Influence of Modulation Factor on Treatment Plan Quality and Irradiation Time in Hippocampus-Sparing Whole-Brain Radiotherapy Using Tomotherapy.

Objectives: Hippocampus-sparing whole-brain radiotherapy (HS-WBRT) using tomotherapy is known to provide a better dose distribution than volumetric-modulated arc therapy but requires an extended irradiation time. The present study aimed to investigate whether irradiation time can be shortened by reducing the modulation factor (MF) without losing the target dose distribution. Methods: Using six tilted computed tomography images in the head area, the planning target volume (PTV) and hippocampal doses, and the irradiation time was investigated with a jaw width of 1 cm, a pitch of 0.200, and the MF changed from 3.0 to 2.6, 2.2, 1.8, and 1.4. Results: No significant changes in the PTV or hippocampus were found with MF in the range from 3.0 to 1.8, but marked deterioration was found with that of 1.4. The irradiation time showed a linear relationship with the MF within the range from 3.0 to 1.8, with 1334, 1158, 986, and 817 s at modulation factors of 3.0, 2.6, 2.2, and 1.8, respectively. However, when the MF was 1.4, the irradiation time was 808 s. Conclusions: When HS-WBRT is performed with a tilted body position and a jaw width of 1 cm, with a MF of 1.8, a favorable balance between dose parameters and irradiation time is achieved, whereas with a MF of 1.4, the quality of the radiotherapy plan deteriorates, and the irradiation time is approximately the same as that with a MF of 1.8.

Cut-off value for normal versus abnormal right-to-left shunt percentages using (99m)Tc-macroaggregated albumin.

OBJECTIVE: To determine the cut-off value for distinguishing a normal versus an abnormal right-to-left shunt percentage on lung perfusion scintigraphy using (99m)Tc-macroaggregated albumin (MAA). MATERIALS AND METHODS: Fifty-three patients (eight patients with a right-to-left shunt and 45 without a right-to-left shunt) who underwent MAA whole-body imaging for the evaluation of right-to-left shunts were divided into group 1 (eight patients with brain MAA uptake) and group 2 (45 patients without brain MAA uptake). Moreover, group 2 was subdivided into two categories (groups 2a and 2b) based on the results of lung computed tomography, electrocardiography examinations, and pulmonary function tests. The average and standard deviation (SD) of each group were compared. In addition, we estimated the cut-off value for a normal right-to-left shunt percentage using whole-body imaging. RESULTS: The average right-to-left shunt percentage values and SD were 23.67±12.17% in group 1, 6.68±1.04% in group 2a, and 6.60±0.84% in group 2b. The shunt percentages of groups 2a and 2b were not significantly different (P=0.77). The estimated normal value (mean±2 SD) of group 2 was 6.64±0.94%. Meanwhile, the cut-off value was estimated as 10% based on the distributions of MAA shunt percentages for groups 1 and 2. CONCLUSION: The normal range (mean±2 SD) was 6.64±1.88%. The cut-off value for the normal right-to-left shunt percentage in MAA scintigraphy was 10%.

Swelling of the prostate gland by permanent brachytherapy may affect seed migration.

OBJECTIVE: The purpose was to monitor implanted seeds and to determine factors contributing to seed migration after permanent prostate brachytherapy. METHODS: Sixty-two consecutive patients with Stage 1 prostate cancer who underwent brachytherapy with (125)I seeds between February 2008 and May 2009 were studied prospectively. On post-operative days 1, 7 and 30, scintigraphy was added to conventional radiography to monitor the migration of the implanted seeds. The prostate volume was measured during the pre-planning stage using ultrasound and during the post-planning stage using computed tomography on post-operative days 0 and 30. Magnetic resonance imaging was performed on day 30. RESULTS: Of the 4843 seeds implanted in the prostates of 62 patients, 108 seeds (2.2%) in 43 patients (69.4%) exhibited seed migration. Thirty-five seeds could not be identified using any of the imaging modalities and were likely passed during urination (0.7% of the total number of seeds). The maximum number of migrated seeds in one patient was 10 of the 85 implanted seeds. The fraction of patients with seed migration or loss increased from 27.4% on day 1 to 69.4% on day 30. The number of seeds that had migrated from the prostate increased from 48 (0.1% of the total number of seeds) on 1 day to 78 (1.0%) on day 7 and 108 (2.2%) on day 30. Of the seeds lost from the prostate, 38.9% embolized to the lungs. The seed loss during the first post-operative month was closely correlated with the swelling of the prostate gland between the pre-planning measurement and the post-planning measurement performed on day 0 (P < 0.0001). CONCLUSIONS: Prostate swelling between the pre-planning and post-planning (day 0) measurements was significantly associated with seed migration, and adequate attention should be given to this issue.

Scintigraphic detection of 125I seeds after permanent brachytherapy for prostate cancer.

UNLABELLED: The purpose of this investigation was to monitor the localization and migration of 125I seeds after permanent brachytherapy for prostate cancer using a new scintigraphic technique that may overcome the drawbacks of conventional x-ray methods. METHODS: 125I seeds emit gamma-rays with an average energy peak of 28 keV. We used a gamma-camera equipped with low-energy high-resolution collimators that were tuned to an energy level of 35 keV with a 70% window width. Sixteen patients with prostate cancer were examined after 125I seed insertion. The number of seeds remaining in the prostate was confirmed using pelvic CT for postoperative dose planning; however, seeds that had migrated outside the prostate could not be detected. Furthermore, the migrated seeds were not completely traceable using chest or abdominal radiography. Thus, we adopted a scintigraphic technique to perform this task. The evaluation of radiography and scintigraphy findings was masked, and the rates of migrated seed detection were statistically examined using the McNemar test. To localize the migrated seeds, we fused the scintigraphic images of the migrated seeds and the patients' contours. RESULTS: Scintigraphy was successfully used to detect 20 migrated seeds of a total of 1,182 implanted seeds, whereas radiography was successfully used to detect 7. The sensitivity of the scintigraphy results was 20 of 20 (100%), whereas that of the radiography results was 7 of 20 (35%). Seed migration was detected in 11 of 16 patients (69%) using scintigraphy, whereas seed migration was detected in only 4 patients (25%) using radiography; this difference was statistically significant (P = 0.016). CONCLUSION: Scintigraphy is more effective for detecting seed migration and monitoring the localization of 125I seeds than radiography. The precise anatomic location of migrated seeds can be pinpointed using fusion images. Scintigraphy may become a standard procedure for monitoring seed migration during 125I brachytherapy in patients with prostate cancer.

Treatment of Churg-Strauss syndrome with high-dose intravenous immunoglobulin.

BACKGROUND: In some patients with Churg-Strauss syndrome (CSS), especially those with myocardial or neural involvement, conventional treatment with corticosteroids with or without cyclophosphamide is not effective. OBJECTIVE: To examine the effects of intravenous high-dose immunoglobulin (IVIG) in patients with CSS who showed poor responsiveness to conventional treatment. METHODS: We consecutively selected patients with CSS who showed any organ involvement despite corticosteroid treatment with or without cyclophosphamide. The diagnosis was based on the classification criteria of the American College of Rheumatology. IVIG therapy was performed with a dose of 400 mg/kg of immunoglobulin daily for 5 days. Neuropathy was evaluated with the manual muscle strength test and by the skin temperature of affected sites. Cardiac function was examined with ejection fraction by echocardiography and 2 imaging tests of myocardium (iodine 123 metaiodobenzylguanidine and thallium 201). RESULTS: The manual muscle strength test results were improved, and the skin temperature of both hands and legs was increased by IVIG therapy. In 5 patients with heart failure, the mean +/- SD ejection fraction of the left ventricle increased from 35.2% +/- 13.9% to 61.0% +/- 10.1% (P < .02). The uptake of iodine 123 metaiodobenzylguanidine of the myocardium increased, indicating that the myocardial viability was improved. The thallium 201 images revealed the presence of perfusion defects, which were improved by IVIG therapy. CONCLUSIONS: Patients with CSS who are resistant to corticosteroid treatment with or without cyclophosphamide may be treated effectively with IVIG therapy.