Objective The aim of the study was to compare the efficacy and safety of whole brain radiotherapy(WBRT) used alone and combined with stereotactic radiosurgery(SRS) in the treatment of limited(1–4)brain metastases. Me...Objective The aim of the study was to compare the efficacy and safety of whole brain radiotherapy(WBRT) used alone and combined with stereotactic radiosurgery(SRS) in the treatment of limited(1–4)brain metastases. Methods We searched for randomized controlled and matched-pair analysis trials comparing WBRT plus SRS versus WBRT alone for brain metastases. The primary outcomes were the overall survival(OS), intracranial control(IC), and localcontrol(LC). The secondary outcome was radiation toxicity. The log hazard ratios(lnHRs) and their variances were extracted from published Kaplan-Meier curves and pooled using the generic inverse variance method in the RevMan 5.3 software. The non-pooled outcome measures were evaluated using descriptive analysis. Results Three randomized controlled trials and two matched-pair analysis studies were included. There was no difference in the OS for limited brain metastases between the two groups [lnHR 0.91(95% CI 0.76–1.09, P = 0.32) vs. 0.72(95% CI 0.44–1.19, P = 0.20)]. The LC and IC were significantly higher in the combined treatment group [lnHR 0.69(95% CI 0.55–0.86, P = 0.001) vs. 0.41(95% CI 0.29–0.58, P < 0.0001)]. For patients with a single lesion, one trial showed a higher survival in the combined treatment group(median OS: 6.5 months vs. 4.9 months, P = 0.04). The combined treatment was not associated with significantly higher incidence of radiation toxicity. Conclusion Combined treatment with WBRT plus SRS should be recommended for patients with limited brain metastases based on the better LC and IC without increased toxicity. It should also be considered a routine treatment option for patients with solitary brain metastases based on the prolonged OS.展开更多
AIM To evaluate brain metastases volume control capabilities of stereotactic radiosurgery(SRS) through serial magnetic resonance(MR) imaging follow-up. METHODS MR examinations of 54 brain metastases in 31 patients bef...AIM To evaluate brain metastases volume control capabilities of stereotactic radiosurgery(SRS) through serial magnetic resonance(MR) imaging follow-up. METHODS MR examinations of 54 brain metastases in 31 patients before and after SRS were reviewed. Patients were included in this study if they had a pre-treatment MR examination and serial follow-up MR examinations at 6 wk, 9 wk, 12 wk, and 12 mo after SRS. The metastasis volume change was categorized at each follow-up as increased(> 20% of the initial volume), stable(± 20% of the initial volume) or decreased(< 20% of the initial volume). RESULTS A local tumor control with a significant(P < 0.05) volume decrease was observed in 25 metastases at 6-wk follow-up. Not significant volume change was observed in 23 metastases and a significant volume increase was observed in 6 metastases. At 9-wk followup, 15 out of 25 metastases that decreased in size at 6 wk had a transient tumor volume increase, followed by tumor regression at 12 wk. At 12-wk follow-up there was a significant reduction in volume in 45 metastases, and a significant volume increase in 4 metastases. At 12-mo follow-up, 19 metastases increased significantly in size(up to 41% of the initial volume). Volume tumor reduction was correlated to histopathologic subtype.CONCLUSION SRS provided an effective local brain metastases volume control that was demonstrated at follow-up MR imaging.展开更多
AIM: To assess how the application of different types of markers affects the tracking accuracy of Cyber Knife's.METHODS: Fifteen patients were recruited and subjected to the ultrasound-guided placement of markers....AIM: To assess how the application of different types of markers affects the tracking accuracy of Cyber Knife's.METHODS: Fifteen patients were recruited and subjected to the ultrasound-guided placement of markers. Two different type of needles 25 gauge(G) and 17 G containing two different fiducial marker, gold notched flexible anchor wire 0.28 mm × 10 mm(25 G needle) and gold cylindrical grain 1 mm × 4 mm(17 G), were used. Seven days after the procedure, a Cyber Knife planning computed tomography(CT) for the simulation of radiation treatment was performed on all patients.A binary CT score was assigned to the fiducial markers visualization. Also, the CT number was calculated for each fiducial and the values compared with a specific threshold.RESULTS: For each patient from 1 to 5, intra-hepatic markers were placed(one in 2 patients, three in 8 patients, four in 3 patients, and five in 2 patients). A total of 48 needles were used(thirty-two 17 G and sixteen 25 G) and 48 gold markers were placed(32 Grain shaped markers and 16 Gold Anchor). The result showed that the CT visualization of the grain markers was better than the anchor markers(P = 5 × 10^(-9)). Furthermore, the grain markers were shown to present minor late complications(P = 3 × 10^(-6)), and the best CT threshold number(P = 0.0005). CONCLUSION: The study revealed that the Gold Anchor fiducial marker is correlated with a greater number of late minor complications and low visualization by the CT.展开更多
The feasibility of a volumetric modulated arc therapy (VMAT) based coronal arc (cARC) technique for treating a single brain metastasis or lesion proximal to the brainstem or optic chiasm was evaluated. Coplanar (CP) a...The feasibility of a volumetric modulated arc therapy (VMAT) based coronal arc (cARC) technique for treating a single brain metastasis or lesion proximal to the brainstem or optic chiasm was evaluated. Coplanar (CP) and non-coplanar (NCP) treatment plans to an anthropomorphic head/neck phantom scanned head-first supine were compared to a cARC plan with the phantom rotated vertically. A set of planning target volumes (PTVs) were contoured centrally between the brainstem and optic chiasm (“Ant PTVs”) and posterior to brainstem (“Post PTVs”). Dosimetric indices such as conformity index (C.I.), gradient measure (G.M.), and dose volume histograms (DVHs) were compared for CP, NCP and cARC techniques. The TG101 guidelines for organs-at-risk (OARs), and 95% of PTV receiving at least 100% of the prescription dose (D95 = 100%) were used as plan objectives. Reductions in D50 and D30 to the brainstem of 85.1% ± 3.9% and 87.6% ± 3.2%, respectively were seen for “Post PTVs”, and 51.1% ± 17.8% and 85.6% ± 6.0% respectively for “Ant PTVs” using cARC versus CP (p ≤ 0.01). For chiasm, reductions of D50 and D30 were 61.7% ± 3.2% and 44.2% ± 8.9% for “Ant PTVs”, by 69.3% ± 8.0% and 74.3% ± 8.2% for “Post PTVs” (p ≤ 0.01). Comparing cARC to NCP led to similar dosimetric improvements. The conformity index (C.I.) was measured to be 1.101 ± 0.038, 1.088 ± 0.054, and 1.060 ± 0.040 for cARC, CP and NCP respectively (p ≤ 0.01). The overall GM in cm was 0.581 ± 0.097, 0.708 ± 0.064, and 0.476 ± 0.050 for cARC, CP and NCP respectively (p ≤ 0.01). The mean distance gradient fall-off (in cm) was 0.249 ± 0.038 (cARC), 0.749 ± 0.107 (CP), and 0.621 ± 0.068 (NCP) at the center slice in anterior-posterior direction of the target volume (p ≤ 0.01). The objective of this study is to compare the dosimetric indices of cARC with CP and NCP techniques. In conclusion, cARC can provide improved dosimetry as compared to CP and NCP for lesion proximal to the brainstem or optic chiasm.展开更多
Purpose: To develop a new statistical index “percent CTV (clinical target vo-lume) coverage probability” (%CCP), defined as the probability that a specific percent (e.g., 95%) of the CTV can be reliably covered by t...Purpose: To develop a new statistical index “percent CTV (clinical target vo-lume) coverage probability” (%CCP), defined as the probability that a specific percent (e.g., 95%) of the CTV can be reliably covered by the prescription dose, for evaluating the coverage loss of brain (fractionated) stereotactic radiosurgery (SRS/fSRS) when the PTV (planning target volume) margin is zero. Methods: The random variable Q for CTV percent coverage was derived using a previously developed model for CTV random motion that follows a three-dimensional (3D) independent normal distribution with a zero mean and a standard deviation of 𝜎<sub>𝑆</sub>(for translation) or 𝜎<sub>𝛿</sub>(for rotation). Assuming both CTV and PTV are spherical with the same diameter d<sub>CTV</sub>, the cumulative distribution function of Q could be obtained analytically using the relation of sphere-sphere intersection. The %CCP was then derived as the reliability function of Q and was used to quantify the coverage loss for selected d<sub>CTV</sub>. Results: The 95%-95% clinical goal (95% of the times, at least 95% of the CTV is covered) is not achievable with d<sub>CTV</sub> mm. For common CTVs (d<sub>CTV</sub> mm) encountered in SRS/fSRS, only 60%-90% of the CTV could be reliably covered by the prescription dose 95% of the time. For 𝜎𝑆</sub></sub>=0.5mm and 𝜎𝛿</sub></sub> =0.4˚, the 95% CCP was the highest when the distance between the CTV and the isocenter 𝑑𝐼⇔𝑇</sub><sub></sub>=0 and gradually decreased with the increasing 𝑑<sub>𝐼⇔𝑇</sub></sub>. Conclusions: The %CCP was successfully derived for evaluating the CTV coverage loss for brain SRS/fSRS. When the PTV margin is zero, the 95%-95% clinical goal cannot be achieved for most targets (d<sub>CTV</sub> mm).展开更多
Recent retrospective studies have reported the use ofstereotactic radiosurgery(SRS) in the treatment of gy-necologic cancers. SRS uses real-time imaging and highdose radiation beams attached to precise robotic armsto ...Recent retrospective studies have reported the use ofstereotactic radiosurgery(SRS) in the treatment of gy-necologic cancers. SRS uses real-time imaging and highdose radiation beams attached to precise robotic armsto target malignant lesions while sparing normal tissue.The purpose of this review is to examine the indicationsfor SRS in gynecologic oncology, review the currentliterature regarding the use of SRS in gynecologic can-cers, and identify future directions for research in thisarea. Literature on stereotactic radiosurgery was re-viewed using the PubMed search engine. Articles writ-ten in English from 1993-2013 were reviewed, and 20 case series and clinical trials were included. The safetyand efficacy SRS has been demonstrated in all gyne-cologic disease sites including cervical, endometrial,vulvar, vaginal, and ovarian cancers. Indications for itsuse include non-central pelvic recurrences in previouslyirradiated patients, complex or non-resectable diseaserecurrence, and solitary brain metastases. Toxicitiesare usually mild, though grade 3-4 toxicities have been reported. SRS is a promising second line treatment modality for patients with primary or recurrent disease who cannot undergo standard surgical or radiation therapy. Further research is required to determine optimal dosing and fractionation schedules, delineate appropriate patient populations, and assess longterm morbidity and survival.展开更多
The developments of medicine always follow innovations in science and technology.In the past decade,such innovations have made cancer-related targeted therapies possible.In general,the term "targeted therapy"...The developments of medicine always follow innovations in science and technology.In the past decade,such innovations have made cancer-related targeted therapies possible.In general,the term "targeted therapy" has been used in reference to cellular and molecular level oriented therapies.However,improvements in the delivery and planning of traditional radiation therapy have also provided cancer patients more options for "targeted" treatment,notably stereotactic radiosurgery(SRS) and stereotactic body radiotherapy(SBRT).In this review,the progress and controversies of SRS and SBRT are discussed to show the role of stereotactic radiation therapy in the ever evolving multidisciplinary care of cancer patients.展开更多
The purpose of the study was to analyze the clinical effect of stereotactic radiosurgery(SRS)(Cyberknife)on hepatocellular carcinoma with portal vein tumor thrombosis(HCC-PVTT).Data from 50 patients with HCC-PVTT who ...The purpose of the study was to analyze the clinical effect of stereotactic radiosurgery(SRS)(Cyberknife)on hepatocellular carcinoma with portal vein tumor thrombosis(HCC-PVTT).Data from 50 patients with HCC-PVTT who received Cyberknife from August 2013 to April 2016 was collected for efficacy analysis.Moreover,survival correlation was evaluated by Cox proportionalhazards model.The total effective rate in 1-3 months after treatment was 64.00%,including 7 cases in complete remission,12 cases in partial remission,13 cases in stable conditions,and 18 cases with enlargement;a 4-24-months follow-up(with an average of 11.58±2.58 months)showed that median survival,1-year cumulative survival rate,and 2-year cumulative survival rate were,respectively,11.86±1.79 months,48.00%,and 20.00%.Moreover,the Cox proportional-hazards model indicates that it was with no correlation between lesion diameter,classification of liver function,pre-operative alphafetoprotein,types of hepatitis,number of tumors,ascites,types of tumor emboli,total dose,and survival rate.SRS is effective for HCC-PVTT and serves as an ideal treatment clinically to help preserve patients’lives,which is worthy of clinical promotion and application.展开更多
As a research paradigAs a research paradigm (1) evaluated measures of animal performance correlated with markers of microglia activation and inflammation as they sought to see the effects of more focused radiation i...As a research paradigAs a research paradigm (1) evaluated measures of animal performance correlated with markers of microglia activation and inflammation as they sought to see the effects of more focused radiation in two-month-old male athymic nude rats.The authors used intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) to irradiate the hippocampus either unilaterally or bilaterally.Treatment plans delivered a total dose of 10 Gy to either one or both hemispheres of the rat brain.Their data suggests that specific behavioral tasks could be reduced by focused radiation delivered to the hippocampus,and in unilaterally treated animals,the contralateral brain seemed to up-regulate repair mechanisms.This report provides additional information relative to the mechanisms of radiobiological effect using targeted radiation.展开更多
Glioblastoma multiforme(GBM) is the most common malignant primary brain tumor with a survival prognosis of 14-16 mo for the highest functioning patients. Despite aggressive, multimodal upfront therapies, the majority ...Glioblastoma multiforme(GBM) is the most common malignant primary brain tumor with a survival prognosis of 14-16 mo for the highest functioning patients. Despite aggressive, multimodal upfront therapies, the majority of GBMs will recur in approximately six months. Salvage therapy options for recurrent GBM(r GBM) are an area of intense research. This study compares recent survival and quality of life outcomes following Gamma Knife radiosurgery(GKRS) salvage therapy. Following a Pub Med search for studies usingGKRS as salvage therapy for malignant gliomas, nine articles from 2005 to July 2013 were identified which evaluated rG BM treatment. In this review, we compare overall survival following diagnosis, overall survival following salvage treatment, progression-free survival, time to recurrence, local tumor control, and adverse radiation effects. This report discusses results for rG BM patient populations alone, not for mixed populations with other tumor histology grades. All nine studies reported median overall survival rates(from diagnosis, range:16.7-33.2 mo; from salvage, range:9-17.9 mo). Three studies identified median progression-free survival(range:4.6-14.9 mo). Two showed median time to recurrence of GBM. Two discussed local tumor control. Six studies reported adverse radiation effects(range:0%-46% of patients). The greatest survival advantages were seen in patients who received GKRS salvage along with other treatments, like resection or bevacizumab, suggesting that appropriately tailored multimodal therapy should be considered with each rG BM patient. However, there needs to be a randomized clinical trial to test GKRS for rG BM before the possibility of selection bias can be dismissed.展开更多
BACKGROUND Graft hepatocellular carcinoma(HCC)recurrence after liver transplant is more frequently encountered.Graft hepatectomy is technically challenging and is associated with high morbidity.Stereotactic body radia...BACKGROUND Graft hepatocellular carcinoma(HCC)recurrence after liver transplant is more frequently encountered.Graft hepatectomy is technically challenging and is associated with high morbidity.Stereotactic body radiation therapy(SBRT)has been shown to be safe and effective for the treatment of primary HCC.However,its role in HCC recurrence in a liver graft remains unclear.AIM To evaluate the safety and efficacy of SBRT for the treatment of graft HCC recurrence after liver transplantation.METHODS A retrospective study was conducted.From 2012 to 2018,6 patients with intrahepatic HCC recurrence after liver transplant were treated with SBRT at Queen Mary Hospital,the University of Hong Kong.The primary outcome was time to overall disease progression and secondary outcomes were time to local progression and best local response,as assessed with the Modified response Evaluation Criteria for Solid Tumours criteria.Patients were monitored for treatment related toxicities and graft dysfunction.RESULTS A total of 9 treatment courses were given for 13 tumours.The median tumour size was 2.3 cm(range 0.7-3.6 cm).Two(22%)patients had inferior vena cava tumour thrombus.The best local treatment response was:5(55%)complete response,1(11%)partial response and 3(33%)stable disease.After a median follow up duration of 15.5 mo,no local progression or mortality was yet observed.The median time to overall disease progression was 6.5 mo.There were 6 regional progression in the liver graft(67%)and 2 distant progression in the lung(22%).There was no grade 3 or above toxicity and there was no graft dysfunction after SBRT.CONCLUSION SBRT appears to be safe in this context.Regional progression is the mode of failure.展开更多
Stereotactic radiosurgery is a non-invasive procedure that utilizes precisely targeted radiation as an ablative surgical tool. Conventional radiosurgery devices, such as the Gamma Knife, rely upon skeletally attached ...Stereotactic radiosurgery is a non-invasive procedure that utilizes precisely targeted radiation as an ablative surgical tool. Conventional radiosurgery devices, such as the Gamma Knife, rely upon skeletally attached Stereotactic frames to immobilize the patient and precisely determine the 3D spatial position of a tumor. A relatively new instrument, the CyberKnife (Accuray, Inc., Sunnyvale, CA), makes it possible to administer radiosurgery without a frame. The CyberKnife localizes clinical targets using a very accurate image-to-image correlation algorithm, and precisely cross-fires high-energy radiation from a lightweight linear accelerator by means of a highly manipulable robotic arm. CyberKnife radiosurgery is an effective alternative to conventional surgery or radiation therapy for a range of tumors and some non-neoplastic disorders. This report will describe CyberKnife technology and oncologic applications in neurosurgery and throughout the body.展开更多
Brain tumors,which are among the most common solid tumors in childhood,remain a leading cause of cancer-related mortality in pediatric population.Gliomas,which may be broadly categorized as low grade glioma and high g...Brain tumors,which are among the most common solid tumors in childhood,remain a leading cause of cancer-related mortality in pediatric population.Gliomas,which may be broadly categorized as low grade glioma and high grade glioma,account for the majority of brain tumors in children.Expectant management,surgery,radiation therapy(RT),chemotherapy,targeted therapy or combinations of these modalities may be used for management of pediatric gliomas.Several patient,tumor and treatment-related characteristics including age,lesion size,grade,location,phenotypic and genotypic features,symptomatology,predicted outcomes and toxicity profile of available therapeutic options should be considered in decision making for optimal treatment.Management of pediatric gliomas poses a formidable challenge to the physicians due to concerns about treatment induced toxicity.Adverse effects of therapy may include neurological deficits,hemiparesis,dysphagia,ataxia,spasticity,endocrine sequelae,neurocognitive and communication impairment,deterioration in quality of life,adverse socioeconomic consequences,and secondary cancers.Nevertheless,improved understanding of molecular pathology and technological advancements may pave the way for progress in management of pediatric glial neoplasms.Multidisciplinary management with close collaboration of disciplines including pediatric oncology,surgery,and radiation oncology is warranted to achieve optimal therapeutic outcomes.In the context of RT,stereotactic irradiation is a viable treatment modality for several central nervous system disorders and brain tumors.Considering the importance of minimizing adverse effects of irradiation,radiosurgery has attracted great attention for clinical applications in both adults and children.Radiosurgical applications offer great potential for improving the toxicity profile of radiation delivery by focused and precise targeting of well-defined tumors under stereotactic immobilization and image guidance.Herein,we provide a concise review of stereotactic irradiation for pediatric glial neoplasms in light of the literature.展开更多
Pilocytic astrocytoma(PA)may be seen in both adults and children as a distinct histologic and biologic subset of low-grade glioma.Surgery is the principal treatment for the management of PAs;however,selected patients ...Pilocytic astrocytoma(PA)may be seen in both adults and children as a distinct histologic and biologic subset of low-grade glioma.Surgery is the principal treatment for the management of PAs;however,selected patients may benefit from irradiation particularly in the setting of inoperability,incomplete resection,or recurrent disease.While conventionally fractionated radiation therapy has been traditionally utilized for radiotherapeutic management,stereotactic irradiation strategies have been introduced more recently to improve the toxicity profile of radiation delivery without compromising tumor control.PAs may be suitable for radiosurgical management due to their typical appearance as well circumscribed lesions.Focused and precise targeting of these well-defined lesions under stereotactic immobilization and image guidance may offer great potential for achieving an improved therapeutic ratio by virtue of radiosurgical techniques.Given the high conformality along with steep dose gradients around the target volume allowing for reduced normal tissue exposure,radiosurgery may be considered a viable modality of radiotherapeutic management.Another advantage of radiosurgery may be the completion of therapy in a usually shorter overall treatment time,which may be particularly well suited for children with requirement of anesthesia during irradiation.Several studies have addressed the utility of radiosurgery particularly as an adjuvant or salvage treatment modality for PA.Nevertheless,despite the growing body of evidence supporting the use of radiosurgery,there is need for a high level of evidence to dictate treatment decisions and establish its optimal role in the management of PA.Herein,we provide a concise review of radiosurgery for PA in light of the literature.展开更多
文摘Objective The aim of the study was to compare the efficacy and safety of whole brain radiotherapy(WBRT) used alone and combined with stereotactic radiosurgery(SRS) in the treatment of limited(1–4)brain metastases. Methods We searched for randomized controlled and matched-pair analysis trials comparing WBRT plus SRS versus WBRT alone for brain metastases. The primary outcomes were the overall survival(OS), intracranial control(IC), and localcontrol(LC). The secondary outcome was radiation toxicity. The log hazard ratios(lnHRs) and their variances were extracted from published Kaplan-Meier curves and pooled using the generic inverse variance method in the RevMan 5.3 software. The non-pooled outcome measures were evaluated using descriptive analysis. Results Three randomized controlled trials and two matched-pair analysis studies were included. There was no difference in the OS for limited brain metastases between the two groups [lnHR 0.91(95% CI 0.76–1.09, P = 0.32) vs. 0.72(95% CI 0.44–1.19, P = 0.20)]. The LC and IC were significantly higher in the combined treatment group [lnHR 0.69(95% CI 0.55–0.86, P = 0.001) vs. 0.41(95% CI 0.29–0.58, P < 0.0001)]. For patients with a single lesion, one trial showed a higher survival in the combined treatment group(median OS: 6.5 months vs. 4.9 months, P = 0.04). The combined treatment was not associated with significantly higher incidence of radiation toxicity. Conclusion Combined treatment with WBRT plus SRS should be recommended for patients with limited brain metastases based on the better LC and IC without increased toxicity. It should also be considered a routine treatment option for patients with solitary brain metastases based on the prolonged OS.
文摘AIM To evaluate brain metastases volume control capabilities of stereotactic radiosurgery(SRS) through serial magnetic resonance(MR) imaging follow-up. METHODS MR examinations of 54 brain metastases in 31 patients before and after SRS were reviewed. Patients were included in this study if they had a pre-treatment MR examination and serial follow-up MR examinations at 6 wk, 9 wk, 12 wk, and 12 mo after SRS. The metastasis volume change was categorized at each follow-up as increased(> 20% of the initial volume), stable(± 20% of the initial volume) or decreased(< 20% of the initial volume). RESULTS A local tumor control with a significant(P < 0.05) volume decrease was observed in 25 metastases at 6-wk follow-up. Not significant volume change was observed in 23 metastases and a significant volume increase was observed in 6 metastases. At 9-wk followup, 15 out of 25 metastases that decreased in size at 6 wk had a transient tumor volume increase, followed by tumor regression at 12 wk. At 12-wk follow-up there was a significant reduction in volume in 45 metastases, and a significant volume increase in 4 metastases. At 12-mo follow-up, 19 metastases increased significantly in size(up to 41% of the initial volume). Volume tumor reduction was correlated to histopathologic subtype.CONCLUSION SRS provided an effective local brain metastases volume control that was demonstrated at follow-up MR imaging.
文摘AIM: To assess how the application of different types of markers affects the tracking accuracy of Cyber Knife's.METHODS: Fifteen patients were recruited and subjected to the ultrasound-guided placement of markers. Two different type of needles 25 gauge(G) and 17 G containing two different fiducial marker, gold notched flexible anchor wire 0.28 mm × 10 mm(25 G needle) and gold cylindrical grain 1 mm × 4 mm(17 G), were used. Seven days after the procedure, a Cyber Knife planning computed tomography(CT) for the simulation of radiation treatment was performed on all patients.A binary CT score was assigned to the fiducial markers visualization. Also, the CT number was calculated for each fiducial and the values compared with a specific threshold.RESULTS: For each patient from 1 to 5, intra-hepatic markers were placed(one in 2 patients, three in 8 patients, four in 3 patients, and five in 2 patients). A total of 48 needles were used(thirty-two 17 G and sixteen 25 G) and 48 gold markers were placed(32 Grain shaped markers and 16 Gold Anchor). The result showed that the CT visualization of the grain markers was better than the anchor markers(P = 5 × 10^(-9)). Furthermore, the grain markers were shown to present minor late complications(P = 3 × 10^(-6)), and the best CT threshold number(P = 0.0005). CONCLUSION: The study revealed that the Gold Anchor fiducial marker is correlated with a greater number of late minor complications and low visualization by the CT.
文摘The feasibility of a volumetric modulated arc therapy (VMAT) based coronal arc (cARC) technique for treating a single brain metastasis or lesion proximal to the brainstem or optic chiasm was evaluated. Coplanar (CP) and non-coplanar (NCP) treatment plans to an anthropomorphic head/neck phantom scanned head-first supine were compared to a cARC plan with the phantom rotated vertically. A set of planning target volumes (PTVs) were contoured centrally between the brainstem and optic chiasm (“Ant PTVs”) and posterior to brainstem (“Post PTVs”). Dosimetric indices such as conformity index (C.I.), gradient measure (G.M.), and dose volume histograms (DVHs) were compared for CP, NCP and cARC techniques. The TG101 guidelines for organs-at-risk (OARs), and 95% of PTV receiving at least 100% of the prescription dose (D95 = 100%) were used as plan objectives. Reductions in D50 and D30 to the brainstem of 85.1% ± 3.9% and 87.6% ± 3.2%, respectively were seen for “Post PTVs”, and 51.1% ± 17.8% and 85.6% ± 6.0% respectively for “Ant PTVs” using cARC versus CP (p ≤ 0.01). For chiasm, reductions of D50 and D30 were 61.7% ± 3.2% and 44.2% ± 8.9% for “Ant PTVs”, by 69.3% ± 8.0% and 74.3% ± 8.2% for “Post PTVs” (p ≤ 0.01). Comparing cARC to NCP led to similar dosimetric improvements. The conformity index (C.I.) was measured to be 1.101 ± 0.038, 1.088 ± 0.054, and 1.060 ± 0.040 for cARC, CP and NCP respectively (p ≤ 0.01). The overall GM in cm was 0.581 ± 0.097, 0.708 ± 0.064, and 0.476 ± 0.050 for cARC, CP and NCP respectively (p ≤ 0.01). The mean distance gradient fall-off (in cm) was 0.249 ± 0.038 (cARC), 0.749 ± 0.107 (CP), and 0.621 ± 0.068 (NCP) at the center slice in anterior-posterior direction of the target volume (p ≤ 0.01). The objective of this study is to compare the dosimetric indices of cARC with CP and NCP techniques. In conclusion, cARC can provide improved dosimetry as compared to CP and NCP for lesion proximal to the brainstem or optic chiasm.
文摘Purpose: To develop a new statistical index “percent CTV (clinical target vo-lume) coverage probability” (%CCP), defined as the probability that a specific percent (e.g., 95%) of the CTV can be reliably covered by the prescription dose, for evaluating the coverage loss of brain (fractionated) stereotactic radiosurgery (SRS/fSRS) when the PTV (planning target volume) margin is zero. Methods: The random variable Q for CTV percent coverage was derived using a previously developed model for CTV random motion that follows a three-dimensional (3D) independent normal distribution with a zero mean and a standard deviation of 𝜎<sub>𝑆</sub>(for translation) or 𝜎<sub>𝛿</sub>(for rotation). Assuming both CTV and PTV are spherical with the same diameter d<sub>CTV</sub>, the cumulative distribution function of Q could be obtained analytically using the relation of sphere-sphere intersection. The %CCP was then derived as the reliability function of Q and was used to quantify the coverage loss for selected d<sub>CTV</sub>. Results: The 95%-95% clinical goal (95% of the times, at least 95% of the CTV is covered) is not achievable with d<sub>CTV</sub> mm. For common CTVs (d<sub>CTV</sub> mm) encountered in SRS/fSRS, only 60%-90% of the CTV could be reliably covered by the prescription dose 95% of the time. For 𝜎𝑆</sub></sub>=0.5mm and 𝜎𝛿</sub></sub> =0.4˚, the 95% CCP was the highest when the distance between the CTV and the isocenter 𝑑𝐼⇔𝑇</sub><sub></sub>=0 and gradually decreased with the increasing 𝑑<sub>𝐼⇔𝑇</sub></sub>. Conclusions: The %CCP was successfully derived for evaluating the CTV coverage loss for brain SRS/fSRS. When the PTV margin is zero, the 95%-95% clinical goal cannot be achieved for most targets (d<sub>CTV</sub> mm).
文摘Recent retrospective studies have reported the use ofstereotactic radiosurgery(SRS) in the treatment of gy-necologic cancers. SRS uses real-time imaging and highdose radiation beams attached to precise robotic armsto target malignant lesions while sparing normal tissue.The purpose of this review is to examine the indicationsfor SRS in gynecologic oncology, review the currentliterature regarding the use of SRS in gynecologic can-cers, and identify future directions for research in thisarea. Literature on stereotactic radiosurgery was re-viewed using the PubMed search engine. Articles writ-ten in English from 1993-2013 were reviewed, and 20 case series and clinical trials were included. The safetyand efficacy SRS has been demonstrated in all gyne-cologic disease sites including cervical, endometrial,vulvar, vaginal, and ovarian cancers. Indications for itsuse include non-central pelvic recurrences in previouslyirradiated patients, complex or non-resectable diseaserecurrence, and solitary brain metastases. Toxicitiesare usually mild, though grade 3-4 toxicities have been reported. SRS is a promising second line treatment modality for patients with primary or recurrent disease who cannot undergo standard surgical or radiation therapy. Further research is required to determine optimal dosing and fractionation schedules, delineate appropriate patient populations, and assess longterm morbidity and survival.
文摘The developments of medicine always follow innovations in science and technology.In the past decade,such innovations have made cancer-related targeted therapies possible.In general,the term "targeted therapy" has been used in reference to cellular and molecular level oriented therapies.However,improvements in the delivery and planning of traditional radiation therapy have also provided cancer patients more options for "targeted" treatment,notably stereotactic radiosurgery(SRS) and stereotactic body radiotherapy(SBRT).In this review,the progress and controversies of SRS and SBRT are discussed to show the role of stereotactic radiation therapy in the ever evolving multidisciplinary care of cancer patients.
文摘The purpose of the study was to analyze the clinical effect of stereotactic radiosurgery(SRS)(Cyberknife)on hepatocellular carcinoma with portal vein tumor thrombosis(HCC-PVTT).Data from 50 patients with HCC-PVTT who received Cyberknife from August 2013 to April 2016 was collected for efficacy analysis.Moreover,survival correlation was evaluated by Cox proportionalhazards model.The total effective rate in 1-3 months after treatment was 64.00%,including 7 cases in complete remission,12 cases in partial remission,13 cases in stable conditions,and 18 cases with enlargement;a 4-24-months follow-up(with an average of 11.58±2.58 months)showed that median survival,1-year cumulative survival rate,and 2-year cumulative survival rate were,respectively,11.86±1.79 months,48.00%,and 20.00%.Moreover,the Cox proportional-hazards model indicates that it was with no correlation between lesion diameter,classification of liver function,pre-operative alphafetoprotein,types of hepatitis,number of tumors,ascites,types of tumor emboli,total dose,and survival rate.SRS is effective for HCC-PVTT and serves as an ideal treatment clinically to help preserve patients’lives,which is worthy of clinical promotion and application.
文摘As a research paradigAs a research paradigm (1) evaluated measures of animal performance correlated with markers of microglia activation and inflammation as they sought to see the effects of more focused radiation in two-month-old male athymic nude rats.The authors used intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) to irradiate the hippocampus either unilaterally or bilaterally.Treatment plans delivered a total dose of 10 Gy to either one or both hemispheres of the rat brain.Their data suggests that specific behavioral tasks could be reduced by focused radiation delivered to the hippocampus,and in unilaterally treated animals,the contralateral brain seemed to up-regulate repair mechanisms.This report provides additional information relative to the mechanisms of radiobiological effect using targeted radiation.
文摘Glioblastoma multiforme(GBM) is the most common malignant primary brain tumor with a survival prognosis of 14-16 mo for the highest functioning patients. Despite aggressive, multimodal upfront therapies, the majority of GBMs will recur in approximately six months. Salvage therapy options for recurrent GBM(r GBM) are an area of intense research. This study compares recent survival and quality of life outcomes following Gamma Knife radiosurgery(GKRS) salvage therapy. Following a Pub Med search for studies usingGKRS as salvage therapy for malignant gliomas, nine articles from 2005 to July 2013 were identified which evaluated rG BM treatment. In this review, we compare overall survival following diagnosis, overall survival following salvage treatment, progression-free survival, time to recurrence, local tumor control, and adverse radiation effects. This report discusses results for rG BM patient populations alone, not for mixed populations with other tumor histology grades. All nine studies reported median overall survival rates(from diagnosis, range:16.7-33.2 mo; from salvage, range:9-17.9 mo). Three studies identified median progression-free survival(range:4.6-14.9 mo). Two showed median time to recurrence of GBM. Two discussed local tumor control. Six studies reported adverse radiation effects(range:0%-46% of patients). The greatest survival advantages were seen in patients who received GKRS salvage along with other treatments, like resection or bevacizumab, suggesting that appropriately tailored multimodal therapy should be considered with each rG BM patient. However, there needs to be a randomized clinical trial to test GKRS for rG BM before the possibility of selection bias can be dismissed.
文摘BACKGROUND Graft hepatocellular carcinoma(HCC)recurrence after liver transplant is more frequently encountered.Graft hepatectomy is technically challenging and is associated with high morbidity.Stereotactic body radiation therapy(SBRT)has been shown to be safe and effective for the treatment of primary HCC.However,its role in HCC recurrence in a liver graft remains unclear.AIM To evaluate the safety and efficacy of SBRT for the treatment of graft HCC recurrence after liver transplantation.METHODS A retrospective study was conducted.From 2012 to 2018,6 patients with intrahepatic HCC recurrence after liver transplant were treated with SBRT at Queen Mary Hospital,the University of Hong Kong.The primary outcome was time to overall disease progression and secondary outcomes were time to local progression and best local response,as assessed with the Modified response Evaluation Criteria for Solid Tumours criteria.Patients were monitored for treatment related toxicities and graft dysfunction.RESULTS A total of 9 treatment courses were given for 13 tumours.The median tumour size was 2.3 cm(range 0.7-3.6 cm).Two(22%)patients had inferior vena cava tumour thrombus.The best local treatment response was:5(55%)complete response,1(11%)partial response and 3(33%)stable disease.After a median follow up duration of 15.5 mo,no local progression or mortality was yet observed.The median time to overall disease progression was 6.5 mo.There were 6 regional progression in the liver graft(67%)and 2 distant progression in the lung(22%).There was no grade 3 or above toxicity and there was no graft dysfunction after SBRT.CONCLUSION SBRT appears to be safe in this context.Regional progression is the mode of failure.
文摘Stereotactic radiosurgery is a non-invasive procedure that utilizes precisely targeted radiation as an ablative surgical tool. Conventional radiosurgery devices, such as the Gamma Knife, rely upon skeletally attached Stereotactic frames to immobilize the patient and precisely determine the 3D spatial position of a tumor. A relatively new instrument, the CyberKnife (Accuray, Inc., Sunnyvale, CA), makes it possible to administer radiosurgery without a frame. The CyberKnife localizes clinical targets using a very accurate image-to-image correlation algorithm, and precisely cross-fires high-energy radiation from a lightweight linear accelerator by means of a highly manipulable robotic arm. CyberKnife radiosurgery is an effective alternative to conventional surgery or radiation therapy for a range of tumors and some non-neoplastic disorders. This report will describe CyberKnife technology and oncologic applications in neurosurgery and throughout the body.
文摘Brain tumors,which are among the most common solid tumors in childhood,remain a leading cause of cancer-related mortality in pediatric population.Gliomas,which may be broadly categorized as low grade glioma and high grade glioma,account for the majority of brain tumors in children.Expectant management,surgery,radiation therapy(RT),chemotherapy,targeted therapy or combinations of these modalities may be used for management of pediatric gliomas.Several patient,tumor and treatment-related characteristics including age,lesion size,grade,location,phenotypic and genotypic features,symptomatology,predicted outcomes and toxicity profile of available therapeutic options should be considered in decision making for optimal treatment.Management of pediatric gliomas poses a formidable challenge to the physicians due to concerns about treatment induced toxicity.Adverse effects of therapy may include neurological deficits,hemiparesis,dysphagia,ataxia,spasticity,endocrine sequelae,neurocognitive and communication impairment,deterioration in quality of life,adverse socioeconomic consequences,and secondary cancers.Nevertheless,improved understanding of molecular pathology and technological advancements may pave the way for progress in management of pediatric glial neoplasms.Multidisciplinary management with close collaboration of disciplines including pediatric oncology,surgery,and radiation oncology is warranted to achieve optimal therapeutic outcomes.In the context of RT,stereotactic irradiation is a viable treatment modality for several central nervous system disorders and brain tumors.Considering the importance of minimizing adverse effects of irradiation,radiosurgery has attracted great attention for clinical applications in both adults and children.Radiosurgical applications offer great potential for improving the toxicity profile of radiation delivery by focused and precise targeting of well-defined tumors under stereotactic immobilization and image guidance.Herein,we provide a concise review of stereotactic irradiation for pediatric glial neoplasms in light of the literature.
文摘Pilocytic astrocytoma(PA)may be seen in both adults and children as a distinct histologic and biologic subset of low-grade glioma.Surgery is the principal treatment for the management of PAs;however,selected patients may benefit from irradiation particularly in the setting of inoperability,incomplete resection,or recurrent disease.While conventionally fractionated radiation therapy has been traditionally utilized for radiotherapeutic management,stereotactic irradiation strategies have been introduced more recently to improve the toxicity profile of radiation delivery without compromising tumor control.PAs may be suitable for radiosurgical management due to their typical appearance as well circumscribed lesions.Focused and precise targeting of these well-defined lesions under stereotactic immobilization and image guidance may offer great potential for achieving an improved therapeutic ratio by virtue of radiosurgical techniques.Given the high conformality along with steep dose gradients around the target volume allowing for reduced normal tissue exposure,radiosurgery may be considered a viable modality of radiotherapeutic management.Another advantage of radiosurgery may be the completion of therapy in a usually shorter overall treatment time,which may be particularly well suited for children with requirement of anesthesia during irradiation.Several studies have addressed the utility of radiosurgery particularly as an adjuvant or salvage treatment modality for PA.Nevertheless,despite the growing body of evidence supporting the use of radiosurgery,there is need for a high level of evidence to dictate treatment decisions and establish its optimal role in the management of PA.Herein,we provide a concise review of radiosurgery for PA in light of the literature.