scholarly journals Evaluation of the Impact of Magnetic Resonance Imaging (MRI) on Gross Tumor Volume (GTV) Definition for Radiation Treatment Planning (RTP) of Inoperable High Grade Gliomas (HGGs)

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Omer Sager ◽  
Ferrat Dincoglan ◽  
Selcuk Demiral ◽  
Hakan Gamsiz ◽  
Bora Uysal ◽  
...  
Keyword(s):  
Gross Tumor Volume ◽  
Tumor Volume ◽  
Radiation Treatment ◽  
Resonance Imaging ◽  
Mr Images ◽  
Radiation Treatment Planning ◽  
Target Definition ◽  
Ct Simulation ◽  
Magnetic Resonance Imaging Mri ◽  
The Impact

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. Results. Median volume of GTV acquired by using CT-simulation images only and by use of CT and MR images was 65.3 (39.6-94.3) cc and 76.1 (46.8-108.9) cc, respectively. Incorporation of MRI into GTV definition has resulted in a median increase of 12.61% (6%-19%) in the volume of GTV defined by using the CT-simulation images only, which was statistically significant (p < 0.05). Conclusion. Incorporation of MRI into RTP of inoperable HGGs may improve GTV definition and may have implications for dose escalation/intensification strategies despite the need for further supporting evidence.

NIMG-62. 68(GA)DOTATATE PET-BASED RADIATION CONTOURING CREATES SMALLER AND MORE PRECISE RADIATION VOLUMES FOR MENINGIOMA PATIENTS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi143-vi143
Author(s):  
Haley Perlow ◽  
Michael Yang ◽  
Michael Siedow ◽  
Yevgeniya Gokun ◽  
Joseph McElroy ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Pet Imaging ◽  
Gross Tumor Volume ◽  
Tumor Volume ◽  
Radiation Treatment ◽  
Progression Free Survival ◽  
Mri Imaging ◽  
Radiation Treatment Planning ◽  
Volume Delineation ◽  
The Mean

Abstract PURPOSE Radiation treatment planning for meningiomas conventionally involves MRI contrast enhanced images to define residual tumor. However, the gross tumor volume may be difficult to delineate for patients with a meningioma in the skull base, sagittal sinus, or post resection. Advanced PET imaging using 68(GA)DOTATATE PET, which has been shown to be more sensitive and specific than MRI imaging, can be used for target volume delineation in these circumstances. We hypothesize that 68(GA)DOTATATE PET scan-based treatment planning will lead to smaller radiation volumes and will detect additional areas of disease compared to standard MRI alone. METHODS Our data evaluated retrospective, deidentified, and blinded gross tumor volume (GTV) contour delineation with 7 CNS specialists (3 neuroradiologists, 4 CNS radiation oncologists) for 26 patients diagnosed with a meningioma who received both a 68(GA)DOTATATE PET and an MRI for radiation treatment planning. Both the MRI and the PET were non-sequentially contoured by each physician for each patient. RESULTS The mean MRI volume for each physician ranged from 24.14-35.52 ccs. The mean PET volume for each physician ranged from 10.59-20.54 ccs. The PET volumes were significantly smaller for 6 out of the 7 physicians. In addition, 7/26 (27%) patients had new non-adjacent areas contoured on PET by at least 6 of the 7 physicians that were not contoured by these physicians on the corresponding MRI. These new areas would not have been in the traditional MRI based volumes. CONCLUSION Our study supports that 68(GA)DOTATATE PET imaging can help radiation oncologist create smaller and more precise radiation treatment volumes. Utilization of 68(GA)DOTATATE PET may find undetected areas of disease which in turn can improve local control and progression free survival. 68(GA)DOTATATE PET guided treatment planning should be studied prospectively.

scholarly journals The Value of SSTR2 Receptor-Targeted PET/CT in Proton Irradiation of Grade I Meningioma

Cancers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 4707
Author(s):  
Maciej J. Pelak ◽  
Birgit Flechl ◽  
Marta Mumot ◽  
Razvan Galalae ◽  
Slavisa Tubin ◽  
...  
Keyword(s):  
Tumor Volume ◽  
Radiation Treatment ◽  
Residual Tumor ◽  
Target Volume ◽  
Particle Therapy ◽  
Patient Treatment ◽  
Radiation Treatment Planning ◽  
New Findings ◽  
Pet Ct ◽  
The Impact

Grade I meningioma is the most common intracranial tumor in adults. The standard imaging for its radiation treatment planning is MRI, and [68Ga]1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated PET/CT can further improve delineation. We investigated the impact of PET/CT on interobserver variability in identifying the tumor in 30 anonymized patients. Four radiation oncologists independently contoured residual tumor volume, first using only MRI and subsequently with the addition of PET/CT. Conformity indices (CIs) were calculated between common volumes, observer pairs and compared to the volumes previously used. Overall, 29/30 tumors (96.6%) showed [68Ga]Ga-DOTA avidity. With help of PET/CT, the participants identified six cases with new lesions not recognized in MRI, including two where new findings would critically alter the target volume used for radiation. The PET/CT-aided series demonstrated superior conformity, as compared to MRI-only between observer pairs (median CI = 0.58 vs. 0.49; p = 0.002), common volumes (CI = 0.34; vs. 0.29; p = 0.002) and matched better the reference volumes actually used for patient treatment (CI = 0.55 vs. 0.39; p = 0.008). Cis in the PET/CT-aided series were lower for meningiomas outside of the skull base (0.2 vs. 0.44; p = 0.03). We conclude that SSTR2 receptor-targeted PET/CT is a valuable tool for planning particle therapy of incompletely resected meningioma. It serves both as a workup procedure and an aid for delineation process that reduces the likelihood of marginal misses.

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