Application of SGRT Combined with IGRT Isocenter Dual-guided Resetting in IMRT for Breast Cancer / 中山大学学报(医学科学版)

ObjectiveThe objective is to investigate the possibility of isocenter dual-guided resetting of surface guided radiation therapy （SGRT） combined with image guided radiation therapy （IGRT） in postoperative radiotherapy for breast cancer. To assess the setup error accuracy between the new resetting mode and the traditional resetting mode. MethodsRetrospective analysis was performed on breast cancer patients who underwent ELEKTA infinity accelerator radiotherapy in sun yat-sen university cancer center from July 13， 2021 to October 15， 2022. According to different reset methods， the patients were divided into a simulation group （41 cases） and a dual-guided group （40 cases）. The simulation group was reset using a simulator， CBCT scans were performed and setup errors were recorded during the first treatment； The dual-guided group was guided by AlignRT and combined with CBCT for isocenter dual-guided resetting， and the setup error obtained by CBCT registration was recorded. The global setup errors of chest region of interest （CROI） ， the local residual errors of supraclavicular region of interest （SROI） and the resetting time of the two reset methods were calculated and compared respectively. The advantages of the CBCT error distribution in the dual-guided resetting of SGRT combined with IGRT were analyzed. ResultsThe median of the global setup errors （X/cm， Y/cm， Z/cm， Rx°， Ry°， Rz°） of the simulation group and the median of the dual-guided group in the CROI were statistically significant （P<0.05） except the Rz and Ry directions. The local residual errors of the two groups of the SROI were calculated. The median of the errors of X/cm， Y/cm， Z/cm， Rx°， Ry°， Rz° were statistically significant （P<0.05） except the X and Y axis. The resetting time of the simulation group was significantly longer than that of the dual-guided group （238.64±28.56） s， t=-24.555， P=0.000， and the difference was statistically significant （P<0.05）. The CBCT error distribution of the dual-guide group was analyzed， and it was found that the absolute values of translation errors of X， Y and Z axis were all within 0.4 cm， while the proportions of ≤ 0.3 cm were 95%， 93% and 93%， respectively. The proportions of rotation errors of Rx， Ry and Rz ≤ 1.5 ° were 90%， 93% and 90%， respectively. ConclusionIn postoperative radiotherapy of breast cancer， SGRT combined with IGRT for isocenter dual-guided resetting can effectively correct the rotational setup errors and residual errors， and improve the accuracy of radiotherapy with less resetting time and high feasibility， which compared with the traditional simulator resetting mode. This precise， unmarked resetting method can be widely used in clinical practice.

Set-up uncertainties with radiation therapy for nasopharyngeal carcinoma / 中华放射肿瘤学杂志

Objective This study is to investigate the set-up accuracy of thermoplastic mask used for immobilization of nasopharyngeal carcinoma (NPC) patients being treated by Intensity Modulated Radia- tion Therapy (IMRT).Methods Nineteen patients with early stage nasopharyngeal carcinoma (T1- T2N0M0),treated by fractionated intensity-modulated radiation therapy,underwent repeated CTs during their 6-week treatment course.We evaluated their anatomic landmark coordinates in a total of 85 repeated CT data sets and respective x,y and z shifts relative to their position in the 19 treatment-planning reference CTs.Results The translation in x,y,and z-axes with their mean value derived from both positive and negative set-up errors was-0.84 mm(x-axis),+0.65 mm(y-axis) and +0.01 mm(z-axis).Mean target isocenter translation was (0.89?0.69) mm,(0.82?0.79) mm,(0.95?1.24) mm in x,y and z-direc- tions,respectively.The mean total magnitude vector and 95% CI of isocenter motion were 1.87 mm and 4.65 mm.The data measured over the 6-week fractionated course of treatment revealed a slight deterioration of isocenter accuracy.The 95% CI,considered by us to be a valuable parameter for characterizing the sys- tem,of 4.17 mm for measurement within the first 3 weeks increased to 5.12 mm in the last 3 weeks of treat- ment.Conclusions The sequential CT scanning is a pronounced valuable method of evaluating the quality of departmental specific patient positioning procedures.The thermoplastic mask is eyed as well suited tool for immobilization and repositioning of NPC patients receiving intensity-modulated radiation therapy.

Intensity modulated radiation therapy for 122 patients with untreated nasopharyngeal carcinoma / 中华放射肿瘤学杂志

Objective To analyse the preliminary clinical results of intensity modulated radiation therapy (IMRT) for 122 untreated nasopharyngeal carcinoma (NPC)pafients.Methods 122 NPC pa- tients received IMRT alone from Feb.2001 to Jun.2004,with 31 females and 91 males,and a median age of 45 years(range 25-66).According to the Fuzhou Stage Classification,there were StageⅠ11 patients, StageⅡ34,StageⅢ62,and StageⅣa 15.IMRT was carried out using an inverse planning system (COR- VUS 5.0,Peacock plan) developed by the NOMOS Corp.The treatment was given with the Multi-leaf Inten- sity Modulating Collimator (MIMIC) using a slice-by-slice arc rotation approach.The prescription dose was 68 Gy/30f to the nasopharynx gross tumor volume (GTV_(nx)),60-66 Gy/30f to positive neck lymph nodes (GTV_(nd)),60 Gy/30f to the first clinical target volume (CTV_1) and 54 Gy/30f to the second clinical target volume (CTV_2).Kaplan-Meier method was used to calculate the overall survival rate (OS),distant metas- tasis-free survival rates (DMFS),and local-regional control rates from the last date of therapy.Log-rank test was used to detect the difference between groups.Results The median follow-up time was 20 months ( range 6 to46 months).The 1-,2-,and 3-year OS was 95.2%,91.4%,85.1%,DMFS was 91.9%, 88.6%,85.6%,and the local-regional control rates was 96.5%,93.2%,93.2%,respectively.Statistics of the local control rate was insignificant either for advanced T(T3+T4) stage or early T(T1+T2) stage diseases(P=0.148).The 2-year regional control rate was insignificant either for patients with N(+) or N (-),but the 2-year DMFS was significant both for patients with N(+) and N(-)lesions(P=0.004).For 17 patients who failed,there were two with residual disease and one with recurrence at the primary site (17.6%),three patients in the neck (17.6%),twelve patients (70.6%) in distant metastases.Conclu- sions Intensity modulated radiation therapy does provide excellent local-regional control for untreated NPC, especially in patients with advanced T stage or N(+) lesion.Distant metastasis is the main cause of failure. N (+) is significantly correlated with distant metastasis.

[Hemodynamic effects of aminophylline and nifedipine in patients with high altitude pulmonary edema].

AIM: To evaluate the hemodynamic effects of aminophylline and nifedipine in patients with HAPE. METHODS: 10 patients with HAPE undergone Swan-Ganz catheter. The parameters of hemodynamics and arterial blood gases in HAPE were measured before and after administration of nifedipine 20 mg sublingually and aminophylline 0.25 g intravenously respectively. RESULTS: After administering 0.25 g aminophylline the mPAP and PVR significantly decreased, the cardiac output and the level of PaO2, SaO2 increased obviously, the mSAP, HR did not change so much. After using 20 mg nifedipine, the mPAP, PVR and mSAP also decreased, while the cardiac output, HR and the level of PaO2, SaO2 did not show any changes. CONCLUSION: Both of aminophylline and nifedipine can attenuate pulmonary hypertension in patients with HAPE, but the effect of aminophylline was better than the effect of nifedipine.

Intensity modulated radiation therapy for 49 patients with recurrent nasopharyngeal carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility, toxicity and tumor control of intensity modulated radiation therapy (IMRT) for recurrent nasopharyngeal carcinoma.</p><p><b>METHODS</b>Fourty-nine patients (Karnofsky performance status (KPS) >or= 80) with local-regional recurrence in the nasopharynx were treated with full course IMRT. Three patients with cervical lymph node metastasis (N1 2 and N3 1) were further supplemented with 5 to 6 courses of chemotherapy (Cisplatin + 5-Fu) after IMRT.</p><p><b>RESULTS</b>The results of treatment plan showed that the mean dose of covering gross tumor volume (GTV) (D(95)) in the nasopharynx was 68.09 Gy and the mean volume of GTV (V(95)) receiving the 95% dose was 98.46%. The mean dose of GTV, clinical target volume CTV1 and CTV2 in the targets were 71.40 Gy, 63.63 Gy and 59.81 Gy. The median follow-up time was 9 months (range 3 to 16 months). The local-regional progression-free survival was 100% with local-regional residual disease in 3 (6.1%) cases but was complicated with nasopharyngeal mucosa necrosis in 14 (28.6%) cases after IMRT.</p><p><b>CONCLUSION</b>Intensity modulated radiation therapy, as a re-treatment option for recurrent nasopharyngeal carcinoma, is able to improve the tumor target coverage and spare the adjacent critical structures. As high dose IMRT can result in radio-necrosis of nasopharyngeal mucosa, the prescription dose of GTV should be suitably decreased to 60 - 65 Gy.</p>