• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.113-124
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• 2005

Purpose : The using of endo-rectal balloon has proposed as optimal method that minimized the motion of prostate and the dose of rectum wall volume for treated prostate cancer patients, so we make the customized rectal balloon device. In this study, we analyzed the efficiency of the Self-customized rectal balloon in the aspects of its reproducibility. Materials and Methods : In 5 patients, for treatment planning, each patient was acquired CT slice images in state of with and without rectal balloon. Also they had CT scanning samely repeated third times in during radiation treatment (IMRT). In each case, we analyzed the deviation of rectal ballon position and verified the isodose distribution of rectum wall at closed prostate. Results : Using the rectal balloon, we minimized the planning target volume (PTV) by decreased the internal motion of prostate and overcome the dose limit of radiation therapy in prostate cancer by increased the gap between the rectum wall and high dose region. Conclusion : The using of rectal balloon, although, was reluctant to treat by patients. View a point of immobilization of prostate internal motion and dose escalation of GTV (gross tumor volume), its using consider large efficients for treated prostate cancer patients.

• 대한방사선치료학회:학술대회논문집
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• 2005.04a
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• pp.29-29
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• 2005

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.136-139
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• 2004

In this study, we used the rectal balloon to overcome the dose limit of the radiation therapy in the prostate cancer. Using the rectal balloon, we could minimize the planning target volume (PTV) by minimizing the internal motion of prostate and increased the gap between the rectum wall and the high dose region. To this purpose, we analyzed the position reproducibility of rectal balloon during the patient setup. Moreover, we studied the clinical feasibility of rectal balloon by performing the IMRT plan.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.735-740
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• 2022

In order to reduce side effects such as rectal bleeding in the Brachytherapy, the rectal retractor and wet gauze have been used to increase the distance between the rectum and the tandem. However, there were disadvantages that it was difficult to insert through a narrow entrance into the vagina and poor reproducibility. Also, based on the CT image of the selected catheter, the distance from the tandem to the rectum with or without the balloon catheter was checked and the reduction of the dose to the rectum was confirmed. As a result of the experiment, catheter No. 7 was selected considering the maximum balloon size at a level that does not affect the distance between the start point of the balloon and the end of the catheter, and the ovoid applicator. Based on the CT image of the selected catheter, the degree of expansion according to the presence or absence of the balloon catheter was compared, and it was found that the distance difference was 0.3 - 1 cm. In addition, it was confirmed that a decrease of about 32% was observed due to this distance difference. Therefore, the actual clinical application of the selected catheter can be used as a substitute for the existing rectal retractor and wet gauze.

• Radiation Oncology Journal
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• v.28 no.3
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• pp.166-176
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• 2010

Purpose: To determine the appropriate prostate planning target volume (PTV) margins for 3-dimensitional (3D) conformal radiotherapy (CRT) and intensity-modulated radiation therapy (IMRT) patients treated with an endorectal balloon (ERB) under our institutional treatment condition. Materials and Methods: Patients were treated in the supine position. An ERB was inserted into the rectum with 70 cc air prior to planning a CT scan and then each treatment fraction. Electronic portal images (EPIs) and digital reconstructed radiographs (DRR) of planning CT images were used to evaluate inter-fractional patient's setup and ERB errors. To register both image sets, we developed an in-house program written in visual $C^{++}$. A new method to determine prostate PTV margins with an ERB was developed by using the common method. Results: The mean value of patient setup errors was within 1 mm in all directions. The ERB inter-fractional errors in the superior-inferior (SI) and anterior-posterior (AP) directions were larger than in the left-right (LR) direction. The calculated 1D symmetric PTV margins were 3.0 mm, 8.2 mm, and 8.5 mm for 3D CRT and 4.1 mm, 7.9 mm, and 10.3 mm for IMRT in LR, SI, and AP, respectively according to the new method including ERB random errors. Conclusion: The ERB random error contributes to the deformation of the prostate, which affects the original treatment planning. Thus, a new PTV margin method includes dose blurring effects of ERB. The correction of ERB systematic error is a prerequisite since the new method only accounts for ERB random error.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.2
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• pp.99-106
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• 2007

Purpose: The patient's position and anatomy during the treatment course little bit varies to some extend due to setup uncertainties and organ motions. These factors could affected to not only the dose coverage of the gross tumor but over dosage of normal tissue. Setup uncertainties and organ motions can be minimized by precise patient positioning and rigid immobilization device but some anatomical site such as prostate, the internal organ motion due to physiological processes are challenge. In planning procedure, the clinical target volume is a little bit enlarged to create a planning target volume that accounts for setup uncertainties and organ motion as well. These uncertainties lead to differences between the calculated dose by treatment planning system and the actually delivered dose. The purpose of this study was to evaluate the differences of interfractional displacement of organ and GTV based on the tomoimages. Materials and Methods: Over the course of 3 months, 3 patients, those who has applied rectal balloon, treated for prostatic cancer patient's tomoimage were studied. During the treatment sessions 26 tomoimages per patient, Total 76 tomoimages were collected. Tomoimage had been taken everyday after initial setup with lead marker attached on the patient's skin center to comparing with C-T simulation images. Tomoimage was taken after rectal balloon inflated with 60 cc of air for prostate gland immobilization for daily treatment just before treatment and it was used routinely in each case. The intrarectal balloon was inserted to a depth of 6 cm from the anal verge. MVCT image was taken with 5 mm slice thickness after the intrarectal balloon in place and inflated. For this study, lead balls are used to guide the registration between the MVCT and CT simulation images. There are three image fusion methods in the tomotherapy, bone technique, bone/tissue technique, and full image technique. We used all this 3 methods to analysis the setup errors. Initially, image fusions were based on the visual alignment of lead ball, CT anatomy and CT simulation contours and then the radiation therapist registered the MVCT images with the CT simulation images based on the bone based, rectal balloon based and GTV based respectively and registered image was compared with each others. The average and standard deviation of each X, Y, Z and rotation from the initial planning center was calculated for each patient. The image fusions were based on the visual alignment of lead ball, CT anatomy and CT simulation contours. Results: There was a significant difference in the mean variations of the rectal balloon among the methods. Statistical results based on the bone fusion shows that maximum x-direction shift was 8 mm and 4.2 mm to the y-direction. It was statistically significant (P=<0.0001) in balloon based fusion, maximum X and Y shift was 6 mm, 16mm respectively. One patient's result was more than 16 mm shift and that was derived from the rectal expansions due to the bowl gas and stool. GTV based fusion results ranging from 2.7 to 6.6 mm to the x-direction and 4.3$\sim$7.8 mm to the y-direction respectively. We have checked rotational error in this study but there are no significant differences among fusion methods and the result was 0.37$\pm$0.36 in bone based fusion and 0.34$\pm$0.38 in GTV based fusion.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.45-52
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• 2015

Purpose : The dose distribution of organ at risk (OAR) and normal tissue is affected by treatment technique in postoperative radiation therapy for prostate cancer. The aim of this study was to compare dose distribution characteristic and to evaluate treatment efficiency by devising VMAT plans according to applying differed number of arc and IMRT plan for postoperative patient of prostate cancer radiation therapy using a rectal balloon. Materials and Methods : Ten patients who received postoperative prostate radiation therapy in our hospital were compared. CT images of patients who inserted rectal balloon were acquired with 3 mm thickness and 10 MV energy of HD120MLC equipped Truebeam STx (Varian, Palo Alto, USA) was applied by using Eclipse (Version 11.0, Varian, Palo Alto, USA). 1 Arc, 2 Arc VMAT plans and 7-field IMRT plan were devised for each patient and same values were applied for dose volume constraint and plan normalization. To evaluate these plans, PTV coverage, conformity index (CI) and homogeneity index (HI) were compared and $R_{50%}$ was calculated to assess low dose spillage as per treatment plan. $D_{25%}$ of rectum and bladder Dmean were compared on OAR. And to evaluate the treatment efficiency, total monitor units(MU) and delivery time were considered. Each assessed result was analyzed by average value of 10 patients. Additionally, portal dosimetry was carried out for accuracy verification of beam delivery. Results : There was no significant difference on PTV coverage and HI among 3 plans. Especially CI and $R_{50%}$ on 7F-IMRT were the highest as 1.230, 3.991 respectively(p=0.00). Rectum $D_{25%}$ was similar between 1A-VMAT and 2A-VMAT. But approximately 7% higher value was observed on 7F-IMRT compare to the others(p=0.02) and bladder Dmean were similar among the all plan(P>0.05). Total MU were 494.7, 479.7, 757.9 respectively(P=0.00) for 1A-VMAT, 2A-VMAT, 7F-IMRT and at the most on 7F-IMRT. The delivery time were 65.2sec, 133.1sec, 145.5sec respectively(p=0.00). The obvious shortest time was observed on 1A-VMAT. All plans indicated over 99.5%(p=0.00) of gamma pass rate (2 mm, 2%) in portal dosimetry quality assurance. Conclusion : As a result of study, postoperative prostate cancer radiation therapy for patient using a rectal balloon, there was no significant difference of PTV coverage but 1A-VMAT and 2A-VMAT were more efficient for dose reduction of normal tissue and OARs. Between VMAT plans. $R_{50%}$ and MU were little lower in 2A-VMAT but 1A-VMAT has the shortest delivery time. So it is regarded to be an effective plan and it can reduce intra-fractional motion of patient also.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.10 no.1
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• pp.51-59
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• 2007

Purpose: Recently well-developed anorectal function tests have revealed that there is an obvious pelvic floor dyssynergia (PFD) pattern in pediatric patients with constipation, as well as in adult's. The use of biofeedback therapy (BT) has been widely implemented in adult PFD patients; however, this approach has only rarely been considered for pediatric PFD patients. Therefore, we assessed the effectiveness of BT in children with PFD. Methods: We studied 70 children with PFD, who were referred to the department of pediatrics at the Asan Medical Center for the management of soiling or chronic constipation from September 2002 to February 2005. Diagnosis of PFD and assessment of the efficacy of BT for PFD treatment were carried out along with several ano-rectal function tests (cine-defecography, ano-rectal manometry, balloon expulsion test and intra-anal EMG); in addition, a questionnaire was administered. The BT based intra-anal EMG was performed. A follow-up telephone interview was performed more than 6 months later. Results: Most of the symptoms and results of the ano-rectal function tests were statistically improved after BT. In comparisons between the BT and control groups (BT refusal group due to poor compliance), the symptoms were statistically improved at follow-up. Therefore, for the shortterm improvement of symptoms, BT was better than conservative therapy alone. The negative feelings associated with ano-rectal function testing and BT were directly associated with failure or success of therapy. Conclusion: Pediatric patients with constipation or soiling that presented with an obvious PFD pattern showed that BT was a useful therapeutic tool for rapid improvement of symptoms.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.6 no.1
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• pp.24-31
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• 2003

Purpose: As diagnostic tools for Hirschsprung's disease (HD), barium enema and rectal biopsy have radiation exposure and invasiveness respectively; however anorectal manometry does not have these disadvantages. We therefore performed this study to evaluate the diagnostic efficacy of anorectal manometry. Methods: We reviewed medical records of infants with one or two symptoms of vomiting, abdominal distension, chronic diarrhea or constipation who had a anorectal manometry followed by barium enema and/or biopsy from July 1995 to May 2002. We evaluated the sensitivity, specificity and predictive value of anorectal manometry and barium enema for diagnosis of HD. We also measured sphincter length, median value of balloon volume at which rectoanal inhibitory reflex (RAIR) occurred. Results: All 61 patients received anorectal manometry, 33 of 61 received barium enema. 18 of 61 were diagnosed as HD according to histology and 43 of 61 were evaluated as a control. The sensitivity, specificity, positive predictive value, negative predictive value of anorectal manometry and barium enema for diagnosis of HD were 1.00, 0.91, 0.82, 1.00 and 0.93, 0.67, 0.70, 0.92 respectively. The mean value of sphincter length in control was $1.68{\pm}0.67$ cm and correlated with age, weight and significantly longitudinal length. The median value of balloon volume at which RAIR occurred was 10 mL and did not correlated with age, weight and longitudinal length. Conclusion: This study suggests that anorectal manometry is an excellent initial screening test for Hirschsprung's disease because of its safety and accuracy.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.53-60
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• 2015

Purpose : The purpose of this study is to evaluate the usefulness of a 3D printed phantom for in-vivo dosimetry of a prostate cancer patient. Materials and Methods : The phantom is produced to equally describe prostate and rectum based on a 3D volume contour of an actual prostate cancer patient who is treated in Asan Medical Center by using a 3D printer (3D EDISON+, Lokit, Korea). CT(Computed tomography) images of phantom are aquired by computed tomography (Lightspeed CT, GE, USA). By using treatment planning system (Eclipse version 10.0, Varian, USA), treatment planning is established after volume of a prostate cancer patient is compared with volume of the phantom. MOSFET(Metal OXIDE Silicon Field Effect Transistor) is estimated to identify precision and is located in 4 measuring points (bladder, prostate, rectal anterior wall and rectal posterior wall) to analyzed treatment planning and measured value. Results : Prostate volume and rectum volume of prostate cancer patient represent 30.61 cc and 51.19 cc respectively. In case of a phantom, prostate volume and rectum volume represent 31.12 cc and 53.52 cc respectively. A variation of volume between a prostate cancer patient and a phantom is less than 3%. Precision of MOSFET represents less than 3%. It indicates linearity and correlation coefficient indicates from 0.99 ~ 1.00 depending on dose variation. Each accuracy of bladder, prostate, rectal anterior wall and rectal posterior wall represent 1.4%, 2.6%, 3.7% and 1.5% respectively. In- vivo dosimetry represents entirely less than 5% considering precision of MOSFET. Conclusion : By using a 3D printer, possibility of phantom production based on prostate is verified precision within 3%. effectiveness of In-vivo dosimetry is confirmed from a phantom which is produced by a 3D printer. In-vivo dosimetry is evaluated entirely less than 5% considering precision of MOSFET. Therefore, This study is confirmed the usefulness of a 3D printed phantom for in-vivo dosimetry of a prostate cancer patient. It is necessary to additional phantom production by a 3D printer and In-vivo dosimetry for other organs of patient.