WE-G-213CD-05: Beam's-Eye-View Prostate Motion Detection during Arc Radiotherapy

PURPOSE

To track prostate motion during clinical arc radiotherapy using a novel statistical motion tracking algorithm in both phantom and patient systems.

METHODS

For the phantom study, a dynamic phantom with a custom tumor model and radiopaque fiducials was used. For the patient study, the clinical data from two prostate patients were acquired during volumetric modulated arc therapy (VMAT). For each patient, two gold fiducials (X-Mark, 1cm and 2cm in length) were implanted in the prostate. A total of 35 fractions with 2-field full arcs were delivered. Beam's-eye- view (BEV) images were acquired in cine mode every five fractions at a frame rate of 2 fps.The prostate motion was measured by two sequential steps: fiducial detection and motion estimation. In the first step, a wavelet- based block matching filter was used to suppress the noise and enhance the fiducials in the BEV images. A trajectory of detected fiducials was generated along the projection angles. Sequentially, the prostate motion was tracked using a statistical maximum a posteriori (MAP) algorithm. The 3-D fiducial position was estimated by maximizing the probability of displacement of 2-D projections.

RESULTS

A total of 8,400 BEV images were processed for this study. The phantom experiments showed that the baseline accuracy of estimation is 0.69+/-0.56 mm. For patient 1, intra- fraction prostate motion was measured to be 0.98+/-0.51 mm for all fractions, and individual fraction motion less than 1 mm. For patient 2, intra- fraction motion was 1.12+/-0.65 mm for all fractions. However, an exceptionally large displacement was measured as 4.9+/-0.74mm in one of the fractions.

CONCLUSIONS

Prostate motion during arc-therapy can be rigorously tracked to an accuracy of one millimeter. This technique is well suited for in-treatment room target tracking and post-therapy evaluation. Varian Medical Systems Inc.

A case of occult bowel perforation after a cycle of chemotherapy for advanced epithelial ovarian carcinoma

Occult bowel perforation is a rare complication in chemotherapy of advanced epithelial ovarian cancer (EOC). The authors present a case of a 75-year-old woman who had appendectomy due to suppurative appendicitis five years prior, that experienced an occult bowel perforation resulting in continuous decline of electrolytes after a single cycle of nedaplatin (NDP) and paclitaxel during neoadjuvant treatment of advanced EOC. To the authors' knowledge, this is the first reported case of an occult bowel perforation after neoadjuvant chemotherapy (NAC) for ovarian cancer. The complication was highly suggestive of a cell lysis mechanism for the perforation.

Uterine sarcoma with abdominal wall metastasis following laparoscopy: case report

PURPOSE

This work aimed to prevent artificial implantation in laparoscopic surgery for gynecological tumors.

METHODS

A case of uterine sarcoma with abdominal wall metastasis following laparoscopy was analyzed for clinical features.

RESULTS

A diagnosis of uterine sarcoma was made in Stage IV and the previous laparoscopic surgery had caused artificial abdominal wall metastasis.

CONCLUSIONS

We need to protect the puncture port in laparoscopic surgery of gynecological tumors to prevent artificial implantation.

The incidence of intra-operative awareness during general anesthesia in China: a multi-center observational study

BACKGROUND

The incidence of awareness in patients undergoing general anesthesia is 0.1-0.2% in Western countries. The medical literatures about awareness during general anesthesia are still rare in China, but some previous studies have reported a higher incidence (1.4-6%) of intra-operative awareness. To find out the reason why the incidence reported in China is much higher than that in Western countries, we performed a prospective, multicenter, non-randomized observational study to determine the true incidence of intra-operative awareness in China.

METHODS

This is a prospective, non-randomized descriptive cohort study that was conducted at 25 academic medical centers in China. Eleven thousand one hundred and eighty-five patients were interviewed by research staff for evaluation of awareness at the first and fourth day after general anesthesia with muscle relaxation. An independent blinded committee evaluated the responses and determined whether awareness occurred. Necessary data were collected for a binary logistic regression analysis.

RESULTS

Data from 11,101 patients were presented. Forty-six cases (0.41%) were reported as definite awareness and 47 additional cases (0.41%) as possible awareness. Three hundred and fifty-five patients (3.19%) had dreams during general anesthesia. Awareness was associated with increased American Society of Anesthesiologists (ASA) physical status, a previous anesthesia, and anesthesia methods of total intravenous anesthesia.

CONCLUSION

The incidence of intra-operative awareness in China is approximately 0.41%, two to three times higher than that widely cited in Western countries. Inappropriately light anesthesia, and the population proportion of surgery and general anesthesia in China may account for the difference. (ClinicalTrials.gov Identifier, NCT00693875.).

Optical signal-to-noise ratio monitoring of an 80 Gbits/s polarization-multiplexed return-to-zero differential phase-shift keying channel

We propose and experimentally demonstrate an optical signal-to-noise ratio (OSNR) monitoring technique for an 80 Gbits/s polarization-multiplexed return-to-zero differential phase-shift keying channel utilizing a narrowband optical filter and a low-speed detector. A maximum power increment of 19.7 dB is measured at a radio frequency (rf) of 250 MHz for monitoring of OSNR up to 27 dB, insensitive to chromatic dispersion of 0-300 ps/nm and polarization-mode dispersion (PMD) of 0-50 ps.

Activity of the descending noradrenergic pathway after surgery in rats

BACKGROUND

Previous studies have shown that activation of the descending noradrenergic inhibition pathway results in analgesia after surgery. However, the time course of activity of the descending noradrenergic pathway after surgery has not been examined previously. Here, we investigated the spinal release of noradrenaline (NA) in the post-operative period in a freely moving rat model of incisional pain.

METHODS

Loop microdialysis catheters were implanted subarachnoidally via the atlanto-occipital membrane in Sprague-Dawley rats. Twelve healthy rats without neural deficits were divided into two groups, Group A and Group B, following 5 days of recovery. A plantar incision in the right hind paws of rats in Group A was performed under 1.2% isoflurane. All rats in Group B were only anesthetized by 1.2% isoflurane for the same duration. The microdialysate samples for NA determination were collected before anesthesia, 3 h and 1, 2 and 3 days after incision (or isoflurane anesthesia in Group B) in both groups. The cumulative pain scores were assessed at the above time points.

RESULTS

The spinal release of NA increased gradually, peaked at 2 days after the incision and remained at the peak level up to the third day after the incision. The cumulative pain scores peaked 3 h after the incision, and gradually decreased afterwards and returned to the baseline values 3 days after the incision.

CONCLUSIONS

The descending NA tone might be apparently more active in the post-operative period. The descending noradrenergic inhibitory pathway plays an important role in post-operative neuroplasticity.

Articular cartilage metabolism in patients with Kashin-Beck Disease: an endemic osteoarthropathy in China

OBJECTIVE

The objective of this study was to investigate CD44 and proteoglycan metabolism in patients suffering from Kashin-Beck Disease (KBD), an endemic osteoarthropathy that affects 2.5 million of 30 million people living in the KBD regions of China.

METHODS

Immunohistochemical analyses of cluster of differentiation-44 (CD44), BC-13 and 3-B-3(-) expression were performed in cartilage sections harvested from KBD and normal patients. In addition, the serum levels of soluble CD44 (sCD44), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase-1 were determined using a sandwich enzyme linked immunosorbent assay.

RESULTS

Hematoxylin & eosin and toluidine blue staining indicated that there was cell necrosis and proteoglycan loss in cartilage from both KBD children and adult cartilage. Strong immunohistochemical staining for CD44, BC-13 and 3-B-3(-) occurred in the majority of adult KBD patients and most KBD children. Furthermore, statistically significant elevated levels of sCD44, IL-1beta and TNF-alpha were found in the sera of both adult and child KBD patients when compared to the levels of normal adult and child controls. Interestingly, IL-1beta and TNF-alpha serum levels were all high in normal children from KBD regions when compared to normal children from non-KBD regions suggesting that unidentified factors (e.g., a genetic predisposition) may protect some people from KBD pathology.

CONCLUSION

Our results demonstrate that altered CD44, IL-1beta and TNF-alpha metabolism occurs in the pathogenesis of KBD and there is an increased aggrecanase-generated proteoglycan loss from KBD adult and child cartilage. These primary metabolic changes are likely to be significant contributing factor causing pathological joint formation and instability that leads to secondary osteoarthritis in KBD patients.