18F-FDG PET/CT for Image-Guided and Intensity-Modulated Radiotherapy

e17524 Background: To report the techniques and results of a large cohort of patients treated with stereotactic body radiotherapy (SBRT) for early-stage non-small-cell lung cancer (NSCLC) using image-guided helical intensity modulated radiation therapy (IMRT) and FDG-PET assisted targeting. Methods: Between February 2005 and August 2010, 79 patients with stage 1 NSCLC were treated with SBRT. 59 patients had T1 tumors and 20 patients had T2 tumors. 62 patients had biopsy proven malignancies and 17 patients were treated empirically based on strong clinical indications. Central tumor location did not disqualify patients. All patients underwent FDG-PET or FDG-PET/CT scanning in the treatment position for planned fusion with a separate kilovoltage (KV) CT simulation. Rigid immobilization was achieved during CT simulation using a double vacuum cast device with abdominal compression. SBRT was delivered via 12 Gy x 4 or 12 Gy x 5 fractionation scheme (48-60 Gy total). Megavoltage CT images were obtained on the treatment unit prior to therapy and repeated mid-fraction with comparison to the KV CT simulation planning images to assure set-up accuracy. Serial follow-up with FDG-PET or FDG-PET/CT studies were performed at 3 months and every 6 months thereafter on all surviving patients. Results: Median patient age was 73 years. Mean tumor size was 2.3 cm (range 0.5 – 6 cm). Median follow-up was 24 months (range 4-78 months). Overall local control rate (LCR) was 94% (95% confidence interval (CI), 86-97%) based on serial FDG-PET. LCR for T1 tumors was 95% vs. 90% for T2 tumors (p = 0.60). Entire cohort overall survival rate (OSR) was 87% (CI, 78-93%) at 1 year and 58% (CI, 47-68%) at 3 years. T1 patients had a 3-year OSR of 71% vs. 43% OSR for T2 patients (p = 0.04). No patients developed life threatening radiation pneumonitis or pulmonary complications. Chest wall pain or rib fracture was reported in 8 patients (10%; CI, 5-19%). Conclusions: Image-guided SBRT with helical IMRT delivered in 4 or 5 fractions of 12 Gy with rigid immobilization and FDG-PET assisted targeting is an effective treatment for early NSCLC and is associated with excellent local control rates and acceptable treatment-related morbidity.

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Detection of additional primary malignant tumor in cancer survivors: the use of PET/CT for image-guided biopsy

Egyptian Journal of Radiology and Nuclear Medicine ◽

10.1186/s43055-020-00316-w ◽

2020 ◽

Vol 51 (1) ◽

Author(s):

Ekhlas Shaban ◽

Rasha Saleh

Keyword(s):

Malignant Tumor ◽

Fdg Pet ◽

Oncology Patients ◽

Primary Malignant Tumor ◽

Image Guided ◽

Guided Biopsy ◽

Immune Histochemistry ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

Abstract Background PET/CT is a well-established tool in the diagnostic workup of oncology patients. With the advance in diagnosis and therapy of oncology patients, survivors are at risk of developing additional malignancies. This study aimed to evaluate the yield of 18F-FDG PET/CT in biopsy guidance for the detection of unexpected additional primary malignancies in patients with known primary cancers. Medical records of patients underwent 18F-FDG PET/CT scans from July 2015 to December 2017 were reviewed, and 644 patients (346 men and 298 women; mean age 59.7, age range from 21: 78) who had been scanned for known cancers were included in this study. Lesions that were newly detected on PET/CT had not been previously detected by other modalities and were atypical in location for metastases were interpreted as suggestive of a new primary malignant tumor. These image findings guide the biopsy for histopathology, immune-histochemistry to confirm the diagnosis. Results PET-positive findings suggestive of new primary malignant tumors were found in 30 (4.67%) of 644 patients. In 21 (3.26%) of 644 patients, these lesions were pathologically proven to be malignant (20 true positive and 1 case false negative). Proven sites were lung (5 cases), colorectal (5 cases), breast (2 case), liver (2 cases), head and neck (2 cases), anal (1 cases), gastric (1 case), lymphoma (1 case), esophagus (1 case), and prostate (1 case). In 9/30 (30%) patients suspected to have additional primary, PET was falsely positive. Biopsy was taken for histology and immune-histochemistry with follow-up record that confirms the diagnosis to validate the PET/CT findings. Conclusions With the use of 18-F FDG PET/CT image- guided biopsy, additional primary malignancies were detected in at least 3.26% of oncology patients; thus, patient cure is possible if such malignancies are treated promptly and aggressively.

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