Purpose To evaluate the diagnostic efficiency of spectral CT imaging combined with oral isotonic mannitol gastrointestinal hypotonic radiography in the diagnosis of preoperative T and N staging of rectal carcinoma. Materials and Methods Forty-seven patients with rectal cancer confirmed by surgery and pathology were included in this study, all the subjects underwent oral isotonic mannitol gastrointestinal hypotonic radiography prior to CT scan, then abdominal and pelvic plain and double-phase contrast-enhanced CT scan in the spectral imaging mode was performed, the optimal contrast-to-noise ratio imaging were got by the spectrum analysis software, then T-stage was evaluated and compared with pathological T-stage; N-stage was evaluated using both traditional method and the spectral curve method, and compared with pathological N-stage. Results ① All the 47 patients were able to successfully complete the examination and the rectal filling and lesion display were satisfactory; ② the best diagnostic accuracy of T-stage by the monochromatic images was 83.0% (39/47), which had a general correlation with pathologic results (Kappa=0.713, P<0.001); ③ the accuracy, sensitivity, specificity, positive predictive value and negative predictive value of N-stage by the traditional method were 78.72%, 80.95%, 76.92%, 73.91% and 83.33%, respectively, which had a general correlation with pathologic results (Kappa=0.574, P<0.001); the accuracy, sensitivity, specificity, positive predictive value and negative predictive value of N-stage by the Spectral curve method were 89.13%, 75.00%, 100.00%, 100.00% and 83.87%, respectively, which had a fair correlation with pathologic results (Kappa=0.772, P<0.001). Spectral curve method had higher Youden index for N-stage evaluation than traditional method (0.64 vs. 0.58). Conclusion Oral isotonic mannitol gastrointestinal hypotonic radiography can provide a good rectal background, and it is a safe and reliable method for rectal examination, when combined with spectrum CT imaging, it is able to display the detail of lesions and identity the homology of lymph nodes, which might help to make more accurate preoperative T, N staging of rectal carcinoma.

Objective:To compare the effect of intraoral and extraoral approach for the sugical treatment of mandibular cysts in the angle and ramus. Methods:Cysts in the mandibular angle and ramus were treated by intraoral approach in 57 cases and extraoral in 18 cases. The following data were collected: operation time, peroperative blood loss, postoperative infection, mouth opening, recurrence rate, injury of the submandibular branch of the facial nerve and sensory function of the inferior alveolar nerve. The data of the two groups were compared statistically. Results:Average operation time (min) of intraoral and extraoral appoarch was 84.65?5.16 and 122.78?10.84(P0.05). Conclusion:Intraoral approach is effective in the treatment of cyst in mandibular angle and ramus.

Objective To research the structure and principle of Helical Tomotherapy, and study the clinical application value of the equipment system. Methods As the first helical radiotherapy system in the mainland of China, its constructions, structure and principle were analyzed and discussed. Results Helical Tomotherapy is a new kind of radiotherapy equipment. The Hi-Art treatment system is a combination of a LINAC and a CT scanner capable of having the function of both systems. It was approved to achieve the best intensity modulated radiation therapy (IMRT), used for adjusting the setup position of the patient with MVCT and as the basis for dose reconstruction and other adaptive radiotherapy processes. It is the first integrated planning, delivery and verification system for IMRT. Conclusion Image-guided radiation therapy (IGRT) and IMRT have introduced a new era in radiation oncology which will better fight cancer and simultaneously improve the patients' quality of life. Having been designed from the ground up for IGRT and IMRT, the tomotherapy system is in the forefront of technical advancements for efficacy and processes to make it efficiently.

3-year practice and questionnaire of the graduates majoring in ophthalmology indicate ophthalmologic typical case image implicates very much clinical information,can satisfy ophthalmologic clinical skills test,reflect examinee's clinical knowledge and technical skill level and guide intern to cultivate clinical thinking capability.

Objective:To evaluate the efficacy of Piezosurgery in split teeth extractions.Methods:A single-center,randomized,split-mouth study was performed using a consecutive serious of unrelated healthy patients attending the departing of oral and maxillofacial surgery,Peking University School and Hospital of Stomatology.40 patients were selected for extraction of maxillary molars without reservation value,splitting or nonvital teeth.They were divided into control (20 patients)and test groups (20 pa-tients)randomly.Surgical treatments for both groups were under local anesthesia.Molar teeth of control group were extracted by common equipments like dental elevators,chisels,forceps,etc.While molar teeth of experimental group were extracted by Piezosurgery,aided with the use of common equipments if needed.Then we compared the duration of surgery,frequency of the usage of chisels,expansion of post-operative bony socket surgical discomfort and postoperative pain between two groups.Results:The ave-rage of operation time was (629.5 ±171.0)s in control group and (456.0 ±337.2)s in test group.The buccal alveolar bone reduced (1.07 ±0.64)mm in control group and (1.49 ±0.61)mm in test group. There was a significant difference between the two groups (P <0.05).The duration of surgery for experi-mental group was significantly longer than that of the control group,but the change of buccal alveolar bone was lower than the control group.For visual analogue scale (VAS)value of surgical discomfort,ex-pansion of postoperative bony socket and the operative fear rate,there were no significant difference be-tween the two groups (P >0.05).Conclusion:Piezosugery can be better to preserve alveolar bone,re-duce trauma and patient’s fear.Application of the piezosugery reflect the characteristics of minimally in-vasive extraction,which has the value of promotion.The Piezosurgery technique have the advantage of re-ducing change of buccal alveolar bone during the surgery,but a longer surgical time was required when compared with the conventional technique.VAS value of surgical discomfort,expansion of postoperative bony socket and the operative fear rate,there were no significant difference.Minimally invasive tooth ex-traction technique has good clinical results and high satisfaction.Piezosurgery proved its worth as the in-strument adapted to limiting the destruction of bone tissue.

Objective:To investigate the value of quantitative CT (QCT) body component parameters before and after transcatheter arterial chemoembolization (TACE) as prognostic indicator for patients with hepatic cell carcinoma (HCC).Methods:Retrospective analysis was performed on 40 patients with advanced HCC who received TACE treatment in Anhui Provincial Hospital Affiliated to Anhui Medical University from November 2013 to May 2017, all of them received QCT scanning before and after treatment. The information were recorded, including gender, age, alpha-fetoprotein (AFP), TNM stage, liver function Child-Pugh grade, portal venous thromboembolism, cirrhosis, maximum tumor diameter, tumor type, and frequency of interventional therapy. QCT parameters were measured before and after treatment, including L1, L2 bone mineral density (BMD), L3-level paravertebral muscle area (MA), subcutaneous fat area (SFA) and visceral fat area (VFA), and the change rate of QCT parameters (ΔBMD, ΔMA, ΔSFA, ΔVFA) before and after TACE were calculated after the QCT scan interval was standardized. The cut-off values of ΔBMD, ΔMA, ΔSFA and ΔVFA to diagnose the prognosis of HCC patients after TACE were obtained by drawing the ROC curves. The Kaplan-Meier method was used to calculate the survival rate, the Log-rank method was used for univariate analysis, and the Cox regression analysis model was used for multivariate analysis to screen out independent factors affecting the prognosis of HCC patients after TACE.Results:ROC curve analysis showed that the cut-off values of ΔBMD, ΔMA, ΔSFA and ΔVFA to diagnose the prognosis of HCC patients after TACE were -8.64%, -6.84%, -9.84% and 5.70%, respectively. Univariate analysis showed that AFP, TNM stage, liver function Child-Pugh grade, portal venous thrombosis, tumor type and ΔMA, ΔSFA, ΔVFA had statistically significant effects on prognosis ( P<0.1). Multivariate analysis showed that ΔMA, ΔVFA and portal venous thromboembolism were independent influencing factors for the prognosis of HCC patients after TACE treatment ( P<0.05). Conclusions:ΔMA, ΔVFA and portal venous thromboembolism have reference value for prognosis assessment of TACE treatment for HCC patients, and QCT body composition analysis is helpful to evaluate the prognosis of HCC patients.

Objective:To understand the clinical features of osteonecrosis of the jaw after bisphospho-nates use for therapy of breast cancer patients with bone metastasis.Methods:The cases diagnosed as bisphosphonates-related osteonecrosis of the jaws (BRONJ)were retrospectively analyzed from January 201 1 to August 201 5 in the Peking University School and Hospital of Stomatology,and those breast cancer patients with bone metastasis were selected.The clinical symptoms,imaging characteristics and treatment results were summarized.Results:A total of 1 4 cases of breast cancer patients with bone me-tastasis were selected,with an average age of 60.21 years.The average time of suffering from breast cancer was 9 .77 years,and the average time of bone metastasis and bisphosphonates drugs use was 5 .67 and 3 .29 years individually.There was no patient with systemic application history of hormone therapy, and no history of diabetes.There were 9 patients with tooth extractions history,and the mean time of bone necrosis symptoms was 8.58 months.There were 1 0 cases with bone necrosis occurring on mandi-ble,3 cases on maxilla,and one case with both upper and lower jaws involved.Among the 1 0 patients with surgical treatment,there were 3 cases cured,and 6 cases improved.However,the clinical symp-toms of 2 cases with conservative treatment were significantly aggravated.Conclusion:The medication time between the bisphosphonates use beginning and the occurrence of BRONJ is relatively long.The his-tory of diabetes and long-time hormone use did not exist in this group.Tooth extraction itself does not de-termine the severity of BRONJ.Mandible is the most common site involved by BRONJ.Surgical treatment can alleviate the clinical symptoms of BRONJ with breast cancer to some extent.

Objective To evaluate the clinical feasibility of quality assurance of helical tomotherapy intensity modulated radiation therapy (IMRT) through a series of clinical case studies. Methods Tomotherapy planning system was used to provide optimized IMRT treatment plans. To verify the dose of IMRT plans,the cylindrical Virtual Water phantom,0.056cm3 AISL, ion chamber and EDR2 film were used for getting the absolute and relative doses from tomotherapy IMRT planning. The film and ion chamber were placed into the phantom. The doses of the interesting points and isodose distribution of the axial plane were measured,then the results were compared with those from the calculation in planning system for verification. Before the irradiation,kVCT images of the phantom were registered by tomotherapy MVCT images. So the setup of phantom was guided for verifying the position. Results The isedose distribution (on the axial plane) measured by the film was well consistent with that calculated by tomotherapy planning system. The error between the measured dose and predicted dose in the measured points was less than 3%. The setup error of the phantom was able to be kept within 1 mm. There was 2 mm offset along the vertical direction of couch from the virtual isocenter to beam isocenter,which should be considered during the phantom/patient setup. Conclusions The procedures for quality assurance of tomotherapy IMRT are feasible in our experience. And helical tomotherapy IMRT QA system has been constituted.

Objective To evaluate the dosimetric effect of carbon fiber tabletop on the patient doses in radiotherapy. Methods The transmission factors of couch and inserts were measured in air and solid water phantom using 0.6 cm3 ion chamber and PTW 2D ion chamber array for 6 MV ,10 MV and 18 MV X-ray,respectively. Absorbed doses at depth of maximum dose ,5 cm and 10 cm in solid water were measured with the 2D ion chamber array. Absorbed doses fluctuations with different gantry angles and air gaps between phantom and couch were also measured. Results The posterior field measurement showed that the reductions of absorbed doses at the depth maximum dose,5 cm and 10 cm were within 5%. The ratios of the absorbed doses with to without couch increased with the oblique incident angles and varied slightly with the air gap at depth of 5 cm. The transmission factors of inserts were less than those of couch owing to its thinner thickness. Conclusion The carbon-fiber tabletop affects the absorbed doses and dose distributions of the target, and this effect changes with the gantry angle and air gap. Special considerations should be taken during treatment planning.

Objective To investigate the feasibility of dose verification of intensity modulated (IM) planning of helical tomotherapy (HT) using two-dimensional ion chamber array (2DICA),and develop an efficient way to validate the dose delivered under the parameters mirroring those during the treatment. Meth-ods A 2DICA,I'mRT MatriXX and MULTICube equivalent solid water phantom from IBA company were used to verify the dose distribution of 10 IM planning. The combined phantom was set up to measure the dose distributions on coronal and sagittal surface. The precise setup of phantom was guided by HTMVCT images. After the irradiation, the measured dose distributions on the coronal and sngittal plane were compared with those calculated by the IM planning system for verification. The results were evaluated and the feasibility of the different measuring methods was studied. Results The dose distribution measured by the MatriXX 2DICA was well consistent with that calculated by the treatment planning system. The errors between the measured dose and predicted dose in the selected points were within ±3%. In the comparison of the pixel-segmented ionization chamber versus treatment planning system using the 3 mm/3% γ criteria, the passing ratio of pixels with γ parameter ≤1 was 97.76% and 96.83%, respectively. Conclusions MatriXX is a-ble to measure the absolute and relative dose distributions simultaneously,which can be used for dose verifi-cation of IM planning.