Choice of radioisotope in stereotactic interstitial radiotherapy of small brain tumors

In stereotactic interstitial radiotherapy, small radioactive sources are placed within the brain tumor to deliver locally high radiation doses. The choice of the radioisotope depends upon the dose distribution around the isotope, energy of the emitted radiation, relative biological effectiveness, and finally, the cost and availability of the isotope. We have analyzed 198gold, 125iodine and 192iridium in terms of these four factors. Our results have shown that 125I is superior to the other two isotopes due to its soft X-rays and dosimetric as well as radiobiological properties. Unfortunately, it is the most expensive of these radioisotopes, and can be difficult to obtain in specific activities.     

Treatment of low malignancy brain neoplasms by means of stereotactic interstitial radiotherapy

The authors report their results of 37 patients with low malignancy brain tumors seated in deep or highly functional areas not amenable to traditional surgery, nor to conventional radiochemotherapy. In the past 5 years these patients were treated by means of stereotactic interstitial radiotherapy. The isotope employed in all cases was 125I. Stereotactic radioisotope implants were always preceded by multiple stereotactic biopsies affording precise histological diagnoses. A 6-month to 5-year follow-up shows a survival rate of 72.6% (29 patients), and of these patients, 80.9% (26 out of 29) had complete social reentry.     

Stereotaxy and thalamic masses. Survey of 44 cases

Thalamic masses are generally considered inoperable; little is known of the precise nature of these lesions. Stereotactic biopsy was performed in 44 patients, with no mortality and low morbidity (only 1 case of transitory hemiparesis). The stereotactic biopsy (minimum 5 specimens taken along the major axis of the lesion) showed that the majority of the young patients (less than 40 years) had low-grade glial neoplasms (grade I-II astrocytomas or oligodendrogliomas), while in older patients highly malignant tumors prevailed. Beside the neoplasms in the children and adults, we found granulomas, abscesses, infarcts, hemorrhages and glioses. Present neuroradiological methods cannot establish a final correct diagnosis in thalamic lesions, so stereotactic biopsy is recommended. A follow-up of 1-6 years is presented for 7 patients who underwent stereotactic 125I brachytherapy.     

Late considerations in the treatment of low-grade malignancy cerebral tumors with iodine-125 brachytherapy

The authors report their series of 45 patients harboring inoperable, low-grade cerebral neoplasms, treated in the past 6 years with 125I stereotactic brachytherapy. The majority of these tumors were grade I and II astrocytomas and oligodendrogliomas (82.2%). A 2.6- to 6-year follow-up shows good results in 65.6% with reduction or disappearance of the lesions on CT images and good social reentry. Nine patients (23.7%) died prior to follow-up. Young patients (less than 40 years) responded well to interstitial radiotherapy, while patients over 40 with the same histological findings of low-grade tumors responded poorly to this type of treatment. Diffuse infiltrating cortico-subcortical tumors, optochiasmatic gliomas, hypothalamic and lower brainstem neoplasms do not respond satisfactorily to 125I radioisotope implantations.     

An applicability study on a CT-guided stereotactic technique for functional neurosurgery

When a CT-guided stereotactic technique for functional neurosurgery is adopted, extremely precise targeting is needed to obtain satisfactory surgical results. In this study the authors have investigated the accuracy of the target points determined by CT-guided techniques and compared with those of conventional roentgenographically controlled stereotactic procedures. Stereotactic surgery, employing the Brown-Roberts-Wells (BRW) system, was performed contemporarily 26 times in 23 patients, that is, 9 times in 8 patients for functional neurosurgery using with the roentgenographic method, and 17 times in 15 patients with the CT-guided method only for intracranial neoplasm biopsy. As a result, there were no problems of accuracy of determining the target points by CT-guided stereotactic surgery with the BRW system. When applying this technique for functional neurosurgery, it should be pointed out that there could be a discrepancy within 2 mm from the conventional target determination.     

Use of navigation bronchoscopy for biopsy and endobronchial fiducial placement

Electromagnetic navigation bronchoscopy (ENB) is a technique that can be used to biopsy pulmonary lesions beyond areas that are traditionally accessible by bronchoscopy. It can also guide biopsies of peribronchial lymph nodes and guide the placement of fiducial markers for stereotactic radiosurgery. With ENB, the patient is placed in a magnetic field and their anatomy is merged with a 3D reconstructed chest cat scan (CCT). A locatable, steerable probe is used to guide a working channel to the target, usually a peripheral tumor. Biopsies can be taken, and markers can be placed. The accuracy of this system depends largely on a small bronchus leading toward to target. The diagnostic yield is similar to CT-guided biopsies, with a false-negative rate of about 30%, although results may be improved with combined ENB and radial endoscopic ultrasound (EUS). The incidence of pneumothorax is 5% to 8% with ENB-directed biopsies compared with approximately 30% with CT-guided transthoracic biopsy.     

Interstitial radiation in recurrent malignant gliomas

Twelve patients with recurrent supratentorial gliomas were treated with implanted 125I seeds. The interval from initial surgery to interstitial radiation ranged from 3 months to 9 years. The techniques for brachytherapy included volume implantation by craniotomy in one, stereotactic implantation with low-activity seeds in 7 and high-activity seeds in 4 patients. The total dose received ranged from 5,500 to 27,000 cGy. CT scans performed sequentially on all patients showed progressive attenuation in areas previously enhancing, suggestive of tumor necrosis produced by the interstitial sources. The mean and median survival of these patients was 23 and 22 weeks, with the 4 most recent patients still alive.     

Diagnostic Accuracy of PET/CT-Guided Percutaneous Biopsies for Malignant Peripheral Nerve Sheath Tumors in Neurofibromatosis Type 1 Patients

Background

Malignant peripheral nerve sheath tumors (MPNST) are one of the most frequent causes of death in patients with neurofibromatosis type 1 (NF1). Early detection is crucial because complete surgical resection is the only curative treatment. It has been previously reported that an ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) image with a T/L (Tumor/Liver) SUV_max ratio > 1.5 provides a high negative predictive value; however, it is not specific enough to make a NF1-related MPNST diagnosis. A formal proof of malignant transformation from a histological analysis is necessary before surgical excision because the procedure can cause mutilation. The objective of the present work was to investigate the effectiveness of and complications associated with PET/CT-guided percutaneous biopsies for an NF1-related MPNST diagnosis.

Methods

PET/CT-guided percutaneous biopsy procedures performed on 26 NF1 patients with a clinical suspicion of MPNST and a suspect lesion from a PET/CT scan (T/L SUV_max ratio > 1.5) were retrospectively evaluated. The localization of the suspected malignant site was determined using PET/CT. A stereotactic (ultrasonic and CT control) core biopsy technique was used with a local anesthesia.

Results

The first PET/CT-guided percutaneous biopsies enabled a pathological diagnosis for all of the patients (no "inconclusive " results were obtained), and no secondary procedures were needed. Among the 26 patients, the histopathological results from the biopsy were malignant in 17 cases and benign (BPNST with atypical cells) in nine cases. No complications from the diagnostic procedure were observed. A surgical resection was performed in 18 patients (seven benign and 11 malignant biopsies), removing the fine needle biopsy scar. In addition, six locally advanced/metastatic MPNST were treated with chemo/radiotherapy, and two BPNST had no progression after a follow-up of 14 and 39 months, respectively. The PET/CT-guided percutaneous biopsy gave 25 accurate diagnoses and one false negative (BPNST with atypical cells on the biopsy and MPNST on the operated tumor), resulting in a diagnostic accuracy rate of 96%. This false negative case may be explained by the high heterogeneity of the tumor: benign areas were contiguous with the malignant ones and associated with inflammation.

Conclusions

PET/CT-guided percutaneous biopsies are an effective and relatively non-traumatic procedure for diagnosis of NF1-related MPNST. It is the most reliable approach for early detection of MPNST.     

CT-guided 125I brachytherapy in the treatment of distant metastases in the oral cavity and maxillofacial region

PURPOSE: We aimed to evaluate the feasibility and clinical effectiveness of CT-guided ¹²⁵I brachytherapy for distant oral and maxillofacial metastases. MATERIALS AND METHODS: We retrospectively analyzed 65 patients with 84 distant oral and maxillofacial metastases. Thirty-one patients with 38 lesions received ¹²⁵I brachytherapy (group A) and 34 with 46 lesions received external beam radiotherapy (EBRT; group B). RESULTS: Median follow-up time was 16 months. The 3-, 6-, 12-, 18-, and 24-month local control rates for group A were 83.9%, 75.9%, 66.7%, 38.4%, and 25.0%, respectively; for group B they were 76.5%, 62.5%, 43.8%, 25.0%, and 0.0%, respectively (P < .05); the median local tumor progression-free survival times were 14 and 9 months, respectively. Group A had a better local tumor progression-free survival (LTPFS) relative to group B (P < .001; HR, 6.961 [95%CI, 2.109, 9.356]). Cox proportional hazards regression analysis indicated that ¹²⁵I brachytherapy, tumor size, and primary pathological type were the independent factors affecting LTPFS. Additionally, ¹²⁵I brachytherapy showed better performance in relieving patient clinical symptoms relative to EBRT (P < .05). Group A also had fewer complications than group B, especially regarding grade 3/4 complications according to Radiation Therapy Oncology Group grading criteria. Mean overall survival times in groups A and B were 17.1 and 14.8 months, respectively. CONCLUSION: CT-guided ¹²⁵I brachytherapy is feasible and safe for distant oral and maxillofacial metastases; it achieved a better local control rate, longer LTPFS and fewer complications without compromising overall survival compared with EBRT.     

Experience using two CT-guided stereotactic biopsy methods

15 patients had intracranial CT-guided stereotactic biopsies. Biopsies were performed either with a Riechert-Mundinger stereotactic frame modified for use in the CT or by using the CT scan to establish the relationship of the intracranial lesion to identifiable bony landmarks, and subsequently performing the biopsy in a standard stereotactic frame. Both systems provided safe and accurate methods for obtaining intracranial tissue.     

放射性粒子125I联合TACE治疗兔VX2肝肿瘤的实验研究

目的:通过研究不同活度的125I粒子以及联合TACE治疗兔VX2肝移植癌的疗效及其病理基础,探讨125I粒子组织间植入治疗肝癌的有效性。方法:建立兔VX2肝癌模型。60只肝癌模型兔随机分成5组,对照组(A组)植入空白剂量(0mCi)125I粒子,B组植入1.0mCi125I粒子,C组植入0.7mCi125I粒子,D组植入0.4mCi125I粒子,E组植入0.7mCi125I粒子+TACE。观察植入前后各组肿瘤体积并计算抑瘤率,切除肿瘤组织及周围正常组织进行常规病理检查。结果:各治疗组肿瘤大小在治疗前后比较具有统计学差异(P<0.01),均小于同期对照组(A组)(P<0.01)。在不同观察时期抑瘤率差别均有统计学意义(P<0.05),各个组间抑瘤率差异在治疗后2周最为明显(P<0.01),但均高于D组(P<0.01)。治疗后6周病理提示D组部分组织内仍可见少量肿瘤细胞,而其余各治疗组均未见明显的肿瘤细胞残存,B组对周围肝组织损伤较大,C组、E组适中。总体疗效E组优于其余各治疗组。结论:125I粒子联合TACE治疗肝癌效果明显优于单一的治疗方案,是肝癌目前较为理想的治疗方案,其中单个粒子活度以0.7mCi左右较为适宜。     

New CT-guided stereotactic apparatus and clinical experience with intracerebral hematomas

The conventional Sugita stereotactic frame has been improved to perform CT-guided stereotactic surgery both in the CT and operating rooms. The development of our instrument and the software of the scanners' computer are presented. Newly designed equipment produced almost no artifacts on the CT image. Using the improved stereotactic frame, we have operated upon 44 intracerebral hematomas in the CT room. More than 80% of the cases had satisfactory results. Two complications were encountered, and 1 patient died from pneumonia. Our initial experience of the pre- and postoperative cerebral blood flow measurement with 133Xe inhalation method and single photon emission CT is described.     

Serious gastric perforation after second stereotactic body radiotherapy for peripheral lung cancer that recurred after initial stereotactic body radiotherapy: a case report

Background

In recent reports, re-irradiation with stereotactic body radiotherapy for lung tumors in patients previously treated with thoracic radiation therapy resulted in several serious toxicities. Serious non-lung toxicities were observed mostly in patients with central tumors, but we experienced a case of fatal gastric perforation after a second stereotactic body radiotherapy in a patient with a peripheral lung tumor.

Case presentation

An 83-year-old Asian man was diagnosed with T2N0M0 lung cancer in the form of squamous cell carcinoma in the lower lobe of his left lung. He was treated with stereotactic body radiotherapy of 40 Gy in 4 fractions and the tumor decreased in size in partial response. The local tumor recurred 8 months after the first stereotactic body radiotherapy, and he was re-irradiated with a second stereotactic body radiotherapy of 50 Gy in 4 fractions. A Sengstaken–Blakemore tube was inserted below his diaphragm by laparoscopic surgery before the second stereotactic body radiotherapy in order to reduce the stomach dose by keeping his stomach apart from the tumor. Two months after the second stereotactic body radiotherapy, he developed fatal gastric perforation and gastropleural fistula penetrating his diaphragm.

Conclusions

To the best of our knowledge, this is the first report about a gastric perforation after stereotactic body radiotherapy for lung tumors and it warns of serious complication of stereotactic body radiotherapy in not only centrally located but also peripherally located tumors like in this case.

     

Experience in the first 100 patients undergoing computerized tomography-guided stereotactic procedures utilizing the Brown-Roberts-Wells guidance system

A series of 100 patients undergoing CT-guided stereotactic procedures for biopsy and/or drainage (n = 87), deep brain electrode placement (n = 9), endoscopy (n = 1), and functional lesioning (n = 3) was reviewed. Only 1 patient required general anesthesia. There were 4 procedural related hematomas, only 1 of which was symptomatic. No other complications were encountered.     

CT-guided stereotactic biopsies of lesions in the medulla and a case of Leigh's disease

CT-guided stereotactic biopsy of lower brain stem lesions in 7 consecutive cases is discussed. A frontal transincisural approach was used. Five patients had astrocytomas histologically. The single patient who had undergone empirical radiation therapy prior to tissue diagnosis revealed only necrosis. One patient was found to have pathology suggestive of Leigh's disease. This patient was not radiated and is the first alive adult to have this diagnosis confirmed. Although controversy still exists in the management of brain stem lesions, we intend to demonstrate the value of tissue diagnosis in the management of such lesions.     

Intracranial Ependymoma: Long-Term Results in a Series of 21 Patients Treated with Stereotactic 125Iodine Brachytherapy

Background

We evaluated the long-term outcome in patients harboring intracranial ependymomas treated with interstitial brachytherapy (IBT).

Methods

Twenty-one patients (M/F = 9/12; median age: 29 years; range: 8–70 years), diagnosed with intracranial ependymoma (1 WHO I, 11 WHO II, 9 WHO III) were treated with IBT using stereotactically implanted ¹²⁵Iodine seeds between 1987 and 2010, either primarily, as adjuvant therapy following incomplete resection, or as salvage treatment upon tumor recurrence. Sixteen of 21 patients underwent microsurgical resection prior to IBT; in 5 patients, IBT was performed primarily after stereotactic biopsy for histological diagnosis. The cumulative tumor surface dose ranged from 50–65 Gy treating a median tumor volume of 3.6 ml (range, 0.3–11.6 ml). A median follow-up period of 105.3 months (range, 12.7–286.2 months) was evaluated.

Results

Actuarial 2-, 5- and 10-years overall- and disease-specific survival rates after IBT were each 90% and 100% at all times for ependymomas WHO I/II, for anaplastic ependymomas WHO III 100%, 100%, 70% and 100%, 100%, 86%, respectively. The neurological status of seven patients improved, while there was no change in 12 and deterioration in 2 patients, respectively. Follow-up MR images disclosed a complete tumor remission in 3, a partial remission in 12 and a stable disease in 6 patients. Treatment-associated morbidity only occurred in a single patient.

Conclusions

This study shows that stereotactic IBT for intracranial ependymomas is safe and can provide a high degree of local tumor control. Due to the low rate of side effects, IBT may evolve into an attractive alternative to microsurgery in ependymomas located in eloquent areas or as a salvage treatment.     

Iodine-125 Seed Implantation in the Treatment of Sacrococcygeal Chordoma: A Case Report

The objective of this was to summarize the efficacy and safety of iodine-125 seed implantation in the treatment of sacrococcygeal chordoma. CT-guided implantation of radioactive iodine-125 seed was applied in treating a patient with sacrococcygeal chordoma. The incidence of complications was recorded and the results were evaluated and analyzed, to compare the postoperative complications and recurrence rate of sacrococcygeal chordoma. The patient was followed up to 15 months after operation. The minimum peripheral dose was 180?Gy, and 8?months after the implantation, the tumor mass was reduced significantly. There was no serious complications detected during the follow-up period. Radioactive iodine-125 seed implantation can improve the target volume dose, with the high doses of radioactive iodine-125 seed, the tumor, which was refractory and insensitive to chemotherapy and radiotherapy, can be effectively controlled and complications are less than surgical treatment. However, the long-term efficacy of this treatment needs further follow-up.     

Present and future developments of stereotactic technology

Incorporation of a surgical computer system into stereotactic methodology provides the facility for efficient utilization of the multiple data bases at the disposal of the modern stereotactician. Computed tomography, magnetic resonance imaging, and digital fluoroscopy data gathered in stereotactic conditions are digitized into a stereotactic surgical matrix for surgical planning and interactive surgical procedures. The advantages of this system are illustrated in stereotactic biopsy, interstitial irradiation, and laser resections of intracranial tumors.     

CT-compatible system for stereotactic biopsy and brachytherapy of infratentorial tumors

Teletherapy of nonresectable radiosensitive brain tumors is the mainstay of adjunctive treatment. In the past two decades brachytherapy has begun to play an ever-increasing role, particularly on the European continent. Yet this attention has been addressed almost exclusively to lesions of the supratentorial space. This article describes modifications of the Riechert-Mundinger stereotactic system which were made by one of us (P.D.) to allow an unencumbered yet precisely computerized stereotactic approach to posterior fossa lesions for biopsy and interstitial radiation with iridium 192. A case report is described to illustrate the technical details involved in such an undertaking.     

Accuracy of the analysis of multiple small fragments of glial tumors obtained by stereotactic biopsy.

To examine the reliability of the diagnoses reached on multiple small fragments of cerebral glial tumors obtained via stereotactic biopsy, samples obtained from 100 consecutive glial tumors (during real or simulated biopsy) were studied by cytology and histology. In comparison to the definitive diagnosis made on the whole tumor, a correct positive diagnosis on the biopsy sample was made by histology in 96% of cases and by cytology in 93% of the cases (with 96% correct results when combining both methods). A correct identification of the tumor type and grade was achieved by histology in 82% of cases and by cytology in 80% of the cases (with 85% correct results when combining both methods). The limits of stereotactic biopsy are related to the difficulty of identifying all of the typical tumor features on tiny tissue fragments of a pleomorphic neoplasm, such as a glioma. This study demonstrates that better results may be obtained by using both cytology and histology to study multiple stereotactic biopsy samples from glial tumors.