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With volume-of-interest (VOI) cone beam computed tomography (CBCT) imaging, one set of projection images are acquired with the VOI collimator at a regular or high exposure level and the second set of projection images are acquired without the collimator at a reduced exposure level. The high exposure VOI scan data inside the VOI and the low exposure full field scan data outside the VOI are then combined together to generate composite projection images for image reconstruction. To investigate and quantify scatter reduction, dose saving, and image quality improvement in VOI CBCT imaging, a flat panel detector based bench-top experimental CBCT system was built to measure the dose, the scatter-to-primary ratio (SPR), the image contrast, noise level, the contrast-tonoise ratio (CNR), and the figure of merits (FOMs) in the CBCT reconstructed images for two polycarbonate cylinders simulating the small and the large phantoms. The results showed that, compared to the FF CBCT technique, radiation doses for the VOI CBCT technique were reduced by a factor of 1.20 and 1.36 for the small and the large phantoms at the phantom center, respectively, and from 2.7 to 3.0 on the edge of the phantom, respectively. Inside the VOI, the SPRs were substantially reduced by a factor of 6.6 and 10.3 for the small and the large phantoms, the contrast signals were improved by a factor of 1.35 and 1.8, and the noise levels were increased by a factor of 1.27 and 1.6, respectively. As the result, the CNRs were improved by a factor of 1.06 and 1.13 for the small and the large phantoms and the FOMs were improved by a factor of 1.4 and 1.7, respectively.

The role of stereotactic body radiation therapy for the elderly with advanced or medically inoperable pancreatic cancer was still debated. Therefore, we evaluated the value of stereotactic body radiation therapy and its association with survival of those patients. A total of 417 elderly patients were retrospectively reviewed from 2012 to 2015. Overall survival (OS), progression‐free survival (PFS), local recurrence‐free survival (LRFS), distant metastasis‐free survival (DMFS), and toxicities were analyzed. Prescription doses ranged from 30–46.8 Gy in 5–8 fractions. Median age was 73 years old. Median OS, PFS, LRFS, and DMFS were 10, 8, 10, and 9.5 months, respectively. One‐year OS, PFS, LRFS, and DMFS rate were 35.5%, 18.2%, 26.6%, and 27.1%, respectively. Tumor stage and tumor response at 6 months and CA19‐9 levels normalization at 3 months after treatment were independent predictors of OS, PFS, LRFS, and DMFS. Patients with early‐stage cancer, better tumor response, and normalization of CA19‐9 levels had significantly longer OS, PFS, LRFS, and DMFS. Patients with the prodrug of 5‐FU and radiotherapy had longer survival than those with gemcitabine‐based chemotherapy and radiotherapy. Patients who received BED 10 ≥ 60 Gy achieved better tumor response compared with those who received BED 10 < 60 Gy. Two patients had grade 4 intestinal strictures. No grade 3 or higher hematologic toxicities occurred. Stereotactic body radiation therapy is safe and effective for elderly patients with advanced or medically inoperable pancreatic cancer. Early efficacy could be predictive of prognosis. Higher doses may be associated with efficacy but need further investigation.

To evaluate the efficacy and safety of CyberKnife Stereotactic Body Radiation Therapy (SBRT) in the treatment of adrenal gland metastases (AGM), we designed a large-scale multicenter retrospective study to report the safety and efficacy of SBRT for inoperable AGM. In this study, 75 (61 males, 14 females) patients with 84 AGM and Karnofsky performance score ≥70 were treated by SBRT from October 2006 to January 2017. Of these, the purpose of treatment were controlling all known metastatic sites for 21 patients while 54 for palliation of bulky adrenal metastases. The efficacy and safety of SBRT were evaluated during follow-up. Potential factors predictive of local control (LC) and overall survival (OS) were identified by univariate and multivariate analysis. Median follow-up time was 12.7 months (range 1.8-96.4). The complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) rates were 23.8%, 23.8%, 31.0% and 21.4%, respectively. The 0.5, 1, and 2-year LC rates were 93.6%, 83.8%, and 62.1%, respectively; OS rates on the same follow-up intervals were 93.7%, 62.5%, and 49.6%, respectively, and the corresponding PFS rates were 48.5%, 33.9%, and 16.0%, respectively. The treatment was well tolerated with 2 patients reporting grade-3 diarrhea and fatigue, respectively. Multivariate analysis showed that simultaneous treatment of SBRT for other metastatic lesions, the number of AGM, initiation of systemic therapy, and the maximum diameter of AGM were predictive of LC rates. Moreover, patients with AGM < 5 cm had a superior OS compared with those with AGM ≥ 5 cm (28.0 months vs. 17.6 months, P = 0.032). SBRT is an effective therapeutic option for treatment of AGM with high LC rates with minimal toxicity. The adrenal gland is one of the commonest metastatic sites in primary tumors of lungs, liver, renal, colorectal, and lymphoma 1. Patients with adrenal gland metastases (AGM) have back or abdominal pain occasionally along with the growth of tumor 2. Rarely, patients with bilateral adrenal metastases may occur adrenal insufficiency which compromises quality of life (QOL) and results in worse outcomes 2. Although salvage chemotherapy and surgery are commonly used to treat AGM, limitations are inevitable. It is mandatory that pathological examinations of the primary tumor should be performed to guide decision making of chemotherapy regimens. Nevertheless, second-line chemotherapy may be less effective or may contribute to severe toxicities when the disease progresses after first-line chemotherapy has failed. Moreover, surgical resection may bring about adrenal insufficiency or other morbidities albeit it is regarded with curative intent 3. Hence, radiotherapy may be an alternative due to its potential efficacy and less risk of adverse effects compared to chemotherapy and surgery.

ObjectiveTo investigate microcirculatory differences between pathologic types of kidney tumor using 320-slice dynamic volume CT perfusion.MethodsPerfusion imaging with 320-slice dynamic volume CT was prospectively performed in 85 patients with pathologically proven clear cell renal cell carcinoma (RCC) (n = 66), papillary RCC (n = 7), chromophobe RCC (n = 5), angiomyolipoma (AML) with minimal fat (n = 7), or RCC (n = 78). Equivalent blood volume (Equiv BV), permeability surface-area product (PS; clearance/unit volume = permeability), and blood flow (BF) of tumor and normal renal cortex were measured and analyzed. Effective radiation dose was calculated.ResultsThere was a significant difference in all three parameters between tumor and normal renal cortex (P<0.001). Equiv BV was significantly different between RCC and AML with minimal fat (P = 0.038) and between clear cell RCC and AML with minimal fat (P<0.001). Mean Equiv BV and BF were significantly higher in clear cell RCC than in papillary RCC (P<0.001 for both) and mean Equiv BV was higher in clear cell RCC than in chromophobe RCC (P<0.001). The effective radiation dose of the CT perfusion protocol was 18.5 mSv.ConclusionPerfusion imaging using 320-slice dynamic volume CT can be used to evaluate hemodynamic features of the whole kidney and kidney tumors, which may be useful in the differential diagnosis of these four pathologic types of kidney tumor.

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BackgroundTo assess the efficacy and safety of stereotactic body radiation therapy (SBRT) in the management of adrenal gland metastases (AGMs) from lung cancer. Moreover, it is the first two-institutional experience and the largest-to-date study to report the safety and efficacy of SBRT for inoperable AGM from lung cancer.MethodsIn this retrospective study, 30 patients (27 males, 3 females) with 32 AGMs were treated by SBRT from October 2006 to June 2016. Of these, 11 patients were treated with the intent of controlling all known metastatic sites and 19 for palliation of bulky AGMs. Follow-up was performed every 3 months for evaluations of efficacy and safety. Factors predictive of overall survival (OS) and local control (LC) were identified with univariate and then multivariate analysis.ResultsMedian follow-up time was 10.7 months (2.9–96.4 months). The complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) rates were 23.3%, 33.3%, 33.3% and 16.7% respectively. The 6-month, 1, and 2-year LC rates were 96.9%, 96.9%, and 72.7% respectively. Additionally, the 6-month, 1, and 2-year OS rates were 85.6%, 58.1%, and 54.0% respectively while 6-month, 1, and 2-year progression free survival (PFS) rates were 39.5%, 24.6%, and 8.2%, respectively. All the patients with cancer-induced pain (8 with abdominal pain and 6 with lumbar back pain) had significant alleviations after SBRT. The treatment was well tolerated with only 1 patient reporting grade-3 diarrhoea. No predictors of OS and LC were found after multivariate analysis, while it was demonstrated that biologic equivalent dose (BED10, α/β = 10) ≥85.5Gy (P = 0.007) and gross tumor volume < 30 ml (P = 0.003) correlated with LC only after univariate analysis.ConclusionSBRT is a safe and effective treatment modality in the management of AGMs from lung cancer with high LC rates and acceptable toxicity.

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