Cone beam computed tomography-guided differences among registration methods for lung cancer and the effects of tumor position,treatment model,and tumor size on positioning errors

Objective To explore the differences in three different registration methods of cone beam computed tomography(CBCT)-guided down-regulated intense radiation therapy for lung cancer as well as the effects of tumor location,treatment mode,and tumor size on registration.Methods This retrospective analysis included 80 lung cancer patients undergoing radiotherapy in our hospital from November 2017 to October 2019 and compared automatic bone registration,automatic grayscale(t+r)registration,and automatic grayscale(t)positioning error on the X-,Y-,and Z-axes under three types of registration methods.The patients were also grouped according to tumor position,treatment mode,and tumor size to compare positioning errors.Results On the X-,Y-,and Z-axes,automatic grayscale(t+r)and automatic grayscale(t)registration showed a better trend.Analysis of the different treatment modes showed differences in the three registration methods;however,these were not statistically significant.Analysis according to tumor sizes showed significant differences between the three registration methods(P<0.05).Analysis according to tumor positions showed differences in the X-and Y-axes that were not significant(P>0.05),while the autopsy registration in the Z-axis showed the largest difference in the mediastinal and hilar lymph nodes(P<0.05).Conclusion The treatment mode was not the main factor affecting registration error in lung cancer.Three registration methods are available for tumors in the upper and lower lungs measuring<3 cm;among these,automatic gray registration is recommended,while any gray registration method is recommended for tumors located in the mediastinal hilar site measuring<3 cm and in the upper and lower lungs≥3 cm.

Ileocecal intussusception caused by two different tumors - which is the culprit lesion? A case report

BACKGROUND Ileocecal intussusception caused by two different tumors is rare,according to a literature review.We describe a case of a male patient with a cauliflower-like mass in the middle of the transverse colon observed by colonoscopy before surgery.It was considered to be intussusception caused by colon cancer.However,a substantial lipomatous mass was seen in the distal end of the intussusception by computed tomography before surgery,which posed a challenge in the preoperative diagnosis.CASE SUMMARY We report a 72-year-old male patient with intussusception.The patient underwent right hemicolectomy and cholecystectomy in our hospital on April 29,2019.During operation,the ileum was inserted into the ascending colon by about 15 cm,and a tumor with a diameter of approximately 3.0 cm was observed in the distal part of the intestine.An atypical liposarcoma/highly differentiated liposarcoma in the adipose tissue was suspected in the postoperative pathology,and a lipoma was diagnosed after MDM2 gene testing.A 4.0 cm×5.0 cm polypoid mass was seen immediately adjacent to the mass,and the postoperative pathology report suggested a high-level tubular adenoma.The patient was eventually cured and discharged with an uneventful follow-up.CONCLUSION Intussusception caused by two different types of masses is extremely rare.At present,surgery is the best treatment once intussusception is diagnosed.

cDNA representational difference analysis of differentially expressed cDNA sequences in human nasopharyngeal carcinoma

Objective To search differentially expressed sequences correlated with pathogenesis of human nasopharyngeal carcinoma (NPC), including the candidates of tumor suppressor genes Methods Representational difference analysis (RDA) was performed to isolate differentially expressed sequences between cDNA from normal human primary cultures of nasopharyngeal epithelial cells and cDNA from NPC cell line HNE1 The source of differentially expressed products were proved by Southern blot, Northern blot and in situ hybridization The fragments were cloned with pGEM T easy kit and sequenced by the chain termination reaction Results Four differentially expressed cDNA fragments were isolated in the fourth subtractive hybridization using cDNA from normal human nasopharyngeal epithelial cells as tester amplicon and cDNA from NPC cell line HNE1 as driver amplicon by cDNA RDA These differential cDNA fragments revealed that they really came from the tester amplicon and were not expressed or down regulated in the NPC HNE1 cells Some of the genes were expressed only in human nasopharyngeal epithelial cells but deleted or down regulated in the biopsies of NPC Of these obtained clones, some were the sequences of the human known genes including house keeping genes, the others represented novel gene sequences Conclusion The differentially expressed products including the candidates of tumor suppressor genes may be associated with the initiation of the NPC