[en] A retrospective analysis was performed to investigate the radioprotective effects of azelastine against radiation dermatitis for patients with head and neck cancers. The effects of azelastine were studied in 19 patients with laryngeal cancers treated by irradiation. As controls, 29 patients with laryngeal cancers treated by irradiation without the administration of azelastine were studied. All patients were irradiated using 3 MV linac X-rays. Azelastine was administered orally twice a day. Moist desquamation was observed in four of 29 control patients whereas no such moist desquamation developed after the administration of azelastine. Two cases of moist desquamation that developed before the administration of azelastine regressed during irradiation in patients placed on azelastine. Radiotherapy was completed without interruption in all patients treated with azelastine. No severe side effects were observed. Azelastine, administered orally, was a safe drug and has the potential of improving skin tolerance in irradiation therapy. (author)

[en] Cross relaxation between macromolecular protons and water protons is known to be important in biologic tissue. In magnetic resonance imaging sequences with a selective saturation of the characteristically short T₂, the macromolecular proton pool can produce contrast in the images so called magnetization transfer contrast [MTC], based on the cross-relaxation process. The magnetization transfer can manipulate both the available longitudinal magnetization and the T₁ of tissues. In a conventional spin echo technique with presaturated RF pulses, the reduction in available magnetization increased contrast on proton density-weighted images. The effects of repetition time TR, RF irradiation duration, and echo time TE on the magnetization transfer effect were studied, and images of the rat head, samples of water and oil were obtained at 7.05T. The signal intensities of the different tissues on the MTC images were compared with those on the control images obtained under identical conditions without the off-resonance irradiation. Quantitative analysis of tissue signal intensity was performed by examining regions of interest from each tissue. The results indicated that when MTC was used in conjunction with spin echo imaging, the shorter the echo time TE was, the higher contrast was obtained. This finding was even true at short TRs. The images reflected somewhat no dependence on either T₁ or T₂ weightings. Non-selective saturation of the water proton pool was also discussed from the point of view of the relaxation times. (author)

[en] Purpose: To evaluate the quality of digitized radiation-planning images at different resolution and to determine the optimal resolution for digital storage. Methods and Materials: Twenty-five planning films were scanned and digitized using a film scanner at a resolution of 72 dots per inch (dpi) with 8-bit depth. The resolution of scanned images was reduced to 48, 36, 24, and 18 dpi using computer software. Image qualities of these five images (72, 48, 36, 24, and 18 dpi) were evaluated and given scores (4 = excellent; 3 = good; 2 = fair; and 1 = poor) by three radiation oncologists. An image data compression algorithm by the Joint Photographic Experts Group (JPEG) (not reversible and some information will be lost) was also evaluated. Results: The scores of digitized images with 72, 48, 36, 24, and 17 dpi resolution were 3.8 ± 0.3, 3.5 ± 0.3, 3.3 ± 0.5, 2.7 ± 0.5, and 1.6 ± 0.3, respectively. The quality of 36-dpi images were definitely worse compared to 72-dpi images, but were good enough as planning films. Digitized planning images with 72- and 36-dpi resolution requires about 800 and 200 KBytes, respectively. The JPEG compression algorithm produces little degradation in 36-dpi images at compression ratios of 5:1. Conclusion: The quality of digitized images with 36-dpi resolution was good enough as radiation-planning images and required 200 KBytes/image

[en] Purpose: The purpose of this study was to evaluate the incidence of radiation otomastoiditis, on using T₂-weighted magnetic resonance (MR) imaging, in relation to radiation fields, doses, intervals, and clinical symptoms after radiotherapy that included the temporal bone in the fields. Methods and Materials: We performed follow-up MR examinations at various intervals after radiotherapy including the temporal bones for 270 ears of 114 patients with various diseases of the head and neck and intracranial regions. The middle ear and mastoid air cells on T₂-weighted images were scored as follows; showing no high signal intensity, a local high signal intensity area, or a high signal intensity area occupying the entire middle ear and all mastoid air cells. The radiation fields as depicted on the lateral simulator films classed as anterior to the clival line, posterior to the clival line, or both. Results: The incidence of radiation otomastoiditis depicted on T₂-weighted MR images increased in the patients who had received irradiation doses of 50 Gy or more. In the patients with doses of less than 50 Gy, the incidence was 18% within 6 months following radiotherapy, 13% at between 6 and 12 months, and 8% after 12 months, whereas it was more than 50% at any period after radiotherapy in the patients with 50 Gy or more. The incidence of radiation otomastoiditis was quite high in the patients whose radiation fields included region both anterior and posterior to the clival line. Conclusion: The incidence of radiation otomastoiditis as demonstrated on T₂-weighted MR images is increased at irradiation doses of 50 Gy or more. To reduce the incidence of severe radiation otomastoiditis, the irradiation fields of the temporal bone when the dose is 50 Gy or more should be limited to as small as possible. The clival line is considered to be a good landmark in reducing the irradiation field when doses of 60-70 Gy are delivered in curative radiotherapy

[en] Purpose: In our previous report we described the clinical value of azelastine, an oral antiallergic agent, as an inhibitor of radiation dermatitis. Here we studied the effect of azelastine on normal skin and tumor size after irradiation in a mouse model. Methods and Materials: The modifying effects of azelastine on both the degree of radiation dermatitis and antitumoral effect of radiation therapy were investigated in the normal skin as well as in SCC VII tumors of C3H/He mice. The right hind legs, with or without tumors, were irradiated with 20-60 Gy at 0.62 Gy/min. Azelastine was administered via the mouse chow, and acute skin reactions and tumor growth curves were compared between the azelastine and control groups. Results: The acute skin reactions of the azelastine group were significantly less prominent than those of the control group (p < 0.01). At a dose of 40 Gy the dose modification factors were 1.19-1.25. The tumor growth curves of the azelastine and control groups were almost identical, indicating that the treatment response of irradiation was not affected by administration of azelastine. Conclusions: Application of azelastine reduces the degree of acute radiation dermatitis without affecting the antitumoral effect of radiation therapy

[en] Purpose: To study the usefulness of dynamic magnetic resonance imaging in the evaluation of head and neck cancers treated with radiation therapy. Methods and Materials: Seventy-six patients (58 males and 18 females; ages 20-82) with head and neck cancers (10 nasopharyngeal carcinomas, 22 mesopharyngeal carcinomas, 10 hypopharyngeal carcinomas, 16 oral cavity carcinomas, 11 lingual carcinomas, and 7 laryngeal carcinomas) were treated by radiation therapy combined with concomitant low-dose cisplatinum. Magnetic resonance imaging (MRI) was performed before and 2 weeks after the irradiation in all cases. After bolus administration of gadopentetate dimeglumine (Gd-DTPA) (0.1 mmol/kg), images were obtained every 30 s (repetition time 200 ms, echo time 16 ms) using a 1.5 or 0.5-T superconductive unit. Biopsy or surgery was performed after radiation therapy and the histologic findings were correlated with the MRI findings (T₁, T₂, dynamic, and enhanced T₁). Results: Complete remission, partial response, and no response were obtained in 18, 36, and 7 cases, respectively. Dynamic MRI correctly diagnosed 17 of the 18 complete remission cases, 33 of the 36 partial response cases, and all of the 7 no-response cases. The accuracy of dynamic MRI, T₁-weighted image, T₂-weighted image, and Gd-enhanced T₁-weighted image was 94.4%, 68%, 82%, and 86%, respectively. Conclusion: Dynamic MRI proved to be useful in the evaluation of the radiation therapy of head and neck cancers

[en] Fifty-two patients with developmental delay of unknown cause underwent MR imaging of the brain. Their ages ranged from 5 months to 22 years, with a mean of 2.2 years. Thirty-seven (71%) had positive MR findings, including nine with congenital malformation, nine with atrophy, six with white matter lesion, five with delayed myelination, five with atrophy and delayed myelination, two with acquired injury of corpus callosum, and one with ulegyria. Congenital malformations obtained included holoprosencephaly, polymicrogyria, dysgenesis of corpus callosum, hypoplasia of cerebellum, and tuberous sclerosis. Abnormal MR findings were frequently observed both in the children with neurologic physical findings and in generally retarded children, while in the children with suspected autism, MR imaging did not demonstrate any abnormalities. Of 24 patients with epilepsy, abnormal MR findings were obtained in 17 patients (71%). The frequency of white matter lesion and atrophy was slightly higher in the patients with epilepsy. However, no significant correlations were found between MR findings and the presence of epilepsy. Also, no significant correlations were obtained between MR findings and the degree of developmental quotient (DQ). Severely injured cases did not necessarily show abnormal findings on MRI. (author)

[en] We used ¹³C MR spectroscopy to follow the metabolism of (1-¹³C) glucose in SCC-VII tumors of C3H/HeN mice. Six different SCC-VII tumors and six muscles of normal legs were used. Spectroscopy was carried out with the intraperitoneal injection of 100 mg of (1-¹³C) glucose. Six distinct resonances were detected: the α and β anomers of the C₁ of glucose, C_2,3,4 of glutamate and glutamine, and the C₃ of lactate. Signals from (1-¹³C) glucose were first detected in the spectra of tumor 10 minutes after injection. Signals decreased faster in the SCC-VII tumors than the muscle of normal leg. The presence of ¹³C of glutamate/gultamine suggested the entry of pyruvate into the TCA cycle in SCC-VII tumor. The more rapid decrease of signals from (1-¹³C) glucose in the SCC-VII tumor may be attributed to the effects of blood flow volume and metabolic activity. (author)

[en] We investigated 710 patients with breast cancer who received radiotherapy after breast-conserving surgery at our institution to evaluate the incidence of radiation-induced bronchiolitis obliterans organizing pneumonia (BOOP) syndrome focusing on the interval from irradiation to onset and the clinical presentation. The predictive value of age (≤50 or >50), chemotherapy and hormone therapy was statistically analyzed to determine whether these are risk factors for BOOP syndrome. Radiation-induced BOOP syndrome was seen in 1.3% (9/710). In most cases, the symptoms were mild and none of the patients required hospitalization. Eight patients (88.9%) responded well to steroid administration, but 5 of these patients relapsed after or during tapering of steroids. Although we could not detect significant risk factors for BOOP syndrome, a higher patient age was associated with a higher incidence of radiation-induced BOOP syndrome after breast-conserving therapy. (author)

[en] The magnetization transfer contrast (MTC) effect depends on the shape, duration, amplitude, and offset frequency of the saturation pulse. In the present study, we investigated optimal combinations of these four parameters in vitro. All experiments were performed with a 7.05 Tesla MR system, and the spin echo technique (TR 500/TE 30) was adopted. We used a simple phantom composed of 1% agar and water, representing restricted and free proton pools, respectively. Signal intensity changes were measured in the agar (Ma) and water (Mw), when the shape, duration, magnitude, and offset frequency of the saturation pulses were varied. The MTC effect was examined with the Mw/Ma ratio. The suppression of Mw was less with the gauss pulse than with the square and sine pulses. The gauss pulse had the best MTC effect. The suppression of both Ma and Mw was greatest with a saturating duration of 60 msec. The MTC effect was greatest with a longer saturation pulse. The larger the amplitude, the stronger the MTC effect obtained. Mw was suppressed with an offset frequency of less than 3 kHz, and the MTC effect was greatest with an offset frequency closer to the spectrum of the free proton pool. In the present study the optimal MTC pulse at 7 Tesla is the gauss pulse with longer duration, maximal amplitude, and approximately 3 kHz off resonance. (author)