• Radiation Oncology Journal
• /
• v.12 no.2
• /
• pp.233-241
• /
• 1994

Purpose : This study was performed to verify dose distribution with the tissue compensator which is used for uniform dose distribution in total body irradiation(TBI). Materials and methods : The compensators were made of lead(0.8mm thickness) and aluminum(1mm or 5mm thickness) plates. The humanoid phantom of adult size was made of paraffin as a real treatment position for bilateral total body technique. The humanoid phantom was set at 360cm of source-axis distance(SAD) and irradiated with geographical field size(FS) $144{\times}144cm^2(40{\times}40cm^2$ at SAD 100cm) which covered the entire phantom. Irradiation was done with 10MV X-ray(CLINAC 1800, Varian Co., USA) of linear accelerator set at Department of Therapeutic Radiology, Chonnam University Hospital. The midline absorbed dose was checked at the various regions such as head, mouth, mid-neck, sternal notch, mid-mediastinum, xiphoid, umbilicus, pelvis, knee and ankle with or without compensator, respectively. We used exposure/exposure rate meter(model 192, Capintec Inc., USA) with ionization chamber(PR 05) for dosimetry, For the dosimetry of thorax region TLD rods of $1x1x6mm^3$ in volume(LiF, Harshaw Co., Netherland) was used at the commercially available humanoid phantom. Results : The absorbed dose of each point without tissue compensator revealed significant difference(from $-11.8\%\;to\;21.1\%$) compared with the umbilicus dose which is a dose prescription point in TBI. The absorbed dose without compensator at sternal notch including shoulder was $11.8\%$ less than the dose of umbilicus. With lead compensator the absorbed doses ranged from $+1.3\%\;to\;-5.3\%$ except mid-neck which revealed over-compensation($-7.9\%$). In case of aluminum compensator the absorbed doses were measured with less difference(from $-2.6{\%}\;to\;5.3\%$) compared with umbilicus dose. Conclusion : Both of lead and aluminum compensators applied to the skull or lower leg revealed a good compensation effect. It was recognized that boost irradiation or choosing reference point of dose prescription at sternal notch according to the lateral thickness of patient in TBI should be considered.

• Progress in Medical Physics
• /
• v.19 no.1
• /
• pp.35-41
• /
• 2008

The main benefit of proton therapy over photon beam radiotherapy is the absence of exit dose, which offers the opportunity for highly conformal dose distributions to target volume while simultaneously irradiating less normal tissue. For proton beam therapy two patient specific beam modifying devices are used. The aperture is used to shape the transverse extension of the proton beam to the shape of the tumor target and a patient-specific compensator attached to the block aperture when required and used to modify the beam range as required by the treatment plan for the patient. A block of range shifting material, shaped on one face in such a way that the distal end of the proton field in the patient takes the shape of the distal end of the target volume. The mechanical quality assurance of range compensator is an essential procedure to confirm the 3 dimensional patient-specific dose distributions. We proposed a new quality assurance method for range compensator based on image processing using X-ray tube of proton therapy treatment room. The depth information, boundaries of each depth of plan compensatorfile and x-ray image of compensator were analyzed and presented over 80% matching results with proposed QA program.

• Progress in Medical Physics
• /
• v.16 no.3
• /
• pp.130-137
• /
• 2005

In total body irradiation (T81) for leukemia, we have a two methode. One is a AP (anterior-posterior) method and the other is a Lateral methode. Our hospital used lateral methode. T81 must consider about body contour, because of homogeneous dose distribution. For compensation about irregular body contour, we use compensator. For T81 treatment, we must be considered, accurate manufacture of compensator and accurate calculation of dose. We developed the automatic program for T81. This program accomplished for compensator design and dose calculation for irregular body. This program was developed for uses to use in a windows environment using the IDL language. In this program, it use energy data for each energy: TMR, output factor, inverse square law, spoiler, field size factor. This program reduces the error to happen due to the manual. As a development of program, we could decrease the time of treatment plan and care the patient accurately.

• Progress in Medical Physics
• /
• v.23 no.4
• /
• pp.269-278
• /
• 2012

Aquaplast Thermoplastic (AT) is a tissue-equivalent oral compensator that has been developed to improve dose uniformity at the common boundary and around the treated area during radiotherapy in patients with head and neck cancer. In order to assess the usefulness of AT, the degree of improvement in dose distribution and physical properties were compared to those of oral compensators made using paraffin, alginate, and putty, which are materials conventionally used in dental imprinting. To assess the physical properties, strength evaluations (compression and drop evaluations) and natural deformation evaluations (volume change over time) were performed; a Gafchromic EBT2 film and a glass dosimeter inserted into a developed phantom for dose verification were used to measure the common boundary dose and the beam profile to assess the dose delivery. When the natural deformation of the oral compensators was assessed over a two-month period, alginate exhibited a maximum of 80% change in volume from moisture evaporation, while the remaining tissue-equivalent properties, including those of AT, showed a change in volume that was less than 3%. In a free-fall test at a height of 1.5 m (repeated 5 times as a strength evaluation), paraffin was easily damaged by the impact, but AT exhibited no damage from the fall. In compressive strength testing, AT was not destroyed even at 8 times the force needed for paraffin. In dose verification using a glass dosimeter, the results showed that in a single test, the tissue-equivalent (about 80 Hounsfield Units [HU]) AT delivered about 4.9% lower surface dose in terms of delivery of an output coefficient (monitor unit), which was 4% lower than putty and exhibited a value of about 1,000 HU or higher during a dose delivery of the same formulation. In addition, when the incident direction of the beam was used as a reference, the uniformity of the dose, as assessed from the beam profile at the boundary after passing through the oral compensators, was 11.41, 3.98, and 4.30 for air, AT, and putty, respectively. The AT oral compensator had a higher strength and lower probability of material transformation than the oral compensators conventionally used as a tissue-equivalent material, and a uniform dose distribution was successfully formed at the boundary and surrounding area including the mouth. It was also possible to deliver a uniformly formulated dose and reduce the skin dose delivery.

• Radiation Oncology Journal
• /
• v.12 no.2
• /
• pp.219-223
• /
• 1994

This paper describes the basic data measurements for total body irradiation with 6 Mv photon beam including compensators design. The technique uses bilateral opposing fields with tissue compensators for the head, neck, lungs, and legs from the hip to toes. In vivo dosimetry was carried out for determining absorbed dose at various regions in 7 patients using diode detectors(MULTIDOSE,k Model 9310, MULTIDATA Co., USA). As a results, the dose uniformity of${\pm}3.5{\%}$(generally, within${\pm}10{\%}$can be achieved with out total body irradiation technique.

• The Journal of the Korea Contents Association
• /
• v.14 no.4
• /
• pp.249-255
• /
• 2014

Total body irradiation use one of the pre-treatment as hematopoietic stem cell transplantation in the treatment of leukemia. According to the study of Korean network for organ sharing 2013 report, continue to increase the number of hematopoietic stem cell transplantation. however, the current dose evaluation fall short before treatment. So purpose of this study is Surface dose and deep organ dose evaluation and then find the most ideal conditions when change of the thickness on tissue compensator in TBI. Result, surface dose in 4 MV, SSD 280 cm, compensators thickness 0.5 cm, was measured the highest dose 5.84 mGy/min. And the ideal dose showed when compensator thickness less than 1 cm.

• Journal of radiological science and technology
• /
• v.38 no.1
• /
• pp.17-21
• /
• 2015

Total body irradiation(TBI) and chemotherapy are the pre-treatment method of a stem cell transplantations of the childhood leukemia. in this study, we evaluate the Quantitative human body dose prior to the treatment. The MCNPX simulation program evaluated by changing the material of the tissue compensators with imitation material of pediatric exposure in a virtual space. As a result, first, the average skin dose with the material of the tissue compensators of Plexiglass tissue compensators is 74.60 mGy/min, Al is 73.96 mGy/min, Cu is 72.26 mGy/min and Pb 67.90 mGy/min respectively. Second, regardless of the tissue compensators material that organ dose were thyroid, gentile, digestive system, brain, lungs, kidneys higher in order. Finally, the ideal distance between body compensator and the patient were 50 cm aparting each other. In conclusion, tissue compensators Al, Cu, Pb are able to replace of the currently used in Plexiglass materials.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2005.05a
• /
• pp.907-910
• /
• 2005

방사선치료에서 결손조직의 보호를 위해 사용되는 기존의 결손조직 보상체는 체표윤곽을 얻기위해 컴퓨터단층촬영영상이나 자기공명촬영영상등의 의료영상을 이용해 왔다. 하지만 이러한 촬영을 위해서는 고가의 비용이 소요되고 방사선치료에 따른 체표윤곽의 변화에 적절히 대응하지 못하는 등의 단점이 지적되고 있다. 따라서 본 연구에서는 사용이 간편한 디지털 카메라로 환자를 촬영한 후 얻은 2차원 이미지를 이용하여 결손조직 보상체를 제작하고 이의 유용성 평가를 위해 기하학적, 선량학적 평가를 수행하였다. 그 결과, 조직결손을 보정하고 정상조직을 보호할 수 있어 임상적용의 가능성을 확인 할 수 있었다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.06a
• /
• pp.10-12
• /
• 2006

U-Health에 대한 연구는 환자, 의료장비에 대한 위치 추적을 통한 의료업무 지원관리 분야로 집중되고 있다. 본 논문에서는 RFID Tag를 의료 측정에 적용한다. 즉, RFID Tag를 이용하여 방사선치료에서 사용되는 결손조직 보상체의 체표 윤곽을 모델링하는 방법을 제안한다. 기존의 모델링 방법은 환자의 체표 윤곽을 컴퓨터단층촬영이나 자기공명촬영을 사용한 의료영상을 이용해왔다. 이러한 방법은 고가의 비용이 소요되고 방사선치료에 따른 체표윤곽의 변화에 대응하지 못한다. 본 연구에서는 U-Health에서 기본적으로 사용하는 RFID Tag를 환자의 체표윤각에 고정하여 3차원 위치정보를 획득한다. 체표윤곽에 위치한 RFID의 상대적 위치를 통해 결손조직 보상체를 제작하고 이의 유용성 평가를 위해 기하학적, 선량학적 평가를 수행하였다.

• The Journal of Korean Society for Radiation Therapy
• /
• v.23 no.1
• /
• pp.41-49
• /
• 2011

Purpose: This study is designed to investigate radiotherapic valuation of Paraffin Wax, which is newly formed for this study and generally utilized in dentistry, and Mouth Piece and Putty impression, which are commonly used in radiotherapy, for oral cavity as a compensator. Materials and Methods: Each compensator was formed by $10{\times}10{\times}1cm$ and measured radiation dose attenuation ratio with reference of water phantom which is made of tissue-equivalent materials. Two patients with oral cancer underwent DRR (Digitally Reconstructed Radiogrph) of Offline Review Program of Aria System and Portal vision for 5 times for each material to evaluate reproducibility by each filling materials. Moreover, MU (monitor unit) changes by dose absorption were considered in the case of inevitable implication of an filling materials in the range for radiotherapy. Results: Radiation dose attenuation ratios were shown -0.7~+3.7% for Mouth Piece, +0.21~+0.39% for Paraffin Wax and -2.71~-1.76% for Putty impression. Error ranges of reproducibility of positions were measured ${\pm}3mm$ for Mouth Piece, ${\pm}2mm$ for Paraffin Wax and ${\pm}2mm$ mm for Putty impression. Difference of prescription MU from dose absorption with an filling material increased +7.8% (250 MU) in Putty impression and -0.9% (230 MU) in Paraffin Wax as converted into a percentage from the standard phantom, Water 232 MU. Conclusion: Dose reduction of boundary between cavity and tissue was observed for Mouth Piece. Mouth Piece also had low reproducibility of positions as it had no reflection of anatomy of oral cavity even though it was a proper material to separate Maxilla and Mandible during therapy. On the other hand, Putty impression was a suitable material to correctly re-position oral cavity as before. However, it risked normal tissues getting unnecessary over irradiation and it caused radiation dose decrease by -2.5% for 1cm volume in comparison of it of water phantom. Dose reduction in Paraffin Wax, Fat Tissue-Equivalent Material, was smaller than other impressions and position reproducibility of it was remarkable as it was possible to make an anatomy reflected impression. It was also well fitted to oral cavity to transfer radiation dose planned in radiotherapy. Thus, Paraffin Wax will be an ideal material in radiotherapy for patients with oral cancer.