Effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy plan for gastric cancer / 中国辐射卫生

Objective To investigate the effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy (IMRT) plan for gastric cancer and to provide a reference for clinical planning. Methods A retrospective analysis was conducted on patients who recently underwent postoperative IMRT for gastric cancer. Twenty patients who received radiotherapy in the centre of Radiation Oncology of Huanggang Central Hospital from August 2022 to January 2023 were selected. That were selected to receive a seven-field coplanar static IMRT plan based on a couch rotation angle of 0° as the control group. Then, based on the coplanar IMRT plan, only the couch rotation angle of gantry angles 30° and 330° was changed to 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, respectively, and nine different non-coplanar plans were established. The homogeneity index (HI), conformity index (CI) of the target volume, and monitor unit (MU), as well as Dmean, V20, and V30 of the left and right kidneys, Dmax, Dmean, V10, V20, and V30 of the spinal cord, and Dmax, Dmean, V10, V20, V30, and V40 of the small intestine and liver were compared among the 10 plans. The MU and the dosimetric parameters of the target volumes and When the couch rotation angle was 60°, the minimum HI and maximum CI of the target volume were 0.0714±0.0089 and 0.9271±0.0108, respectively, and the minimum MU was 438±26, with the best homogeneity and conformity in the target volume and the shortest machine treatment time (P＜0.05). When the couch rotation angle was 10°, the Dmax of the small intestine was lowest, being (4620.73±99.27) cGy. When the couch rotation angle was 60°, the Dmean of the left and right kidneys was lowest, being (1246.30±130.35) cGy and (1001.52±103.33) cGy, respectively; the V20 of the left and right kidneys was lowest, being 22.87±6.29 and 19.69±1.84, respectively; the V10 and V30 of the spinal cord were lowest, being 40.08±4.92 and 1.68±0.34, respectively (P＜0.05). Conclusion The couch rotation angle has some influence on the postoperative treatment planning for patients with gastric cancer. In the design of non-coplanar plan for gastric cancer, the couch rotation angle of 60° contributes to establishing a better radiotherapy plan.

Improved Design and Acceptance Test of Localization Couch for New Type of CT Simulator / 中国医疗器械杂志

Accurate CT simulation is the key link of precision radiotherapy, and the performance of the localization couch of CT simulator directly affects the accuracy of radiotherapy. With the rapid development of precision radiotherapy, conventional large aperture radiotherapy special CT simulator is difficult to meet the needs of precision radiotherapy localization, so most radiotherapy centers choose high-end diagnostic CT machines equipped with a flat tabletop for radiotherapy localization. In clinical work, the performance testing of the CT simulator localization couch is easy to be ignored. In addition, there are some problems such as insufficient precision in transforming the cradle-shaped couch top of diagnostic CT into a special flat couch top for radiotherapy. This paper provided an in-depth description of the improved design and performance test of the localization couch of the first special GE Revolution CT simulator for radiotherapy introduced by West China Hospital of Sichuan University. After the improvement, all the acceptance tests of the localization couch are in line with the standard, and the performance meets the high-precision radiotherapy localization needs of patients with different body weight in the center.

Para uma suspensão do tempo ordinário - a experiência da festa, do tédio e do divã / For a suspension of ordinary time - the experience of partying, boredom, and couch

RESUMO: Este ensaio pretende analisar se, em nossos dias, ainda é possível uma suspensão do tempo ordinário. Ou seja, pretende explorar várias dimensões de nossas vidas nas quais o tempo cronológico poderia ou não ser colocado em suspensão; se sim, tal possibilidade nos levaria a experienciar outra forma de temporalidade? Principio a análise desde a perspectiva da experiência nas festas populares - o carnaval, por exemplo, ainda seria um espaço de transgressão (do ordinário ao profano)? Enveredo então por uma reflexão sobre o passatempo e a indústria cultural. E, em um segundo movimento, investigo se poderíamos suspender aquele tempo ordinário em nossa vida privada, como na experiência do tédio. Outras possibilidades visadas são os casos do divã e do amor. Nestes últimos, teríamos realmente uma outra experiência de temporalidade?

Abstract: This essay aims to examine whether, nowadays, it is still possible to suspend ordinary time. In other words, aims to explore the various dimensions of our lives in which chronological time could be suspended; if so, such a possibility would lead us to experience another form of temporality? Beginning the analysis from the perspective of experience in popular festivities - carnival, for instance, would still be a space of transgression (of the ordinary to the profane)? Follows a reflection about pastimes and the culture industry. Next, I investigate if we could suspend ordinary time in our private life, as the experience of boredom. Other possibilities would be the cases of couch and of love. In those latter, would we really have a different experience of temporality?

Characteristics and clinical application of the TomoDose diode array for quality control of Tomotherapy / 中华放射肿瘤学杂志

Objective To evaluate the dosimetric characteristics of the TomoDose diode and its application in detecting the couch velocity and assessing the beam Profile stability for convenient and efficient quality control of Tomotherapy.Methods Fundamental properties of the TomoDose detector,such as dose linearity,dose per pulse dependence,directional dependence and field size dependence were tested by the water-equivalent phantom and the results were statistically compared with those measured by the ion-chamber (0.057 cm3,A 1SL).Five different couch velocities with a time interval of 0.0005 s were designed to test the sensitivity of TomoDose for detecting the couch velocity,and then the clinical data of 7 patients with different couch velocities were selected to verify the test accuracy.The beam profile of three different jaws of 1.0,2.5 and 5.0 cm were measured using TomoDose with water-equivalent phantom in the x and y directions under the same conditions as water tank with an underwater depth of 15,50,100,150 and 200 mm,respectively.The Profile data obtained by water tank and TomoDose were evaluated using the Gamma (γ) evaluation method with the 2％/1 mm criterion.Results The dose linearity of the TomoDose and ion chamber was in a linear pattern within the beam-on-time ≤ 30 s.The difference between the TomoDose and ion chamber was less than 2％ for the dose per pulse dependence,and the response trends of them were consistent.TomoDose showed angular response dependence with a maximum difference of 2.53％ for the gantry angle of ±60°.For the field size dependence,the response difference between the TomoDose and ion chamber was increased with the decreasing field size when the Jaw was 5.0 cm,and the maximum deviation was 0.78％ when the field size was 5.0 cm×2.5 cm.TomoDose could detect the couch distance error of 0.5 mm,and determine the couch velocity deviation of＜ 0.6％.For the Profile stability testing:In the x direction,there was always γ＜1 at the underwater depth of 15 mm for all values of Jaw;when the underwater depth was not 15 mm,there was always γ＜ 1 in the main beam region (off-axis distance＜ 200 mm),whereas in the penumbra region (off-axis distance＞ 200 mm),the value of γ was larger and even with γ＞ l.In the y direction,all comparison results of Profile under three field width demonstrated that γ index was larger on the edge of beam,whereas γ＜1 was found in all cases.Conclusions TomoDose is suitable f or the quality control of Tomotherapy,which can accurately measure the couch velocity,precisely monitor the stability of beam Profile of Tomotherapy and complete the quality control process in a convenient and efficient manner.

Analysis of the setup errors and residual errors for ExacTrac X-ray image-guidance system for radiotherapy of somal tumors / 中华放射医学与防护杂志

Objective To retrospectively analyze the setup error in radiotherapy of somal tumors and body metastases using the ExacTrac X-ray portal image,and to evaluate the feasibility and effectiveness of 6D setup error correction in body radiotherapy.Methods The translational and rotational setup errors were calculated by registering the bony structures on the ExacTrac X-setup images to that of the digitally reconstructed setup images,and the corresponding residual errors were calculated together.Results The translational and rotational setup errors in the x (left-right),y (superior-inferior),z (anterior-posterior) and Rx (sagittal),Ry (transverse),Rz (coronal) directions were(2.27±2.02) mm,(4.49±2.52) mm,(2.27± 1.37) mm and (1.02 ± 0.73) °,(0.67 ± 0.68) °,(0.76 ± 0.84) °,respectively.The residual translational and rotational setup errors in the x(r),y(r),z(r) and Rx(r),Ry(r),Rz(r) directions were(0.27±0.48)mm,(0.37±0.45)mm,(0.22±0.30)mm and (0.17±0.33)°,(0.14±0.34)°,(0.16± 0.28) ° respectively.Conclusions Besides the translational setup errors,a certain amount of rotational setup errors exist in radiotherapy of somal tumors and body metastases.By using the 6D setup error correction of the ExacTrac system,a translational less than 0.4 mm and rotational setup errors less than 0.2° could be achieved.

A setting approach for tolerance table of couch position in record and verify system / 中华放射肿瘤学杂志

Objective To evaluate the effect of the tolerance table of different couch positions in the record and verify system (R&V system) upon the setup accuracy.Methods Clinical data of 715 patients (15 743 fractions of treatment) were extracted from the R&V system database and assigned into four categories including thorax and abdomen,head and neck,breast,and rectum based on the disease site and immobilization device.The first day couch position (FstD) and cumulative average couch position (CumA)were utilized as the references to analyze the couch setup of each faction of treatment,and to establish the tolerance tables of different sites.The sensitivity and specificity of two methods were evaluated by the actual clinical treatment record of the patients.Results For the FstD as the reference,the couch tolerance in the breast was significantly higher than those in other parts.When the CumA was used as the reference,the couch tolerance tended to be stable after a certain fractions of treatment,and the tolerance of all sites was less than that of the FstD.The tolerance tables significantly differed between these two methods (P=0.000).Both two methods possessed high specificity,whereas the CumA method yielded higher sensitivity than the FstD approach.Conclusion Setting a reasonable tolerance table of couch position can effectively improve the setup accuracy.

Feasibility and effectiveness of self-made tiltable treatment couch in minimizing setup errors of radiotherapy for thoracic and abdominal tumors / 中华放射肿瘤学杂志

Objective A self-made tiltable treatment couch was adopted for CT simulation positioning and radiotherapy to evaluate the feasibility and effectiveness to minimize the setup errors. Methods Twenty-two patients with thoracic and abdominal tumors receiving radiotherapy in Department of Radiation Oncology,Peking Union Medical College between March and September 2016 were recruited in this study. All patients were randomly divided into the experimental(n=11)and control groups(n=11).In the study group,the tiltable treatment couch was adopted to switch the patients from the standing position to the supine position,and conventional supine position was utilized in the control group. All patients received CT positioning under spontaneous breathing. Image registration was performed according to the standard recommendations of IGRT group. The image registration data for the translational and rotation errors of CBCT were recorded and analyzed. The setup errors were calculated by four-parameter model between two groups. Results In the experimental group,the translational error of the x direction was(-0.012±0.128)cm with a variation range of(0.29-0.70 cm),(0.272±0.123)cm for the y direction(0.23-0.70 cm)and(0.089± 0.105)cm for the z direction(0.14-0.53 cm),respectively. In the control group,the translational error of the x direction was(0.006±0.198)cm(0.27-0.75 cm),(-0.108±0.396)cm for the y direction(0.56-2.08 cm)and(- 0.096± 0.176)cm for the z direction(0.34-0.89 cm), respectively. Conclusions Application of the self-made tiltable treatment couch can enhance the setup reproducibility and reduce the setup errors,especially in the y direction during radiotherapy for the thoracic and abdominal tumors.

The necessity of inclusion of a virtual treatment couch involved in the XiO treatment planning system / 中华放射医学与防护杂志

Objective To investigate the dosimetric effect of carbon fiber couch through virtual simulation in the XiO treatment planning system (TPS).Methods A treatment couch model of iBEAM evo Extension 650 was scanned with a big bore spiral CT and its contour was stored in the XiO TPS.The attenuation coefficient of couch was obtained by measuring the attenuated dose with and without a solid water phantom on the couch at different gantry angles (100°-180°).The optimal relative electron density (RED) values of the carbon fiber (CF) cover and foam core (FC) were adjusted according to the comparison between measured and simulated attenuation dose.The effects of the couch in the TPS on pass rate were evaluated by Octavius 4D phantom with 10 cases with lung cancer.Results The optimal RED values of CF and FC were 0.75 and 0.10 g/cm3,respectively.The measured attenuation error was the maximal at gantry angle of 120° (4.84％) without the treatment couch in the TPS.The average measured attenuation errors without the couch in the TPS dropped significantly from (2.54 ± 1.48) ％ to (-0.04 ± 0.36) ％ after inclusion of the treatment couch during dose calculation (Z =-3.621,P ＜ 0.05).The three-dimensional dose verification γ pass rate (3 mm/3％) without the couch increased significantly from (91.79± 1.25)％ to (94.74± 1.69)％ after inclusion of the couch in the dose calculation (t =6.027,P ＜ 0.05).Conclusions The effect of couch on the attenuation dose is significant.Inclusion of a virtual model of couch in XiO TPS can simulate the attenuation effect properly and improve the accuracy of dose calculation.

Study on feasibility of Brainlab combined with 6-degree-of-freedom couch in radiotherapy of head and neck / 重庆医学

Objective To study the feasibility of Brainlab plus 6-degree-of-freedom(6D) couch in the radiotherapy of head and neck by using their setup error.Methods Twenty-four patients with head and neck neoplasms in our hospital during AugustOctober 2016 were taken as the examples.After positioning by technician,each Brainlab was carried out,the setup errors in 3 translation directions of left-to-right(X),head-to-foot(Y) and abdomen to-back(Z) and 3 pivoting directions of Rx,Ry and Rz were obtained after registration of positioned CT image.After adjustment,Brainlab re-scanning was conducted for getting corrected errors.Results The online correction by Brainlab plus 6D obviously reduced the setup errors.The setup errors in all directions approached to 0,in which the difference between Ry and Rz directions had no statistical significance(P＞0.05),while the difference among the X,Y,Z and RX directions was statistically significant(P＜0.05).Conclusion The online corrections of Brainlab combined with 6D considerably reduces the errors in translation and rotation directions in radiotherapy of head and neck neoplasms,thus reduces normal tissue received amount and increases the radiotherapeutic accuracy.

Application of ExacTrac X-ray image guidance system to frameless stereotactic radiosurgery of intracranial tumor / 医疗卫生装备

Objective To study the setup accuracy and other factors during frameless stereotactic radiosurgery (SRS) of intracraial tumor using ExacTrac X-ray image guide system.Methods Totally 119 intracranial tumor patients from August 2014 to February 2016 underwent auto setup with infrared marker.Bilateral oblique cross field images were obtained with ExacTrac X-ray system,and went through comparison,registration and correction with the digitally reconstructed ones of the planning system.Then the translation accuracy errors at LAT,LNG and VRT directions and corresponding rotational accuracy errors were acquired,and the errors experienced extended analysis.Results The translation errors at LAT,LNG and VRT directions acquired with ExacTrac X-ray image guidance system and 6DOF couch were (0.16±0.13) mm,(0.17±0.14) mm and (0.15±0.11) mm respectively,the corresponding rotational errors were (0.21±0.15),(0.18±0.15),(0.18±0.14)° respectively,and the vector error was (0.32±0.16) mm.All of 3 translation and 3 rotational errors were in the SRS error range.Conclusion ExacTrac X-ray image guidance system combined with 6 degrees-of-freedom couch increases the treatment accuracy during frameless SRS,and thus is worthy promoting practically.

Analyzing of correlation between the setup error and the couch position in radiotherapy / 中华放射肿瘤学杂志

Objective To investigate the correlation between setup error and couch position error in radiotherapy.Methods A total of 25 patients with thoracic and abdominal tumors who recently finished image-guided radiotherapy were randomly selected.The data on couch position during treatment were obtained through the record validation system, and then the couch position error was calculated.The Pearson correlation analysis was used to investigate the correlation between setup error and couch position error during treatment.Results In the ≥5 setup errors among the 25 patients, the correlation coefficient between random setup error and random couch position error was 0.83(P=0.00), and the correlation coefficient between systematic setup error and systematic couch position error was 0.36(P=0.11).Conclusions In radiotherapy, the random setup error is highly correlated with the random couch position error, while a moderate or low correlation exists between the systematic setup error and the systematic couch position error.

Comparison of two treatment couch model in Monaco treatment planning system / 中华放射肿瘤学杂志

Objective To construct the uniform electron density couch model (model A ED =0.25) and two components non uniform electron density couch model (model B FD =0.5and foam core=0.1) in the Monaco treatment planning system for the iBEAM(R) evo Extension 415,and to compare which model can better quantify the treatment couch influence on radiation dose.Methods Phantom was positioned in the center of the couch,the attenuation of the couch was evaluated with 6 MV for a field size of 10 cm× 10 cm.Dose measurements of couch attenuation were performed at gantry angles from 180.0° to 122.8°,using a 0.125cc semiflex ionization chamber (PTW),isocentrically placed in the center of a homogeneous cylindrical phantom.Each experimental setup was first measured on the linear accelerator and then reproduced in the TPS.By adjusting the relative-to water electron density (ED) values of the couch,the measured attenuation was replicated.The model accuracies of the model A and model B were evaluated by comparing the measured and calculated results at the minimum computational grid (2 mm) and maximum computing grid (5 mm),respectively.Results The maximum measured and calculated percentage deviation for the central phantom position was 4.01％.The couch model was included in the TPS with a uniform ED of 0.25 or a 2 component model with a fiber ED=0.5 and foam core ED=0.1.For model A and B under 2 and 5 mm voxel grid size,the mean absorbed dose with couch was reduced to 0.61％,0.84％,0.71％ and 0.92％from 2.8％ without couch.Conclusions Model A has a good agreement between measured and calculated dose distributions for all different voxel grid sizes and gantry angles.It can accurately describes the dose perturbations due to the presence of the couch and should therefore be used during treatment planning.

Application of the standard equation of a circle to prevention of collision between the gantry and the couch / 中国癌症杂志

Background and purpose:The radiation should move at the same direction in accordance with the position of the couch during radiotherapy due to the different location of gross target volume. However, under the condition of the long distance movement of the couch, collisions between the gantry and the couch (or the patients) may happen. To avoid the collisions between the gantry and the couch, the motion area conlfiction between the gantry and the couch was analyzed.Methods:The distance from isocenter to the surface center of linear accelerator head, and the width and the thickness of treatment bed were measured when the treatment bed was empty, and gantry and collimator were at zero position. Forty sets of bed movement data were collected. The sum of squares ofX-andY-coordinates of reference point was calculated and compared with squares of rotation radius. Then, it was anticipated whether the linear accelerator head will collide with treatment bed. Finally, practical veriifcation was made.Results:Whether linear accelerator head collides with treatment bed depends on the difference between the sum of squares ofX-andY-coordinates and the squares of rotation radius. No collisions will happen when the sum of squares ofX-andY-coordinates is less than that of the squares of rotation radius.Conclusion:It is feasible to avoid collisions of linear accelerator head with treatment bed by comparing the sum of squares ofX-andY-coordinates of reference point with squares of rotation radius.

Skype análise / Skype analysis / Skype análisis

O autor discute a necessidade de utilizar, na prática clínica, a análise a distância em circunstâncias determinadas. Comenta a bibliografia sobre análise por telefone e relata aspectos de sua experiência no uso do Skype, que conta com exíguas publicações a respeito. Vê inúmeros pontos positivos que validam sua aplicação, ainda que a sensorialidade do encontro analítico esteja diminuída. Propõe que deve ser vista como uma modalidade específica: a Skype análise.

This paper discusses the need for distance analysis in clinical practice in certain circumstances. The author comments on the bibliography of telephone analysis and describes aspects of his experience with Skype analysis, about which there are few published works. He argues that positive aspects validate its use, even though sensoriality of the analytic encounter is diminished. He suggests Skype analysis as a specific form of analysis.

El autor discute la necesidad del uso, en la práctica clínica, del análisis a distancia, en determinadas circunstancias. Comenta la bibliografía sobre el análisis por teléfono y relata aspectos de su experiencia con el uso del Skype, que cuenta con escasas publicaciones al respecto. Observa inúmeros aspectos positivos que validan su aplicación, aunque la sensorialidad del encuentro analítico esté disminuida. Propone que debe verse como una modalidad específica, la Skype análisis.

Using compensate angles to correct rotation set-up errors in radiotherapy / 中国医学装备

Objective:The purpose of this paper is to introduce a method of using compensate angles to eliminate rotation set-up errors without six-degree of freedom couch. Methods: To detect six-degree of freedom set-up errors, cone-beam computed tomography (CBCT) scans were acquired. These set-up errors were defined as a matrix to transform from accelerator coordinate system to patient coordinate system. Two independent vectors were defined to describe angles of gantry, collimator and couch in accelerator machine. Transformation of vectors were determined by transformation matrix and re-calculated back to the machine angles. Results:It was found that compensate angles can fully corrected the rotation angles in set-up with limited time consuming. It is feasible to implement compensate angles in routinely radiation procedure. Conclusion:With this method, it is possible to implement the complete corrections of set-up errors in radiotherapy without six-degree of freedom couch and it is convenient in operation as well.

The effect of carbon fiber couch on dose distribution of conformal intensity modulated plan / 中华放射肿瘤学杂志

Objective To evaluate the effect of carbon fiber couch on dose distribution of radiotherapy planning and verification pass rate.Methods Establishing the carbon fiber treatment couch model in Pinnacle8.0m Treatment Planning system (TPS),and then this model was used to correct dose calculations of oblique fields in the treatment plans of 10 cases of nasopharyngeal carcinoma,10 cases of breast cancer and 10 cases of lung cancer and evaluate the effect of carbon fiber couch on the whole dose distribution of the plans.Then these plans were measured by three-dimensional dose verification equipment Delta4 to confirm the improvement extent of Gamma pass rate after considering the carbon fiber treatment couch.Results For the majority of plans,when the carbon fiber couch was taken into consideration,the target doses was significantly reduced (4772 cGy-7266 cGy vs.4859 cGy-7347 cGy,P=0.000-0.002) and the relative deviation of D95 was 1％ to 3％.Measurement results of Delta4 showed that Gamma pass rate (3 mm/3％ criteria) increased in all plans (96.4％-98.8％ vs.93.4％-97.3％,P =0.000),some of that were up to 5 percentage when the couch model was applied.Conclusions Target doses will be overestimated if the treatment couch is ignored in TPS measurement.,However it should arouse enough attention when the disease with smaller doses corresponding gradient.

A Correction Method of Dose to Attenuation Rate of Transmitting Photon Beam Through Couch Top for Radiosurgery Using Novalis / 의학물리

This study has its own goal to deliver the accurate dose on the target volume by calculating and modifying the attenuation rate of photon beam transmitting the couch top with geometric model. The experiment was that the transmission rate and attenuation rate of photon beam transmitting the couch top was predicted by the geometric model, then compared and analyzed with what was measured experimentally based on that. The result showed that the predicted value by the geometric model accorded closely with the experimental value. In addition, in order to judge whether the practical clinical application is available, the point dose, measured after modifying the attenuation rate modelinged according to the treatment plan of a patient of spine radiosurgery, was compared with the one done nothing. The result was that the former showed decreased error range with treatment planned one than the latter. This papers calculated the transmission and attenuation rate with the geometric model transmitting the couch top and verified it experimentally. This method is expected to be very useful in not only the radiosurgery using Novalis but also the general radiation therapy.

The positioning accuracy study of the cone-beam computed tomography in combination with the sixdegree couch table / 中华放射肿瘤学杂志

Objective To scrutinize the positioning accuracy and reproducibility of the cone-beam computed tomography system in combination with the six-degree couch table (Hexapod Robot Treatment Table, HRTT). Methods The mechanical stability of the X-ray volume imaging (XVI) system was tested,in terms of the reproducibility. And the influence of the moveable parts, including the KV panel and the source arm, on the accuracy of the XVI image registration was analyzed. The accuracy between the bone and grey value registration was compared using a head-and-neck phantom. The accuracy of the HRTT for translational, rotational, and a combination of translational and rotational corrections was investigated in consecutive measurements. Results The performance of XVI system itself was stable with translational and rotational error of below 0. 4 mm and below 0. 3°, respectively. The mean position accuracy of the XVI system in combination with the HRTT summarized over all measurements was below 0. 6 mm and below 0. 4° for translational and rotational corrections, respectively. The grey value match was more accurate than the bone match. Conclusions The XVI image acquisition and registration procedure were highly reproducible.Both translational and rotational positioning errors can be corrected very precisely with the HRTT. The HRTT is therefore well suited to complement CBCT to take full advantage of position correction in six degrees of freedom for image guided radiotherapy.

Real-time Body Surface Motion Tracking using the Couch Based Computer-controlled Motion Phantom (CBMP) and Ultrasonic Sensor: A Feasibility Study / 의학물리

Respiration gating radiotherapy technique developed in consideration of the movement of body surface and internal organs during respiration, is categorized into the method of analyzing the respiratory volume for data processing and that of keeping track of fiducial landmark or dermatologic markers based on radiography. However, since these methods require high-priced equipments for treatment and are used for the specific radiotherapy. Therefore, we should develop new essential method whilst ruling out the possible problems. This study aims to obtain body surface motion by using the couch based computer-controlled motion phantom (CBMP) and US sensor, and to develop respiration gating techniques that can adjust patients' beds by using opposite values of the data obtained. The CBMP made to measure body surface motion is composed of a BS II microprocessor, sensor, host computer and stepping motor etc. And the program to control and operate it was developed. After the CBMP was adjusted by entering random movement data, and the phantom movements were acquired using the sensors, the two data were compared and analyzed. And then, after the movements by respiration were acquired by using a rabbit, the real-time respiration gating techniques were drawn by operating the phantom with the opposite values of the data. The result of analyzing the acquisition-correction delay time for the data value shows that the data value coincided within 1% and that the acquisition-correction delay time was obtained real-time (2.34 x 10(-4) sec). And the movement was the maximum movement was 6 mm in Z direction, in which the respiratory cycle was 2.9 seconds. This study successfully confirms the clinical application possibility of respiration gating techniques by using a CBMP and sensor.