Observation of intrafraction prostate displacement through the course of conventionally fractionated radiotherapy for prostate cancer.

PURPOSE: Intrafraction prostate displacement (IFPD) through the course of conventionally fractionated radiotherapy was observed by real-time tracking. MATERIALS AND METHODS: IFPD was observed by using a CyberKnife real-time tracking system over 39 serial fractions in two patients. Stereoscopic X-ray images tracking the implanted fiducial markers were obtained with mean intervals of 58 s. In preparation for treatment, urination was performed routinely 1 h before treatment and rectal gas was evacuated if necessary. Patients were immobilized by a thermoplastic body shell. RESULTS: The maximal absolute values of IFPD in all 78 fractions were 7.9, 2.1, and 11.5 mm in cranio-caudal (CC), left-right (LR), and antero-posterior (AP) direction, respectively. Only in 5 % of fractions (4/78 fractions), the maximal absolute values of IFPD were 5.0 mm or larger. In these fractions, large IFPD was temporary or persistent. IFPD of ≥3 mm was detected in only ~2-3 % of all obtained tracking images. CONCLUSIONS: Daily maximal IFPD changed day by day. Although maximal IFPD was more than 10 mm, IFPD of ≥3 mm was observed in a comparatively small proportion of treatment time. Through the course of conventionally fractionated radiotherapy, fractions with IFPD of ≥5 mm were infrequent.

Characteristics of small bowel tumors detected by double balloon endoscopy.

BACKGROUND: A few reports suggest that the emergence of double balloon endoscopy (DBE) has likely changed the clinical picture of small bowel tumors (SBTs). AIM: To further clarify the characteristics of SBTs detected by DBE. METHODS: A retrospective chart review was conducted in 227 patients who had undergone DBE. RESULTS: The SBT group contained more symptomatic patients than the non-SBT group (90% vs. 49%, P<0.0005) with a significantly higher rate of gastrointestinal symptoms at presentation (72% vs. 33%, P<0.005). Twenty patients (8.8%) were eventually diagnosed with SBT, and their indications for DBE were obscure gastrointestinal bleeding (n=5), abdominal pain (n=5), abdominal fullness (n=5), vomiting (n=2), and diarrhea (n=1). Tumors were located in the jejunum in 14 patients (70%) and in the ileum in 6 (30%). A final histological diagnosis was assigned to all 20 patients: primary adenocarcinoma (n=8, 40%), malignant lymphoma (n=5, 25%), metastatic cancer (n=4, 20%), gastrointestinal stromal tumor (n=1, 5%), carcinoid tumor (n=1, 5%) and inflammatory fibroid polyp (n=1, 5%). Stenosis or ulceration were the most frequently observed endoscopic findings (n=13, 65%). All primary adenocarcinomas and three of four (75%) metastatic cancers showed stenosis or ulceration. Three of five (60%) malignant lymphomas showed multiple lymphomatous polyps. All patients but one underwent surgical resection or chemotherapy or both. CONCLUSION: DBE is a safe and useful procedure that enables a precise diagnosis of SBTs.

Brain metastasis from hepatocellular carcinoma treated with a cyber-knife.

A 70-year-old right-handed Japanese man who had undergone surgical resection for hepatocellular carcinoma (HCC) 2 years earlier was diagnosed with lung metastasis 3 months before consulting our hospital with a headache and visual field disturbance. Head computed tomography revealed a brain tumor with an intracerebral hemorrhage. Using (99m)Tc-PMT (pyridoxal-5-methly-triptophan) scintigraphy, we determined that the brain tumor was metastasis from the HCC and utilized the cyber-knife for treatment. The prognosis of patients with brain metastasis from HCC has been reported to be poor. Use of the cyber-knife was non-invasive, and proved to be effective for improving prognosis and quality of life.

[Assessment of lower limb artery disease by ultrasound imaging].

Lower limb artery ultrasound is portable and can be used in first aid outpatient clinics and at the bedside. In addition, I can assess blood vessel properties and evaluate bloodstream change non-invasively in real time, an inspection that is indispensable for the diagnosis and treatment of peripheral artery disease.

Influence of collimator size on three-dimensional conformal radiotherapy of the cyberknife.

PURPOSE: In stereotactic conformal radiotherapy of the CyberKnife, multiple narrow beams from a cylindrical collimator are delivered to a planning target volume (PTV) without an isocenter by inverse planning. The influence of collimator size on stereotactic conformal radiotherapy was examined. MATERIALS AND METHODS: Five targets including two spherical targets (2.1 ml, 16.4 ml), an ellipsoidal target (2.9 ml), and two irregularly shaped targets (1.6 ml, 6.6 ml) were evaluated. Conformity and homogeneity of dose distribution, doses covering 95% volume of PTVs (D95), dose volume histograms (DVHs), and patterns of dose distribution were investigated in relation to collimator size for each target. We evaluated conformity and homogeneity using VD95/PTV (VD95 = volume covered by a D95 isodose surface) and Dmax/Dmin (Dmax, Dmin = maximum and minimum dose within the PTV, respectively), respectively. RESULTS: Conformity and homogeneity were not significantly influenced by collimator size. By using a considerably smaller collimator compared with the minor axis of the target the central dose of the target fell by less than 10% and D95 often decreased slightly. CONCLUSION: In stereotactic conformal radiotherapy of the CyberKnife, a smaller collimator tended to reduce the central dose and D95. These characteristics of the CyberKnife system should be considered.