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Objective@#To study the feasibility of using the PTW729 2D array ion-chamber to verify the relative dose distribution calculated with the Acuros BV algorithm. Both advantages and disadvantages of the method were analyzed to provide reference for practical clinical practices.@*Methods@#Based on self-built measurement phantoms, the dose distribution on the same slice of the phantom was measured with PTW729 and film, respectively, under the same measurement condition and plan. The dose distributions obtained by the two method were compared with the result calculated with Acuros BV, separately, by using γ analytical tool. And the stability of the PTW729 was tested.@*Results@#The γ comparison value was 95.9% between the film and Acuros BV, 98.9% between the PTW729 and Acuros BV and 88.0% between the film and PTW729, with 95.0%, 100.0%, and 100.0%, in their stability test respectively.@*Conclusions@#PTW729 2D array ion-chamber can be applied to the rapid verification of Acuros BV algorithm-calculated relative dose distribution.
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Objective To study the feasibility of using the PTW729 2D array ion-chamber to verify the relative dose distribution calculated with the Acuros BV algorithm.Both advantages and disadvantages of the method were analyzed to provide reference for practical clinical practices.Methods Based on self-built measurement phantoms,the dose distribution on the same slice of the phantom was measured with PTW729 and film,respectively,under the same measurement condition and plan.The dose distributions obtained by the two method were compared with the result calculated with Acuros BV,separately,by using γ analytical tool.And the stability of the PTW729 was tested.Results The γ comparison value was 95.9％ between the film and Acuros BV,98.9％ between the PTW729 and Acuros BV and 88.0％ between the film and PTW729,with 95.0％,i00.0％,and 100.0％,in their stability test respectively.Conclusions PTW729 2D array ion-chamber can be applied to the rapid verification of Acuros BV algorithm-calculated relative dose distribution.
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Objective: To investigate the application of 3D-printed minimally-invasiveguided template in the treatment of recurrent cer-vical cancer after surgery, assisting interstitial brachytherapy. Methods: From July 2017 to April 2018, a total of 10 patients admitted to Cangzhou Hospital of Integrated Traditional Chinese and Western Medicine in Hebei province with recurrent cervical cancer after radi-cal surgery underwent the 3D-printed customized template-assisted interstitial brachytherapy. According to the specific conditions of patients, different vaginal localization templates were selected for CT simulation localization. The main guidance needle space distribu-tion was designed, and 3D minimally-invasive guidance templates were printed. Then, needles were inserted according to the main guide channel of the template commissioned by medical photosensitive resin. The high-risk clinical target volume (HR-CTV) of 6 Gy/fraction was administered (4 to 6 fractions). Results: Overall, 10 patients were treated with implantation for a total of 52 times. Treat-ment with average scanning CT number for each brachytherapy was (1.58±0.70) times. The average elapsed time for each brachythera-py implant treatment, from plug implant to inserting planting needle satisfactorily with the location of the tumor, was (10.88±2.94) minutes. The mean number of metal needles used was (5.69±1.91) in each brachytherapy. The mean D90 value for high-risk clinical tar-get volume (HR-CTV) was (6.41±0.29) Gy. The cumulative D2cm3 values for the bladder, rectum, and sigmoid colon were (4.75±0.37) Gy, (3.93±0.26) Gy, and (4.33±0.24) Gy, respectively. After 3 months of treatment, the efficacy was evaluated in 8 cases with CR and 2 cas-es with PR. Conclusions: The technology of 3D-printed minimally-invasive guided template shows the advantage of accurate location and superior repeatability in the application of interstitial brachytherapy in treating recurrent cervical cancer after operation, which in-volves less time and insertion needles. The patients had minor aches and few complications. The tumor shrank significantly, which indi-cated a bright future of the technology's clinical application.
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Objective: To investigate clinical features of distant metastases from malignant salivary gland carcinomas after treated by 125I internal brachy therapy alone.Methods: Between 2002 and 2010, 43 patients with locally advanced unresectable or recurrent malignant salivary gland carcinomas were treated by 125I internal brachy therapy alone at Peking University School and Hospital of Stomatology.All of them had been follow-up at least 2 years.The primary sites of malignant salivary gland carcinomas were the parotid for 12 patients, infratemporal fossa for 9 patients, tongue for 7 patients, maxilla for 6 patients, parapharyngeal for 4 patients, floor of months for 3 patients, submandibular gland for 1 patient, and lip for 1 patient.The overall survival rate, local control rate, and distant metastases were retrospectively reviewed.Results: Distant metastases occurred in 23 of the 43 patients (53.5%).Distant metastases developed from 5 to 96 months, with an average interval of (27.0±23.7) months from the time of initial diagnosis, the mean interval was 21 months.The commonest site of distant metastases overall was the lung 69.6%(16/23).The most common pathological types of distant metastases were adenoid cystic carcinoma (14/23, 60.9%) and nonspecific adenocarcinoma (7/23, 30.4%).At the time of the last follow-up, 26 patients died, and 18 of them due to distant metastases (69.2%, 18/26).In the study, 27 patients got complete remission(CR), 12 got partial remission(PR) more than 50%, 2 less than 50%, and 2 patients were invalid.The effective rate (CR+ PR) was 90.7%.The 3 year loco-regional control rate and survival rate were 60.1%, 82.6%, respectively, and the 5 year's 53.4% and 56.0%.Conclusion: The 125I brachy therapy is a feasible and effective modality for the treatment of locally advanced unresectable or recurrent malignant salivary gland carcinomas.However, further studies are needed with larger numbers of patients and for a longer follow-up assessment.Distant metastasis was the main cause of treatment failure, and the lung was the most common site of distant metastases.
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Objective To study the safety and effectiveness of modified radioactive 125I seed implantation in treatment of lung cancer patients with poor lung function. Methods Thirty one lung cancer patients with poor lung function were enrolled into this study. All of them were implanted 125I seed with technology of fan-shaped distribution and coaxial puncture. Brachytherapy planning system(TPS) was used to draw up a preoperative implantation plan. Fan-shaped seed distribution system was used to simulate surgical program, and implantation pitch was 0.5 to 1.0 cm. Real-time adjustment is necessary during surgery. Dose distributions were checked by TPS immediately after implantation. Match peripheral dose(MPD),the dose of 90% tumor volume(D90)and the tumor volume covered by 90% prescription dose(D90)were calculated. Intraoperative and postoperative surgery-related complications were analyzed. All patients were followed up to 6 months, at month 2, 4 and 6 post-procedure, CT scan was performed to evaluate the local control rate of tumors. Results The technical success rate was 100% for placement of the 125I seed. MPD of the tumors was 90 to 140 Gy. D90 was 95 to 146 Gy,median dose was 118 Gy.V90 was 92%to 97%,median dose was 94%. Surgery-related complications included pulmonary hemorrhage(1 patient), pleural cavity hemorrhage (2 patients), pneumothorax(2 patients). The 2-month, 4-month and 6-monthlocal control rates were 31%(10/32), 78%(25/32) and 90%(29/32)respectively. The overall complete remission(CR) rate was18%(6/32), partial response(PR) rate was 72%(23/32), stable disease(SD)rate was6%(2/32), progression disease(PD) rate was 3%(1/32).Acute radiation pneumonitis Grade 0 in 29 patients, Grade Ⅰin 4 patients; advanced radiation pneumonitis:grade 0 in 30 patients and gradeⅠin 3 patients. Conclusions The technology of fan-shaped distribution and coaxial puncture for radioactive 125I seed implantation was safe and effective to treat lung cancer patients with poor lung function.