Impact of [11C]Methionine Positron Emission Tomography for Target Definition of Glioblastoma Multiforme in Radiation Therapy Planning (original) (raw)
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British Journal of Radiology, 2011
Objectives: Delineation of clinical target volume (CTV) is still controversial in glioblastomas. In order to assess the differences in volume and shape of the radiotherapy target, the use of pre-operative vs post-operative/pre-radiotherapy T 1 and T 2 weighted MRI was compared. Methods: 4 CTVs were delineated in 24 patients pre-operatively and post-operatively using T 1 contrast-enhanced (T1 PRE CTV and T1 POST CTV) and T 2 weighted images (T2 PRE CTV and T2 POST CTV). Pre-operative MRI examinations were performed the day before surgery, whereas post-operative examinations were acquired 1 month after surgery and before chemoradiation. A concordance index (CI) was defined as the ratio between the overlapping and composite volumes. Results: The volumes of T1 PRE CTV and T1 POST CTV were not statistically different (248 ¡ 88 vs 254 ¡ 101), although volume differences .100 cm 3 were observed in 6 out of 24 patients. A marked increase due to tumour progression was shown in three patients. Three patients showed a decrease because of a reduced mass effect. A significant reduction occurred between pre-operative and post-operative T 2 volumes (139 ¡ 68 vs 78 ¡ 59). Lack of concordance was observed between T1 PRE CTV and T1 POST CTV (CI50.67 ¡ 0.09), T2 PRE CTV and T2 POST CTV (CI50.39 ¡ 0.20) and comparing the portion of the T1 PRE CTV and T1 POST CTV not covered by that defined on T2 PRE CTV images (CI50.45 ¡ 0.16 and 0.44 ¡ 0.17, respectively). Conclusion: Using T 2 MRI, huge variations can be observed in peritumoural oedema, which are probably due to steroid treatment. Using T 1 MRI, brain shifts after surgery and possible progressive enhancing lesions produce substantial differences in CTVs. Our data support the use of post-operative/pre-radiotherapy T 1 weighted MRI for planning purposes.
Technology in cancer research & treatment, 2004
Radiation therapy is a central modality in the treatment of glioblastoma multiforme (GBM). Integral to adequate radiation therapy delivery is the appropriate determination of tumor volume and extent at the time treatment is being delivered. As a matter of routine practice, radiation therapy treatment fields are designed based on tumor volumes evident on pre-operative or immediate post-operative MRIs; another MRI is generally not obtained for planning boost fields. In some instances the time interval from surgery to radiotherapy initiation is up to 5 weeks and the boost or "cone-down phase" commences 4-5 weeks later. The contrast enhanced T1 MRI may not be a totally reliable indicator of active tumor, especially in regions where such blood-brain barrier breakdown has not occurred. Moreover, these volumes may change during the course of treatment. This may lead to a geographic miss when mid-treatment boost volumes are designed based on a pre-radiotherapy MRI. The goal of thi...
Radiotherapy and Oncology, 2014
To evaluate the impact of fluid-attenuated-inversion-recovery MRI (FLAIR/MRI) and Carbon-11-labeled-methionine PET (11C-MET-PET) on high grade glioma (HGG) tumor volume delineation for radiotherapy planning. Material and methods: Sixty-nine patients with HGG were evaluated. The clinical target volumes (CTV1, generated by adding a 10 mm margin to FLAIRMRI area, CTV2 by adding a 20 mm margin to enhanced T1MRI) and biological target volume (BTV) were delineated on pre-operative MRI images and 11CMETPET respectively. Results: The overlap between CTV1 and CTV2 showed a low correlation between the two volumes with CTV1 not always fully included into the CTV2. In all cases the whole BTV was included into the CTV1, while in 35/69 patients (50%) part of BTV was outside the CTV2 despite larger margins were added. In all cases recurrences were within the CTV1 volume and in 19/38 (50%) partially outside the CTV2. In all patients relapse corresponded to the BTV area. Conclusions: Our data suggest that the target volume definition using FLAIR-MRI is more adequate compared to enhanced T1MRI. 11C-METPET uptake could help identify microscopic residual areas.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2002
The use of (18)F-FDG PET for brain tumors has been shown to be accurate in identifying areas of active disease. Radiation dose escalation in the treatment of glioblastoma multiforme (GBM) may lead to improved disease control. On the basis of these premises, we initiated a pilot study to investigate the use of (18)F-FDG PET for the guidance of radiation dose escalation in the treatment of GBM. Patients were considered eligible to participate in the study if they had a diagnosis of GBM, were at least 18 y old, and had a score of at least 60 on the Karnofsky Scale. Patients were treated with standard conformal fractionated radiotherapy (1.8 Gy per fraction, to 59.4 Gy), with volumes defined by MRI. At a dose of 45-50.4 Gy, patients underwent (18)F-FDG PET for boost target delineation. Final noncoplanar fields (3-4) were designed to treat the volume of abnormal (18)F-FDG uptake plus a 0.5-cm margin for an additional 20 Gy (2 Gy per fraction), to a total dose of 79.4 Gy. If no abnormal (...
Radiotherapy and Oncology, 2005
To investigate the interobserver variability of intracranial tumour delineation on computed tomography (CT) scans using pre-operative MR hardcopies (CT+MR(conv)) or CT-MR (pre-operative) registered images (CT+MR(matched)).Five physicians outlined the ‘initial’ clinical tumour volume (CTV0) of seven patients affected by HGG and candidates for radiotherapy (RT) after radical resection. The observers performed on screen-tumour delineation using post-operative CT images of the patients in the treatment position and pre-operative MR radiographs (CT+MR(conv)); they also outlined CTV0 with both CT and corresponding MR axial image on screen (CT+MR(matched)). The accuracy of the image fusion was quantitatively assessed. An analysis was conducted to assess the variability among the five observers in CT+MR(conv) and CT+MR(matched) modality.The registration accuracy in 3D space is always less than 3.7 mm. The concordance index was significantly better in CT+MR(matched) (47.4±12.4%) than in CT+MR(conv) (14.1±12.7%) modality (P<0.02). The intersecting volumes represent 67±15 and 24±18% of the patient mean volume for CT+MR(matched) and CT+MR(conv), respectively (P<0.02).The use of CT and MR registered imaging reduces interobserver variability in target volume delineation for post-operative irradiation of HGG; smaller margins around target volume could be adopted in defining irradiation technique.
Research Square (Research Square), 2023
To investigate differences in uptake regions between methyl-11 C-L-methionine positron emission tomography ( 11 C-MET PET) and gadolinium (Gd)-enhanced MRI, and to examine the effects on dose distribution of changing the threshold value for de nition of tumor boundaries. Twenty consecutive patients with grade 3 or 4 glioma who had recurrence after postoperative RT between April 2016 and October 2017 were examined in the study. This study is simulation study assuming all patients received RT. Clinical target volume (CTV) was contoured using the Gd-enhanced region (CTV-Gd), T2-high region (CTV-T2), tumor/normal tissue (T/N) ratios of 11 C-MET PET of 1.3 and 2.0 (CTV (T/N 1.3), CTV (T/N 2.0)), and the PET-edge method (CTV(P-E)) for stereotactic radiotherapy planning for recurrent malignant glioma after radiotherapy. Differences among CTVs were evaluated and the dose distribution for the normal brain was simulated for each CTV. The Jaccard index (JI) for concordance of CTV (Gd) with CTVs using 11 C-MET PET was highest for CTV (T/N 2.0), with a value of 0.7. In a comparison of pixel values of MRI and PET, the correlation coe cient for cases with higher JI was signi cantly greater than that for lower JI cases (0.37 vs. 0.20, P = 0.007). D50% and D33% of the brain in radiotherapy planning using each CTV differed signi cantly (P = 0.03, P = 0.02) and those using CTV (T/N 1.3) were higher than with use of CTV (Gd). V90% and V95% for each CTV differed in a simulation study for actual treatment using CTV (Gd) (P = 1.0×10 - 7 , P = 3.0×10 - 9 ) and those using CTV (T/N 1.3) and CTV (P-E) were lower than with CTV (Gd). Comparing with CTV (T2), the JI showed no signi cant difference with any CTV using PET. D50% and D33% of the brain were signi cantly higher than any CTV using PET. The region of 11 C-MET accumulation is not necessarily similar to the Gd-enhanced or T2 high region. A change of the tumor boundary using 11 C-MET PET can cause signi cant changes in doses to the brain and the CTV.
Journal of Nuclear Medicine & Radiation Therapy, 2014
Background: Glioblastoma is the commonest brain tumor of adults carrying a very poor prognosis. Targeting the tumor accurately during surgery and radiotherapy holds promise in future. PET with various tracers is being explored worldwide to enhance the accuracy of target delineation. This study was undertaken to evaluate the differences and correlation between the target volumes delineated by using MRI and 18F-FDG PET during RT planning and to evaluate whether inclusion of PET is helpful in better coverage of high risk area for recurrence. Materials and Methods: Fifteen post-operative patients of glioblastoma were prospectively enrolled. Planning images were acquired with CT, MRI and delayed PET. Image fusion was done to delineate MR-based (GTV-MR, CTV-MR, PTV-MR), PET-based (GTV-PET, CTV-PET) and combined (GTV-X, CTV-X) volumes. Only MR-based volume was used for actual treatment. Mean volumes were calculated for each group for volumetric analysis. Concordance Index (CI) was calculated for GTV and CTV as CI = [(M + P)/X]-1, to find correlation between volumes, such that full concordance and full non-concordance between MRI and PET volumes would yield a value of 1 and 0 respectively. On recurrence, the recurrent volumes (rVol) were marked and correlated with initial CTV-MR, CTV-PET and CTV-X to calculate the proportion of rVol covered within these volumes. Observation and Results: Mean GTV-MR, GTV-PET and GTV-X were 84.4 cc, 11 cc and 89.2 cc, respectively. Median follow-up was 16.6 months for the overall group and 26.1 months for the surviving patients. Overall 1,2 years survival was 80% and 20% respectively. Conclusion: Inclusion of PET-based abnormality while delineating the target volumes for glioblastoma leads to a non-significant increase in target volumes with better coverage of the high-risk region. Thus, targeting the common volume (CTV-X) for treatment may prove beneficial in avoiding marginal recurrences in glioblastoma.
Concepts in Magnetic Resonance Part A
Aim and Background. Inoperable high-grade gliomas (HGGs) comprise a specific group of brain tumors portending a very poor prognosis. In the absence of surgical management, radiation therapy (RT) offers the primary local treatment modality for inoperable HGGs. Optimal target definition for radiation treatment planning (RTP) of HGGs is a difficult task given the diffusely infiltrative nature of the disease. In this context, detailed multimodality imaging information may add to the accuracy of target definition in HGGs. We evaluated the impact of Magnetic Resonance Imaging (MRI) on Gross Tumor Volume (GTV) definition for RTP of inoperable HGGs in this study. Materials and Methods. Twenty-five inoperable patients with a clinical diagnosis of HGG were included in the study. GTV definition was based on Computed Tomography- (CT-) simulation images only or both CT-simulation and MR images, and a comparative assessment was performed to investigate the incorporation of MRI into RTP of HGGs. R...
Changing Trends in Radiotherapy for Glioblastoma Multiforme and Effects on Normal Tissue Doses
Istanbul Medical Journal
Amaç: Çalışmanın amacı glioblastoma multiforme (GBM) radyoterapisindeki (RT) geçmişten günümüze değişen eğilimlerin ortaya konulması ve risk altındaki organ dozlarındaki değişimin gösterilmesidir. Yöntemler: GBM tanısı ile postopereatif temozolamid ve RT ile tedavi edilen 10 hastanın simülasyon bilgisayarlı tomografi görüntüleri retrospektif olarak incelenerek pre-ve postoperatif manyetik rezonans görüntüleri (MRG) ile rjiid füzyon yapıldı ve 9 ayrı volüm oluşturuldu. Volümler total kranyum ışınlamadan postoperatif iki fazlı ışınlamaya değişkenlik gösterirken, RT uygulaması 2-boyutlu (2B) Co-60 tedavisinden 3-boyutlu (3B) volumetrik ark tedaviye (VMAT) değişiyordu. Risk altındaki organlar (organs at risk-OAR) konturlandı. Beyin-hedef hacmi planlama (PTV) D mean , beyin sapı D max , göz D max ipsilateral/ kontralateral, kiazma D max , koklea D mean ipsilateal/kontralateral, lakrimal gland D max ipsilateral/konrtalateral, lens D max ipsilateral/ kontralateral, pituiter gland D max dozları kaydedildi. 7, 8, 9. planlar (preop MRG'den oluşturulan volümün 3B-konformal RT-3B-KRT planı ile postop MRG'den oluşturulan 3B-KRT ve VMAT planları) karşılaştırıldı. Paired sample t-testi ile istatistiksel analiz yapıldı. Bulgular: Total kranyum RT uygulandığı dönemlerde normal beyin dokusunun hepsi 45-60 Gy alırken VMAT ile beyin-PTV D mean medyan 35 Gy'e düşmüştür. Aynı zamanda göz ve lensler dışında risk altındaki organlar verilen tüm dozu alarak 60 Gy uygulanan gruplarda doz sınırlamaları aşılmıştır. Hem PTV-Radyasyon Terapisi Onkoloji Grubu (RTOG) preop hem de PTV-RTOGpostop 3D-CRT planına göre beyin-PTVinitial volüm Dmean ve beyin-PTVboost Dmean dozları dahil olmak üzere tüm OAR dozlarında iki plan arasında istatistiksel anlamlı fark yoktu. VMAT planı ile hem PTV-RTOGpreop hem de PTV RTOGpostop volümlerine göre yapılan 3D-CRT planlarından istatistiksel anlamlı daha düşük OAR dozları elde edildi. Sonuç: Tarihsel süreçte ışınlanan volüm ve normal doku dozlarında belirgin azalma olmuştur. RTOG'nin postoperatif volüm tanımına göre konformal ve VMAT planları karşılaştırıldığında VMAT planlamada daha düşük normal doku dozları elde edilmektedir. Anahtar Kelimeler: 3D konformal radyoterapi, yoğunluk ayarlı radyoterapi, glioblastoma multiforme, volümetrik ark tedavisi Introduction: The aim of the study is to reveal the changing trends in radiotherapy (RT) for glioblastoma multiforme (GBM) from past to present and to show the changes in organs at risk (OARs) doses. Methods: We re-planned 10 GBM patients who were previously irradiated. Rigid fusion was performed through pre-and postoperative magnetic resonance imaging (MRI) and simulation computed tomography, and 9 separate volumes were created. While volumes varied from whole brain RT (WBRT) to postoperative two-phase irradiation, RT application ranged from 2-dimensional Co-60 treatment to 3-dimensional volumetric modulated arc therapy (VMAT). OARs were contoured, and doses were noted. A 3 dimensional-conformal RT (3D-CRT) plan of the volume created by preoperative MRI was compared to 3D-CRT and VMAT plans generated by postoperative MRI. Statistical analysis was performed using Paired sample t-test. Results: During the time of WBRT, normal brain tissue was receiving 45-60 Gy. Through VMAT, the median brain-planning target volume (PTV) Dmean decreased to 35 Gy. According to both PTV-Radiation Therapy Oncology Group (RTOG)preop and PTV-RTOGpreop 3D-CRT plannings, there was no difference in all OARs doses between plans, including brain-PTV initial volume Dmean and brain-PTV boost Dmean doses. Significantly lower OARs doses were obtained from 3D-CRT plans based on both PTV-RTOGpreop and PTV-RTOGpostop volumes with the VMAT planning. Conclusion: With changing trends in RT for GBM, there has been a significant decrease in treatment volumes and normal tissue doses. According to the postoperative volume definition of RTOG, lower normal tissue doses are obtained from VMAT plans, compared to the conformal treatment plans.