal cord irradiation]

The question whether a reirradiation is possible, with either curative of palliative intent, is a frequent issue and a true therapeutic challenge, in particular for a critical organ sensitive to cumulative dose, such as the spinal cord. Preclinical experimental data, based on debatable models that are hardly transferable to patients, suggest that there is a possibility of reirradiation, beyond the classical threshold for dose constraints, taking into account the "time-dose factor". Although the underlying biological mechanisms are however uncertain, scarce clinical data seem to confirm that the tolerance of spinal cord to reirradiation does exist, provided that a particular attention to total dose is given. In the context where modern stereotactic irradiation facilities expand therapeutic perspectives, we review the literature on possibilities of reirradiation, through the example of spinal cord reirradiation.