Synchronous monitoring of external/internal respiratory motion: validity of respiration-gated radiotherapy for liver tumors.

PURPOSE: Four-dimensional (4D) radiotherapy, in particular respiration gating for the treatment of lung tumors, is gaining popularity. Its utility for other sites, however, has not been investigated fully. The purpose of this study was to see whether 4D therapy is feasible for liver tumors. MATERIAL AND METHODS: Six patients (five with hepatomas and one with metastatic liver tumor) had a fiducial, gold marker 1.5 mm in diameter implanted in the vicinity of their liver tumors. The inner and external (i.e., upper abdominal wall) respiratory movements were simultaneously recorded using a real-time tumor-tracking radiotherapy system and respiration monitor equipment applied to the mid to upper abdomen. RESULTS: The fluctuations from the baseline position of liver tumors were small; the mean absolute value was 3.92 +/- 1.94 mm. The mean right-left, anteroposterior, and craniocaudal total movements were 4.19 +/- 2.46, 7.23 +/- 2.96, and 15.98 +/- 6.02 mm, respectively. The phase shift was negligible. CONCLUSION: Liver tumors may be suitable for respiration-gated radiotherapy, and they may become curable with 4D radiotherapy.

Exhale fluctuation in respiratory-gated radiotherapy of the lung: a pitfall of respiratory gating shown in a synchronized internal/external marker recording study.

PURPOSE: For optimal respiratory-gated radiotherapy, exhale fluctuation was assessed by monitoring internal fiducials in a synchronized internal/external marker detection system. METHODS: Synchronized internal/external position data were collected during the entire course of treatments for 12 lung patients with 24 fiducials. Baseline was determined in the exhale phase during pre-treatment observation time, and a gating level of external waves was set in each treatment session in a simulation of respiratory-gated radiotherapy. Patients were treated under a real-time tumor-tracking (RTRT) system with an external (abdominal) respiratory motion detector. In the simulation, external gating windows were defined as those below the 30% amplitude level (i.e., imaginary beams would be triggered when part of the respiratory wave falls into this window). Exhale fluctuation (EF) was defined as the phenomenon in which the lowest point of the external wave crossed downward past the pre-determined baseline. Gating efficiency (GE) was defined as the ratio between the amount of gate-ON time and the total treatment time. RESULTS: EF occurred in 18.4% of total measurements. EF varied depending on the patient, fiducial sites, and treatment session. The mean incidence of EF for each patient varied from 2.9% to 37.5% (18.4+/-9.9). The EF magnitude was 0.2-12.2 mm in the left-right direction, 0.7-12.7 mm in the cranio-caudal direction, and 0.4-9.7 mm in the anterior-posterior direction. Total fiducial movement was 0.5-28.7 mm. GE was 36.1-69.2% (55.4+/-11.0). EF magnitude correlated with total fiducial movement. CONCLUSION: This study showed that EF is not a rare phenomenon and needs to be taken into consideration for individualized precise 4D radiotherapy.

Serous psammocarcinoma of the ovary: CT and MR findings.

Serous psammocarcinoma, a rare variant of ovarian serous carcinoma, is characterized histologically by the pervasive presence of psammoma bodies. In this case, computed tomography scans showed extensively calcified pelvic and peritoneal masses. The pelvic mass appeared sandy on enhanced T1-weighted magnetic resonance images. These imaging results suggest that the presence of abundant psammomatous calcifications in primary and disseminated lesions may be a radiological marker of ovarian psammocarcinoma.

Spontaneous rupture of renal angiomyolipoma: value of multidetector CT angiography for interventional therapy.

Renal angiomyolipomas have a high risk of rupture when they are large and associated with aneurysms. When renal angiomyolipomas rupture, some patients go into shock. Immediate interventional therapies to stop bleeding are required. In the present case, multidetector computed tomographic angiography provided useful information for planning the interventional therapy. Because of the information, transcatheter arterial embolization was safely performed while preserving most renal function.

Reflux in the left ovarian vein: analysis of MDCT findings in asymptomatic women.

OBJECTIVE: The aim of this study was to clarify the CT features of ovarian vein reflux in asymptomatic women and to determine the possible cause of the reflux. MATERIALS AND METHODS: One hundred ten multiparous or uniparous and 41 nulliparous asymptomatic women were examined on MDCT. Degree, pathway, and associated findings of ovarian vein reflux were evaluated. We measured the diameters of the left renal vein (LRV), the ovarian veins, and the parauterine veins. Ratios of LRV diameters (lateral-aortomesenteric) were obtained. These data were then compared between the women with reflux and those without reflux. RESULTS: Reflux was found in 44% (48/110) of parous and 5% (2/41) of nulliparous women. Reflux flowed into the right ovarian vein through the parauterine and uterine veins in 25 women. Twenty-four of these 25 women were multiparous. In these cases, the parauterine veins showed varicose dilation (5.9 +/- 1.6 mm [mean +/- SD]). There was a statistically significant difference in left ovarian vein diameter (8.3 +/- 2.1 mm vs 4.9 +/- 1.3 mm, p < 0.0001) between parous women with reflux and those without reflux, respectively. The LRV diameter ratio (lateral-aortomesenteric) was also statistically significant (3.6 +/- 1.3 vs 1.7 +/- 0.7, p < 0.0001) between the same two groups. CONCLUSION: Reflux into the left ovarian vein is seen up into the contralateral ovarian plexus by passing through the dilated parauterine and uterine veins. This CT finding is common in asymptomatic multiparous women. Narrowing of the LRV at its aortomesenteric portion can be one of the causes of such reflux.