Evaluating the Toxicity Reduction With Computed Tomographic Ventilation Functional Avoidance Radiation Therapy

PURPOSE

Computed tomographic (CT) ventilation imaging is a new modality that uses 4-dimensional (4D) CT information to calculate lung ventilation. Although retrospective studies have reported on the reduction in dose to functional lung, no work to our knowledge has been published in which the dosimetric improvements have been translated to a reduction in the probability of pulmonary toxicity. Our work estimates the reduction in toxicity for CT ventilation-based functional avoidance planning.

METHODS AND MATERIALS

Seventy previously treated lung cancer patients who underwent 4DCT imaging were used for the study. CT ventilation maps were calculated with 4DCT deformable image registration and a density change-based algorithm. Pneumonitis was graded on the basis of imaging and clinical presentation. Maximum likelihood methods were used to generate normal tissue complication probability (NTCP) models predicting grade 2 or higher (2+) and grade 3+ pneumonitis as a function of dose (V5 Gy, V10 Gy, V20 Gy, V30 Gy, and mean dose) to functional lung. For 30 patients a functional plan was generated with the goal of reducing dose to the functional lung while meeting Radiation Therapy Oncology Group 0617 constraints. The NTCP models were applied to the functional plans and the clinically used plans to calculate toxicity reduction.

RESULTS

By the use of functional avoidance planning, absolute reductions in grade 2+ NTCP of 6.3%, 7.8%, and 4.8% were achieved based on the mean fV20 Gy, fV30 Gy, and mean dose to functional lung metrics, respectively. Absolute grade 3+ NTCP reductions of 3.6%, 4.8%, and 2.4% were achieved with fV20 Gy, fV30 Gy, and mean dose to functional lung. Maximum absolute reductions of 52.3% and 16.4% were seen for grade 2+ and grade 3+ pneumonitis for individual patients.

CONCLUSION

Our study quantifies the possible toxicity reduction from CT ventilation-based functional avoidance planning. Reductions in grades 2+ and 3+ pneumonitis were 7.1% and 4.7% based on mean dose-function metrics, with reductions as high as 52.3% for individual patients. Our work provides seminal data for determining the potential toxicity benefit from incorporating CT ventilation into thoracic treatment planning.

Preparation of SrTiO3 Thin Films by Ecr and Thermal Mocvd

SrTiO3 thin films were prepared by ECR and thermal MOCVD. In thermal-CVD mode, Sr content and Ti content were at a maximum at 0.56 Torr. Results showed that SrO deposition is a surface reaction limited process between 500 and 650°C, whereas TiO2 deposition is surface reaction limited between 500 and 600 °C, and diffusion limited above 600 °C. At a low pressure of 8 mTorr, ECR oxygen plasma was found to help decompose Ti(i-OC3H7)4. In ECR-CVD mode, the deposition temperature could be lowered to 400 °C. TEM and SEM analyses showed that SrTiO3 thin films have a columnar structure. The size of the grains depends on film thickness, and their shape on film composition (Sr/Ti ). Films prepared by thermal-CVD had a lateral step coverage of 50 %. 40 nm SrTiO3 thin films (Sr/Ti = 1.0) prepared by thermal-CVD on Pt/TaOx/Si and annealed for 2 hours in O2 had a maximum dielectric constant of 139 (Cs = 31 fF/μm2 and teq = 1.1 nm) and a leakage current density of 6x10−8 A/cm2 at 1.0 V.

Interface Structure and Dielectric Properties of SrTiO3 Thin Film Sputter-Deposited onto Si Substrates

SrTiO3 thin film preparation onto Si substrates using RF magnetron sputtering has been studied for a high capacitance density required for the next generation of LSI's. Structural and chemical analysis on the interface between SrTiO3 film and Si was carried out with cross-sectional TEM, EDX, and AES. Dielectric properties were measured on AuTi/SrTiO3/Si/Ti/Au capacitors. The as-grown dielectric films on Si were analyzed and found to consist of three layers; SiO2, amorphous SrTiO3 and crystalline SrTiO3, from interface toward film surface. By annealing at 600 °C, the amorphous SrTiO3 layer was recrystallized, and consequently the capacitance value increased. A typical specific capacitance was 4.7 fF/μm2 and the leakage current was in the order of 10−8 A/cm2, for 180 nm thick SrTiO3 film. The dielectric constant decreased from 147 to 56 with decreasing SrTiO3 film thickness from 480 nm to 80 nm. This is due to the low dielectric constant SiO2 layer (ε=3.9) at the interface. From the film thickness dependence of the ε value, the SiO2 layer thickness was calculated to be 3.9 nm, which agreed well with the value directly observed in the TEM.

To avoid SiO2 layer formation, barrier layers between SrTiO3 and Si have been studied. Among various refractory and noble metals, RuSi and a multi-layer of Pt/Ti have been found to be promising candidates for the barrier material. When RuSi film or Pt/Ti film was formed between SrTiO3 film and Si substrate, dielectric constant of about 190 was obtained in dependent of the SrTiO3 film thickness in the range of 80–250 nm. Analysis on the barrier layers was performed by means of RBS, XPS and XRD.

Over-expression of S100A2 in pancreatic cancer correlates with progression and poor prognosis

Controversy exists regarding the clinical significance of S100A2 in the progression of tumours. In pancreatic cancer, little is known about the role of S100A2. The aim of this study was to clarify the clinical significance of S100A2 expression in pancreatic carcinogenesis. We microdissected invasive ductal carcinoma (IDC) cells from 22 lesions, pancreatic intraepithelial neoplasia (PanIN) cells from five lesions, intraductal papillary mucinous neoplasm (IPMN) cells from 38 lesions, pancreatitis-affected epithelial (PAE) cells from 16 lesions, and normal ductal cells from 18 normal pancreatic tissues. S100A2 expression in 14 pancreatic cancer cell lines, microdissected cells and formalin-fixed paraffin-embedded (FFPE) samples was examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Microdissection analyses revealed that IDC cells expressed higher levels of S100A2 than did IPMN, PAE or normal cells (all comparisons, p < 0.007). Cell lines from metastatic sites expressed higher levels of S100A2 than those from primary sites. PanIN cells expressed higher levels of S100A2 than normal cells (p = 0.018). IDC cells associated with poorly differentiated adenocarcinoma expressed higher levels of S100A2 than did IDC cells without poorly differentiated adenocarcinoma (p = 0.006). Analyses of FFPE samples revealed that levels of S100A2 were higher in samples from patients who survived < 1000 days after surgery than in those from patients who survived > 1000 days (p = 0.043). Immunohistochemical analysis was consistent with qRT-PCR. S100A2 may be a marker of tumour progression or prognosis in pancreatic carcinogenesis and pancreatic cancer.

[21-year-old man with squamous cell carcinoma of the lung]

Lung cancer among people in their twenties is rare and accounts for only 0.1-0.4% of all cases. We describe a case of squamous cell carcinoma of the lung in a 21-year-old man. The otherwise healthy patient presented with a 1 month history of cough. Chest radiography showed a well-defined round mass 5 cm in size in the right lower lobe. Computed tomography also showed a 3 cm hilar lymph node. Bronchoscopy revealed a white polypoid mass obstructing the right basal bronchus. Transbronchial biopsy revealed poorly differentiated squamous cell carcinoma of the lung. Clinical diagnosis was T2N1M0, stage IIB lung cancer. Right lower lobectomy with mediastinal lymph node dissection was performed. Lymph node metastases were proven histologically in the pretracheal, subcarinal, hilar, and intrapulmonary regions. Pathological diagnosis was T2N2M0, stage IIIA lung cancer. Endobronchial and mediastinal lymph node metastases were found 2 months after surgery. He received 3 rounds of chemotherapy with cisplatin and docetaxel and irradiation to the right hilum and mediastinum at a total dose of 60 Gy in 30 fractions. He is alive 6 months after surgery.

Endovascular surgery for ruptured aneurysms with vasospasm

SUMMARY

With the existence of vasospasm, it is recommended that direct clipping surgery for a ruptured aneurysm be delayed until its disappearance, but this may be associated with aneurysmal re-rupture resulting in a poor outcome for the patients. Indications for endovascular coil embolization in such cases are discussed. Since November in 2003, we have applied endovascular coil embolization in 11 consecutive patients with ruptured aneurysms and apparent vasospasm of the parent artery from two to 17 days (average: eight days) after initial subarachnoid hemorrhage. Three patients had aneurysmal re-rupture before treatment, but the other eight had only experienced the one episode of subarachnoid hemorrhage. With one exception, all endovascular procedures could be successfully performed, resulting in complete occlusion of aneurysms and remarkable dilatation of inserted spastic vessels without technical complications or aneurysmal re-rupture. For the one case of failure because of a tortuous artery, direct clipping surgery was performed after disappearance of vasospasm. Cerebral infarction occurred in four, but only one correlated with the distribution of catheterization, and neurological deficits had completely disappeared three months after the onset. This preliminary report concerning a small number of patients suggests that endovascular coil embolization is not contra-indicated for aneurysms with vasospasm requiring catheterization. A large study for confirmation is now warranted.

Detection of small particles in fluid flow using a self-mixing laser

We describe a highly sensitive, real-time method of detecting small particles in a fluid flow by self-mixing laser Doppler measurement with a laser-diode-pumped, thin-slice solid-state laser with extremely high optical sensitivity. Asymmetric power spectra of the laser output modulated by the re-injected scattered light from the small particles moving in a dilute sample-flow, through a small-diameter glass pipe, were observed. The observed power spectra are shown to reflect the velocity distribution of the fluid flow, which obeys Poiseuille's law. Quick measurements of flow rate and kinetic viscosities of water-glycerol mixtures were also performed successfully. Measurable low-concentration limits for 262-nm polystyrene latex spheres and 3-mum red blood cells in a fluid flow were below 1 and 10 ppm, respectively, in the present self-mixing laser Doppler velocimeter system.

[Endobronchial neurinoma treated with left lower lobectomy]

Benign endobronchial tumors are rare, and among these endobronchial neurinoma is extremely rare. We describe a case of endobronchial neurinoma successfully treated with left lower lobectomy. A 58-year-old man presented with an 8-month history of cough. During this period he was repeatedly treated with antibiotics for pneumonia of the left lower lobe. Chest X-ray showed atelectasis of the left lower lobe. Computed tomography (CT) of the chest showed a mass in the left main and lower lobe bronchi. Bronchoscopy revealed the mass almost completely obstructing the left main bronchus. Although transbronchial biopsy was inconclusive and yielded necrotic tissue with Aspergillus hyphae, lung cancer was highly suspected based on clinical and radiographic findings. He underwent left lower lobectomy and was discharged 14 days after surgery in good condition. Pathological diagnosis was an endobronchial neurinoma 4 cm in size arising from the left basal bronchus. On immunohistochemical staining, the tumor was positive for S-100 protein and negative for a-smooth muscle actin. He took itraconazole at a daily dose of 200 mg orally for 6 months. He remains well 52 months after surgery without any evidence of recurrence.

[Diffuse malignant pleural mesothelioma]

Malignant pleural mesothelioma is an uncommon neoplasm that caused 647 deaths in Japan in 2004. The incidence of the disease is increasing and is estimated to reach its peak in 2025. We reviewed the clinical features in 11 consecutive patients with pathologically confirmed diffuse malignant pleural mesothelioma in our institution from January 1997 to December 2002. Of the 11 patients, 9 were male and 2 were female with a mean age of 66 (range, 55 to 90) years. Symptoms included dyspnea in 4 patients, chest pain in 3, dyspnea plus chest pain in 2, and cough in 2. Median period between symptom onset and presentation was 1 (range, 0 to 6) month. A history of asbestos exposure was identified in 3 patients and suspected in 5. A definitive diagnosis was made by closed pleural biopsy in 8 patients, pleural fluid cytology in 2, and autopsy in 1. Histological subtypes included epithelioid in 6 patients, sarcomatoid in 2, biphasic in 1, and unknown in 2. International Mesothelioma Interest Group (IMIG) staging included stage II in 6 patients, stage III in 3, and stage IV in 2. Median period between presentation and diagnosis was 1 (range, 0 to 22) month. Treatment included intrapleural chemotherapy in 4 patients, extrapleural pneumonectomy in 3, pleural drainage in 2, and best supportive care in 2. During the follow-up period, 9 patients died and 2 survived. Median survival time after diagnosis was 3 (range, 0 to 51) months. Of the 11 patients, 7 (64%) died within 6 months after the first presentation, and only 1 (9%) lived longer than 2 years after diagnosis.

Successful coil embolization for a "three-hump" internal carotid artery anterior wall aneurysm: a case report

SUMMARY

We describe an unusually shaped aneurysm arising from the anterior wall of the internal carotid artery (ICA) that was treated successfully with Guglielmi detachable coils (GDCs). A 38-year-old woman presented with sudden onset of headache and was transferred to our hospital. Computed tomography revealed thin subarachnoid hemorrhage in the basal cisterns. Three-dimensional rotational angiography clearly showed a "three-hump" anterior wall aneurysm of the ICA. The two distal humps of the aneurysm were successfully obliterated with GDCs, but the proximal hump was too small to treat by coil embolization. The patient was discharged without neurological deficit. Anterior wall (blisterlike) aneurysms of the ICA have a high risk of rupture due to fragility of the wall. These aneurysms are considered difficult to manage by traditional surgical approaches. Our experience suggests that endovascular GDC embolization is a good alternative treatment modality for patients with such an aneurysm.