A questionnaire about radiation safety management of the draining-water system at nuclear medicine facilities

We conducted a questionnaire survey about radiation-safety management condition in Japanese nuclear medicine facilities to make materials of proposition for more reasonable management of medical radioactive waste. We distributed a questionnaire to institutions equipped with Nuclear Medicine facilities. Of 1,125 institutions, 642 institutes (52.8%) returned effective answers. The questionnaire covered the following areas: 1) scale of an institution, 2) presence of enforcement of radiotherapy, 3) system of a tank, 4) size and number of each tank, 5) a form of draining-water system, 6) a displacement in a radioactive rays management area, 7) a measurement method of the concentration of medical radioactive waste in draining water system, 8) planned and used quantity of radioisotopes for medical examination and treatment, 9) an average displacement of hospital for one month. In most institutions, a ratio of dose limitation of radioisotope in draining-water system was less than 1.0, defined as an upper limitation in ordinance. In 499 hospitals without facilities of hospitalization for unsealed radioisotope therapy, 473 hospitals reported that sum of ratios of dose limits in a draining-water system was less than 1.0. It was calculated by used dose of radioisotope and monthly displacement from hospital, on the premise that all used radioisotope entered in the general draining-water system. When a drainage including radioactivity from a controlled area join with that from other area before it flows out of a institution, it may be diluted and its radioactive concentration should be less than its upper limitation defined in the rule. Especially, in all institutions with a monthly displacement of more than 25,000 m3, the sum of ratio of the concentration of each radionuclide to the concentration limit dose calculated by used dose of radioisotope, indicated less than 1.0.     

Scintigraphic evaluation of myocardial uptake of thallium 201 and technetium 99m pyrophosphate utilizing a rat model of chronic doxorubicin cardiotoxicity

To evaluate the usefulness of myocardial scintigraphy as a monitoring tool for chronic doxorubicin (DXR) cardiotoxicity, a rat model was used to investigate the relationship between the myocardial uptake of thallium 201 (Tl) or rechnetium 99m pyrophosphate (^99mTc-PPi) and histological changes of the heart. Although there was no significant difference in myocardial Tl uptake between control and DXR-treated rats at an early phase after Tl injection, late-phase Tl uptake was significantly higher in the DXR-treated rats than in the control rats, indicating a slow wash-out of Tl from the myocardium. The wash-out rate calculated from scintigraphic examination of DXR-treated rats was significantly decreased with increasing degree of cardiomyopathy. Since the Tl wash-out rate was sharply decreased even in animals with minimal histological changes, it may be a possible monitoring tool for the early detection of chronic DXR cardiotoxicity. On the other hand, myocardial^99mTc-PPi images could be obtained only in rats with severe myocardial changes and hence would not useful for early detection.     

Direct Effects of [Greek small letter alpha]1- and [Greek small letter alpha]2-Adrenergic Agonists on Spinal and Cerebral Pial Vessels in Dogs

Background: The effects of adrenergic agonists, often used as local anesthetic additives or spinal analgesics, on spinal vessels have not been firmly established. The authors investigated the effects of [Greek small letter alpha]2- and [Greek small letter alpha]1-adrenergic agonists on spinal and cerebral pial vessels in vivo.

Methods: Pentobarbital-anesthetized dogs (n = 28) were prepared for measurement of spinal pial-vessel diameter in a spinal-window preparation. The authors applied dexmedetomidine, clonidine, phenylephrine, or epinephrine in three different concentrations (0.5, 5.0, and 50 [micro sign]g/ml; [2.1, 1.9, 2.5, and 2.3] x [10-6, 10-5, and 10-4] M, respectively) under the window (one drug in each dog) and measured spinal pial arteriolar and venular diameters in a sequential manner. To enable the comparison of their effects on cerebral vessels, the authors also administered these drugs under a cranial window.

Results: On topical administration, each drug constricted spinal pial arterioles in a concentration-dependent manner. Phenylephrine and epinephrine induced a significantly larger arteriolar constriction than dexmedetomidine or clonidine at 5 [micro sign]g/ml (8%, 11%, 0%, and 1%, respectively). Spinal pial venules tended to be less constricted than arterioles. In cerebral arterioles, greater constrictions were induced by dexmedetomidine and clonidine than those induced by phenylephrine and epinephrine (14%, 8%, 0%, and 1%, respectively). Cerebral pial venules tended to exhibit larger constrictions than cerebral arterioles (unlike in spinal vessels).     

Feasibility of laparoscopic gastrectomy for advanced gastric cancer with positive peritoneal cytology

Purpose

The role of gastrectomy for patients with positive peritoneal cytology, but a negative macroscopic peritoneal implant (P?/cy+), remains unclear. The aim of this study was to evaluate laparoscopic gastrectomy for P?/cy+ patients.

Methods

This study reviewed a prospectively maintained gastric cancer database of gastric-cancer patients those underwent surgical resection. P?/cy+ gastric cancer that had invaded the subserosa, or deeper layers, of the stomach wall without distant organ metastases was considered operable in this institution. P?/cy+ patients underwent either open or laparoscopic gastrectomy with D2 lymphadenectomy. The short-term results were examined to assess differences in outcome between the two groups.

Results

Eighteen P?/cy+ patients without distant organ metastases underwent surgery between 2000 and 2010. Laparoscopic gastrectomy was performed in nine patients and open gastrectomy in nine patients. The estimated blood loss was significantly smaller, the resumption of food intake earlier, and the length of postoperative hospital stay shorter in the patients that underwent laparoscopic gastrectomy than in the patients that underwent open gastrectomy. There were no significant differences in the 2-year survival rates between the groups.

Conclusion

Laparoscopic gastrectomy for P?/cy+ patients is a minimally invasive and safe oncologic procedure with good short-term results.     

The effect of graft-tunnel diameter disparity on intraosseous healing of the flexor tendon graft in anterior cruciate ligament reconstruction

BACKGROUND: Graft-to-tunnel healing is a significant factor in anterior cruciate ligament reconstruction, but there have been few studies on the effect of graft-tunnel diameter disparity on intraosseous healing of the flexor tendon graft. HYPOTHESIS: Graft-tunnel diameter disparity of 2 mm has no effect on the pull-out strength of the graft from the bone tunnel. STUDY DESIGN: Controlled laboratory study. METHODS: Forty-two beagle dogs were divided into three groups. In each animal, reconstruction was performed in the left knee by using a 4-mm diameter autogenous flexor tendon for groups 1 and 2 and by using a 4-mm wide bone-patellar tendon-bone graft in group 3. A 4-mm diameter tunnel was drilled in the tibia of groups 1 and 3 and a 6-mm diameter tunnel, in group 2. In each group, seven animals were sacrificed at 3 and 6 weeks. RESULTS: The perpendicular fibers connecting the graft to the bone were generated in groups 1 and 2, and the number appeared to be higher in group 2, where the space was greater. There was no significant difference in the ultimate failure load between groups 1 and 2 at each period. CONCLUSION: Graft-tunnel diameter disparity of up to 2 mm may not adversely affect intraosseous healing of the flexor tendon graft. CLINICAL RELEVANCE: Surgeons need not be overly concerned about minor graft-tunnel diameter disparities.     

Small hypervascular hepatocellular carcinoma revealed by double arterial phase CT performed with single breath-hold scanning and automatic bolus tracking

OBJECTIVE: The purpose of this study was to evaluate the usefulness of double arterial phase CT for the detection of small hypervascular hepatocellular carcinomas, using an automated bolus-tracking technique to initiate the hepatic arterial phase CT. MATERIALS AND METHODS: Double arterial and late phase contrast-enhanced helical CT scans were obtained on 287 consecutive patients suspected of having hepatocellular carcinoma. These included 56 patients with 90 small (< or 3 cm) hepatocellular carcinomas and 50 patients with no hepatocellular carcinomas. CT scans of these patients were interpreted by three reviewers. The first arterial phase scan was initiated automatically 10 sec after the bolus-tracking program detected the threshold enhancement of 50 H in the abdominal aorta. Three reviewers interpreted the late phase CT scans in combination with the first, second, or both hepatic arterial phases. Measures of the reviewers' detection of hepatocellular carcinoma included analysis of interobserver variation, sensitivity, specificity, and area under receiver operating characteristic curve (A(z)). RESULTS: The time elapsed from bolus initiation to threshold aortic enhancement ranged from 10 to 24 sec (mean, 13 sec), resulting in initiation of the first arterial phase CT scan from 20 to 34 sec (mean, 23 sec). The combination of late phase CT and both first and second arterial phase images showed significantly better performance than the combination of the late phase and either the first or second arterial phases, although the difference was most evident in comparison with the combination of second arterial and late phases. CONCLUSION: An automated bolus-tracking program can be used to optimize the timing of hepatic arterial phase CT. Multiphasic CT performed using this technique is useful in detection of small hepatocellular carcinoma.     

CT and MR features of nasopharyngeal carcinoma in children and young adults

AIM: To clarify CT and MR features of nasopharyngeal carcinoma (NPC) in children and young adults. METHOD: CT and MR findings of 13 patients (30 years old or younger) with a histopathologic diagnosis of NPC were reviewed. RESULTS: Skull base invasion (12/13), lymphadenopathy (10/13), and infiltrative growth (8/8) were common findings. The signal intensity of tumours was slightly higher than that of muscles in six cases and isointense to that of muscles in two cases on T1-weighted images; it was higher than that of muscle and lower than that of cerebellar grey matter on T2-weighted images in all cases. Internal signals were homogeneous in both pre- and post-Gd-enhanced MR images in all cases. CONCLUSIONS: Despite its rarity in this age group, NPC should be included in a differential diagnosis when CT and MR imaging reveal these features.     

The usefulness of transcatheter arterial embolization for patients with blunt polytrauma showing transient response to fluid resuscitation

BACKGROUND: This study aimed to determine whether nonsurgical management using transcatheter arterial embolization (TAE) is safe for patients with blunt multiple trauma who transiently respond to the initial fluid resuscitation. METHODS: Contrast computed tomography was performed for patients with blunt abdominal injuries, excluding those who did not respond to initial fluid resuscitation. Angiography was performed for patients with injuries showing contrast extravasation or solid organ injury classified, according to the American Association for the Surgery of Trauma, as grade 3 or higher on computed tomography. Transcatheter arterial embolization was performed when angiography showed arterial extravasation. The protocol was abandoned for any patients who became profoundly hypotensive (with systolic blood pressure 60 mm Hg or lower) during computed tomography or angiography. RESULTS: Between January 2000 and December 2002, 269 patients with blunt abdominal injuries underwent TAE immediately after admission. Of these patients, 41 had injuries in at least two regions and underwent TAE for these regions. Among them, 22 patients were hemodynamically stable or showed rapid response to fluid resuscitation. The nonsurgical treatment was successful in all these cases. The remaining 19 patients (Injury Severity Score, 37.3 +/- 8.2), who showed a transient response, were the subjects of this study. Of these patients, 15 underwent TAE for injuries in two regions (13 pelvic fractures, 7 splenic injuries, 6 hepatic injuries, 3 facial bleeding, and 1 renal injury), and 4 patients underwent TAE for injuries in three regions (4 had splenic injuries, 3 hepatic injuries, 2 renal injuries, 2 pelvic fractures, and 1 facial bleeding). For all these patients, TAE was successfully performed. Before TAE, the systolic blood pressure was 79.9 +/- 8.4 mm Hg, and the shock index was 1.45 +/- 0.25 mm Hg. After TAE, the corresponding values were 120.6 +/- 19.3 mm Hg and 0.87 +/- 0.16 mm Hg, respectively (p < 0.001). The rate of fluid administration required after TAE (214.2 +/- 139.3 mL/hour) was significantly less than that required before TAE (1244.2 +/- 347.1 mL/hour; range, 632-1,728 mL/hour) (p < 0.001). The deaths of two patients were classified as nonpreventable on the basis of the Trauma and Injury Severity Score (TRISS), and their respective probabilities of survival were determined to be 0.13 and 0.03. CONCLUSION: Nonsurgical management using TAE can be performed safely even for patients with blunt multiple trauma who are in hemorrhagic hypotension if their hemodynamics are improved by resuscitation with 2 L of fluid.     

Aortic root replacement with a freestyle stentless valve for aortitis syndrome with ascending aortic aneurysm and aortic regurgitation.

A 47-year-old woman who had been diagnosed as having aortitis syndrome underwent aortic root replacement for an ascending aortic aneurysm and aortic regurgitation. Because the patient has been treated with steroids for more than 20 years, a Freestyle stentless valve was used to avoid the risk of valve detachment. There were no complications observed during the postoperative course. Although long-term follow-up will be necessary to observe the valve durability, the Freestyle stentless valve seems to be useful for aortic root replacement in patients at high risk of valve detachment due to aortitis syndrome.     

Multiple chronic subdural hematoma in shaken-baby syndrome

We described a case of shaken-baby syndrome with multiple chronic subdural hematomas. A 10-month-old male baby was admitted to our hospital because of loss of consciousness and convulsions. CT scan revealed an acute subarachnoid hemorrhage extending into the interhemispheric fissure and supracerebellar space. The patient was treated conservatively, and discharged from the hospitaL Two months after ictus, a baby was admitted to our hospital with general fatigue. CT scan demonstrated multiple chronic subdural hematomas. Burr hole irrigation and drainage brought about complete disappearance of these lesions. Retrospectively, it was found that these multiple subdural hematomas were due to shaken-baby syndrome. Shaken-baby syndrome is a form of child abuse that can cause significant head injury, and subdural hematoma is the most common manifestation. It is well known that the outcome of shaken-baby syndrome is generally not good. It is important to suspect shaken-baby syndrome when a chronic subdural hematoma is seen in a baby.