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The Leksell GammaPlan (LGP) with an inverse planning (IP) tool has been upgraded to version 11.1 since its launch in 2010. We evaluated its IP planning performance by re-planning 16 targets that had been planned using forward planning (FP). The FP and IP plans were compared. A planning guideline for IP process was developed aiming for an unbiased comparison. Sixteen brain metastases (BMs) without nearby critical structures were included in the study (size > 1 cm for all targets). All prior FP were re-planned in the LGP using IP and maintaining the same beam-on time and coverage. The dose to all the targets was scaled to 20 Gy in a single fraction at 50% isodose line (IDL) for FP and IP comparison purpose. The coverage and beam-on time were nearly the same for both the FP and IP plans. For all the IP plans, the mean selectivity was 0.85 ± 0.04 (vs 0.83 ± 0.04 in FP plans, p = 0.02), the mean GI was 2.92 ± 0.21 (vs 3.18 ± 0.60 in FP plans, p = 0.047), the mean V12Gy was 8.18 ± 8.57 cc (vs 9.09 ± 9.08 cc in FP plans, p = 0.001), the mean V8Gy was 14.63 ± 15.14 cc (vs 16.34 ± 16.17 cc in FP plans, p = 0.001), and the mean V5Gy was 29.01 ± 28.77 cc (vs 32.77 ± 31.41 cc in FP plans, p = 0.001). The number of shots was higher in IP plans (means of 16.69 ± 8.11 vs 10.81 ± 6.87 in FP plans, p = 0.001). We retrospectively re-planned 16 FP plans using the IP tool while meeting the quality limiting factors for the FP plans. The dosimetry parameters from the IP plans outperformed the treated FP plans and the IP tool should be preferred for tumors with size > 1 cm. [ABSTRACT FROM AUTHOR]

Inconsistencies permeate the literature regarding small bowel dose tolerance limits for stereotactic body radiation therapy (SBRT) treatments. In this review, we organized these diverse published limits with MD Anderson at Cooper data into a unified framework, constructing the dose-volume histogram (DVH) Risk Map, demonstrating low-risk and high-risk SBRT dose tolerance limits for small bowel. Statistical models of clinical data from 2 institutions were used to assess the safety spectrum of doses used in the exposure of the gastrointestinal tract in SBRT; 30% of the analyzed cases had vascular endothelial growth factor inhibitors (VEGFI) or other biological agents within 2 years before or after SBRT. For every dose tolerance limit in the DVH Risk Map, the probit dose-response model was used to estimate the risk level from our clinical data. Using the current literature, 21 Gy to 5 cc of small bowel in 3 fractions has low toxicity and is reasonably safe, with 6.5% estimated risk of grade 3 or higher complications, per Common Terminology Criteria for Adverse Events version 4.0. In the same fractionation for the same volume, if lower risk is required, 16.2 Gy has an estimated risk of only 2.5%. Other volumes and fractionations are also reviewed; for all analyzed high-risk small bowel limits, the risk is 8.2% or less, and the low-risk limits have 4% or lower estimated risk. The results support current clinical practice, with some possibility for dose escalation. [ABSTRACT FROM AUTHOR]

Abstract: Current gated radiation therapy starts with simulation 4DCT images of a patient with lung cancer. We propose a method to confirm the phase of 4DCT for planning and setup position at the time of treatment. An intensity-based rigid algorithm was developed in this work to register an orthogonal set of on-board projection X-ray images with each phase of the 4DCT. Multiple DRRs for one of ten 4DCT phases are first generated and the correlation coefficient (CC) between the projection X-ray image and each DRR is computed. The maximum value of CC for the phase is found via a simulated annealing optimization process. The whole process repeats for all ten phases. The 4DCT phase that has the highest CC is identified as the breathing phase of the X-ray. The phase verification process is validated by a moving phantom study. Thus, the method may be used to independently confirm the correspondence between the gating phase at the times of 4DCT simulation and radiotherapy delivery. When the intended X-ray phase and actual gating phase are consistent, the registration of the DRRs and the projection images may also yield the values of patient shifts for treatment setup. This method could serve as the 4D analog of the conventional setup film as it provides both verification of the specific phase at the time of treatment and isocenter positioning shifts for treatment delivery. [Copyright &y& Elsevier]

Citrus leaf blotch virus (CLBV) commonly occurs in some horticultural crops including kiwifruit. Sichuan Province is one of the major kiwifruit producing areas in southwestern China. In order to investigate the occurrence of CLBV infecting kiwifruit in Sichuan Province, an efficient reverse transcription loop-mediated isothermal amplification (RT-LAMP) combined with a lateral flow dipstick (LFD) was established as an effective diagnostic method for visually detecting the occurrence of CLBV. In the present study, a set of LAMP specific primers were designed based on the conserved region of coat protein gene of CLBV and the RT-LAMP-LFD assay could be accomplished in 60 min after extraction and cDNA synthesis. The optimized RT-LAMP-LFD method showed high specificity and sensitivity to CLBV, and displayed 1000 times higher sensitivity than that of conventional RT-PCR. Furthermore, 90 kiwifruit samples collected from Sichuan Province were screened by this developed method. The results showed that the incidence of CLBV in kiwifruit was 20% in Sichuan Province. Phylogenetic analysis revealed that all the CLBV Sichuan isolates were divided into different branches in group I and has some genetic distance with other host plants like citrus, rose and sweet cherry. Over all, this study provides a time saving and highly efficient diagnostic tool for monitoring CLBV infection status in kiwifruit. • A rapid and efficient RT-LAMP-LFD method was developed for the detection of CLBV in kiwifruits. • The RT-LAMP-LFD could be completed in 60 min (50 min for RT-LAMP, 10 min for LFD) after extraction and cDNA synthesis. • The RT-LAMP-LFD method was 1000-fold more sensitive than the conventional RT-PCR. • The incidence and genetic variation of CLBV on kiwifruits in Sichuan Province were evaluated. [ABSTRACT FROM AUTHOR]

Purpose: To quantify the target and normal structures on dose distributing variations during intensity-modulated radiotherapy (IMRT) and to assess the value of replanning for nasopharyngeal carcinoma (NPC) patients. Methods and Materials: Twenty-eight NPC patients treated with IMRT were recruited. The IMRT was delivered in 33 fractions, to 70 to 76Gy, to the gross tumor volume (GTV). Before the 25th fraction of IMRT, a new simulation computed tomography (CT) scan was acquired for all patients. According to the dose constraint criterion in the Radiation Therapy Oncology Group (RTOG) 0225 protocol, the replanning was generated on the new simulation CT. With the Quality Assessment Center of a CORVUS 6.3 treatment planning system, a phantom plan was generated for each patient by applying the beam configurations of the initial plan to the anatomy of the new simulation CT. The dose–volume histograms of the phantom plan were compared with the replanning. Results: The percentage of prescription dose delivered to the clinical target volume (CTV1) was significantly increased by 4.91% ± 10.89%, whereas the maximum dose to the spinal cord, mean dose to the left parotid, and V30 to the right parotid were significantly decreased by 5.00 ± 9.23Gy, 4.23 ± 10.03Gy, and 11.47% ± 18.89% respectively in the replanning, compared with the phantom plan (p < 0.05). Based on the dose constraint criterion in the RTOG0225 protocol, 50% of phantom plans (14/28) were out of limit for the dose to the normal critical structures, whereas no plan was out of limit in replanning (p < 0.001). Conclusion: Replanning for patients with NPC before the 25th fraction during IMRT helps to ensure adequate dose to the target volumes and safe doses to critical normal structures. [Copyright &y& Elsevier]