Medicina Nuclear e Radioterapia

Background: Intralabyrinthine schwannoma are rare benign tumors exclusively managed to date with observation or surgical removal. We analyze results of radiosurgical treatment of these lesions.

Methods: Retrospective analysis of medical data of 454 patients with vestibular schwannomas treated by Gamma Knife in our center was performed. We identify 12 patients treated for a schwannoma located partially or totally into the cochleo-vestibular structures. Ten patients with a clinical and radiological follow-up of more than 1 year were selected for further analysis.

Results: Patients had hearing worsening at different stages, sometimes associated with tinnitus, imbalance or vertigo. The median duration of symptoms before treatment was 3.3 years. Anatomical location of the ILS was intravestibular, intracochlear, intravestibulocochlear, transmacular or transmodiolar (2 patients for each location). We cover 100% of the tumor volume in all patients with a mean margin dose of 11.7 Gy (range 11-12 Gy). The mean follow-up duration was 2.8 years (range 1.5-6.5 years). For 5 patients with functional hearing before treatment, 2 patients had unchanged audiological status at last follow-up, 1 patient had moderate hearing worsening, and 2 patients became cophotic (functional hearing preservation rate of 40%). Facial palsy, even partial and transient, did not occur. No patient experienced permanent worsening of tinnitus, imbalance or vertigo after irradiation.

Conclusions: Gamma Knife radiation therapy seems to be a safe and effective treatment alternative to surgery for patients with intralabyrinthine schwannomas. Radiosurgery can be performed in this indication without significant morbidity with the precision of current robotized Gamma Knife.

With increasing emphasis on reducing the volume of radiation therapy fields while maintaining or improving precision of treatment and reducing radiation-related normal tissue toxicity, treatment position verification and correction before delivering radiotherapy had gained major importance. A variety of techniques have been developed that can accomplish this goal with aplomb, albeit each with its own set of limitations. The best method that eliminates uncertainties in treatment without a huge cost remains to be defined, but it is clear that carrying out “high precision radiotherapy” without periodic image guidance is as accurate as shooting in a dark room. This review discusses the concept of image guidance in radiotherapy, various techniques available along with expected benefits and pitfalls of these systems.

ntroduction: Patients with head and neck cancers are often treated with external beam radiation therapy. Unfortunately this therapy is not without its unintended consequences. One of these side effects include the development of radiation induced hypothyroidism. Our study is designed to pay special attention to variables like gender and smoking history and analyze their relationship with the development of hypothyroidism. Methods: Tumor Registry Database at the University of Florida, College of Medicine in Jacksonville was utilized for our retrospective study to gather information on patients who had previously received external beam radiations for head and neck cancers. Patients’ charts were reviewed over a period of thirteen years from January 1st 2000 to November 30th 2013. General characteristics were examined including age, gender, race/ethnicity, and smoking history. Hypothyroidism was defined as TSH value greater than 5.0 along with appropriate decrease in free serum thyroxine (T4) levels after exposure to external beam radiation. Results were then analyzed using the Univariate statistical analysis which was done using the SAS software. Alpha level of significance was set to 0.05 and associations were expressed in terms of Odds ratio (OR) with 95% confidence intervals (CI). Results: We found a total of 1116 patients in our database who have received external beam radiations for head and neck cancers. Out of these 72 (6.45%) patient developed hypothyroidism. Out of 263 African American patients 20 (7.6%) had hypothyroidism, whereas 49 (6%) out of 819 white people had this outcome. As for gender 32 out of 341 females (9.4%) and 40 out of 775 males had hypothyroidism. Thirty five out of 544 (6.4%) with no family history and 19 (2.4%) out of 205 (9.3%) with positive family history for cancer had the outcome too. Finally 43(6.5%) out of 664 smokers and 17(8.3%) out of 206 non-smokers were found to develop hypothyroid as well. Both groups were found to have homogenous average age at diagnosis. When conducting the univariate analysis, the strongest predicting variable was gender as hypothyroid patients were 1.90 (95% CI 1.17 – 3.09) times more likely to be females, and these results were statistically significant with p-value of 0.008. More patients tended to be African Americans with OR 1.21 (CI 0.822 - 1.78), had positive family history of cancer, (negative family history had OR 0.67 (CI 0.38 – 1.21), and less likely to be smokers (OR 0.77 (0.43 – 1.38). However, Race, family history of cancer and smoking history did not achieve any statistical significance as evident by the p-values. Conclusion: In our patient population, females were more likely to develop radiation induced hypothyroidism.

Background: In boron neutron capture therapy (BNCT), the intravenous administration of boron-containing compounds such as boronophenylalanine (BPA) and borocaptate sodium (BSH) is followed by irradiation with thermal neutrons. In the present study, we determined whether a boron-rich boron carbide (B4C) nanoparticle could be used for BNCT.
Methods: B4C nanoparticles were obtained by the laser fragmentation of boron particles in ethyl acetate. Neutron irradiation was delivered via a neutron beam at the Kyoto University Research Reactor (KUR).
Results: Cell viability was lower in oral squamous cell carcinoma (SCC) cells exposed to neutrons in the presence of B4C particles than in those exposed to neutrons only. The combination of B4C particles and neutron irradiation also decreased the formation of colonies.Injecting B4C particles into the oral SCC xenografts of nude mice increased the concentration of 10B in the tumors, but not in the kidney, liver, or spleen. The body weights of animals were not affected by neutron irradiation to B4C-injected tumors.Tumor volumes were lowerTumor volumes were lower in the B4C- mediated BNCT group than in the neutron group. Conclusion: These results indicate that B4C particles can be used locally as a boron compound in BNCT for oral SCC.

Objective: To measure the impact of multiple fields in filed (MFIF) technique on dose homogeneity, doses to organs at risk (OARs) and acute skin toxicity in comparison to physical wedged (PW) tangential technique. Methods: The study population consisted of 75 patients who had breast-conserving surgery and whole-breast radiation using MFIF. These patients were matched one-to-one to a control group of 75 patients treated with PW tangents, following ethical board approval and signing informed consents. Acute skin reaction was graded by CTCAE 3.0 scoring and multiple regression analysis of covariates was performed. Results: CTCAE grade2 acute skin reaction occurred in 61.3% PW vs. 32% MFIF while grade 3 was encountered in 24% PW vs. 10.7% MFIF patients (P<0.01). Multiple regression analysis confirmed the excessive skin reaction to the related radiation therapy technique (P=0.0002) and whole breast PTV (P<0.001). Homogeneity index within PTV was significantly improved in MFIF plans (0.84 ± 0.7) compared with PW (0.94 ± 0.15) with a (P<0.01). There was also a significant reduction, in lung V20 from 14.3% ± 1.1 to 10.6 % ± 1.4 (P<0.01), heart V30 from 7% ± 5.8 to 6% ± 4.9 (p<0.001). Contralateral breast volume receiving dose more than 2 Gy was also reduced 2.3% ± 0.5 PW to 1.2% ± 0.2 MFIF (P<0.01). Conclusion: The MFIF technique significantly improved PTV dose homogeneity index, while significantly reduced the incidence of grade 2/3 acute skin reaction and doses to OARs when compared to PW tangential fields in whole breast radiotherapy.

Dural based sarcoma is a rare aggressive neoplasm arising from the multipotent primitive mesenchymal stem cells of the dura. A 61-year-old male patient presented with complaints of loss of visual acuity in his right eye for 1 week. Neuroimaging revealed a tumour located at the right temporal lobe. The mass was dural-based. Three years ago dural based lesion was seen. In that period radiological diagnosis was meningioma. Within three years, the lesion has grown and radiologically presumed meningioma view has been disappeared. After surgical resection of the mass pathological diagnosis of primary dural based sarcoma was made. As in soft tissue sarcomas, diagnosis is mainly based on light microscopy, while immunohistochemistry can improve accuracy of diagnosis. In this article we would like to highlight two things: one is dural sarcoma and meningioma cannot be distinguished radiologically, and the other is the patient's three-year history

Background: Acute Lymphoblastic leukemia (ALL) and Posterior Fossa Tumors (PFT) are the most common types of cancer in Brazilian children. Parallel to the sophistication of treatment and increased survival rates, the concern about the neurotoxicity of anti-neoplastic treatment and its impact on neurodevelopment has been growing. The objective of this study was to compare the cognitive impact of treatment modality on intellective capacity of children survivors of PFT and ALL. Method: 22 Children and adolescents aged from 6 to 14 years old have participated in this study, being 06 children diagnosed with Astrocytoma, 06 diagnosed with medulloblastoma and 10 diagnosed with ALL. Children with astrocytoma underwent surgery for tumor resection; children with medulloblastoma were submitted to surgical resection, systemic chemotherapy and cranial and neuraxis radiation therapy (54Gy) and; children with ALL underwent systemic and intrathecal chemotherapy. Intellectual functioning was evaluated through WISC-III, and performance of subgroups was compared using One Way ANOVA followed by post hoc LSD. Results: Children with astrocytoma obtained average performance in all assessed domains, while children with medulloblastoma and ALL obtained downgraded scores. In all indices children with ALL obtained better results than children with medulloblastoma, except on verbal scores (VIQ and VCI) and Freedom from Distractibility Index (FDI). Statistical analysis revealed significant contrasts in performance of groups, mainly between children with medulloblastoma and other groups in non-verbal scores, as Processing Speed Index (PSI). Conclusion: Data suggest that the combination of surgery, systemic chemotherapy and radiotherapy may intensify the incidence of cognitive effects. Moreover, reinforce the hypothesis that cranial radiation therapy underlies severe cognitive losses, through damage to cortical and subcortical white matter, so that motor and mental processing speed is affected. The combination of intrathecal and systemic chemotherapy in turn promotes significant impacts on executive functioning, in particular on working memory.

Background and purpose: During the radiotherapy of breast cancer, especially when the supraclavicular lymph nodes are planned to be treated, a portion of thyroid gland may also be included in the treatment field. In this study we compared thyroid gland dose volume histograms (DVHs) of breast cancer patients receiving radiotherapy, planned in both CT-based three-dimensional planning system and MVCT-based image guidance aspect of helical tomotherapy system. Material and method: 20 breast carcinoma patients who were treated with 3-D conformal radiotherapy technique were evaluated concerning their thyroid gland dose distribution. The estimated minimum, mean and maximum thyroid gland doses were calculated for both 3-D conformal radiothreapy and tomothreapy planning systems. Additionally the volume of thyroid gland that received less than 30 Gy and more than 30 Gy were determined. Results: The maximum, mean and minimum doses of thyroid glands supposed to receive were found to be better with tomotherapy comparing to 3-D conformal therapy plans. The thyroid gland volume that receives more than 30 Gy was smaller in tomothreapy planning system comparing to 3-D conformal therapy planning system. Conclusion: Lower doses of radiation exposure to thyroid gland is possible with Tomotherapy.

Though medulloblastoma frequently involves the leptomeninges at diagnosis, distant metastases are rare on initial presentation. We present a 15-year-old patient with medulloblastoma and equivocal radiographic evidence of an intracerebral metastasis at the time of diagnosis.