Gross tumor volume dependency on phase sorting methods of four-dimensional computed tomography images for lung cancer

PURPOSE: To see the gross tumor volume (GTV) dependency according to the phase selection and reconstruction methods, we measured and analyzed the changes of tumor volume and motion at each phase in 20 cases with lung cancer patients who underwent image-guided radiotherapy. MATERIALS AND METHODS: We retrospectively analyzed four-dimensional computed tomography (4D-CT) images in 20 cases of 19 patients who underwent image-guided radiotherapy. The 4D-CT images were reconstructed by the maximum intensity projection (MIP) and the minimum intensity projection (Min-IP) method after sorting phase as 40%–60%, 30%–70%, and 0%–90%. We analyzed the relationship between the range of motion and the change of GTV according to the reconstruction method. RESULTS: The motion ranges of GTVs are statistically significant only for the tumor motion in craniocaudal direction. The discrepancies of GTV volume and motion between MIP and Min-IP increased rapidly as the wider ranges of duty cycles are selected. CONCLUSION: As narrow as possible duty cycle such as 40%–60% and MIP reconstruction was suitable for lung cancer if the respiration was stable. Selecting the reconstruction methods and duty cycle is important for small size and for large motion range tumors.

Gross tumor volume dependency on phase sorting methods of four-dimensional computed tomography images for lung cancer

PURPOSE: To see the gross tumor volume (GTV) dependency according to the phase selection and reconstruction methods, we measured and analyzed the changes of tumor volume and motion at each phase in 20 cases with lung cancer patients who underwent image-guided radiotherapy. MATERIALS AND METHODS: We retrospectively analyzed four-dimensional computed tomography (4D-CT) images in 20 cases of 19 patients who underwent image-guided radiotherapy. The 4D-CT images were reconstructed by the maximum intensity projection (MIP) and the minimum intensity projection (Min-IP) method after sorting phase as 40%–60%, 30%–70%, and 0%–90%. We analyzed the relationship between the range of motion and the change of GTV according to the reconstruction method. RESULTS: The motion ranges of GTVs are statistically significant only for the tumor motion in craniocaudal direction. The discrepancies of GTV volume and motion between MIP and Min-IP increased rapidly as the wider ranges of duty cycles are selected. CONCLUSION: As narrow as possible duty cycle such as 40%–60% and MIP reconstruction was suitable for lung cancer if the respiration was stable. Selecting the reconstruction methods and duty cycle is important for small size and for large motion range tumors.

Effects of L-ascorbic acid on the production of pro-inflammatory and anti-inflammatory cytokines in C57BL/6 mouse splenocytes / 고신대학교의과대학학술지

OBJECTIVE: The imbalance between pro-inflammatory and anti-inflammatory cytokines may underlie different pain states. Although ascorbic acid is the most important physiological antioxidant that affects host defense mechanisms and immune homeostasis, there is limited information on the effects of ascorbic acid on the production of cytokines. METHODS: In this study, we investigated the in vitro effect of L-ascorbic acid (AA) on the production of pro-inflammatory and anti-inflammatory cytokines by stimulating C57BL/6 mouse splenocytes with the polyclonal activators lipopolysaccharide or concanavalin A. RESULTS: AA significantly downregulated the expression of IL-6, IL-12, and TNF-alpha at 48 h and 72 h in mouse splenocytes treated with a combination of polyclonal activators and AA. AA treatment also resulted in upregulation of IL-4 and IL-10 at 72 h. These findings demonstrated that AA significantly potentiated production of anti-inflammatory cytokines whereas there was an inverse association between AA and expression of pro-inflammatory cytokines in mouse splenocytes. CONCLUSION: AA may have potential applications in the reduction of inflammatory pain because of its function in modulating the production of cytokines. However, further in vivo investigations are necessary to elucidate the mechanisms involved.

Comparison between audio-only and audiovisual biofeedback for regulating patients' respiration during four-dimensional radiotherapy

PURPOSE: To compare audio-only biofeedback to conventional audiovisual biofeedback for regulating patients' respiration during four-dimensional radiotherapy, limiting damage to healthy surrounding tissues caused by organ movement. MATERIALS AND METHODS: Six healthy volunteers were assisted by audiovisual or audio-only biofeedback systems to regulate their respirations. Volunteers breathed through a mask developed for this study by following computer-generated guiding curves displayed on a screen, combined with instructional sounds. They then performed breathing following instructional sounds only. The guiding signals and the volunteers' respiratory signals were logged at 20 samples per second. RESULTS: The standard deviations between the guiding and respiratory curves for the audiovisual and audio-only biofeedback systems were 21.55% and 23.19%, respectively; the average correlation coefficients were 0.9778 and 0.9756, respectively. The regularities between audiovisual and audio-only biofeedback for six volunteers' respirations were same statistically from the paired t-test. CONCLUSION: The difference between the audiovisual and audio-only biofeedback methods was not significant. Audio-only biofeedback has many advantages, as patients do not require a mask and can quickly adapt to this method in the clinic.

Analysis of Overall Setup Accuracy Using On-Board Imager(R) / 의학물리

We evaluated the overall setup accuracy for the On-Board Imager (OBI, Varian Medical Systems Inc., Palo Alto, CA, USA), with attention to the laser, the gantry, and operator performance. We let experienced technicians place the marker block on the couch using a lock bar system, with alignment to the isocenter of the laser, every morning. A pair of radiographic images of the marker block was acquired at 0degrees and 270degrees angles to the kV arm to correct the position using a 2D/2D matching technique. Once the desired match was achieved, the couch was moved remotely to correct the setup error and the parameters were saved. The average for the vertical and the longitudinal displacements were 0.65 mm and 0.66 mm, and 0.01 mm for the lateral displacement. The average for the vertical and longitudinal displacements were statistically significant at the 0.05 level (p value=0.000 for both), while the p value for the lateral direction was 0.829. These results show that the tendencies to displacement in vertical and longitudinal directions occur through systematic error, while systematic error was not found in the lateral displacement. This daily overall evaluation is practical and easy to find the systematic and random errors in the setup system; however, a daily QA for laser and OBI alignment is still needed to minimize the systematic error in aligning patients.

Survival and Complication Rate of Radiation Therapy in Stage I and II Carcinoma of uterine Cervix / 대한치료방사선과학회지

PURPOSE: To analyze survival rate and late rectal and bladder complication for patients with stage with stage I and II carcinoma of uterine cervix treated by radiation alone or combined with chemotherapy. MATERIALS AND METHODS: Between November 1984 and December 1993, 127 patients with stage I and II carcinoma of uterine cervix treated by radiation alone or combined therapy of radiation and chemotherapy. Retrospective analysis for survival rate was carried out on eligible 107 patients and review for complication was possible in 91 patients. The median follow-up was 47 months (range 3-118) and the median age of patients was 56 years (range 31-76). 26 patients were stage IB by FIGO classification. 40 were stage IIA and 41 were stage IIB. 86 cases were treated by radiation alone and 21 were treated by radiation and chemotherapy. 101 patients were treated with intracavitary radiation therapy (ICRT), of these, 80 were received low dose rate (LDR) ICRT and 21 were received high dose rate (HDR) ICRT. Of the patients who received LDR ICRT, 63 were treated by 1 intracavitary insertion and 17 were underwent 2 insertions. And we evaluated the external radiation dose and midline shield. RESULTS: Acturial survival rate at 5 years was 92% for stage IB, 75% for stage IIA, 53% for stage IIB and 69% in all patients. Grade 1 rectal complications were developed in 20 cases(22%), grade 2 were in 22 cases (24%), 22 cases (24%) of grade 1 urineary complications and 17 cases (19%) of grade 2 urinary complications were observed But no patients had severe complications that needed surgical management or admission care. Maximum bladder dose for the group of patients with urinary complications was higher than that for the patients without urinary complications(7608cGy v 6960cGy, p<0.01). Maximum rectal dose for the group of patients with rectal complications was higher than that for the patients without urinary complications (7041cGy v 6269cGy, p<0.01). While there was no significant difference for survival rate or bladder complication incidence as a function of dose to whole pelvis, Grade 2 rectal complication incidence was significantly lower for the patients receiving less than 4500cGy(6.3% v 25.5%, p<0.05). There was no significant difference between HDR ICRT group and LDR ICRT group for survival rate according to stage, on the other hand complication incidence was higher in the HDR group than LDR group. This was maybe due to different prescription doses between HDR group and LDR group. Midline shield neither improved survival rate nor deceased complication rate. The number of insertion in LDR ICRT group did not affect on survival and complication rate. CONCLUSION: In stage I and II carcinoma of uterine cervix, there was no significant difference for 5 year survival rate by radiation therapy technique. Rectal complication incidence was as a function of dose to whole pelvis and there were positive correlations of maximum dose of rectum and bladder and each complication incidence. So we recommand whole pelvis dose less than 4500cGy and maximum dose of rectum and bladder as low as possible.

Results of Radiotherapy in Nasopharyngeal Cancer / 대한치료방사선과학회지

PURPOSE: The aim of this study was to assess the effectiveness, survival rate and complication of radiation therapy in nasopharyngeal cancer. MATERIALS AND METHODS: From January 1980 to May 1989, Fifty Patients who had nasopharyngeal carcinoma treated with curative radiation therapy at Kosin Medical Center were retrospectively studied. Thirty seven patients(74%) were treated with radiation therapy alone(Group I) and 13 patients (26%) treated with combination fo chemotherapy and radiation(Group II). Age distribution was 16-75 years(median:45.8 years). In histologic type, squamous cell carcinoma was in 30 patients(60%), undifferentiated carcinoma in 17 patinets(34%), and lymphoepithelioma in 3 patients(6%). According to AJCC staging system, 4 patinets(8%) were in T1, 13 patients(2%) in T2, 20 patients(40%) in T3, 13 patients(26%) in T4 and 7 patients(14%) in N0, 6 patients(12%) in N1, 23 patients(46%) in N2, 14 patients (28%) in N3. Total radiaton dose ranges were 5250-9200 cGy(median : 7355 cGy) in Group I and 5360-8400 cGy(median :6758cGy) in Group II. Radiotherapy on 4-6MV linear accelerator and/or 6-12MeV electron in boost radiation was given with conventional thechnique to 26 patinets(52%), with hyperfractionation(115-120cGy/fr., 2times/day) to 16 patients(32%), with accelerated fractionation(160cGy/fr., 2 times/day) to 8 patients(16%). In Chemotherapy, 5 FU 1000mg daily for 5 consecutive days, pepleomycin 10mg on days 1 and 3, and cisplatin 100mg on day 1 were administered with 3 weeks interval, total 1 to 3 cycles(average 1.8cycles) prior to radiation therapy. Follow up duration was 6-140 months(mean:58 months). Statistics was calculated with Chi-square and Fisher's exact test. RESULTS: Complete local control rates in Group I and II were 75.7%, 69.2%. Overall 5 year survival rates in Group I and II were 56.8%, 30.8%. Five year survival rates by histologic type in Group I and II were 52.2, 14.3% in squamous cell carcinoma an d 54.5%, 50% in undifferentiated carcinoma. Survival rates in Group I were superior to those of Group II though there were not statistically significant. In both group, survival rates seem to be increased according to increasing total dose of radiation up to 7500cGy, but not increased beyond it. There were not statistically significant differences in survival rates by age, , stage, and radiation tehchniques in both group. Twenty four patients (48%) experienced treatment failures. Complications were found in 12 patients(24%). The most common one was osteomyelitis(4 patients, 33.3%) involving mandible (3 patients) and maxilla(1patient). CONCLUSION: Chemotherapy in combination with radiotherapy was found to be not effective to nasopharyngeal cancer and the survival rate was also inferior to that of radiation alone group though it was statistically not significant due to small population in chemotherapy combined group.