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.

Skin Damage Sustained During Head-and-Neck and Shoulder Radiotherapy Due to the Curvature of Skin and the Use of Immobilization Mask / 의학물리

The purpose of this study was to measure curvature contour skin dose using radiochromic film and TLD for a conventional open field. We also attempted to quantify the degradation of skin sparing associated with use of immobilization devices for high energy photon beams and to calculate the skin dose with a help of Monte Carlo (MC) simulation. To simulate head-and-neck and shoulder treatment, a cylindrical solid water phantom 11 cm in diameter was irradiated with 6 MV x-rays using 40x40 cm2 field at 100 cm source axis distance (SAD) to the center of the phantom. Aquaplastic mesh mask was placed on the surface of the cylindrical phantom that mimicked relevant clinical situations. The skin dose profile was obtained by taking measurements from 0degrees to 360degrees around the circumference of the cylindrical phantom. The skin doses obtained from radiochromic film were found to be 47% of the maximum dose of D(max) at the 0degrees beam entry position and 61% at the 90degrees oblique beam position without the mask. Using the mask (1.5 mm), the skin dose received was 59% at 0degrees incidence and 78% at 80degrees incidence. Skin dose results were also gathered using thin thermoluminescent dosimeters (TLD). With the mask, the skin dose was 66% at 0degrees incidence and 80% at 80degrees incidence. This method with the mask revealed the similar pattern as film measurement. For the treatments of the head-and-neck and shoulder regions in which immobilization mask was used, skin doses at around tangential angle were nearly the same as the prescription dose. When a sloping skin contour is encountered, skin doses may be abated using thinner and more perforated immoblization devices which should still maintain immoblization.

Analysis of Bone Mineral Density and Related Factors after Pelvic Radiotherapy in Patients with Cervical Cancer / 대한방사선종양학회지

PURPOSE: This study was designed to evaluate the effects on bone mineral density (BMD) and related factors according to the distance from the radiation field at different sites. This study was conducted on patients with uterine cervical cancer who received pelvic radiotherapy. MATERIALS AND METHODS: We selected 96 patients with cervical cancer who underwent determination of BMD from November 2002 to December 2006 after pelvic radiotherapy at Kosin University Gospel Hospital. The T-score and Z-score for the first lumbar spine (L1), fourth lumbar spine (L4) and femur neck (F) were analyzed to determine the difference in BMD among the sites by the use of ANOVA and the post-hoc test. The study subjects were evaluated for age, body weight, body mass index (BMI), post-radiotherapy follow-up duration, intracavitary radiotherapy (ICR) and hormonal replacement therapy (HRT). Association between the characteristics of the study subjects and T-score for each site was evaluated by the use of Pearson's correlation and multiple regression analysis. RESULTS: The average T-score for all ages was -1.94 for the L1, -0.42 for the L4 and -0.53 for the F. The average Z-score for all ages was -1.11 for the L1, -0.40 for the L4 and -0.48 for the F. The T-score and Z-score for the L4 and F were significantly different from the scores for the L1 (p<0.05). There was no significant difference between the L4 and F. Results for patients younger than 60 years were the same as for all ages. Age and ICR were negatively correlated and body weight and HRT were positively correlated with the T-score for all sites (p<0.05). BMI was positively correlated with the T-score for the L4 and F (p<0.05). Based on the use of multiple regression analysis, age was negatively associated with the T-score for the L1 and F and was positively correlated for the L4 (p<0.05). Body weight was positively associated with the T-score for all sites (p<0.05). ICR was negatively associated with the T-score for the L1 (p<0.05). HRT was positively associated with the T-score for the L4 and F (p<0.05). CONCLUSION: The T-score and Z-score for the L4 and F were significantly higher than the scores for the L1, a finding in contrast to some previous studies on normal women. It was thought that radiation could partly influence BMD because of a higher T-score and Z-score for sites around the radiotherapy field. We suggest that a further long-term study is necessary to determine the clinical significance of these findings, which will influence the diagnosis of osteoporosis based on BMD in patients with cervical cancer who have received radiotherapy.

Concurrent Chemoradiotherapy with Biweekly Gemcitabine and Cisplatin in Patients with Locally Advanced Non-small Cell Lung Cancer / 대한방사선종양학회지

PURPOSE: In cases of locally advanced non-small cell lung cancer (NSCLC), concurrent chemoradiotherapy (CCRT) is the leading therapeutic modality. However, much controversy exists about the chemotherapeutic regimens and radiation methods. MATERIALS AND METHODS: During concurrent chemoradiotherapy, three or four cycles of gemcitabine (500 mg/m2) and cisplatin (30 mg/m2) were administered every two weeks while 50.4 Gy of irradiation was administered in 28 fractions (once/day, 5 treatment days/week) to the tumor site, mediastinum, and the involved lymph node region. In addition, a booster irradiation dose of 18 Gy in 10 fractions was administered to the primary tumor site unless the disease progressed. Two or three cycles of consolidation chemotherapy were performed with gemcitabine (1,200 mg/m2, 1st and 8th day) and cisplatin (60 mg/m2) every three weeks. RESULTS: A total of 29 patients were evaluable for modality response. Response and treatment toxicities were assessed after concurrent chemoradiotherapy and consolidation chemotherapy, respectively. One patient (4%) achieved a complete response; whereas 20 patients (69%) achieved a partial response after concurrent chemoradiotherapy. Following the consolidation chemotherapy, three patients (10.3%) achieved complete responses and 21 patients (72.4%) achieved partial responses. The median follow-up period was 20 months (range 3m39 months) and the median survival time was 16 months (95% CI; 2.4m39.2 months). The survival rates in one, two, and three years after the completion of treatment were 62.7%, 43.9%, and 20%, respectively. Complications associated to this treatment modality included grade 3 or 4 esophagitis, which occurred in 15 patients (51.7%). In addition, an incidence of 24% for grade 3 and 14% for grade 4 neutropenia. Lastly, grade 2 radiation pneumonitis occurred in 6 patients (22%). CONCLUSION: The response rate and survival time of concurrent chemoradiotherapy with biweekly gemcitabine (500 mg/m2) and cisplatin (30 mg/m2) were encouraging in patients with locally advanced NSCLC. However, treatment related toxicities were significant, indicating that further modification of therapy seems to be warranted.

Concurrent Docetaxel/Cisplatin and Thoracic Radiotherapy for Locally Advanced Non-Small Cell Lung Cancer / 결핵및호흡기질환

BACKGROUND: There are many combinations of treatment for locally advanced non-small cell lung cancer (NSCLC). Recent studies have showed the efficacy of concurrent chemoradiotherapy (CCRT) in NSCLC. At present, however, there is no consensus about the optimal dosages and timing of radiation and chemotherapeutic agents. The aims of study were to determine the feasibility, toxicity, response rate, and survival rate in locally advanced NSCLC patients treated with doxetaxel and cisplatin based CCRT. METHOD: Sixteen patients with unresectable stage III NSCLC were evaluated from May 2000 until September 2001. Induction chemoradiotherapy consisted of 3 cycles of docetaxel (75 mg/m2/IV on day 1) and cisplatin (60 mg/m2/IV on day 1) chemotherapy every 3 weeks and concomitant hyperfractionated chest irradiation (1.15 Gy/BID, total dose of 69 Gy) in 6 weeks. Patient who had complete or partial response, and stable disease were applied consolidation chemotherapy of docetaxel and cisplatin. RESULTS: All patients showed response to CCRT. Four patients achieved complete response (25%), partial responses in 12 patients (75%). The major common toxicities were grade III or more of neutropenia (87.3%), grade III esophagitis (68.8%), pneumonia (18.8%) and grade III radiation pneumonitis (12.5%). Thirteen patients were ceased during follow-up period. Median survival time was 19.9 months (95% CI; 4.3-39.7 months). The survival rates in one, two, and three years are 68.7%, 43.7%, and 29.1%, respectively. Local recurrence was found in 11 patients (66.8%), bone metastasis in 2, and brain metastasis in 1 patient. CONCLUSION: The response rate and survival time of CCRT with docetaxel/cisplatin in locally advanced NSCLC were encouraging, but treatment related toxicities were high. Further modification of therapy seems to be warranted.

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.

Results of Radiation Therapy in Stage III Uterine Cevical Cancer / 대한치료방사선과학회지

PURPOSE: The aim of this study is to analyze the survival rate, treatment failure and complication of radiation therapy alone in stage III uterine cervical cancer. MATERIALS AND METHODS: From January 1980 through December 1985, 227 patients with stage II uterine cervical cancer treated with radiation therapy at Kosin Medical Center were retrospectively studied. Among 227 patients, 72 patients(31.7%) were stage IIIa, and 155 patients(68.3%) were stage IIIb according to FIGO classification. Age distribution was 32-71 years(median: 62 years). Sixty nine patients(95.8%) in stage IIIa and 150 patients(96.8%) in stage IIIb were squamous cell carcinoma. Pelvic lymphnode metastasis at initial diagnosis was 8 patients (11.1%) in stage IIIa and 29 patients(18.7%) in stage IIIb. Among 72 patients with stage IIIa, 36 patients(50%) were treated with external radiation therapy alone by conventional technique (180-200 cGy/fr). And 36 patients(50%) were treated with external radiation therapy with intracavitary radiotherapy(ICR) with Cs137 sources, and among 155 patients with stage IIIb, 80 patients(51.6%) were treated with external radiation therapy alone and 75 patients(48.4%) were treated with external radiation therapy with ICR. Total radiation doses of stage IIIa and IIIb were 65-105 Gy(median : 78.5 Gy) and 65-125.5 Gy (median :83.5 Gy). Survival rate was calculated by life-table method. RESULTS: Complete response rates were 58.3% (42 patients) in state IIIa and 56.1%(87 patients) in stage Iiib. Overall 5 year survival rates were 57% in stage IIIa and 40% in stage IIIb. Five year survival rates by radiation technique in stage IIIa and IIIb were 64%, 40% in group treated in combination of external radiation and ICR, and 50%, 40% in the group of external radiation therapy alone(P=NS). Five year survival rates by response of radiation therapy in stage IIIa and IIIb were 90%, 66% in responder group, and 10%, 7% in non-responder group (p<0.01). There were statistically no significances of 5 year survival rate by total radiation doses and external radiation doses (40 Gy vs 50 Gy) of whole or true pelvis in stage IIIa and IIIb(P=NS). Treatement failures rates were 40.3%(29 patients) in stage IIIa and 57.4%(89 patients) in stage IIIb, 17 patients (23.6%) in stage IIIa and 46 patients (29.7%) in stage IIIb experienced complications. Total radiation doses more than 85 Gy produced serious complication in both stage IIIa(50%) and Iib(50%), Serious complicaton rates were higher in group received externl radiaton doses of 50 Gy than 40 Gy to whole or true pelvis in stage IIIa and IIIb. Seious rectal complication developed in rectal doses more than 65 Gy, and serious bladder complication developed in bladder doses more than 75 Gy. Major cause of deah was cachexia due to locoregional failure in both stage IIIa(34.7%) and IIIb(43.9%). CONCLUSION: From this study, we found that external radiation therapy with ICR was found to have a tendency to be superior to external radiation therapy alone in survival rate, local control rate and complication rate but not different in statistics, and external radiation doses of 50 Gy than 40 Gy tho whole or true pelvis produced serious rectal and bladder complications in stage III uterine cervical cancer.

Dosimetric Consideration of the Lung Block in the Mantle Field / 대한치료방사선과학회지

PURPOSE: To evaluate the dose under lung block as a function of depth and the effectiveness of a block as a function of block width. MATERIALS AND METHODS: Field size of mantle field was 22.8 x 32.4 cm2 . Dose distribution of the mantle field was measured with two dimensional water phantom system. To analyze the effectiveness of the lung block, central axis plane, 5cm off-axis plane, and 10cm off-axis plane were studied. RESULTS: The dose under the lung block was recorded with maximum at the depth between , 5cm and 10cm . In the central axis plane, dosimetric block width was 10-15% les than physical block width. In the 5cm off-axis plane. Dosimetric block width was 4-9% less than physical block width. In the 10cm off-axis plane, dosimetric block width was 2% less than physical block width. CONCLUSION: Depth dependence of the dose under the lung block was founded. Also, block width dependence of the lung block was founded. To induce the accurate relation between the physical block width and the "effective" block width, it needs more detailed understanding of the variables involved.

The Study of Tissue Dose Perturbation by Air Cavity with 6MV Photon Beam / 대한치료방사선과학회지

PURPOSE: To determine the perturbation effect in the tissue downstream from surface layers of lesions located in the air/tumor-tissue interface of larynx using 6MV photon beam. MATERIALS AND METHODS: Thermoluminescent dosimeters(TLDs). Were embedded at 3 measurement locations in slab no.7 of a humanoid phantom and exposed to forward and backward direction using various field sizes(4X4cm2 - 15X15 cm2). RESULTS: At the air/tissue interface, forward dose perturbation factor(FDPF) is about 1.085 with 4X4 cm2, 1.05 with 7X7 cm2, 1.048 with 10X10cm2, and 1.041 with 15X15cm2. Backscatter dose perturbation factor(BDPF) is about 0.99 with 4X4cm2, 0.981 with 7X7cm2, 0.956 with 10X10cm2 and 0.97 with 15X15cm2 . CONCLUSION: FDPF is greater as field size is smaller. And FDPF is smaller as the distance is further from the air/tissue interface.

The Study of Tissue Dose Perturbation by Air Cavity with 6MV Photon Beam / 대한치료방사선과학회지

PURPOSE: To determine the perturbation effect in the tissue downstream from surface layers of lesions located in the air/tumor-tissue interface of larynx using 6MV photon beam. MATERIALS AND METHODS: Thermoluminescent dosimeters(TLDs). Were embedded at 3 measurement locations in slab no.7 of a humanoid phantom and exposed to forward and backward direction using various field sizes(4X4cm2 - 15X15 cm2). RESULTS: At the air/tissue interface, forward dose perturbation factor(FDPF) is about 1.085 with 4X4 cm2, 1.05 with 7X7 cm2, 1.048 with 10X10cm2, and 1.041 with 15X15cm2. Backscatter dose perturbation factor(BDPF) is about 0.99 with 4X4cm2, 0.981 with 7X7cm2, 0.956 with 10X10cm2 and 0.97 with 15X15cm2 . CONCLUSION: FDPF is greater as field size is smaller. And FDPF is smaller as the distance is further from the air/tissue interface.

Radiotherapy of Carcinoma of Maxillary Antrum / 대한치료방사선과학회지

Seventy-nine patients with carcinoma of maxillary antrum treated at the department of therapeutic radiology, Kosin Medical Center, between June 1980 and December 1986 were analyzed retrospectively for survival rate and treatment failure. Forty-three patients were treated with radiotherapy alone and thirty-six patients were treated with combination of surgery and radiotherapy. The overall 5 year survival rate was 32%, patients that were treated with radiotherapy alone had a 5-year survival rate of 23%, and patients who were treated with combination of surgery and radiotherapy had a 5-year survival rate of 42%. 54 patients(68.4%) failed to be cured. Among these 54 patients, 37 patients(68.5%) had only locoregional failure, 16 patients(29.6%) had locoregional failure and distant metastases and 1 patient had only distant metastasis. From above study combination of surgery and radiotherapy might be a better treatment modality for carcinoma of the maxillary antrum.

Analysis of Radiotherapy Associated Factors in Stage IIb Carcinoma of Uterine Cervix / 대한치료방사선과학회지

331 patients of stage IIb uterine cervix cancer treated by radiation alone at Kosin Medical Center between June 1980 and Dec. 1985 were analysed to determine parameters of radiotherapy associated to disease states. Survival rate was highest among the reported (82.8% for crude and 82.4% for disease free survival). Pelvic control rate in 6 weeks after the end of radiotherapy was 93.6% in the patients treated with ICR following total pelvic radiation and 71.6% with small field additional external irradiation. 5 year survival rate in those who achieved pelvic control was 98. 9% and 12.9% in those who had pelvic failure and/or metastasis after radiation. The survival rate figured maximal 88.5% with dosage of 7500~8500 cgy to point A with acceptable incidence of complications (4.9%) but without increasing survival above it and minimal 74.1% with dosage of less than 6500 cgy. The treatment failure was counted 18.7% (62 of 331 patients): Local failure 72. 6% ( 45 of 62 patients), locoregional failure 3.2% (2 of 62 patients) and distant failure 24% (15 of 62 patients). Late complications were found In 50 patients (15.1%) and 42% of them was rectal bleeding and stenosis. The dose of 8500 cgy to point A was found to be critical for complication and 70% of complications occurred above it and was more serious one such as fistula. Rectal complications were developed above rectal dose 6500 cgy and bladder complication above bladder dose 7500 cgy. Major cause of death was cachexia due to locoregional failure (73.7% of death), next was due to metastasis to lung, liver and bone, and only 3 patients died of complication of intestinal perforations and obstruction. In conclusion higher external radiation dose for a bulky uterine cervix and barrel shaped uterus was essential for local control.