Contrast-induced nephropathy (CIN) has now been the third most common cause of acquired renal failure. Diabetes mellitus (DM), the type of contrast agent used and the intra-arterial route of administration are three important risk factors inducing CIN. The incidence rate of CIN is very high in patients with DM or renal insufficiency after iodinated contrast was administered. Unfortunately, it has not yet attracted physicians’and radiologists’sufficient attention. This paper aims to make an evidence-based evaluation of the safety and rephrotoxicity of various contrast agents when they are used in patients with DM. Usually, intravenous administration of contrast media will not cause permanent damage to the kidney in highrisk patients. Low-osmolarity contrast media is relatively safe for patients with DM only, while it takes much risk of CIN when low-osmolarity contrast media is used in patients with diabetic nephropathy or in patients of DM accompanied with renal insufficiency, for such patients, the iso-osmolarity contrast media, iodixanol, can be used.

Cone-beam computed tomography (CBCT)-guided radiotherapy has been widely used in radiotherapy, but it still has many limitations.Using magnetic resonance imaging (MRI) instead of CBCT for imaging-guided radiotherapy can not only make use of the advantages of MRI, but it also allows for online and real-time tracking of tumor motion and biological changes.This technique truly realizes the real-time MRI-guided adaptive radiotherapy (ART) in anatomy and biology, and sets another milestone in the advancement of radiotherapy.This review summarizes the technical advantages of MRI-guided radiotherapy, the basic structure and type of MR-Linac, and the technical difficulties and solutions of MRIgART.

Objective　 To improve the recognization and the diagnostic accuracy of brachial cleft cyst (BCC) by CT scan. Methods 　CT findings of 10 BCC proved surgically and pathologically were retrospectively reviewed. Results　 BCC，CT number 22～33 Hu；with the enhanced wall and the non-enhanced cystic part. If infections exist，the margin would be obscure and the internal density be increased. These cysts commonly located in the anterior triangle area of the neck or along the anterior border of the sternocleidomastoid muscle. The first brachial cleft fistula was not displayed. Conclusion　 CT scan can not only clearly show the location，enhanced characters and the relationship to the adjacent tissues of the BCC，but also can be possible to make the diagnosis of the BCC，but not the brachial cleft fistula.

Objective To investigate the feasibility of CT pulmonary angiography (CTPA) with 80 kVp and contrast agent of iodixanol (270 mg I/ml) by filtered back projection(FBP) reconstruction.Methods In total,52 patients who underwent CTPA were randomly divided into two equally-sized groups,control group and experimental group.The volume computed tomography dose index (CTDIvol) and dose-length product (DLP)were recorded,and the weighted computed tomography dose index (CTDIw) and effective dose (E) were calculated.The image quality was visually evaluated and measured,and statistical analyses were performed on the image quality and the radiation dose.Results The sex,age,height,weight and body mass index (BMI) had no statistical difference between two groups (P ＞ 0.05).The average iodine dosage decreased by 22.9％ in the experimental group compared with the control group.Compared with the control group,the CTDIvol,DLP,CTDIw and E decreased by 73.5％,75.1％,73.5％ and 75.8％,respectively.The differences were statistically significant (t =＜0.001,30.5,＜ 0.001,-28.7,P ＜ 0.05).The image quality of the two groups met the requirement of diagnosis and there were no significant statistic differences between visually evaluating and objectively measuring the image quality (P ＞ 0.05).Conclusions Using 80 kVp and iodixanol for CTPA,FBP reconstruction image quality can meet diagnostic requirements.At the same time the radiation dose,the contrast agent dose and the X-ray tube wastage are reduced respectively.

Objective To investigate the value of 18 F-fluorodeoxyglucose FDG) positron emission tomography (PET)-computed tomography (CT) in predicting the progression-free survival (PFS)and overall survival (OS) of patients with esophageal squamous cell carcinoma (ESCC) after threedimensional (3D) radiotherapy.Methods A retrospective analysis was performed on 98 ESCC patients,who underwent FDG PET-CT before 3D radiotherapy from 2004 to 2010,to investigate their 1-,3-,and 5-year PFS and OS rates.The relationship of maximum standard uptake value (SUVmax),mean SUV (SUVmean),metabolic target volume (MTV),length of primary tumor on PET-CT before radiotherapy,and number of tumors on PET with PFS and OS were analyzed.The SUVs and clinical data were analysed by independent samples t-test or Hotelling T2 test; the Kaplan-Meier method was used for calculating PFS and OS rates,and the Logrank test was used for survival difference analysis;the prognostic factors were analysed using the Cox proportional hazard model.Results The follow-up rate was 100％ ;56 patients were followed up for at least 3 years,and 27 for at 5 years.The SUVmax SUVmean and MTV of primary tumor,length of primary tumor on PET-CT before radiotherapy,and number of tumors on PET were correlated with PFS and OS (x2 =8.99-41.82,all P ＜ 0.01).The Cox regression analysis showed that PFS could be well predicted based on SUVmean (x2 =4.41,P =0.036,RR =1.398) and number of tumors on PET (x2 =6.79,P =0.009,RR =3.650) and that OS could be well predicted based on number of tumors on PET (x2 =5.03,P =0.025,RR =3.740).Conclusions When estimating the long-term response to precise radiotherapy in patients with ESCC,SUV mean and number of tumors on PET may be used to predict PFS,and number of tumors on PET may be used to predict OS.

Objective To compare the dosimetric differences among three-dimensional conformal radiotherapy(3D-CRT),intensity-modulated radiotherapy(IMRT)and RapidArc for prophylactic carnial irradiation(PCI)in small cell lung cancer(SCLC)patients.Methods Ten patients with SCLC were enrolled into this study.3D-CRT,9-field IMRT(IMRT)and double arc RapidArc plans were designed and optimized for each patient.The goal was to deliver 25 Gy to ≥ 95％ of the planning target volume(PTV)while the same normal-tissue dose constraints were achieved.The dose distribution and conformal index (CI),homogeneity index(HI)of target volume,the maximum dose(D2 ％),the minimum dose(D98 ％),target coverage of PTV(V95 and V100),and Dmean and Dmax of organs at risk(OAR)were analyzed by using the dose volume histogram(DVH).The monitor units and delivery time were also evaluated.Results All plans met the clinical requirements.PTV dosimetric parameters(CI,HI,D2％,D98％,V95 and V100)of RapidArc and IMRT were superior to those of 3D-CRT with significant difference(P＜0.05).The maximum doses to the optic nerves,brainstem and the mean dose to the parotid glands of the IMRT and RapidArc plans were all significantly lower than those of the 3D-CRT plan(P＜0.05),while 3D-CRT plan provided the lowest maximum doses and mean dose of the lens and eyes(P＜0.05).Compared with IMRT plan,no obvious advantage in PTV dosimetric parameters could be observed in RapidArc plans.In terms of organ sparing,no statistical difference was observed between IMRT and RapidArc plans.The number of monitor units for 3D-CRT,IMRT and RapidArc were 287.8,1388.8 and 346.6,respectively.Conclusions Compared with 3D-CRT,IMRT and RapidArc show better dosimetric quality.The 3D-CRT plan has a significantly lower dose on the lens and eyes,less MU and shorter delivery time than IMRT and RapidArc plans.

Objective To compare the difference of decreasing radiation-induce lung injure among CT scans including active breathing control (ABC), slow CT scan and general axial CT scan under free breathing (FB) in precise radiotherapy of peripheral non-small cell lung cancer (NSCLC). Methods Ten patients of peripheral NSCLC were included. For each patient, three CT scans were obtained: (1) the general axial CT scans under FB;(2) the fast spiral CT scans under ABC;(3) the slow CT scans under FB. Three treatment plans based on three CT scans were optimized. Gross tumor volume (GTV), clinical target volume (CTV) and planning target volume (PTV) along with V20 (lung volume accepted > 20 Gy/all lung volume ×100%) and Dmean (average dosage accepted irradiation of all lung)of three treatment plans were calculated and compared. Results The GTV and CTV of the slow CT plan seem in largest, and those of ABC plan in smallest, but no statistics signification among the three plans (F = 1.513, P = 0.238;F = 1.376, P = 0.270). However, The PIV of the FB plan was largest, and the difference of PTV between plans of ABC and FB, plans of slow CT scans and FB were statistics significant (F = 26. 148, P = 0.000). The differences of V20 and Dmean between plans of FBand ABC, plans of FB and slow CT scans were statistics significant yet (F = 7.623, P = 0.002;F = 18.217, P = 0.000). Conclusion Compared with FB conditions, ABC or the slow CT scan method in precise radiotherapy of peripheral NSCLC can decrease radiation volume and dose to normal tissues as well as the probability of decreasing radiation-induce lung injure.

Objective To evaluate therapeutic effects and complications of concurrent three-dimensional conformal radiotherapy (3DCRT) and chemotherapy in patients with limited-stage small cell lung cancer (LSCLC).Methods From June 2000 to August 2005, 93 histologically proved LSCLC patients were randomized into two groups:3DCRT group (n =46) and conventional group (n =47).In both groups, patients received one cycle chemotherapy, followed by concurrent chemoradiotherapy and then received consolidate chemotherapy.Chemotherapy was four to six cycles of PE regimen.Conventional irradiation field was setup in conventional group, while in 3 DCRT group clinical target volume (CTV) only involved visible tumor and adjacent lymphatic region.Radiotherapy was delivered at 2 Gy per fraction, 5 fractions per week to a median total dose of 60 -64 Gy.Those who achieved a complete response were treated with prophylactic cranial irradiation (PCI) with 30 Gy in 10 fractions.Results The follow-up rate was 100% in both groups.The number of patients completed 1-, 2-and 3-year follow-up were 36, 34 and 16 in 3DCRT group, 14, 7 and 8 in conventional group, respectively.The complete and overall response rate were 52% and 89% in 3DCRT group, while 47% and 85% in conventional group, respectively.The 1-, 2-and 3-year survival rates were 78%, 35% and 15% in 3DCRT group, 72%, 30% and 17% in conventional group, respectively.The median survival time was 23.2 and 22.8 months, respectively.There was no statistical difference in short-term (Χ~2 = 0.34 ,P = O.759) and long-term outcomes (Χ~2 = 0.18 ,P = 0.92).In 3DCRT group, the incidence of grade 1 +2 acute radiation pneumonitis and esophagitis, grade 1 +2 and grade 3 chronic radiation pneumonitis were lower than those in conventional group.There was no grade 3 or 4 acute radiation pneumonitis or esophagitis, or grade 4 chronic radiation pneumonitis in both groups.There was no difference in grade 1 + 2, grade 3 or grade 4 acute myelo-suppression between the two groups.Conclusions In the treatment of LSCLC, concurrent 3DCRT and chemotherapy can achieve satisfactory short-term and long-term outcomes with acceptable complications.

Objective To evaluate the role of thoracic three-dimensional conformal radiotherapy (3DCRT) in patients with extensive-stage small cell lung cancer (ES-SCLC).Methods A total of 171 patients with ES-SCLC admitted from 2004 to 2009 were included in the study.Eighty-six patients received thoracic 3DCRT and systemic chemotherapy (CT),while 85 patients received systemic CT alone.3DCRT was delivered at 1.5 Gy/fraction twice daily or 2.0 Gy/fraction once daily,with a total dose ranging from 40 to 62 Gy.The CT regimen consisted of carboplatin/cisplatin and etoposide.The survival time and survival rate were calculated by the Kaplan-Meier method,and the log-rank test was used for univariate prognostic analysis;the Cox model was used for multivariate prognostic analysis.Results The follow-up rate was 100％.The median overall survival (OS) time and the 2-and 5-year OS rates were 15 months,31.5％,and 2.4％,respectively,for all patients;they were 18 months,35.3％,and 2.4％,respectively,for the CT/3DCRT group,versus 12 months,14.5％,and 2.4％ for the CT group (P =0.023).The median progression-free survival (PFS) time and the 1-and 2-year PFS rates were 8 months,27.5％,and 2.4％,respectively,for all patients;they were 9 months,35.4％,and 6.0％,respectively,for the CT/3DCRT group,versus 6 months,20.5％,and 6.0％ for the CT group (P =0.004).In the CT/3DCRT group,the 22 patients who received 45 Gy at 1.5 Gy/fraction twice daily had a median PFS time of 11 months,versus 9 months for the 26 patients who received 60 Gy at 2.0 Gy/fraction once daily (P =0.037).Multivariate analysis revealed that receiving ≥ 4 cycles of CT (P =0.001) and 3DCRT (P =0.008) were favorable prognostic factors for OS.Conclusions Thoracic 3DCRT can improve the OS and PFS in patients with EDSCLC,and it has good efficacy when delivered with a total dose of 45 Gy at 1.5 Gy/fraction twice daily.Thoracic 3DCRT and receiving ≥4 cycles of CT are independent favorable prognostic factors for OS.

ObjectiveTo investigate the value of 64-slice CT urography (CTU) in diagnosis of urologic diseases.Methods Sixty patients with suspected urinary system diseases underwent 64-slice CT volume scanning and 3D reconstructions.The diagnostic value of 64-slice CTU was evaluated.ResultsThere were 14 patients with urinary system cancers,2 with ureter polyp,9 with tuberculosis of urinary system,13 with urinary system calculus,13 with nonmalignant ureterostenosis combined with hydronephrosis,2 with ureterostenosis and hydronephrosis induced by nearby organic damage,2 with traumatism,1 with renal occlusion,as well as 4 after urinary tract surgeries and 2 without abnormality.Totally 28 cases was confirmed with surgery and pathology,the sensitivity,specificity and accuracy of MSCTU for upper tract tumor was 100％(14/14),85.71％ (12/14) and 92.86％ (26/28),respectively.ConclusionMSCTU is able to directly and clearly show urologic diseases.It can be regarded as the first choice in patients with clinically suspected urinary tract diseases,especially tumors.