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This paper discusses the feasibility of a monitoring program for the quality assurance status of activity meters. We sent a questionnaire to clinical nuclear medicine departments of medical institutions, requesting information on their activity meters and quality assurance practices. On-site visits were conducted with exemption-level standard sources (Co-57, Cs-137 and Ba-133) for dose calibrators in nuclear medicine departments including physical inspection, accuracy and reproducibility. A method offering a quick check on the detection efficiency of the space dimension inside the activity meters was also introduced. For dose calibrator quality assurance, the daily checks had the highest implementation. However, annual checks and upon acceptance/after a repair check were reduced to 50% and 44%, respectively. The accuracy results of dose calibrators showed that all models exceeded the ±10% criteria with Co-57 and Cs-137 sources. The reproducibility results showed that some models exceeded the ±5% criteria with Co-57 and Cs-137 sources. The appropriate application of exemption-level standard sources considering the uncertainty that affects the measurement is discussed.
Assuntos
Radioisótopos de Césio , Reprodutibilidade dos Testes , IncertezaRESUMO
Primary brain malignancy is a rare tumor with a global incidence of less than 10 per 100,000 people. Hence, there is limited power for identifying risk loci in individual studies, especially for Han Chinese. We performed a genome-wide association study (GWAS) in Taiwan, including 195 cases and 195 controls. We identified five new genes for malignant neoplasms of the brain: EDARADD (rs645507, 1p31.3, p = 7.71 × 10-5, odds ratio (OR) = 1.893), RBFOX1 (rs8044700, p = 2.35 × 10-5, OR = 2.36), LMF1 (rs3751667, p = 7.24 × 10-7, OR = 2.17), DPP6 (rs67433368, p = 8.32 × 10-5, OR = 3.94), and NDUFB9 (rs7827791, p = 9.73 × 10-6, OR = 4.42). These data support that genetic susceptibility toward GBM or non-GBM tumors is highly distinct, likely reflecting different etiologies. Combined with signaling analysis, we found that RNA modification may be related to major risk factors in primary malignant neoplasms of the brain.
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Background: Radiotherapy (RT) provides a modern treatment to enhance the malignant glioma control rate. The purpose of our study was to determine the effect of tumor coverage on disease prognosis and to predict optimal RT plans to achieve a lower normal tissue complication probability (NTCP). Methods: Ten malignant-glioma patients with tumors adjacent to organs at risk (OARs) were collected. The patients were divided into two groups according to adequate coverage or not, and prognosis was analyzed. Then, using intensity-modulated radiation therapy (IMRT), volume-modulated arc therapy (VMAT), and helical tomotherapy (TOMO) to simulate new treatment plans for 10 patients, the advantages of these planning systems were revealed for subsequent prediction of NTCP. Results: The results of clinical analysis indicated that overall survival (p = 0.078) between the adequate and inadequate groups showed no differences, while the adequate group had better recurrence-free survival (p = 0.018) and progression-free survival (p = 0.009). TOMO had better CI (p < 0.001) and also predicted a lower total-irradiated dose to the normal brain (p = 0.001) and a lower NTCP (p = 0.027). Conclusions: The TOMO system provided optimal therapeutic planning, reducing NTCP and achieving better coverage. Combined with the clinical results, our findings suggest that TOMO can make malignant glioma patients close to OARs achieve better disease control.
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CONCLUSION: IMRT provided better conformity, less toxicity and better function restoration for advanced hypopharyngeal carcinoma after major surgery with ileocolic flap reconstruction. OBJECTIVES: To compare the results of adjuvant conventional radiotherapy (2DRT) with intensity modulated radiation therapy (IMRT) for locally advanced hypopharyngeal cancer after resection and ileocolic free flap reconstruction and to design treatment plans for those two modalities plus 3D conformal radiotherapy (3DCRT) for dose distribution comparison. METHODS: 13 locally advanced hypopharyngeal cancer patients were enrolled, 8 treated with 2DRT and 5 with IMRT. Different plans were planned for 3 IMRT-treated patients for comparing dose distribution. RESULTS: After major surgery, patients treated with IMRT had less toxicity and better functional restoration than those with 2DRT. IMRT and 3DCRT both showed lower dose to the spinal cord than did 2DRT. Only IMRT showed reduced dose to ileocolic flap.
