• Radiation Oncology Journal
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• v.33 no.2
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• pp.134-141
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• 2015

Purpose: This study investigates morphologic change of the rectosigmoid colon using a belly board in prone position and distended bladder in patients with rectal cancer. We evaluate the possibility of excluding the proximal margin of anastomosis from the radiation field by straightening the rectosigmoid colon. Materials and Methods: Nineteen patients who received preoperative radiotherapy between 2006 and 2009 underwent simulation in a prone position (group A). These patients were compared to 19 patients treated using a belly board in prone position and a distended bladder protocol (group B). Rectosigmoid colon in the pelvic cavity was delineated on planning computed tomography (CT) images. A total dose of 45 Gy was planned for the whole pelvic field with superior margin of the sacral promontory. The volume and redundancy of rectosigmoid colon was assessed. Results: Patients in group B had straighter rectosigmoid colons than those in group A (no redundancy; group A vs. group B, 10% vs. 42%; p = 0.03). The volume of rectosigmoid colon in the radiation field was significantly larger in group A (56.7 vs. 49.1 mL; p = 0.009). In dose volume histogram analysis, the mean irradiated volume was lower in patients in group B (V45 27.2 vs. 18.2 mL; p = 0.004). In Pearson correlation coefficient analysis, the in-field volume of rectosigmoid colon was significantly correlated with the bladder volume (R = 0.86, p = 0.003). Conclusion: Use of a belly board and distended bladder protocol could contribute to exclusion of the proximal margin of anastomosis from the radiation field.

• Radiation Oncology Journal
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• v.15 no.1
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• pp.57-64
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• 1997

Purpose : Before we report the results of curative radiotherapy in cervix cancer patients, we review the significance and safety of our dose specification methods in the brachytherapy system to have the insight of the potential Predictive value of doses at specified points. Matersials and Methods : We analyze the 리5 cases of cervix cancer patients treated with intracavitary brachytherapy in the lateral simulation film we draw the isodose curve and observe the absorbed dose rate of point A, the reference point of bladder(SBD) and rectum(SRD). In the sagittal view of Pelvic MRI film we demarcate the tumor volume(TV) and determine whether the prescription dose curve of point A covers the tumor volume adequately by drawing the isodose curve as correctly as possible. Also we estimate the maximum Point dose of bladder(MBD) and rectum(MRD) and calculate the inclusion area where the absorbed dose rate is higher than that of point A in the bladder(HBV) and rectum(HRV), respectively. Results : Of forty-five cases, the isodose curve of point A seems to cover tumor volume optimally in only 24(53%). The optimal tumor coverage seems to be associated not with the stage of the disease but with the tumor volume. There is no statistically significant association between SBD/SRD and MBD/MRD, respectively. SRD has statistically marginally significant association with HRV, while TV has statistically significant association with HBV and HRV. Conclusion : Our current treatment calculation methods seem to have the defect in the aspects of the nonoptimal coverage of the bulky tumor and the inappropriate estimation of bladder dose. We therefore need to modify the applicator geometry to optimize the dose distribution at the position of lower tandem source. Also it appears that the position of the bladder in relation to the applicators needs to be defined individually to define 'hot spots'.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.179-186
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• 2016

Purpose : To figure out if the treatment plan for rectum, bladder and prostate that have a lot of interfraction errors satisfies dosimetric limits without adaptive plan by analyzing MR image. Materials and Methods : This study was based on 5 prostate cancer patients who had IMRT(total dose: 70Gy) Using ViewRay MRIdian System(ViewRay, ViewRay Inc., Cleveland, OH, USA) The treatment plans were made on the same CT images to compare with the plan quality according to adaptive plan, and the Eclipse(Ver 10.0.42, Varian, USA) was used. After registrate the 5 treatment MR images to the CT images for treatment plan to analyze the interfraction changes of organ, we measured the dose volume histogram and the changes of the absolute volume for each organ by appling the first treatment plan to each image. Over 5 fractions, the total dose for PTV was $V_{36.25}$ Gy $${\geq_-}$$ 95%. To confirm that the prescription dose satisfies the SBRT dose limit for prostate, we measured $V_{100%}$, $V_{95%}$, $V_{90%}$ for CTV and $V_{100%}$, $V_{90%}$, $V_{80%}$ $V_{50%}$ of rectum and bladder. Results : All dose average value of CTV, rectum and bladder satisfied dose limit, but there was a case that exceeded dose limit more than one after analyzing the each image of treatment. After measuring the changes of absolute volume comparing the MR image of the first treatment plan with the one of the interfraction treatment, the difference values were maximum 1.72 times at rectum and maximum 2.0 times at bladder. In case of rectum, the expected values were planned under the dose limit, on average, $V_{100%}=0.32%$, $V_{90%}=3.33%$, $V_{80%}=7.71%$, $V_{50%}=23.55%$ in the first treatment plan. In case of rectum, the average of absolute volume in first plan was 117.9 cc. However, the average of really treated volume was 79.2 cc. In case of CTV, the 100% prescription dose area didn't satisfy even though the margin for PTV was 5 mm because of the variation of rectal and bladder volume. Conclusion : There was no case that the value from average of five fractions is over the dosimetric limits. However, dosimetric errors of rectum and bladder in each fraction was significant. Therefore, the precise delivery is needed in case of prostate SBRT. The real-time tracking and adaptive plan is necessary to meet the precision delivery.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.143-156
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• 2005

Background: The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. Materials and Methods: The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of $23.4\~59.4$ Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-IBT) was also peformed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of $14.4\~43.2$ Gy (Median 36.0) of EBRT in 495 patients, while In the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder & rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor ($\alpha/\beta$=10) and late-responding tissues ($\alpha/\beta$=3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED $Gy_3$ and the risk of complication was assessed using serial multiple logistic regression models. The associations between R-BED $Gy_3$ and rectal complications and between V-BED $Gy_3$ and bladder complications were assessed using multiple logistic regression models after adjustment for age, stage, tumor size and treatment duration. Serial Coxs proportional hazard regression models were used to estimate the relative risks of recurrence due to MD-BED $Gy_{10}$, and the treatment duration. Results: The overall complication rate for RTOG Grades $1\~4$ toxicities was $33.1\%$. The 5-year actuarial pelvic control rate for ail 743 patients was $83\%$. The midline cumulative BED dose, which is the sum of external midline BED and HDR-ICBT point A BED, ranged from 62.0 to 121.9 $Gy_{10}$ (median 93.0) for tumors and from 93.6 to 187.3 $Gy_3$ (median 137.6) for late responding tissues. The median cumulative values of actual rectal (R-BED $Gy_3$) and bladder Point BED (V-BED $Gy_3$) were 118.7 $Gy_3$ (range $48.8\~265.2$) and 126.1 $Gy_3$ (range: $54.9\~267.5$), respectively. MD-BED $Gy_3$ showed a good correlation with rectal (p=0.003), but not with bladder complications (p=0.095). R-BED $Gy_3$ had a very strong association (p=<0.0001), and was more predictive of rectal complications than A-BED $Gy_3$. B-BED $Gy_3$ also showed significance in the prediction of bladder complications in a trend test (p=0.0298). No statistically significant dose-response relationship for pelvic control was observed. The Sandwich and Continuous techniques, which differ according to when the ICR was inserted during the EBRT and due to the physicians preference, showed no differences in the local control and complication rates; there were also no differences in the 3 vs. 5 Gy fraction size of HDR-ICBT. Conclusion: The main reasons optimal dose-fractionation guidelines are not easily established is due to the absence of a dose-response relationship for tumor control as a result of the high-dose gradient of HDR-ICBT, individual differences In tumor responses to radiation therapy and the complexity of affecting factors. Therefore, in our opinion, there is a necessity for individualized tailored therapy, along with general guidelines, in the definitive radiation treatment for cervix cancer. This study also demonstrated the strong predictive value of actual rectal and bladder reference dosing therefore, vaginal gauze packing might be very Important. To maintain the BED dose to less than the threshold resulting in complication, early midline shielding, the HDR-ICBT total dose and fractional dose reduction should be considered.

• Progress in Medical Physics
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• v.21 no.2
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• pp.183-191
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• 2010

In this study, the patient with localized prostate cancer who had previously been treated at Ajou University Hospital was randomly selected since March, 2009. we performed IMRT and 2RA plans and the same dose objectives were used for CTVs, PTVs, rectum, bladder, and femoral head of the respective plans. Arc optimizations and dose calculations were performed using Eclipse versions 8.6. In this paper, we evaluated the performance of IMRT and RA plans to investigate the clinical effect of RA for prostate cancer case. In our comparison of treatment techniques, RA was found to be superior to IMRT being better dose conformity of target volume. As for the rectum and bladder, RA was better than IMRT at decreasing the volume irradiated. RA has the ability to avoid critical organs selectively through applied same dose constraints while maximally treating the target dose. Therefore, this result suggests that there should be less rectal toxicity with RA compared with IMRT, with no compromise in tumor margin. These findings, which show more favorable rectal, bladder, and femoral head DVHs with RA, imply that should not result in excess risk of toxicity when this technique is used. Many experiences with RA have shown not only dosimetric advantage, but also improved clinical toxicity when comparing with IMRT. The main drawbacks of RA are the more complex and time-consuming treatment planning process and the need for more exact physics quality assurance (QA).

• Journal of radiological science and technology
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• v.42 no.3
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• pp.217-222
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• 2019

The purpose of this study is to evaluate the dose distribution by gantry rotation and MLC moving speed on treatment planning system(TPS) and linear accelerator. The dose analyzer phantom(Delta 4) was scanned by CT simulator for treatment planning. The planning target volumes(PTVs) of prostate and pancreas was prescribed 6,500 cGy, 5,000 cGy on VMAT(Volumetric Modulated Arc Therapy) by TPS while MLC speed changed. The analyzer phantom was irradiated linear accelerator using by planned parameters. Dose distribution of PTVs were evaluated by the homogeneity index, conformity index, dose volume histogram of organ at risk(rectum, bladder, spinal cord, kidney). And irradiated dose analysis were evaluated dose distribution and conformity by gamma index. The PTV dose of pancreas was 4,993 cGy during 0.1 cm/deg leaf and gantry that was the most closest prescribed dose(5,000 cGy). The dose of spinal cord, left kidney, and right kidney were accessed the lowest during 0.1 cm/deg, 1.5 cm/deg, 0.3 cm/deg. The PTV dose of prostate was 6,466 cGy during 0.1 cm/deg leaf and gantry that was the most closest prescribed dose(6,500 cGy). The dose of bladder and rectum were accessed the lowest during 0.3 cm/deg, 2.0 cm/deg. For gamma index, pancreas and prostate were analyzed the lowest error 100% at 0.8, 1.0 cm/deg and 99.6% at 0.3, 0.5 cm/deg. We should used the optimal leaf speed according to the gantry rotation if the treatment cases are performed VMAT.

• Radiation Oncology Journal
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• v.13 no.4
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• pp.349-357
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• 1995

Purpose : To analyze survival rate and late rectal and bladder complication for patients 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 patiens 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 : Actuarial 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 urinary complications and 17 cases ($19{\%}$) of grade 2 urinary complications were observed But no patient 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 (7608 cGy v 6960cGy. p<0.01) Maximum rectal dose for the group of patients with rectal complications was higher than that for the patients without rectal 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 differance 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 decreased complication rate. The number of insertion in LDR ICRT group did not affect on survival and compication rate. Conclusion : In stage I and II carcinoma of uterine cervix there was no significant differance 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.

• Progress in Medical Physics
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• v.33 no.4
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• pp.101-107
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• 2022

Purpose: Radiotherapy after bladder filling protocol (BFP) is known to enhance treatment quality and reduce side effects in prostate cancer, a common male solid cancer globally. However, due to the need to hold back urine during treatment, patients frequently complain of discomfort, and treatment is frequently suspended when patients urinate during treatment and urine penetrates the treatment device, causing malfunction. Therefore, the effect of minimizing treatment time when partial-arc volumetric modulated arc therapy (VMAT) was used instead of full-arc was assessed in this study. Methods: A total of 70 plans were created in 10 patients using 7 different arc sizes, and the treatment time for each plan was calculated. Results: Reduced arc size by half resulted in a 54.4% decrease in mean treatment duration, with a proportional tendency observed. Furthermore, the effect of VMAT arc size reduction on target dose homogeneity was significantly limited, and the effect on surrounding organs at risk (OAR) was negligible. It should be noted, however, that when the arc size decreases by >40%, the dose increases in the area without OAR around the target. Conclusions: The results of this study demonstrated that partial-arc VMAT for enhancing treatment convenience and efficacy of prostate cancer patients undergoing BFP can achieve a considerable reduction in treatment time while preserving treatment quality, and it is expected to be useful for partial-arc VMAT plan design and implementation in practice.

• Journal of Yeungnam Medical Science
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• v.23 no.1
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• pp.52-61
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• 2006

Background: Korean ginseng (KG) has been used as a general tonic, and for voiding dysfunction for a long time in oriental society. However, scientific basic studies on the use of KG, have been rare, especially for voiding and erectile dysfunction. This study was performed to investigate the effects of KG on voiding and erectile function by examining the effects of total saponin (TS) on the bladder, urethral and penile cavernosal smooth muscle. Materials and methods: To examine the effects of TS, NewZeland white rabbits were used to obtain tissue strips from the smooth muscle of the bladder, proximal urethra and corpus cavernosum. Adult Sprague Dawley rats were used to examine the changes in urodynamic findings and penile erection after administration of TS. Results: In proximal urethral strips, the rate of relaxation of the proximal urethra was increased from $9.0{\pm}2.9$ to $33.7{\pm}4.8%$ in a dose-dependent manner when the concentration of TS was added accumulatively from 0.25 mg/ml to 4.0 mg/ml (p<0.05). However, no significant response was observed in the bladder strips within these concentration ranges. For the corpus cavernosal strips, the rate of relaxation ranged from $5.8{\pm}2.1$ to $36.7{\pm}5.8%$, increasing in a dose-dependent manner when TS was increased from 1.0 mg/ml to 4.0 mg/ml (p<0.05). After administration of 0.1 ml of TS (32 mg/ml) in the rat, the bladder pressure was $37.5{\pm}8.5$ mmHg at $52.1{\pm}7.0$ sec. during isovolumetric bladder contraction, showing no significant differences from $35.7{\pm}7.8mmHg$ and $50.7{\pm}7.2$ sec, respectively, before treatment. However, when 0.1 ml of TS (32 mg/ml) was administered, the relative reduction of urethral pressure was $6.9{\pm}0.5mmHg$ at $62{\pm}7.5$ sec, which was significantly higher compared to $4.6{\pm}1.1mmHg$ at $45{\pm}10$ sec before treatment (p<0.05). For the cavernosal injection study, the change in intracavernosal pressure (${\Delta}ICP$) was examined after administering 0.1 ml of TS. The cumulative additions of TS at concentrations from 0.5 mg/ml to 32 mg/ml increased ${\Delta}ICP$ from $1.3{\pm}0.5$ to $21.3{\pm}7.8mmHg$ in a dose-dependent manner (p<0.05). The duration of tumescence was from $0.3{\pm}0.1$ to $5.2{\pm}0.2$ min, showing dose-dependent increase (p<0.05). Furthermore, the cumulative addition of TS at concentrations from 0.5 mg/ml upto 32 mg/ml did not cause any significant change in systemic blood pressure. Conclusion: These results suggest that ginseng improves voiding functions, which is mainly achieved by TS relaxing the proximal urethra, the most important part of the bladder outlet function. In addition, ginseng safely induced a penile erection hemodynamically by relaxing the corpus cavernosum.

• Journal of Radiation Protection and Research
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• v.32 no.3
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• pp.105-110
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• 2007

Purpose : In spite of recent remarkable improvement of diagnostic imaging modalities such as CT, MRI, and PET and radiation therapy planing systems, ICR plan of uterine cervix cancer, based on recommendation of ICRU38(2D film-based) such as Point A, is still used widely. A 3-dimensional ICR plan based on CT image provides dose-volume histogram(DVH) information of the tumor and normal tissue. In this study, we compared tumor-dose, rectal-dose and bladder-dose through an analysis of DVH between CTV plan and ICRU38 plan based on CT image. Method and Material : We analyzed 11 patients with a cervix cancer who received the ICR of Ir-192 HDR. After 40Gy of external beam radiation therapy, ICR plan was established using PLATO(Nucletron) v.14.2 planing system. CT scan was done to all the patients using CT-simulator(Ultra Z, Philips). We contoured CTV, rectum and bladder on the CT image and established CTV plan which delivers the 100% dose to CTV and ICRU plan which delivers the 100% dose to the point A. Result : The volume$(average{\pm}SD)$ of CTV, rectum and bladder in all of 11 patients is $21.8{\pm}6.6cm^3,\;60.9{\pm}25.0cm^3,\;111.6{\pm}40.1cm^3$ respectively. The volume covered by 100% isodose curve is $126.7{\pm}18.9cm^3$ in ICRU plan and $98.2{\pm}74.5cm^3$ in CTV plan(p=0.0001), respectively. In (On) ICRU planning, $22.0cm^3$ of CTV volume was not covered by 100% isodose curve in one patient whose residual tumor size is greater than 4cm, while more than 100% dose was irradiated unnecessarily to the normal organ of $62.2{\pm}4.8cm^3$ other than the tumor in the remaining 10 patients with a residual tumor less than 4cm in size. Bladder dose recommended by ICRU 38 was $90.1{\pm}21.3%$ and $68.7{\pm}26.6%$ in ICRU plan and in CTV plan respectively(p=0.001) while rectal dose recommended by ICRU 38 was $86.4{\pm}18.3%$ and $76.9{\pm}15.6%$ in ICRU plan and in CTV plan, respectively(p=0.08). Bladder and rectum maximum dose was $137.2{\pm}50.1%,\;101.1{\pm}41.8%$ in ICRU plan and $107.6{\pm}47.9%,\;86.9{\pm}30.8%$ in CTV plan, respectively. Therefore, the radiation dose to normal organ was lower in CTV plan than in ICRU plan. But the normal tissue dose was remarkably higher than a recommended dose in CTV plan in one patient whose residual tumor size was greater than 4cm. The volume of rectum receiving more than 80% isodose (V80rec) was $1.8{\pm}2.4cm^3$ in ICRU plan and $0.7{\pm}1.0cm^3$ in CTV plan(p=0.02). The volume of bladder receiving more than 80% isodose(V80bla) was $12.2{\pm}8.9cm^3$ in ICRU plan and $3.5{\pm}4.1cm^3$ in CTV plan(p=0.005). According to these parameters, CTV plan could also save more normal tissue compared to ICRU38 plan. Conclusion : An unnecessary excessive radiation dose is irradiated to normal tissues within 100% isodose area in the traditional ICRU plan in case of a small size of cervix cancer, but if we use CTV plan based on CT image, the normal tissue dose could be reduced remarkably without a compromise of tumor dose. However, in a large tumor case, we need more research on an effective 3D-planing to reduce the normal tissue dose.