Head and neck cancer patient positioning using synthetic CT data in MRI-only radiation therapy

Purpose

The accuracy and precision of patient positioning is crucial in radiotherapy; however, there are no publications available using synthetic computed tomography (sCT) that evaluate rotations in head and neck (H&N) patients positioning or the effect of translation and rotation combined. The aim of this work was to evaluate the differences between using sCT with the CT for 2D‐ and 3D‐patient positioning in a magnetic resonance imaging (MRI)‐only workflow.

Methods

This study included 14 H&N cancer patients, with generated sCT data (MRI Planner v2.2) and the CT deformably registered to the MRI. Patient positioning was evaluated by comparing sCT against CT data: 3D cone beam CT (CBCT) was registered to the deformed CT (dCT) and sCT in six degrees of freedom (DoF) with a rigid auto‐registration algorithm and bone threshold, and 2D deformed digital reconstructed radiographs (dDRR) and synthetic DRRs (sDRR) were manually registered to orthogonal projections in five DoF by six blinded observers. The difference in displacement in all DoF were calculated for dCT and sCT, as well as for dDRR and sDRR. The interobserver variation was evaluated by separate application of the paired dDRR and sDRR registration matrices to the original coordinates of the planning target volume (PTV) structures and calculation of the Euclidean distance between the corresponding points. The Dice similarity coefficient (DSC) was calculated between dDRR/sDRR‐registered PTVs.

Results

The mean difference in patient positioning using CBCT was <0.7 mm and <0.3° and using orthogonal projections <0.4 mm and <0.2° in all directions. The maximum Euclidean distance was 5.1 mm, the corresponding mean (1SD) Euclidean distance and mean DSC were 3.5 ± 0.7 mm and 0.93, respectively.

Conclusions

This study shows that the sCT‐based patient positioning gives a comparable result with that based on CT images, allowing sCT to replace CT as reference for patient treatment positioning.

Structure delineation in the presence of metal - A comparative phantom study using single and dual-energy computed tomography with and without metal artefact reduction

Background and purpose

Metal artefacts in computed tomography (CT) images impairs structure delineation. These artefacts can potentially be reduced with dual-energy CT (DECT) with or without using metal artefact reduction (MAR). The purpose was to investigate how structure delineation in DECT with or without MAR and single-energy CT (SECT) images were affected by metals.

Materials and methods

A phantom with known irregular structures was developed. Reference structures were determined from a low-noise scan without metal. Bilateral hip prostheses were simulated with steel or titanium inserts. The phantom was scanned with SECT and fast-kV switching DECT with optional MAR. Four radiation oncologists delineated the structures in two phantom set-ups. Delineated structures were evaluated with Dice similarity coefficient (DSC) and Hausdorff distance relative to the reference structures.

Results

With titanium inserts, more structures were detected for non-MAR DECT compared to SECT while the same or less were detected with steel inserts. MAR improved delineation in DECT images. For steel inserts, three structures in the region of artefacts, were delineated by at least two oncologists with MAR-DECT compared to none with non-MAR DECT or SECT. The highest values of DSC for MAR-DECT were 0.69, 0.81 and 0.77 for those structures.

Conclusions

Delineation was improved with non-MAR DECT compared to SECT, especially for titanium inserts. A larger improvement was seen with the use of MAR for both steel and titanium inserts. The improvement was dependent on the location of the structure relative to the inserts, and the structure contrast relative to the background.

Results of preoperative chemoradiotherapy for patients with advanced cancer of the nasal cavity and paranasal sinuses

OBJECTIVES

Curative treatment of nasal cavity and paranasal sinus cancer is challenging due to the proximity to critical anatomical structures. The purpose of this study was to analyze the impact of trimodality therapy with preoperative chemotherapy and reduced-dose radiotherapy followed by organ-preserving surgery for treating patients with nasal cavity and paranasal sinus cancer.

METHODS

This retrospective study included all 156 patients diagnosed with sinonasal cancer in western Sweden between 1986 and 2009. We determined the treatment selection pattern and treatment outcomes for 79 patients treated with preoperative chemoradiotherapy.

RESULTS

Squamous cell carcinoma was the most common histology. The five-year overall survival was 54%, and 85% of these patients had T3 or T4 tumors. The five-year cumulative incidence rate of local recurrence was 32%. The five-year overall survival in patients with squamous cell carcinoma and adenocarcinoma was 45% and 76%, respectively. The median preoperative radiation dose was 48 Gy. Orbital exenteration was performed in 7% of patients.

CONCLUSIONS

Preoperative chemoradiotherapy may be beneficial for patients with advanced sinonasal cancer when primary radical surgery is challenging. Survival outcomes were comparable to outcomes reported in the literature despite conservative surgery and relatively low radiation doses in patients with locally advanced tumors.

MR-OPERA: A Multicenter/Multivendor Validation of Magnetic Resonance Imaging-Only Prostate Treatment Planning Using Synthetic Computed Tomography Images

PURPOSE

To validate the dosimetric accuracy and clinical robustness of a commercially available software for magnetic resonance (MR) to synthetic computed tomography (sCT) conversion, in an MR imaging-only workflow for 170 prostate cancer patients.

METHODS AND MATERIALS

The 4 participating centers had MriPlanner (Spectronic Medical), an atlas-based sCT generation software, installed as a cloud-based service. A T2-weighted MR sequence, covering the body contour, was added to the clinical protocol. The MR images were sent from the MR scanner workstation to the MriPlanner platform. The sCT was automatically returned to the treatment planning system. Four MR scanners and 2 magnetic field strengths were included in the study. For each patient, a CT-treatment plan was created and approved according to clinical practice. The sCT was rigidly registered to the CT, and the clinical treatment plan was recalculated on the sCT. The dose distributions from the CT plan and the sCT plan were compared according to a set of dose-volume histogram parameters and gamma evaluation. Treatment techniques included volumetric modulated arc therapy, intensity modulated radiation therapy, and conventional treatment using 2 treatment planning systems and different dose calculation algorithms.

RESULTS

The overall (multicenter/multivendor) mean dose differences between sCT and CT dose distributions were below 0.3% for all evaluated organs and targets. Gamma evaluation showed a mean pass rate of 99.12% (0.63%, 1 SD) in the complete body volume and 99.97% (0.13%, 1 SD) in the planning target volume using a 2%/2-mm global gamma criteria.

CONCLUSIONS

Results of the study show that the sCT conversion method can be used clinically, with minimal differences between sCT and CT dose distributions for target and relevant organs at risk. The small differences seen are consistent between centers, indicating that an MR imaging-only workflow using MriPlanner is robust for a variety of field strengths, vendors, and treatment techniques.

Moderate superficial hypothermia prolongs bleeding time in humans

BACKGROUND

In vitro and in vivo studies have shown that mild systemic hypothermia influences platelet adhesion and aggregation and coagulation reactions. We wanted to test the hypothesis that mild local hypothermia in healthy volunteers with preserved core temperature increased bleeding time. A secondary aim was to evaluate if local cooling influenced whole blood coagulation measured by thrombelastograph (TEG) in the same setting.

METHODS

Bleeding time was measured at the left volar forearm at a baseline skin temperature of 32 degrees C and after cooling to 30 degrees C and 28 degrees C in a water bath. Skin temperature was continuously measured by contact thermistors. Measurements of coagulation by TEG were performed at baseline skin temperature before cooling and after cooling to 28 degrees C skin temperature. Tympanic membrane temperature was continuously measured.

RESULTS

Compared with baseline, bleeding time was significantly prolonged at 30 degrees C skin temperature and further prolonged at 28 degrees C skin temperature. No significant differences were measured in any of the TEG parameters. During the procedure, tympanic membrane temperature did not change.

CONCLUSION

Lowering the skin temperature from 32 degrees C to 30 degrees C and 28 degrees C with a preserved core temperature more than doubled the bleeding time. Whole blood coagulation measured by TEG was not influenced by the local cooling. In addition to core temperature, local temperature may offer information in understanding the surgical site of bleeding.

Longitudinal evaluation of patients with cancer in the oral tongue, tonsils, or base of tongue--does interstitial radiation dose affect quality of life?

PURPOSE

To evaluate health-related quality of life (HRQL) in patients with oral tongue, tonsil, or base of tongue cancer in a prospective longitudinal study and explore correlations between HRQL scores and interstitial radiation dose, dose rate, and volume of implant.

METHODS AND MATERIALS

Ninety patients with oral tongue cancer (n=30) and tonsil or base of tongue cancer (n=60) were assessed with the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire Core-30 and the European Organization of Research and Treatment of Cancer Head and Neck module at diagnosis, and after 3, 12, and 36 months of starting treatment.

RESULTS

The HRQL of all patients decreased during treatment. Most HRQL scores returned to baseline values after 3 years; however, 60% of patients with oral tongue cancer and 80% with tonsil and base of tongue cancer reported problems with dry mouth and half of the patients with tonsil and base of tongue cancer reported problems with swallowing solid food at the 3-year followup. No correlations between brachytherapy quality indices and HRQL scores were found.

CONCLUSIONS

Patients with oral tongue, tonsil, or base of tongue cancer reported significant problems with dry mouth and swallowing solid food throughout this 3-year followup study.

Nitric oxide production in the sphenoidal sinus by the inducible and constitutive isozymes of nitric oxide synthase

OBJECTIVE

To study the production of nitric oxide (NO), and the presence of different isoforms of the NO-synthesising enzyme, NO-synthase (NOS), in the paranasal sinus.

MATERIALS AND METHODS

Ten patients, undergoing surgery for pituitary adenoma, were examined for the presence of NO gas in the sphenoidal and maxillary sinus. The distribution of different NOS isozymes in mucosal biopsies from sphenoid and maxillary sinus and ethmoidal cells was studied.

RESULTS

The mean concentration of NO was 2575 ppb in the sphenoidal sinus and 6792 ppb in the maxillary sinus. Morphological analyses revealed intense NADPH-diaphorase staining throughout the epithelium. Immunoreactivity against NOS2 (inducible NOS) was observed in the apical cell layer but not of the basal layer. NOS1 (neuronal NOS)-immunoreactivity was mainly seen in the subapical part of the epithelium and NOS3 (endothelial NOS)-immunoreactivity was observed only in the most apical part of the epithelium.

CONCLUSION

NO concentration in the sphenoidal sinus is about the same as in the nasal cavity and approximately half of the concentration found in the maxillary sinus. All of the three main different isozymes of NOS can be demonstrated in the mucosa of the sphenoidal and maxillary sinus and ethmoidal cells, NOS2 being the most abundant isoform.

The effect of omalizumab on nasal allergic inflammation

BACKGROUND

In sensitized patients, coupling between IgE and FcepsilonRI receptors on mast cells leads to release of proinflammatory mediators and a subsequent influx of inflammatory cells to the affected organ. Omalizumab (Xolair; formerly rhuMAb-E25) binds to circulating IgE, thus preventing induction of the allergic process.

OBJECTIVE

We investigated the effect of treatment with omalizumab on seasonal allergic rhinitis and related changes in inflammatory cell numbers in nasal biopsy specimens.

METHODS

Patients were randomized to treatment with omalizumab or placebo before the pollen season; the treatment was started and continued during season. Symptoms and use of medication were recorded, and blood samples and nasal biopsy specimens were obtained before and during season. Immunocytochemistry was performed on biopsy sections through use of the following antibodies: anti-CD4, CD8 (T lymphocytes), EG2, and anti-eosinophil peroxidase (eosinophils), anti-tryptase (mast cells), human neutrophil lipocalin (neutrophils), and antibodies against IgE and FcepsilonRI.

RESULTS

During the season, blood eosinophils increased in placebo-treated patients but not in omalizumab-treated patients (P =.01); the difference between the treatment groups was significant (P =.04). Free IgE in serum decreased significantly (P =.0002) in omalizumab-treated patients but not in placebo-treated patients; the difference between the groups was significant (P =.0001). In nasal biopsy specimens, the number of eosinophil peroxidase-positive staining cells increased in the placebo-treated patients (P =.003) but not in the actively treated patients during the season; the difference between the groups was significant (P =.0001). The number of IgE(+) staining cells decreased significantly in the omalizumab group during the season in comparison with the placebo group (P =.04).

CONCLUSION

The clinical benefit of treatment with omalizumab is associated with an anti-inflammatory effect on cellular markers in blood and nasal tissue.

Nasopharyngeal glioma in a new-born girl

Nasal gliomas are uncommon tumours of neurogenic origin that occur sporadically. They are diagnosed with MRI and a preoperative biopsy, and surgery is the treatment of choice. Most of the gliomas emerge from the nasal cavity, but only a few cases of nasopharyngeal gliomas have been reported. We present one case of a nasopharyngeal glioma and two cases of nasal gliomas.

Juvenile nasopharyngeal angiofibroma: long-term results in preoperative embolized and non-embolized patients

A treatment and follow-up study of 32 patients with juvenile nasopharyngeal angiofibroma (JNA) was performed at our clinic between 1974 and 1998. The majority had undergone surgery either via an antral approach or with a lateral rhinotomy. In the 1970s, surgery was combined with ligature of the external carotid artery and, since 1981, it has been combined with preoperative embolization. Two patients received radiotherapy (45 Gy) as primary treatment and the 3 cases of multiple recurrence received radiotherapy (30-45 Gy) as secondary treatment. No recurrence was found in patients treated with radiotherapy. The overall recurrence rate was 25%; the recurrence rate in non-embolized patients was 8% and among embolized patients it was 41%. We found no statistically verified differences in recurrence rate between embolized and non-embolized patients. No statistically significant difference was found in either recurrence or peroperative bleeding when comparing preoperatively embolized patients with non-embolized patients. Regression analyses showed that the only factor affecting recurrence was age, i.e. the younger the patient was at diagnosis the greater the risk of developing recurrence. The development of imaging and embolization techniques will hopefully contribute in the future towards reducing the recurrence rate.

Transsphenoidal adenomectomy in Cushing's disease via a lateral rhinotomy approach

BACKGROUND

Cushing's disease may be treated by surgical pituitary adenomectomy. We present a surgical approach to the pituitary gland that increases the possibilities of a selective adenomectomy, and compare our results with those of other studies.

METHODS

A retrospective study of patients with Cushing's disease undergoing transsphenoidal selective adenomectomy via a lateral rhinotomy at Sahlgrenska University Hospital from 1984-93 is presented. Thirty-one patients (26 women, five men; mean age: 44 years, range: 13-75 years) with Cushing's disease were followed for a median time of 4.5 years after operation (range: 1-10 years). Preoperative and postoperative urinary and serum cortisol, and circadian rhythm of serum cortisol were measured. We also measured serum TSH, T4, PRL, FSH, LH, and testosterone as well as urine and plasma osmolality.

RESULTS

Our remission rate was 77% and the recurrence rate 3%. Hormonal insufficiency was rare. Hypothyroidism and hypogonadism were present in 3% of the patients, and diabetes insipidus occurred in 6% of the patients.

CONCLUSION

Selective adenomectomy with its good opportunities for cure and improvement should be regarded as the treatment of choice for Cushing's disease. Using the lateral rhinotomy approach to the sphenoidal cavity results in good accessibility to the sella turcica and its pituitary adenomas, a low frequency of postoperative pituitary insufficiency, and a high remission rate.

Regenerating human nasal mucosa cells express peptide growth factors

The goal of this study was to investigate if the distribution of peptide growth factors in the human nasal mucosa could be correlated to its maintenance and to repair processes. Biopsy specimens from clinically healthy humans, aged 6 months to 70 years, were investigated immunohistochemically. In the intact human nasal mucosa, only scattered basal epithelial cells and rare, randomly distributed cells in the lamina propria expressed peptide growth factor immunoreactivity. In contrast, in areas with deficient epithelial lining and infiltration of inflammatory cells, intense insulinlike growth factor I immunoreactivity was demonstrable in reactive epithelial cells, while adjacent, more differentiated cells were nonreactive. Vascular wall cells, fibroblasts, macrophages, and exocrine gland cells in the reactive nasal mucosa showed variable insulinlike growth factor I immunoreactivity and, at lower frequencies and intensities, immunoreactivity to insulinlike growth factor II, basic fibroblast growth factor, platelet-derived growth factor, and transforming growth factor beta, as did cells in the normally nonreactive exocrine glands. Macrophages and vascular smooth-muscle cells could in addition express platelet-derived growth factor immunoreactivity. Increased cell proliferation was recognized in reactive areas of the nasal mucosa specimens, ie, in those concomitantly showing distinct peptide growth factor immunoreactivity. We concluded that a complex pattern of peptide growth factor immunoreactivity is transiently expressed by reactive and regenerating nasal mucosal cells, contrasting with the nonreactive normal, differentiated cells. The close correlation between the appearance of peptide growth factors and the local repair and maintenance processes supports our working hypothesis that peptide growth factors are of functional importance for the nasal mucosa.

Transient expression of insulin-like growth factor I immunoreactivity by vascular cells during angiogenesis

The present study was undertaken to investigate whether vascular cells show insulin-like growth factor I (IGF-I; somatomedin C) immunoreactivity under normal conditions and/or during angiogenesis in humans and animals, as the trophic peptide IGF-I is considered important for cell growth and differentiation. In adult animals normal blood vessels, i.e., arteries, veins, and capillaries, did not show any IGF-I immunoreactivity. In newborn animals every vascular cell showed IGF-I immunoreactivity; the frequency and intensity thereafter decreased and eventually vanished as the animals approached maturity. Injury of a tissue or organ rapidly induced extensive blood vessel formation and such new blood vessels transiently expressed IGF-I immunoreactivity. Endothelial cells in budding capillaries showed distinct cytoplasmic IGF-I immunoreactivity, as did endothelial cells, smooth muscle cells, and fibroblast in newly formed arteries and veins. In biopsies of human tissue, transient IGF-I immunoreactivity was evident in vascular cells during angiogenesis after injury, as it also was in granulation tissue, skin wounds, and scar capsules around implants. Increased IGF-I immunoreactivity was further demonstrated in vascular cells in biopsies from patients with other changes involving blood vessel formation, e.g., nasal polyps, and in specimens from patients with arteritis, tendonitis, synovitis, Wegener's granulomatosis, idiopathic midline destructive disease, neurofibromatosis (von Recklinghausen's disease), and muscular dystrophy. It is concluded that during angiogenesis, obviously irrespective of inducing factors and mechanisms, vascular wall cells transiently show IGF-I immunoreactivity.

Immunohistochemical demonstration of insulin-like growth factor I in inflammatory lesions in Wegener's granulomatosis and idiopathic midline destructive disease

The immunoreactivity of the trophic peptide insulin-like growth factor I (IGF-I; somatomedin C) was mapped in nasal mucosa biopsies from three patients with Wegener's granulomatosis (WG) and one with idiopathic midline destructive disease (IMDD; idiopathic midline granuloma). Strongly increased IGF-I immuno-reactivity restricted to cells bordering and in vessel walls and in granulomas (WG) was demonstrated, while necrotic and noninflammatory areas were negative. Treatment with steroids and cyclophosphamide reduced the IGF-I immunoreactivity. The abnormally increased IGF-I immunoreactivities in WG and IMDD probably reflects the reactive growth processes in diseased tissue and is not thought to be the primary cause of either disease. IGF-I may be formed locally by cells in and close to the vascular walls in areas with active disease resulting in e.g. vascular growth, granuloma formation, and finally vessel obliteration and necrosis. IGF-I is likely to form, possibly in concert with other trophic factors, a link in the chain of events resulting in the tissue abnormalities in WG and IMDD.

Insulinlike growth factor I immunoreactivity in nasal polyps

Nasal polyps from 15 patients were all found to express increased insulinlike growth factor I immunoreactivity. A hypothesis for the formation of nasal polyps is described: macrophages, seen in allergic and infectious reactions, produce and release growth factors, tentatively including insulinlike growth factor I. In enclosed paranasal sinuses this results in an accumulation of insulinlike growth factor I stimulating the growth of both epithelium and blood vessels in the sinuses. The mucosa increasingly bulges out through the ostium after having filled out the sinusity. Continuing growth stimulation is supplied by the inflammatory reaction, endothelial cells in the polyp, and activated macrophages inside or outside the polyp.

Transiently increased insulin-like growth factor. I. Immunoreactivity in UVB-irradiated mouse skin

UVB-irradiation during 3 d for 90, 180, and 180 sec, respectively, at a daily dose of 0.1 and 0.2 joule/cm2, respectively, induced slight inflammatory reactions in the mouse ear. The insulin-like growth factor I (IGF-I) immunoreactivity, normally demonstrable only in scattered basal epidermal cells, rapidly increased in intensity and frequency in the epidermis. After 3 d of UVB irradiation almost all epidermal cells were outlined by IGF-I immunoreactivity in their plasma membrane. The Langerhans cells expressed intense IGF-I immunoreactivity throughout their cytoplasm. The elevated IGF-I immunoreactivity ceased after 5-7 d and was normalized in 3 weeks. The number of Ia positive epithelial Langerhans cells did not seem to be affected by UVB irradiation. It is concluded that the increased IGF-I immunoreactivity is likely to reflect formation of the trophic peptide IGF-I, most evidently by Langerhans cells, in early events of the inflammatory, reactive response of the skin to UVB irradiation.

Insulin-like growth factor I is a possible pathogenic mechanism in nasal polyps

High concentrations of the trophic peptide insulin-like growth factor I (IGF-I; somatomedin C; SmC) were demonstrated immunocytochemically in all nasal polyps examined, except in areas with necrosis or tissue defects. Most epithelial cells, activated macrophages, and proliferating blood vessels, proved positive, contrasting with the low degree of cellular staining in adjacent normal nasal mucosa. It is proposed that nasal mucosal inflammatory reactions induce local formation and accumulation of IGF-I, which may eventually result in very high IGF-I concentrations in the paranasal sinuses due to the tendency these have to be enclosed, i.e. producing reduced drainage. Assuming that IGF-I constitutes the pathogenic factor, appropriate treatment should be given to reduce the inflammatory reactions and improve drainage.

Somatomedin C as tentative pathogenic factor in neurofibromatosis

The distribution of somatomedin C (Sm-C; insulin-like growth factor I; IGF-I) immunoreactivity was examined in biopsies from three patients having the diagnosis neurofibromatosis established on clinical and histopathological criteria. All biopsies showed increased Sm-C immunoreactivity limited to areas with neurofibromas. Schwann cells, adjacent spindle-shaped fibroblast-like cells and newly formed blood vessels were positive. In addition, Sm-C immunoreactivity could be demonstrated in cells in the buccal epithelium. There was faint or no Sm-C immunoreactivity in biopsies from normal tissue of the patients and in specimens from control subjects. We propose that an abnormally increased local production of Sm-C, most likely by Schwann cells, forms a link in the chain of pathogenic events resulting in the disease neurofibromatosis.