Application of robotic stereotactic radiotherapy to peripheral stage I non-small cell lung cancer with curative intent.

AIMS: To determine the effectiveness of robotic stereotactic radiotherapy with image guidance and real-time respiratory tracking against early stage peripheral lung cancer. MATERIALS AND METHODS: We treated patients with stage I non-small cell lung cancer (NSCLC) with CyberKnife and analysed their clinical characteristics and outcomes. All patients had co-morbid conditions that precluded lobectomy. The clinical target volume (CTV) included the gross tumour volume (GTV) and a 6mm margin in all directions to account for microscopic extension. The planning target volume (PTV) equalled CTV+2mm in all directions for uncertainty. Tumour motion was tracked using a combination of Synchrony and Xsight Spine tracking methods with the aid of a single gold marker implanted in the centre of the tumour, or using the newer Xsight Lung method without markers for selected tumours. A 60-67.5 Gy dose was prescribed to the 60-80% isodose line (median 65%) and given in three to five fractions. Patients were followed every 3 months for a median of 27.5 months (range 24-53 months). RESULTS: Of the 67 patients with NSCLC stage IA or IB treated between January 2004 and December 2008, we report the results of a cohort of 31 with peripheral stage I tumours of 0.6-71 cm(3) volume treated between January 2004 and December 2007 with total doses between 60 and 67.5 Gy in three to five fractions. The median D(max) was 88.2 Gy and the median V(95) of the PTV was 99.6% or 27.9 cm(3). No grade 3 or above toxicity was encountered. Four cases of radiation pneumonitis and one case of oesophagitis were observed. In those patients whose pre- and post-treatment results were available, no change in pulmonary function tests was observed. Actuarial local control was 93.2% for 1 year and 85.8% for up to 4.5 years. One-year overall survival was 93.6% and 83.5% for up to 4.5 years, as projected by Kaplan-Meier analyses. CONCLUSIONS: In this small cohort of patients with stage I peripheral NSCLC, robotic stereotactic radiotherapy seems to be a safe and obviously superior alternative to conventionally fractionated radiotherapy, with results that may be approaching those obtained with lobectomy without the associated morbidity.

Noninvasive Raman spectroscopy in living mice for evaluation of tumor targeting with carbon nanotubes.

An optimized noninvasive Raman microscope was used to evaluate tumor targeting and localization of single walled carbon nanotubes (SWNTs) in mice. Raman images were acquired in two groups of tumor-bearing mice. The control group received plain-SWNTs, whereas the experimental group received tumor targeting RGD-SWNTs intravenously. Raman imaging commenced over the next 72 h and revealed increased accumulation of RGD-SWNTs in tumor ( p < 0.05) as opposed to plain-SWNTs. These results support the development of a new preclinical Raman imager.

Noninvasive molecular imaging of small living subjects using Raman spectroscopy.

Molecular imaging of living subjects continues to rapidly evolve with bioluminescence and fluorescence strategies, in particular being frequently used for small-animal models. This article presents noninvasive deep-tissue molecular images in a living subject with the use of Raman spectroscopy. We describe a strategy for small-animal optical imaging based on Raman spectroscopy and Raman nanoparticles. Surface-enhanced Raman scattering nanoparticles and single-wall carbon nanotubes were used to demonstrate whole-body Raman imaging, nanoparticle pharmacokinetics, multiplexing, and in vivo tumor targeting, using an imaging system adapted for small-animal Raman imaging. The imaging modality reported here holds significant potential as a strategy for biomedical imaging of living subjects.

125I eye plaque dose distribution including penumbra characteristics.

The two main purposes of this work are (1) to determine the penumbra characteristics for 125I eye plaque and the relative influence of the plaque and eye-air interface on the dose distribution, and (2) to initiate development of a treatment planning algorithm for clinical dose calculations. Dose was measured in a newly designed solid water eye phantom for an 125I (6711) seed at the center of a 20 mm COMS eye plaque using thermoluminescent dosimeter (TLD) "cubes" and "minichips" inside and outside the eye, in the longitudinal and transverse central planes. TLD cubes were used in most locations, except for short distances from the seed and in the penumbra region. In the presence of both the plaque and the eye-air interface, the dose along the central axis was found to be reduced by 10% at 1 cm and up to 20% at 2.5 cm, relative to the bulk homogeneous phantom case. In addition, the overall dose reduction was greater for larger off-axis coordinates at a given depth. The penumbra characteristics due to the lip collimation were quantified, particularly the dependence of penumbra center and width on depth. Only small differences were observed between the profiles in the transverse and longitudinal planes. In the bulk geometry (without the eye-air interface), the dose reduction due to the presence of the plaque alone was found to be 7% at a depth of 2.5 cm. The additional reduction of 13% observed, with the presence of eye-air interface (20% combined), can be attributed to the lack of backscattering from the air in front of the eye. The dose-reduction effect due to the anterior air interface alone became unnoticeable at a depth of 1.1 cm (1.5 cm from the eye-air interface). An analytic fit to measured data was developed for clinical dose calculations for a centrally loaded seed. The central axis values of the dose rates multiplied by distance squared, Dr2, were fitted with a double exponential function of depth. The off-axis profile of Dr2, at a given depth, was parametrized by a modified Fermi-Dirac function to model both the penumbra characteristics due the plaque lip collimation and the effect of oblique filtration by silastic.

High-sensitivity GafChromic film dosimetry for 125I seed.

The dose response of high-sensitivity GafChromic film to photons from 125I seeds for doses up to 200 Gy was established. The optical densities were measured using two types of densitometers: (a) a Macbeth spot densitometer with broadband light spectrum, and (b) an LKB He-Ne laser scanning microdensitometer with red light of wavelength 632.8 nm. The net optical density was found to be a power function of dose with exponents of 0.858 and 0.997, for the Macbeth and LKB densitometers, respectively. Film sensitivity with the LKB densitometer was about double of that with the Macbeth densitometer. The dose measurements were performed using the high-sensitivity GafChromic films for 125I model 6702 seed in solid water phantom. Each film was positioned parallel to the seed's long axis and centered at the seed's transverse axis. Films were exposed at various distances, ranging from contact to 3 cm from the seed center. The radiation dose delivered to the film center varied from 7 to 50 Gy, depending on the distance. The optical density at the film center was measured using both types of densitometers. Dose conversion was achieved with the established dose response curves for the respective densitometers. The dose values, along the seed's transverse axis obtained using both densitometers, were compared with each other, and also compared with published thermoluminescent dosimeter (TLD) data and Monte Carlo results. General agreement was found. It was concluded that the high-sensitivity GafChromic film measurement is a feasible method for 125I seed dosimetry in solid water phantom.(ABSTRACT TRUNCATED AT 250 WORDS)