Volumetric Image Guidance Using Carina vs Spine as Registration Landmarks for Conventionally Fractionated Lung Radiotherapy

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Lavoie, Caroline; Higgins, Jane; Bissonnette, Jean-Pierre [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, M5G 2M9 (Canada); Le, Lisa W. [Department of Biostatistics, Princess Margaret Hospital, Toronto, Ontario, M5G 2M9 (Canada); Sun, Alexander; Brade, Anthony; Hope, Andrew; Cho, John [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, M5G 2M9 (Canada); Bezjak, Andrea, E-mail: andrea.bezjak@rmp.uhn.on.ca [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, M5G 2M9 (Canada)

2012-12-01

Purpose: To compare the relative accuracy of 2 image guided radiation therapy methods using carina vs spine as landmarks and then to identify which landmark is superior relative to tumor coverage. Methods and Materials: For 98 lung patients, 2596 daily image-guidance cone-beam computed tomography scans were analyzed. Tattoos were used for initial patient alignment; then, spine and carina registrations were performed independently. A separate analysis assessed the adequacy of gross tumor volume, internal target volume, and planning target volume coverage on cone-beam computed tomography using the initial, middle, and final fractions of radiation therapy. Coverage was recorded for primary tumor (T), nodes (N), and combined target (T+N). Three scenarios were compared: tattoos alignment, spine registration, and carina registration. Results: Spine and carina registrations identified setup errors {>=}5 mm in 35% and 46% of fractions, respectively. The mean vector difference between spine and carina matching had a magnitude of 3.3 mm. Spine and carina improved combined target coverage, compared with tattoos, in 50% and 34% (spine) to 54% and 46% (carina) of the first and final fractions, respectively. Carina matching showed greater combined target coverage in 17% and 23% of fractions for the first and final fractions, respectively; with spine matching, this was only observed in 4% (first) and 6% (final) of fractions. Carina matching provided superior nodes coverage at the end of radiation compared with spine matching (P=.0006), without compromising primary tumor coverage. Conclusion: Frequent patient setup errors occur in locally advanced lung cancer patients. Spine and carina registrations improved combined target coverage throughout the treatment course, but carina matching provided superior combined target coverage.

Volumetric Image Guidance Using Carina vs Spine as Registration Landmarks for Conventionally Fractionated Lung Radiotherapy

International Nuclear Information System (INIS)

Lavoie, Caroline; Higgins, Jane; Bissonnette, Jean-Pierre; Le, Lisa W.; Sun, Alexander; Brade, Anthony; Hope, Andrew; Cho, John; Bezjak, Andrea

2012-01-01

Purpose: To compare the relative accuracy of 2 image guided radiation therapy methods using carina vs spine as landmarks and then to identify which landmark is superior relative to tumor coverage. Methods and Materials: For 98 lung patients, 2596 daily image-guidance cone-beam computed tomography scans were analyzed. Tattoos were used for initial patient alignment; then, spine and carina registrations were performed independently. A separate analysis assessed the adequacy of gross tumor volume, internal target volume, and planning target volume coverage on cone-beam computed tomography using the initial, middle, and final fractions of radiation therapy. Coverage was recorded for primary tumor (T), nodes (N), and combined target (T+N). Three scenarios were compared: tattoos alignment, spine registration, and carina registration. Results: Spine and carina registrations identified setup errors ≥5 mm in 35% and 46% of fractions, respectively. The mean vector difference between spine and carina matching had a magnitude of 3.3 mm. Spine and carina improved combined target coverage, compared with tattoos, in 50% and 34% (spine) to 54% and 46% (carina) of the first and final fractions, respectively. Carina matching showed greater combined target coverage in 17% and 23% of fractions for the first and final fractions, respectively; with spine matching, this was only observed in 4% (first) and 6% (final) of fractions. Carina matching provided superior nodes coverage at the end of radiation compared with spine matching (P=.0006), without compromising primary tumor coverage. Conclusion: Frequent patient setup errors occur in locally advanced lung cancer patients. Spine and carina registrations improved combined target coverage throughout the treatment course, but carina matching provided superior combined target coverage.

Image-guided intensity-modulated radiotherapy of prostate cancer. Analysis of interfractional errors and acute toxicity

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Rudat, Volker; Nour, A.; Hammoud, M.; Alaradi, A.; Mohammed, A. [Saad Specialist Hospital, Department of Radiation Oncology, Al Khobar (Saudi Arabia)

2016-02-15

The aim of the study was to estimate interfractional deviations in patient and prostate position, the impact of the frequency of online verification on the treatment margins, and to assess acute radiation reactions of high-dose external beam image-guided intensity-modulated radiotherapy (IG-IMRT) of localized prostate cancer. IG-IMRT was performed by daily online verification of implanted fiducial prostate markers using a megavoltage electronic portal imaging device (EPID). A total of 1011 image-guided treatment fractions from 23 consecutive unselected prostate cancer patients were analyzed. The median total dose was 79.2 Gy (range 77.4-81.0 Gy). Acute radiation reactions were assessed weekly during radiotherapy using the Common Terminology Criteria for Adverse Events (CTCAE) v.4.03. A relevant combined patient set-up and prostate motion population random error of 4-5 mm was observed. Compared to daily IGRT, image guidance every other day required an expansion of the CTV-PTV (clinical target volume-planning target volume) margin of 8.1, 6.6, and 4.1 mm in the longitudinal, vertical, and lateral directions, thereby, increasing the PTV by approximately 30-40 %. No grade 3 or 4 acute radiation reactions were observed with daily IG-IMRT. A high dose with surprisingly low acute toxicity can be applied with daily IG-IMRT using implanted fiducial prostate markers. Daily image guidance is clearly superior to image guidance every other fraction concerning adequate target coverage with minimal margins. (orig.) [German] Ziel der Studie war es, die interfraktionelle Variabilitaet der Patientenlagerung und Prostataposition, den Einfluss der Bildgebungsfrequenz und die akuten Strahlenreaktionen bei einer hochdosierten bildgesteuerten intensitaetsmodulierten Strahlentherapie (IG-IMRT) des Prostatakarzinoms zu untersuchen. IG-IMRT wurde durch taegliche Verifikation von implantierten roentgendichten Prostatamarkern mittels Megavolt-Bildgebung (''electronic portal imaging

IMRT for Image-Guided Single Vocal Cord Irradiation

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Osman, Sarah O.S., E-mail: s.osman@erasmusmc.nl [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Astreinidou, Eleftheria; Boer, Hans C.J. de; Keskin-Cambay, Fatma; Breedveld, Sebastiaan; Voet, Peter; Al-Mamgani, Abrahim; Heijmen, Ben J.M.; Levendag, Peter C. [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands)

2012-02-01

Purpose: We have been developing an image-guided single vocal cord irradiation technique to treat patients with stage T1a glottic carcinoma. In the present study, we compared the dose coverage to the affected vocal cord and the dose delivered to the organs at risk using conventional, intensity-modulated radiotherapy (IMRT) coplanar, and IMRT non-coplanar techniques. Methods and Materials: For 10 patients, conventional treatment plans using two laterally opposed wedged 6-MV photon beams were calculated in XiO (Elekta-CMS treatment planning system). An in-house IMRT/beam angle optimization algorithm was used to obtain the coplanar and non-coplanar optimized beam angles. Using these angles, the IMRT plans were generated in Monaco (IMRT treatment planning system, Elekta-CMS) with the implemented Monte Carlo dose calculation algorithm. The organs at risk included the contralateral vocal cord, arytenoids, swallowing muscles, carotid arteries, and spinal cord. The prescription dose was 66 Gy in 33 fractions. Results: For the conventional plans and coplanar and non-coplanar IMRT plans, the population-averaged mean dose {+-} standard deviation to the planning target volume was 67 {+-} 1 Gy. The contralateral vocal cord dose was reduced from 66 {+-} 1 Gy in the conventional plans to 39 {+-} 8 Gy and 36 {+-} 6 Gy in the coplanar and non-coplanar IMRT plans, respectively. IMRT consistently reduced the doses to the other organs at risk. Conclusions: Single vocal cord irradiation with IMRT resulted in good target coverage and provided significant sparing of the critical structures. This has the potential to improve the quality-of-life outcomes after RT and maintain the same local control rates.

IMRT for Image-Guided Single Vocal Cord Irradiation

International Nuclear Information System (INIS)

Osman, Sarah O.S.; Astreinidou, Eleftheria; Boer, Hans C.J. de; Keskin-Cambay, Fatma; Breedveld, Sebastiaan; Voet, Peter; Al-Mamgani, Abrahim; Heijmen, Ben J.M.; Levendag, Peter C.

2012-01-01

Purpose: We have been developing an image-guided single vocal cord irradiation technique to treat patients with stage T1a glottic carcinoma. In the present study, we compared the dose coverage to the affected vocal cord and the dose delivered to the organs at risk using conventional, intensity-modulated radiotherapy (IMRT) coplanar, and IMRT non-coplanar techniques. Methods and Materials: For 10 patients, conventional treatment plans using two laterally opposed wedged 6-MV photon beams were calculated in XiO (Elekta-CMS treatment planning system). An in-house IMRT/beam angle optimization algorithm was used to obtain the coplanar and non-coplanar optimized beam angles. Using these angles, the IMRT plans were generated in Monaco (IMRT treatment planning system, Elekta-CMS) with the implemented Monte Carlo dose calculation algorithm. The organs at risk included the contralateral vocal cord, arytenoids, swallowing muscles, carotid arteries, and spinal cord. The prescription dose was 66 Gy in 33 fractions. Results: For the conventional plans and coplanar and non-coplanar IMRT plans, the population-averaged mean dose ± standard deviation to the planning target volume was 67 ± 1 Gy. The contralateral vocal cord dose was reduced from 66 ± 1 Gy in the conventional plans to 39 ± 8 Gy and 36 ± 6 Gy in the coplanar and non-coplanar IMRT plans, respectively. IMRT consistently reduced the doses to the other organs at risk. Conclusions: Single vocal cord irradiation with IMRT resulted in good target coverage and provided significant sparing of the critical structures. This has the potential to improve the quality-of-life outcomes after RT and maintain the same local control rates.

Feasibility of magnetic resonance imaging-guided high intensity focused ultrasound therapy for ablating uterine fibroids in patients with bowel lies anterior to uterus

International Nuclear Information System (INIS)

Zhang Lian; Chen Wenzhi; Liu Yinjiang; Hu Xiao; Zhou Kun; Chen Li; Peng Song; Zhu Hui; Zou Huiling; Bai Jin; Wang Zhibiao

2010-01-01

Purpose: To prospectively evaluate the feasibility of magnetic resonance (MR) imaging-guided high intensity focused ultrasound (HIFU) therapeutic ablation of uterine fibroids in patients with bowel lies anterior to uterus. Materials and methods: Twenty-one patients with 23 uterine fibroids underwent MR imaging-guided high intensity focused ultrasound treatment, with a mean age of 39.4 ± 6.9 (20-49) years, with fibroids average measuring 6.0 ± 1.6 (range, 2.9-9.5) cm in diameter. After being compressed with a degassed water balloon on abdominal wall, MR imaging-guided high intensity focused ultrasound treatment was performed under conscious sedation by using fentanyl and midazolam. This procedure was performed by a Haifu JM focused ultrasound tumour therapeutic system (JM2.5C, Chongqing Haifu Technology Co., Ltd., China), in combination with a 1.5-Tesla MRI system (Symphony, Siemens, Germany), which provides real-time guidance and control. Contrast-enhanced MR imaging was performed to evaluate the efficacy of thermal ablation immediately and 3 months after HIFU treatment. The treatment time and adverse events were recorded. Results: The mean fibroid volume was 97.0 ± 78.3 (range, 12.7-318.3) cm 3 . According to the treatment plan, an average 75.0 ± 11.4% (range, 37.8-92.4%) of the fibroid volume was treated. The mean fibroid volume immediately after HIFU was 109.7 ± 93.1 (range, 11.9-389.6) cm 3 , slightly enlarged because of edema. The average non-perfused volume was 83.3 ± 71.7 (range, 7.7-282.9) cm 3 , the average fractional ablation, which was defined as non-perfused volume divided by the fibroid volume immediately after HIFU treatment, was 76.9 ± 18.7% (range, 21.0-97.0%). There were no statistically significant differences between the treatment volume and the non-perfused volume. Follow-up magnetic resonance imaging (MRI) at 3 months obtained in 12 patients, the fibroid volume decreased by 31.4 ± 29.3% (range, -1.9 to 60.0%) in average, with paired t

Feasibility of magnetic resonance imaging-guided high intensity focused ultrasound therapy for ablating uterine fibroids in patients with bowel lies anterior to uterus

Energy Technology Data Exchange (ETDEWEB)

Zhang Lian; Chen Wenzhi [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); Liu Yinjiang; Hu Xiao [National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Zhou Kun [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); Chen Li [National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Peng Song; Zhu Hui [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); Zou Huiling [National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Bai Jin [Institute of Ultrasound Engineering in Medicine of Chongqing University of Medical Sciences, Chongqing 400016 (China); Wang Zhibiao [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Institute of Ultrasound Engineering in Medicine of Chongqing University of Medical Sciences, Chongqing 400016 (China)], E-mail: wangzhibiao@haifu.com.cn

2010-02-15

Purpose: To prospectively evaluate the feasibility of magnetic resonance (MR) imaging-guided high intensity focused ultrasound (HIFU) therapeutic ablation of uterine fibroids in patients with bowel lies anterior to uterus. Materials and methods: Twenty-one patients with 23 uterine fibroids underwent MR imaging-guided high intensity focused ultrasound treatment, with a mean age of 39.4 {+-} 6.9 (20-49) years, with fibroids average measuring 6.0 {+-} 1.6 (range, 2.9-9.5) cm in diameter. After being compressed with a degassed water balloon on abdominal wall, MR imaging-guided high intensity focused ultrasound treatment was performed under conscious sedation by using fentanyl and midazolam. This procedure was performed by a Haifu JM focused ultrasound tumour therapeutic system (JM2.5C, Chongqing Haifu Technology Co., Ltd., China), in combination with a 1.5-Tesla MRI system (Symphony, Siemens, Germany), which provides real-time guidance and control. Contrast-enhanced MR imaging was performed to evaluate the efficacy of thermal ablation immediately and 3 months after HIFU treatment. The treatment time and adverse events were recorded. Results: The mean fibroid volume was 97.0 {+-} 78.3 (range, 12.7-318.3) cm{sup 3}. According to the treatment plan, an average 75.0 {+-} 11.4% (range, 37.8-92.4%) of the fibroid volume was treated. The mean fibroid volume immediately after HIFU was 109.7 {+-} 93.1 (range, 11.9-389.6) cm{sup 3}, slightly enlarged because of edema. The average non-perfused volume was 83.3 {+-} 71.7 (range, 7.7-282.9) cm{sup 3}, the average fractional ablation, which was defined as non-perfused volume divided by the fibroid volume immediately after HIFU treatment, was 76.9 {+-} 18.7% (range, 21.0-97.0%). There were no statistically significant differences between the treatment volume and the non-perfused volume. Follow-up magnetic resonance imaging (MRI) at 3 months obtained in 12 patients, the fibroid volume decreased by 31.4 {+-} 29.3% (range, -1.9 to 60

Magnetic resonance imaging guided reirradiation of recurrent and second primary head and neck cancer.

Science.gov (United States)

Chen, Allen M; Cao, Minsong; Hsu, Sophia; Lamb, James; Mikaeilian, Argin; Yang, Yingli; Agazaryan, Nzhde; Low, Daniel A; Steinberg, Michael L

2017-01-01

To report a single-institutional experience using magnetic resonance imaging (MRI) guided radiation therapy for the reirradiation of recurrent and second cancers of the head and neck. Between October 2014 and August 2016, 13 consecutive patients with recurrent or new primary cancers of the head and neck that occurred in a previously irradiated field were prospectively enrolled in an institutional registry trial to investigate the feasibility and efficacy of MRI guided radiation therapy using a 0.35-T MRI scanner with a cobalt-60 radiation therapy source called the ViewRay system (ViewRay Inc., Cleveland, OH). Eligibility criteria included biopsy-proven evidence of recurrent or new primary squamous cell carcinoma of the head and neck, measurable disease, and previous radiation to >60 Gy. MRI guided reirradiation was delivered either using intensity modulated radiation therapy with conventional fractionation to a median dose of 66 Gy or stereotactic body radiation therapy (SBRT) using 7 to 8 Gy fractions on nonconsecutive days to a median dose of 40 Gy. Two patients (17%) received concurrent chemotherapy. The 1- and 2-year estimates of in-field control were 72% and 72%, respectively. A total of 227 daily MRI scans were obtained to guide reirradiation. The 2-year estimates of overall survival and progression-free survival were 53% and 59%, respectively. There were no treatment-related fatalities or hospitalizations. Complications included skin desquamation, odynophagia, otitis externa, keratitis and/or conjunctivitis, and 1 case of aspiration pneumonia. Our preliminary findings show that reirradiation with MRI guided radiation therapy results in effective disease control with relatively low morbidity for patients with recurrent and second primary cancers of the head and neck. The superior soft tissue resolution of the MRI scans that were used for planning and delivery has the potential to improve the therapeutic ratio.

Method for automatic localization of MR-visible markers using morphological image processing and conventional pulse sequences: feasibility for image-guided procedures.

Science.gov (United States)

Busse, Harald; Trampel, Robert; Gründer, Wilfried; Moche, Michael; Kahn, Thomas

2007-10-01

To evaluate the feasibility and accuracy of an automated method to determine the 3D position of MR-visible markers. Inductively coupled RF coils were imaged in a whole-body 1.5T scanner using the body coil and two conventional gradient echo sequences (FLASH and TrueFISP) and large imaging volumes up to (300 mm(3)). To minimize background signals, a flip angle of approximately 1 degrees was used. Morphological 2D image processing in orthogonal scan planes was used to determine the 3D positions of a configuration of three fiducial markers (FMC). The accuracies of the marker positions and of the orientation of the plane defined by the FMC were evaluated at various distances r(M) from the isocenter. Fiducial marker detection with conventional equipment (pulse sequences, imaging coils) was very reliable and highly reproducible over a wide range of experimental conditions. For r(M) image processing is feasible, simple, and very accurate. In combination with safe wireless markers, the method is found to be useful for image-guided procedures. (c) 2007 Wiley-Liss, Inc.

Promising results with image guided intensity modulated radiotherapy for muscle invasive bladder cancer

International Nuclear Information System (INIS)

Whalley, D.; Caine, H.; McCloud, P.; Guo, L.; Kneebone, A.; Eade, T.

2015-01-01

To describe the feasibility of image guided intensity modulated radiotherapy (IG-IMRT) using daily soft tissue matching in the treatment of bladder cancer. Twenty-eight patients with muscle-invasive carcinoma of the bladder were recruited to a protocol of definitive radiation using IMRT with accelerated hypofractionation with simultaneous integrated boost (SIB). Isotropic margins of .5 and 1 cm were used to generate the high risk and intermediate risk planning target volumes respectively. Cone beam CT (CBCT) was acquired daily and a soft tissue match was performed. Cystoscopy was scheduled 6 weeks post treatment. The median age was 83 years (range 58-92). Twenty patients had stage II or III disease, and eight were stage IV. Gross disease received 66 Gy in 30 fractions in 11 patients (ten with concurrent chemotherapy) or 55 Gy in 20 fractions for those of poorer performance status or with palliative intent. All patients completed radiation treatment as planned. Three patients ceased chemotherapy early due to toxicity. Six patients (21 %) had acute Grade ≥ 2 genitourinary (GU) toxicity and six (21 %) had acute Grade ≥ 2 gastrointestinal (GI) toxicity. Five patients (18 %) developed Grade ≥2 late GU toxicity and no ≥2 late GI toxicity was observed. Nineteen patients underwent cystoscopy following radiation, with complete response (CR) in 16 cases (86 %), including all patients treated with chemoradiotherapy. Eight patients relapsed, four of which were local relapses. Of the patients with local recurrence, one underwent salvage cystectomy. For patients treated with definitive intent, freedom from locoregional recurrence (FFLR) and overall survival (OS) was 90 %/100 % for chemoradiotherapy versus 86 %/69 % for radiotherapy alone. IG- IMRT using daily soft tissue matching is a feasible in the treatment of bladder cancer, enabling the delivery of accelerated synchronous integrated boost with good early local control outcomes and low toxicity

Temporary organ displacement coupled with image-guided, intensity-modulated radiotherapy for paraspinal tumors

International Nuclear Information System (INIS)

Katsoulakis, Evangelia; Thornton, Raymond H; Yamada, Yoshiya; Solomon, Stephen B; Maybody, Majid; Housman, Douglas; Niyazov, Greg; Riaz, Nadeem; Lovelock, Michael; Spratt, Daniel E; Erinjeri, Joseph P

2013-01-01

To investigate the feasibility and dosimetric improvements of a novel technique to temporarily displace critical structures in the pelvis and abdomen from tumor during high-dose radiotherapy. Between 2010 and 2012, 11 patients received high-dose image-guided intensity-modulated radiotherapy with temporary organ displacement (TOD) at our institution. In all cases, imaging revealed tumor abutting critical structures. An all-purpose drainage catheter was introduced between the gross tumor volume (GTV) and critical organs at risk (OAR) and infused with normal saline (NS) containing 5-10% iohexol. Radiation planning was performed with the displaced OARs and positional reproducibility was confirmed with cone-beam CT (CBCT). Patients were treated within 36 hours of catheter placement. Radiation plans were re-optimized using pre-TOD OARs to the same prescription and dosimetrically compared with post-TOD plans. A two-tailed permutation test was performed on each dosimetric measure. The bowel/rectum was displaced in six patients and kidney in four patients. One patient was excluded due to poor visualization of the OAR; thus 10 patients were analyzed. A mean of 229 ml (range, 80–1000) of NS 5-10% iohexol infusion resulted in OAR mean displacement of 17.5 mm (range, 7–32). The median dose prescribed was 2400 cGy in one fraction (range, 2100–3000 in 3 fractions). The mean GTV D min and PTV D min pre- and post-bowel TOD IG-IMRT dosimetry significantly increased from 1473 cGy to 2086 cGy (p=0.015) and 714 cGy to 1214 cGy (p=0.021), respectively. TOD increased mean PTV D95 by 27.14% of prescription (p=0.014) while the PTV D05 decreased by 9.2% (p=0.011). TOD of the bowel resulted in a 39% decrease in mean bowel D max (p=0.008) confirmed by CBCT. TOD of the kidney significantly decreased mean kidney dose and D max by 25% (0.022). TOD was well tolerated, reproducible, and facilitated dose escalation to previously radioresistant tumors abutting critical structures while

Outcomes and Toxicity for Hypofractionated and Single-Fraction Image-Guided Stereotactic Radiosurgery for Sarcomas Metastasizing to the Spine

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Folkert, Michael R. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Bilsky, Mark H. [Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Tom, Ashlyn K. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Oh, Jung Hun [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Alektiar, Kaled M. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Laufer, Ilya [Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Tap, William D. [Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Yamada, Yoshiya, E-mail: yamadaj@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

2014-04-01

Purpose: Conventional radiation treatment (20-40 Gy in 5-20 fractions, 2-5 Gy per fraction) for sarcoma metastatic to the spine provides subtherapeutic doses, resulting in poor durable local control (LC) (50%-77% at 1 year). Hypofractionated (HF) and/or single-fraction (SF) image-guided stereotactic radiosurgery (IG-SRS) may provide a more effective means of managing these lesions. Methods and Materials: Patients with pathologically proven high-grade sarcoma metastatic to the spine treated with HF and SF IG-SRS were included. LC and overall survival (OS) were analyzed by the use of Kaplan-Meier statistics. Univariate and multivariate analyses were performed by the use of Cox regression with competing-risks analysis; all confidence intervals are 95%. Toxicities were assessed according to Common Terminology Criteria for Adverse Events, version 4.0. Results: From May 2005 to November 11, 2012, 88 patients with 120 discrete metastases received HF (3-6 fractions; median dose, 28.5 Gy; n=52, 43.3%) or SF IG-SRS (median dose, 24 Gy; n=68, 56.7%). The median follow-up time was 12.3 months. At 12 months, LC was 87.9% (confidence interval [CI], 81.3%-94.5%), OS was 60.6% (CI, 49.6%-71.6%), and median survival was 16.9 months. SF IG-SRS demonstrated superior LC to HF IG-SRS (12-month LC of 90.8% [CI, 83%-98.6%] vs 84.1% [CI, 72.9%-95.3%] P=.007) and retained significance on multivariate analysis (P=.030, hazard ratio 0.345; CI, 0.132-0.901]. Treatment was well tolerated, with 1% acute grade 3 toxicity, 4.5% chronic grade 3 toxicity, and no grade >3 toxicities. Conclusions: In the largest series of metastatic sarcoma to the spine to date, IG-SRS provides excellent LC in the setting of an aggressive disease with low radiation sensitivity and poor prognosis. Single-fraction IG-SRS is associated with the highest rates of LC with minimal toxicity.

SU-E-J-258: Inter- and Intra-Fraction Setup Stability and Couch Change Tolerance for Image Guided Radiation Therapy

International Nuclear Information System (INIS)

Teboh, Forbang R; Agee, M; Rowe, L; Creasy, T; Schultz, J; Bell, R; Wong, J; Armour, E

2014-01-01

Purpose: Immobilization devices combine rigid patient fixation as well as comfort and play a key role providing the stability required for accurate radiation delivery. In the setup step, couch re-positioning needed to align the patient is derived via registration of acquired versus reference image. For subsequent fractions, replicating the initial setup should yield identical alignment errors when compared to the reference. This is not always the case and further couch re-positioning can be needed. An important quality assurance measure is to set couch tolerances beyond which additional investigations are needed. The purpose of this work was to study the inter-fraction couch changes needed to re-align the patient and the intra-fraction stability of the alignment as a guide to establish the couch tolerances. Methods: Data from twelve patients treated on the Accuray CyberKnife (CK) system for fractionated intracranial radiotherapy and immobilized with Aquaplast RT, U-frame, F-Head-Support (Qfix, PA, USA) was used. Each fraction involved image acquisitions and registration with the reference to re-align the patient. The absolute couch position corresponding to the approved setup alignment was recorded per fraction. Intra-fraction set-up corrections were recorded throughout the treatment. Results: The average approved setup alignment was 0.03±0.28mm, 0.15±0.22mm, 0.06±0.31mm in the L/R, A/P, S/I directions respectively and 0.00±0.35degrees, 0.03±0.32degrees, 0.08±0.45degrees for roll, pitch and yaw respectively. The inter-fraction reproducibility of the couch position was 6.65mm, 10.55mm, and 4.77mm in the L/R, A/P and S/I directions respectively and 0.82degrees, 0.71degrees for roll and pitch respectively. Intra-fraction monitoring showed small average errors of 0.21±0.21mm, 0.00±0.08mm, 0.23±0.22mm in the L/R, A/P, S/I directions respectively and 0.03±0.12degrees, 0.04±0.25degrees, and 0.13±0.15degrees in the roll, pitch and yaw respectively. Conclusion

SU-E-J-258: Inter- and Intra-Fraction Setup Stability and Couch Change Tolerance for Image Guided Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Teboh, Forbang R; Agee, M; Rowe, L; Creasy, T; Schultz, J; Bell, R; Wong, J; Armour, E [Johns Hopkins University, Baltimore, MD (United States)

2014-06-01

Purpose: Immobilization devices combine rigid patient fixation as well as comfort and play a key role providing the stability required for accurate radiation delivery. In the setup step, couch re-positioning needed to align the patient is derived via registration of acquired versus reference image. For subsequent fractions, replicating the initial setup should yield identical alignment errors when compared to the reference. This is not always the case and further couch re-positioning can be needed. An important quality assurance measure is to set couch tolerances beyond which additional investigations are needed. The purpose of this work was to study the inter-fraction couch changes needed to re-align the patient and the intra-fraction stability of the alignment as a guide to establish the couch tolerances. Methods: Data from twelve patients treated on the Accuray CyberKnife (CK) system for fractionated intracranial radiotherapy and immobilized with Aquaplast RT, U-frame, F-Head-Support (Qfix, PA, USA) was used. Each fraction involved image acquisitions and registration with the reference to re-align the patient. The absolute couch position corresponding to the approved setup alignment was recorded per fraction. Intra-fraction set-up corrections were recorded throughout the treatment. Results: The average approved setup alignment was 0.03±0.28mm, 0.15±0.22mm, 0.06±0.31mm in the L/R, A/P, S/I directions respectively and 0.00±0.35degrees, 0.03±0.32degrees, 0.08±0.45degrees for roll, pitch and yaw respectively. The inter-fraction reproducibility of the couch position was 6.65mm, 10.55mm, and 4.77mm in the L/R, A/P and S/I directions respectively and 0.82degrees, 0.71degrees for roll and pitch respectively. Intra-fraction monitoring showed small average errors of 0.21±0.21mm, 0.00±0.08mm, 0.23±0.22mm in the L/R, A/P, S/I directions respectively and 0.03±0.12degrees, 0.04±0.25degrees, and 0.13±0.15degrees in the roll, pitch and yaw respectively. Conclusion

Introducing an on-line adaptive procedure for prostate image guided intensity modulate proton therapy.

Science.gov (United States)

Zhang, M; Westerly, D C; Mackie, T R

2011-08-07

With on-line image guidance (IG), prostate shifts relative to the bony anatomy can be corrected by realigning the patient with respect to the treatment fields. In image guided intensity modulated proton therapy (IG-IMPT), because the proton range is more sensitive to the material it travels through, the realignment may introduce large dose variations. This effect is studied in this work and an on-line adaptive procedure is proposed to restore the planned dose to the target. A 2D anthropomorphic phantom was constructed from a real prostate patient's CT image. Two-field laterally opposing spot 3D-modulation and 24-field full arc distal edge tracking (DET) plans were generated with a prescription of 70 Gy to the planning target volume. For the simulated delivery, we considered two types of procedures: the non-adaptive procedure and the on-line adaptive procedure. In the non-adaptive procedure, only patient realignment to match the prostate location in the planning CT was performed. In the on-line adaptive procedure, on top of the patient realignment, the kinetic energy for each individual proton pencil beam was re-determined from the on-line CT image acquired after the realignment and subsequently used for delivery. Dose distributions were re-calculated for individual fractions for different plans and different delivery procedures. The results show, without adaptive, that both the 3D-modulation and the DET plans experienced delivered dose degradation by having large cold or hot spots in the prostate. The DET plan had worse dose degradation than the 3D-modulation plan. The adaptive procedure effectively restored the planned dose distribution in the DET plan, with delivered prostate D(98%), D(50%) and D(2%) values less than 1% from the prescription. In the 3D-modulation plan, in certain cases the adaptive procedure was not effective to reduce the delivered dose degradation and yield similar results as the non-adaptive procedure. In conclusion, based on this 2D phantom

Reliability-guided digital image correlation for image deformation measurement

International Nuclear Information System (INIS)

Pan Bing

2009-01-01

A universally applicable reliability-guided digital image correlation (DIC) method is proposed for reliable image deformation measurement. The zero-mean normalized cross correlation (ZNCC) coefficient is used to identify the reliability of the point computed. The correlation calculation begins with a seed point and is then guided by the ZNCC coefficient. That means the neighbors of the point with the highest ZNCC coefficient in a queue for computed points will be processed first. Thus the calculation path is always along the most reliable direction, and possible error propagation of the conventional DIC method can be avoided. The proposed novel DIC method is universally applicable to the images with shadows, discontinuous areas, and deformation discontinuity. Two image pairs were used to evaluate the performance of the proposed technique, and the successful results clearly demonstrate its robustness and effectiveness

Acute Toxicity After Image-Guided Intensity Modulated Radiation Therapy Compared to 3D Conformal Radiation Therapy in Prostate Cancer Patients

NARCIS (Netherlands)

Wortel, Ruud C.; Incrocci, Luca; Pos, Floris J.; Lebesque, Joos V.; Witte, Marnix G.; van der Heide, Uulke A.; van Herk, Marcel; Heemsbergen, Wilma D.

2015-01-01

Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows significant dose reductions to organs at risk in prostate cancer patients. However, clinical data identifying the benefits of IG-IMRT in daily practice are scarce. The purpose of this study was to compare dose distributions

Comparison of long-term survival and toxicity of simultaneous integrated boost vs conventional fractionation with intensity-modulated radiotherapy for the treatment of nasopharyngeal carcinoma

Directory of Open Access Journals (Sweden)

Tao HM

2016-03-01

Full Text Available Hengmin Tao,1,2 Yumei Wei,1 Wei Huang,1 Xiujuan Gai,1,2 Baosheng Li11Department of 6th Radiation Oncology, Shandong Cancer Hospital and Institute, 2School of Medicine and Life Sciences, Jinan University-Shandong Academy of Medical Sciences, Jinan, People’s Republic of ChinaAim: In recent years, the intensity-modulated radiotherapy with simultaneous integrated boost (IMRT-SIB and intensity-modulated radiotherapy with conventional fractionation (IMRT-CF have been involved in the treatment of nasopharyngeal carcinoma (NPC. However, the potential clinical effects and toxicities are still controversial.Methods: Here, 107 patients with biopsy-proven locally advanced NPC between March 2004 and January 2011 were enrolled in the retrospective study. Among them, 54 patients received IMRT-SIB, and 53 patients received IMRT-CF. Subsequently, overall survival (OS, 5-year progression-free survival (PFS, 5-year locoregional recurrence-free survival (LRFS, and relevant toxicities were analyzed.Results: In the present study, all patients completed the treatment, and the overall median follow-up time was 80 months (range: 8–126 months. The 5-year OS analysis revealed no significant difference between the IMRT-SIB and IMRT-CF groups (80.9% vs 80.5%, P=0.568. In addition, there were also no significant between-group differences in 5-year PFS (73.3% vs 74.4%, P=0.773 and 5-year LRFS (88.1% vs 90.8%, P=0.903. Notably, the dose to critical organs (spinal cord, brainstem, and parotid gland in patients treated by IMRT-CF was significantly lower than that in patients treated by IMRT-SIB (all P<0.05.Conclusion: Both IMRT-SIB and IMRT-CF techniques are effective in treating locally advanced NPC, with similar OS, PFS, and LRFS. However, IMRT-CF has more advantages than IMRT-SIB in protecting spinal cord, brainstem, and parotid gland from acute and late toxicities, such as xerostomia. Further prospective study is warranted to confirm our findings.Keywords: intensity

Fractionated radiosurgery for painful spinal metastases: DOSIS - a phase II trial

International Nuclear Information System (INIS)

Guckenberger, Matthias; Hawkins, Maria; Flentje, Michael; Sweeney, Reinhart A

2012-01-01

One third of all cancer patients will develop bone metastases and the vertebral column is involved in approximately 70% of these patients. Conventional radiotherapy with of 1–10 fractions and total doses of 8-30 Gy is the current standard for painful vertebral metastases; however, the median pain response is short with 3–6 months and local tumor control is limited with these rather low irradiation doses. Recent advances in radiotherapy technology – intensity modulated radiotherapy for generation of highly conformal dose distributions and image-guidance for precise treatment delivery – have made dose-escalated radiosurgery of spinal metastases possible and early results of pain and local tumor control are promising. The current study will investigate efficacy and safety of radiosurgery for painful vertebral metastases and three characteristics will distinguish this study. 1) A prognostic score for overall survival will be used for selection of patients with longer life expectancy to allow for analysis of long-term efficacy and safety. 2) Fractionated radiosurgery will be performed with the number of treatment fractions adjusted to either good (10 fractions) or intermediate (5 fractions) life expectancy. Fractionation will allow inclusion of tumors immediately abutting the spinal cord due to higher biological effective doses at the tumor - spinal cord interface compared to single fraction treatment. 3) Dose intensification will be performed in the involved parts of the vertebrae only, while uninvolved parts are treated with conventional doses using the simultaneous integrated boost concept. It is the study hypothesis that hypo-fractionated image-guided radiosurgery significantly improves pain relief compared to historic data of conventionally fractionated radiotherapy. Primary endpoint is pain response 3 months after radiosurgery, which is defined as pain reduction of ≥ 2 points at the treated vertebral site on the 0 to 10 Visual Analogue Scale. 60 patients

Feasibility of intensity-modulated and image-guided radiotherapy for locally advanced esophageal cancer

International Nuclear Information System (INIS)

Nguyen, Nam P; Desai, Anand; Smith-Raymond, Lexie; Jang, Siyoung; Vock, Jacqueline; Vinh-Hung, Vincent; Chi, Alexander; Vos, Paul; Pugh, Judith; Vo, Richard A; Ceizyk, Misty

2014-01-01

In this study the feasibility of intensity-modulated radiotherapy (IMRT) and tomotherapy-based image-guided radiotherapy (IGRT) for locally advanced esophageal cancer was assessed. A retrospective study of ten patients with locally advanced esophageal cancer who underwent concurrent chemotherapy with IMRT (1) and IGRT (9) was conducted. The gross tumor volume was treated to a median dose of 70 Gy (62.4-75 Gy). At a median follow-up of 14 months (1-39 months), three patients developed local failures, six patients developed distant metastases, and complications occurred in two patients (1 tracheoesophageal fistula, 1 esophageal stricture requiring repeated dilatations). No patients developed grade 3-4 pneumonitis or cardiac complications. IMRT and IGRT may be effective for the treatment of locally advanced esophageal cancer with acceptable complications

Cervical Gross Tumor Volume Dose Predicts Local Control Using Magnetic Resonance Imaging/Diffusion-Weighted Imaging—Guided High-Dose-Rate and Positron Emission Tomography/Computed Tomography—Guided Intensity Modulated Radiation Therapy

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Dyk, Pawel; Jiang, Naomi; Sun, Baozhou; DeWees, Todd A. [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Fowler, Kathryn J.; Narra, Vamsi [Department of Diagnostic Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Garcia-Ramirez, Jose L.; Schwarz, Julie K. [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Grigsby, Perry W., E-mail: pgrigsby@wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Division of Gynecologic Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Alvin J. Siteman Cancer Center, Washington University School of Medicine, St Louis, Missouri (United States)

2014-11-15

Purpose: Magnetic resonance imaging/diffusion weighted-imaging (MRI/DWI)-guided high-dose-rate (HDR) brachytherapy and {sup 18}F-fluorodeoxyglucose (FDG) — positron emission tomography/computed tomography (PET/CT)-guided intensity modulated radiation therapy (IMRT) for the definitive treatment of cervical cancer is a novel treatment technique. The purpose of this study was to report our analysis of dose-volume parameters predicting gross tumor volume (GTV) control. Methods and Materials: We analyzed the records of 134 patients with International Federation of Gynecology and Obstetrics stages IB1-IVB cervical cancer treated with combined MRI-guided HDR and IMRT from July 2009 to July 2011. IMRT was targeted to the metabolic tumor volume and lymph nodes by use of FDG-PET/CT simulation. The GTV for each HDR fraction was delineated by use of T2-weighted or apparent diffusion coefficient maps from diffusion-weighted sequences. The D100, D90, and Dmean delivered to the GTV from HDR and IMRT were summed to EQD2. Results: One hundred twenty-five patients received all irradiation treatment as planned, and 9 did not complete treatment. All 134 patients are included in this analysis. Treatment failure in the cervix occurred in 24 patients (18.0%). Patients with cervix failures had a lower D100, D90, and Dmean than those who did not experience failure in the cervix. The respective doses to the GTV were 41, 58, and 136 Gy for failures compared with 67, 99, and 236 Gy for those who did not experience failure (P<.001). Probit analysis estimated the minimum D100, D90, and Dmean doses required for ≥90% local control to be 69, 98, and 260 Gy (P<.001). Conclusions: Total dose delivered to the GTV from combined MRI-guided HDR and PET/CT-guided IMRT is highly correlated with local tumor control. The findings can be directly applied in the clinic for dose adaptation to maximize local control.

Atlas-guided generation of pseudo-CT images for MRI-only and hybrid PET-MRI-guided radiotherapy treatment planning

Science.gov (United States)

Arabi, Hossein; Koutsouvelis, Nikolaos; Rouzaud, Michel; Miralbell, Raymond; Zaidi, Habib

2016-09-01

Magnetic resonance imaging (MRI)-guided attenuation correction (AC) of positron emission tomography (PET) data and/or radiation therapy (RT) treatment planning is challenged by the lack of a direct link between MRI voxel intensities and electron density. Therefore, even if this is not a trivial task, a pseudo-computed tomography (CT) image must be predicted from MRI alone. In this work, we propose a two-step (segmentation and fusion) atlas-based algorithm focusing on bone tissue identification to create a pseudo-CT image from conventional MRI sequences and evaluate its performance against the conventional MRI segmentation technique and a recently proposed multi-atlas approach. The clinical studies consisted of pelvic CT, PET and MRI scans of 12 patients with loco-regionally advanced rectal disease. In the first step, bone segmentation of the target image is optimized through local weighted atlas voting. The obtained bone map is then used to assess the quality of deformed atlases to perform voxel-wise weighted atlas fusion. To evaluate the performance of the method, a leave-one-out cross-validation (LOOCV) scheme was devised to find optimal parameters for the model. Geometric evaluation of the produced pseudo-CT images and quantitative analysis of the accuracy of PET AC were performed. Moreover, a dosimetric evaluation of volumetric modulated arc therapy photon treatment plans calculated using the different pseudo-CT images was carried out and compared to those produced using CT images serving as references. The pseudo-CT images produced using the proposed method exhibit bone identification accuracy of 0.89 based on the Dice similarity metric compared to 0.75 achieved by the other atlas-based method. The superior bone extraction resulted in a mean standard uptake value bias of  -1.5  ±  5.0% (mean  ±  SD) in bony structures compared to  -19.9  ±  11.8% and  -8.1  ±  8.2% achieved by MRI segmentation-based (water

Clinical Experience With Image-Guided Radiotherapy in an Accelerated Partial Breast Intensity-Modulated Radiotherapy Protocol

International Nuclear Information System (INIS)

Leonard, Charles E.; Tallhamer, Michael M.S.; Johnson, Tim; Hunter, Kari C.M.D.; Howell, Kathryn; Kercher, Jane; Widener, Jodi; Kaske, Terese; Paul, Devchand; Sedlacek, Scot; Carter, Dennis L.

2010-01-01

Purpose: To explore the feasibility of fiducial markers for the use of image-guided radiotherapy (IGRT) in an accelerated partial breast intensity modulated radiotherapy protocol. Methods and Materials: Nineteen patients consented to an institutional review board approved protocol of accelerated partial breast intensity-modulated radiotherapy with fiducial marker placement and treatment with IGRT. Patients (1 patient with bilateral breast cancer; 20 total breasts) underwent ultrasound guided implantation of three 1.2- x 3-mm gold markers placed around the surgical cavity. For each patient, table shifts (inferior/superior, right/left lateral, and anterior/posterior) and minimum, maximum, mean error with standard deviation were recorded for each of the 10 BID treatments. The dose contribution of daily orthogonal films was also examined. Results: All IGRT patients underwent successful marker placement. In all, 200 IGRT treatment sessions were performed. The average vector displacement was 4 mm (range, 2-7 mm). The average superior/inferior shift was 2 mm (range, 0-5 mm), the average lateral shift was 2 mm (range, 1-4 mm), and the average anterior/posterior shift was 3 mm (range, 1 5 mm). Conclusions: This study shows that the use of IGRT can be successfully used in an accelerated partial breast intensity-modulated radiotherapy protocol. The authors believe that this technique has increased daily treatment accuracy and permitted reduction in the margin added to the clinical target volume to form the planning target volume.

Integral test phantom for dosimetric quality assurance of image guided and intensity modulated stereotactic radiotherapy.

Science.gov (United States)

Létourneau, Daniel; Keller, Harald; Sharpe, Michael B; Jaffray, David A

2007-05-01

The objective of this work is to develop a dosimetric phantom quality assurance (QA) of linear accelerators capable of cone-beam CT (CBCT) image guided and intensity-modulated radiotherapy (IG-IMRT). This phantom is to be used in an integral test to quantify in real-time both the performance of the image guidance and the dose delivery systems in terms of dose localization. The prototype IG-IMRT QA phantom consisted of a cylindrical imaging phantom (CatPhan) combined with an array of 11 radiation diodes mounted on a 10 cm diameter disk, oriented perpendicular to the phantom axis. Basic diode response characterization was performed for 6 and 18 MV photons. The diode response was compared to planning system calculations in the open and penumbrae regions of simple and complex beam arrangements. The clinical use of the QA phantom was illustrated in an integral test of an IG-IMRT treatment designed for a clinical spinal radiosurgery case. The sensitivity of the phantom to multileaf collimator (MLC) calibration and setup errors in the clinical setting was assessed by introducing errors in the IMRT plan or by displacing the phantom. The diodes offered good response linearity and long-term reproducibility for both 6 and 18 MV. Axial dosimetry of coplanar beams (in a plane containing the beam axes) was made possible with the nearly isoplanatic response of the diodes over 360 degrees of gantry (usually within +/-1%). For single beam geometry, errors in phantom placement as small as 0.5 mm could be accurately detected (in gradient > or = 1% /mm). In clinical setting, MLC systematic errors of 1 mm on a single MLC bank introduced in the IMRT plan were easily detectable with the QA phantom. The QA phantom demonstrated also sufficient sensitivity for the detection of setup errors as small as 1 mm for the IMRT delivery. These results demonstrated that the prototype can accurately and efficiently verify the entire IG-IMRT process. This tool, in conjunction with image guidance

Integral test phantom for dosimetric quality assurance of image guided and intensity modulated stereotactic radiotherapy

International Nuclear Information System (INIS)

Letourneau, Daniel; Keller, Harald; Sharpe, Michael B.; Jaffray, David A.

2007-01-01

The objective of this work is to develop a dosimetric phantom quality assurance (QA) of linear accelerators capable of cone-beam CT (CBCT) image guided and intensity-modulated radiotherapy (IG-IMRT). This phantom is to be used in an integral test to quantify in real-time both the performance of the image guidance and the dose delivery systems in terms of dose localization. The prototype IG-IMRT QA phantom consisted of a cylindrical imaging phantom (CatPhan) combined with an array of 11 radiation diodes mounted on a 10 cm diameter disk, oriented perpendicular to the phantom axis. Basic diode response characterization was performed for 6 and 18 MV photons. The diode response was compared to planning system calculations in the open and penumbrae regions of simple and complex beam arrangements. The clinical use of the QA phantom was illustrated in an integral test of an IG-IMRT treatment designed for a clinical spinal radiosurgery case. The sensitivity of the phantom to multileaf collimator (MLC) calibration and setup errors in the clinical setting was assessed by introducing errors in the IMRT plan or by displacing the phantom. The diodes offered good response linearity and long-term reproducibility for both 6 and 18 MV. Axial dosimetry of coplanar beams (in a plane containing the beam axes) was made possible with the nearly isoplanatic response of the diodes over 360 deg. of gantry (usually within ±1%). For single beam geometry, errors in phantom placement as small as 0.5 mm could be accurately detected (in gradient ≥1%/mm). In clinical setting, MLC systematic errors of 1 mm on a single MLC bank introduced in the IMRT plan were easily detectable with the QA phantom. The QA phantom demonstrated also sufficient sensitivity for the detection of setup errors as small as 1 mm for the IMRT delivery. These results demonstrated that the prototype can accurately and efficiently verify the entire IG-IMRT process. This tool, in conjunction with image guidance capabilities

Tumor Localization Using Cone-Beam CT Reduces Setup Margins in Conventionally Fractionated Radiotherapy for Lung Tumors

International Nuclear Information System (INIS)

Yeung, Anamaria R.; Li, Jonathan G.; Shi Wenyin; Newlin, Heather E.; Chvetsov, Alexei; Liu, Chihray; Palta, Jatinder R.; Olivier, Kenneth

2009-01-01

Purpose: To determine whether setup margins can be reduced using cone-beam computed tomography (CBCT) to localize tumor in conventionally fractionated radiotherapy for lung tumors. Methods and Materials: A total of 22 lung cancer patients were treated with curative intent with conventionally fractionated radiotherapy using daily image guidance with CBCT. Of these, 13 lung cancer patients had sufficient CBCT scans for analysis (389 CBCT scans). The patients underwent treatment simulation in the BodyFix immobilization system using four-dimensional CT to account for respiratory motion. Daily alignment was first done according to skin tattoos, followed by CBCT. All 389 CBCT scans were retrospectively registered to the planning CT scans using automated soft-tissue and bony registration; the resulting couch shifts in three dimensions were recorded. Results: The daily alignment to skin tattoos with no image guidance resulted in systematic (Σ) and random (σ) errors of 3.2-5.6 mm and 2.0-3.5 mm, respectively. The margin required to account for the setup error introduced by aligning to skin tattoos with no image guidance was approximately 1-1.6 cm. The difference in the couch shifts obtained from the bone and soft-tissue registration resulted in systematic (Σ) and random (σ) errors of 1.5-4.1 mm and 1.8-5.3 mm, respectively. The margin required to account for the setup error introduced using bony anatomy as a surrogate for the target, instead of localizing the target itself, was 0.5-1.4 cm. Conclusion: Using daily CBCT soft-tissue registration to localize the tumor in conventionally fractionated radiotherapy reduced the required setup margin by up to approximately 1.5 cm compared with both no image guidance and image guidance using bony anatomy as a surrogate for the target.

Image encryption using the fractional wavelet transform

International Nuclear Information System (INIS)

Vilardy, Juan M; Useche, J; Torres, C O; Mattos, L

2011-01-01

In this paper a technique for the coding of digital images is developed using Fractional Wavelet Transform (FWT) and random phase masks (RPMs). The digital image to encrypt is transformed with the FWT, after the coefficients resulting from the FWT (Approximation, Details: Horizontal, vertical and diagonal) are multiplied each one by different RPMs (statistically independent) and these latest results is applied an Inverse Wavelet Transform (IWT), obtaining the encrypted digital image. The decryption technique is the same encryption technique in reverse sense. This technique provides immediate advantages security compared to conventional techniques, in this technique the mother wavelet family and fractional orders associated with the FWT are additional keys that make access difficult to information to an unauthorized person (besides the RPMs used), thereby the level of encryption security is extraordinarily increased. In this work the mathematical support for the use of the FWT in the computational algorithm for the encryption is also developed.

Rectal dose variation during the course of image-guided radiation therapy of prostate cancer

International Nuclear Information System (INIS)

Chen Lili; Paskalev, Kamen; Xu Xiu; Zhu, Jennifer; Wang Lu; Price, Robert A.; Hu Wei; Feigenberg, Steven J.; Horwitz, Eric M.; Pollack, Alan; Charlie Ma, C.M.

2010-01-01

Background and purpose: To investigate the change in rectal dose during the treatment course for intensity-modulated radiotherapy (IMRT) of prostate cancer with image-guidance. Materials and methods: Twenty prostate cancer patients were recruited for this retrospective study. All patients have been treated with IMRT. For each patient, MR and CT images were fused for target and critical structure delineation. IMRT treatment planning was performed on the simulation CT images. Inter-fractional motion during the course of treatment was corrected using a CT-on-rails system. The rectum was outlined on both the original treatment plan and the subsequent daily CT images from the CT-on-rails by the same investigator. Dose distributions on these daily CT images were recalculated with the isocenter shifts relative to the simulation CT images using the leaf sequences/MUs based on the original treatment plan. The rectal doses from the subsequent daily CTs were compared with the original doses planned on the simulation CT using our clinical acceptance criteria. Results: Based on 20 patients with 139 daily CT sets, 28% of the subsequent treatment dose distributions did not meet our criterion of V 40 65 < 17%. The inter-fractional rectal volume variation is significant for some patients. Conclusions: Due to the large inter-fractional variation of the rectal volume, it is more favorable to plan prostate IMRT based on an empty rectum and deliver treatment to patients with an empty rectum. Over 70% of actual treatments showed better rectal doses than our clinical acceptance criteria. A significant fraction (27%) of the actual treatments would benefit from adaptive image-guided radiotherapy based on daily CT images.

Stereotactic Image-Guided Intensity Modulated Radiotherapy Using the HI-ART II Helical Tomotherapy System

International Nuclear Information System (INIS)

Holmes, Timothy W.; Hudes, Richard; Dziuba, Sylwester; Kazi, Abdul; Hall, Mark; Dawson, Dana

2008-01-01

The highly integrated adaptive radiation therapy (HI-ART II) helical tomotherapy unit is a new radiotherapy machine designed to achieve highly precise and accurate treatments at all body sites. The precision and accuracy of the HI-ART II is similar to that provided by stereotactic radiosurgery systems, hence the historical distinction between external beam radiotherapy and stereotactic procedures based on differing precision requirements is removed for this device. The objectives of this work are: (1) to describe stereotactic helical tomotherapy processes (SRS, SBRT); (2) to show that the precision and accuracy of the HI-ART meet the requirements defined for SRS and SBRT; and (3) to describe the clinical implementation of a stereotactic image-guided intensity modulated radiation therapy (IG-IMRT) system that incorporates optical motion management

[Accelerated partial breast irradiation with image-guided intensity-modulated radiotherapy following breast-conserving surgery - preliminary results of a phase II clinical study].

Science.gov (United States)

Mészáros, Norbert; Major, Tibor; Stelczer, Gábor; Zaka, Zoltán; Mózsa, Emõke; Fodor, János; Polgár, Csaba

2015-06-01

The purpose of the study was to implement accelerated partial breast irradiation (APBI) by means of image-guided intensity-modulated radiotherapy (IG-IMRT) following breast-conserving surgery (BCS) for low-risk early invasive breast cancer. Between July 2011 and March 2014, 60 patients with low-risk early invasive (St I-II) breast cancer who underwent BCS were enrolled in our phase II prospective study. Postoperative APBI was given by means of step and shoot IG-IMRT using 4 to 5 fields to a total dose of 36.9 Gy (9×4.1 Gy) using a twice-a-day fractionation. Before each fraction, series of CT images were taken from the region of the target volume using a kV CT on-rail mounted in the treatment room. An image fusion software was used for automatic image registration of the planning and verification CT images. Patient set-up errors were detected in three directions (LAT, LONG, VERT), and inaccuracies were adjusted by automatic movements of the treatment table. Breast cancer related events, acute and late toxicities, and cosmetic results were registered and analysed. At a median follow-up of 24 months (range 12-44) neither locoregional nor distant failure was observed. Grade 1 (G1), G2 erythema, G1 oedema, and G1 and G2 pain occurred in 21 (35%), 2 (3.3%), 23 (38.3%), 6 (10%) and 2 (3.3%) patients, respectively. No G3-4 acute side effects were detected. Among late radiation side effects G1 pigmentation, G1 fibrosis, and G1 fat necrosis occurred in 5 (8.3%), 7 (11.7%), and 2 (3.3%) patients, respectively. No ≥G2 late toxicity was detected. Excellent and good cosmetic outcome was detected in 45 (75%) and 15 (25%) patients. IG-IMRT is a reproducible and feasible technique for the delivery of APBI following conservative surgery for the treatment of low-risk, early-stage invasive breast carcinoma. Preliminary results are promising, early radiation side effects are minimal, and cosmetic results are excellent.

Clinical Outcome of Dose-Escalated Image-Guided Radiotherapy for Spinal Metastases

International Nuclear Information System (INIS)

Guckenberger, Matthias; Goebel, Joachim; Wilbert, Juergen; Baier, Kurt; Richter, Anne; Sweeney, Reinhart A.; Bratengeier, Klaus; Flentje, Michael

2009-01-01

Purpose: To evaluate the outcomes after dose-escalated radiotherapy (RT) for spinal metastases and paraspinal tumors. Methods and Materials: A total of 14 patients, 12 with spinal metastases and a long life expectancy and 2 with paraspinal tumors, were treated for 16 lesions with intensity-modulated, image-guided RT. A median biologic effective dose of 74 Gy 10 (range, 55-86) in a median of 20 fractions (range, 3-34) was prescribed to the target volume. The spinal canal was treated to 40 Gy in 20 fractions using a second intensity-modulated RT dose level in the case of epidural involvement. Results: After median follow-up of 17 months, one local recurrence was observed, for an actuarial local control rate of 88% after 2 years. Local control was associated with rapid and long-term pain relief. Of 11 patients treated for a solitary spinal metastasis, 6 developed systemic disease progression. The actuarial overall survival rate for metastatic patients was 85% and 63% after 1 and 2 years, respectively. Acute Grade 2-3 skin toxicity was seen in 2 patients with no late toxicity greater than Grade 2. No radiation-induced myelopathy was observed. Conclusion: Dose-escalated irradiation of spinal metastases was safe and resulted in excellent local control. Oligometastatic patients with a long life expectancy and epidural involvement are considered to benefit the most from fractionated RT.

Fractionated radiosurgery for painful spinal metastases: DOSIS - a phase II trial

Directory of Open Access Journals (Sweden)

Guckenberger Matthias

2012-11-01

Full Text Available Abstract Background One third of all cancer patients will develop bone metastases and the vertebral column is involved in approximately 70% of these patients. Conventional radiotherapy with of 1–10 fractions and total doses of 8-30 Gy is the current standard for painful vertebral metastases; however, the median pain response is short with 3–6 months and local tumor control is limited with these rather low irradiation doses. Recent advances in radiotherapy technology – intensity modulated radiotherapy for generation of highly conformal dose distributions and image-guidance for precise treatment delivery – have made dose-escalated radiosurgery of spinal metastases possible and early results of pain and local tumor control are promising. The current study will investigate efficacy and safety of radiosurgery for painful vertebral metastases and three characteristics will distinguish this study. 1 A prognostic score for overall survival will be used for selection of patients with longer life expectancy to allow for analysis of long-term efficacy and safety. 2 Fractionated radiosurgery will be performed with the number of treatment fractions adjusted to either good (10 fractions or intermediate (5 fractions life expectancy. Fractionation will allow inclusion of tumors immediately abutting the spinal cord due to higher biological effective doses at the tumor - spinal cord interface compared to single fraction treatment. 3 Dose intensification will be performed in the involved parts of the vertebrae only, while uninvolved parts are treated with conventional doses using the simultaneous integrated boost concept. Methods / Design It is the study hypothesis that hypo-fractionated image-guided radiosurgery significantly improves pain relief compared to historic data of conventionally fractionated radiotherapy. Primary endpoint is pain response 3 months after radiosurgery, which is defined as pain reduction of ≥ 2 points at the treated

Dosimetric impact of image-guided 3D conformal radiation therapy of prostate cancer

International Nuclear Information System (INIS)

Schaly, B; Song, W; Bauman, G S; Battista, J J; Van Dyk, J

2005-01-01

The goal of this work is to quantify the impact of image-guided conformal radiation therapy (CRT) on the dose distribution by correcting patient setup uncertainty and inter-fraction tumour motion. This was a retrospective analysis that used five randomly selected prostate cancer patients that underwent approximately 15 computed tomography (CT) scans during their radiation treatment course. The beam arrangement from the treatment plan was imported into each repeat CT study and the dose distribution was recalculated for the new beam setups. Various setup scenarios were then compared to assess the impact of image guidance on radiation treatment precision. These included (1) daily alignment to skin markers, thus representing a conventional beam setup without image guidance (2) alignment to bony anatomy for correction of daily patient setup error, thus representing on-line portal image guidance, and (3) alignment to the 'CTV of the day' for correction of inter-fraction tumour motion, thus representing on-line CT or ultrasound image guidance. Treatment scenarios (1) and (3) were repeated with a reduced CTV to PTV margin, where the former represents a treatment using small margins without daily image guidance. Daily realignment of the treatment beams to the prostate showed an average increase in minimum tumour dose of 1.5 Gy, in all cases where tumour 'geographic miss' without image guidance was apparent. However, normal tissue sparing did not improve unless the PTV margin was reduced. Daily realignment to the tumour combined with reducing the margin size by a factor of 2 resulted in an average escalation in tumour dose of 9.0 Gy for all five static plans. However, the prescription dose could be escalated by 13.8 Gy when accounting for changes in anatomy by accumulating daily doses using nonlinear image registration techniques. These results provide quantitative information on the effectiveness of image-guided radiation treatment of prostate cancer and demonstrate that

Image Guided Hypofractionated Postprostatectomy Intensity Modulated Radiation Therapy for Prostate Cancer

Energy Technology Data Exchange (ETDEWEB)

Lewis, Stephen L.; Patel, Pretesh; Song, Haijun [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Freedland, Stephen J. [Surgery Section, Durham Veterans Administration, and Division of Urology, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California (United States); Bynum, Sigrun; Oh, Daniel; Palta, Manisha; Yoo, David; Oleson, James [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Salama, Joseph K., E-mail: joseph.salama@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

2016-03-01

Purpose: Hypofractionated radiation therapy (RT) has promising long-term biochemical relapse-free survival (bRFS) with comparable toxicity for definitive treatment of prostate cancer. However, data reporting outcomes after adjuvant and salvage postprostatectomy hypofractionated RT are sparse. Therefore, we report the toxicity and clinical outcomes after postprostatectomy hypofractionated RT. Methods and Materials: From a prospectively maintained database, men receiving image guided hypofractionated intensity modulated RT (HIMRT) with 2.5-Gy fractions constituted our study population. Androgen deprivation therapy was used at the discretion of the radiation oncologist. Acute toxicities were graded according to the Common Terminology Criteria for Adverse Events version 4.0. Late toxicities were scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale. Biochemical recurrence was defined as an increase of 0.1 in prostate-specific antigen (PSA) from posttreatment nadir or an increase in PSA despite treatment. The Kaplan-Meier method was used for the time-to-event outcomes. Results: Between April 2008 and April 2012, 56 men received postoperative HIMRT. The median follow-up time was 48 months (range, 21-67 months). Thirty percent had pre-RT PSA <0.1; the median pre-RT detectable PSA was 0.32 ng/mL. The median RT dose was 65 Gy (range, 57.5-65 Gy). Ten patients received neoadjuvant and concurrent hormone therapy. Posttreatment acute urinary toxicity was limited. There was no acute grade 3 toxicity. Late genitourinary (GU) toxicity of any grade was noted in 52% of patients, 40% of whom had pre-RT urinary incontinence. The 4-year actuarial rate of late grade 3 GU toxicity (exclusively gross hematuria) was 28% (95% confidence interval [CI], 16%-41%). Most grade 3 GU toxicity resolved; only 7% had persistent grade ≥3 toxicity at the last follow-up visit. Fourteen patients experienced biochemical recurrence at a

SU-F-T-29: The Important of Each Fraction Image-Guided Planning for Postoperative HDR-Brachytherapy in Endometrial Carcinoma

Energy Technology Data Exchange (ETDEWEB)

Piriyasang, D; Pattaranutaporn, P; Manokhoon, K [Ramathibodi Hospital, Rachatewi, Bangkok (Thailand)

2016-06-15

Purpose: Cylindrical applicators are often used for postoperative HDRbrachytherapy in endometrial carcinoma. It has been considered that dosimetric variation between fractions for this treatment is minimal and might not be necessary to perform treatment planning for every fractions. At our institute, it is traditional to perform treatment planning with CT simulation on the first fraction and uses this plan for the rest of treatment. This study was aim to evaluate the errors of critical structure doses between the fractions when simulation and planning were done for first fraction only. Methods: Treatment plans of 10 endometrial carcinoma patients who received postoperative HDR-brachytherapy and underwent CT-simulation for every HDR-fractions at our department were retrospectively reviewed. All of these patients were treated with cylindrical applicator and prescribed dose 15Gy in 3 fractions to 0.5cm from vaginal surface. The treatment plan from the first fraction was used to simulate in second and third CT-simulation. Radiation dose for critical structures in term of Dose-to-2cc (D2cc) were evaluated and compared between planning CT. Results: The D2cc for bladder and rectum were evaluated. For bladder, the mean error of D2cc estimation for second and third fractions was 7.6% (0.1–20.1%, SD=5.7). And the mean error for D2cc of rectum was 8.5% (0.1–29.4%, SD=8.5). Conclusion: The critical structure doses could be significant difference between fractions which may affects treatment outcomes or toxicities. From our data, image-guided brachytherapy at least with CT-Simulation should be done for every treatment fractions.

Minimally invasive, imaging guided virtual autopsy compared to conventional autopsy in foetal, newborn and infant cases: study protocol for the paediatric virtual autopsy trial

Science.gov (United States)

2014-01-01

Background In light of declining autopsy rates around the world, post-mortem MR imaging is a promising alternative to conventional autopsy in the investigation of infant death. A major drawback of this non-invasive autopsy approach is the fact that histopathological and microbiological examination of the tissue is not possible. The objective of this prospective study is to compare the performance of minimally invasive, virtual autopsy, including CT-guided biopsy, with conventional autopsy procedures in a paediatric population. Methods/Design Foetuses, newborns and infants that are referred for autopsy at three different institutions associated with the University of Zurich will be eligible for recruitment. All bodies will be examined with a commercial CT and a 3 Tesla MRI scanner, masked to the results of conventional autopsy. After cross-sectional imaging, CT-guided tissue sampling will be performed by a multifunctional robotic system (Virtobot) allowing for automated post-mortem biopsies. Virtual autopsy results will be classified with regards to the likely final diagnosis and major pathological findings and compared to the results of conventional autopsy, which remains the diagnostic gold standard. Discussion There is an urgent need for the development of alternative post-mortem examination methods, not only as a counselling tool for families and as a quality control measure for clinical diagnosis and treatment but also as an instrument to advance medical knowledge and clinical practice. This interdisciplinary study will determine whether virtual autopsy will narrow the gap in information between non-invasive and traditional autopsy procedures. Trial Registration ClinicalTrials.gov: NCT01888380 PMID:24438163

Feasibility of Computed Tomography-Guided Methods for Spatial Normalization of Dopamine Transporter Positron Emission Tomography Image.

Science.gov (United States)

Kim, Jin Su; Cho, Hanna; Choi, Jae Yong; Lee, Seung Ha; Ryu, Young Hoon; Lyoo, Chul Hyoung; Lee, Myung Sik

2015-01-01

Spatial normalization is a prerequisite step for analyzing positron emission tomography (PET) images both by using volume-of-interest (VOI) template and voxel-based analysis. Magnetic resonance (MR) or ligand-specific PET templates are currently used for spatial normalization of PET images. We used computed tomography (CT) images acquired with PET/CT scanner for the spatial normalization for [18F]-N-3-fluoropropyl-2-betacarboxymethoxy-3-beta-(4-iodophenyl) nortropane (FP-CIT) PET images and compared target-to-cerebellar standardized uptake value ratio (SUVR) values with those obtained from MR- or PET-guided spatial normalization method in healthy controls and patients with Parkinson's disease (PD). We included 71 healthy controls and 56 patients with PD who underwent [18F]-FP-CIT PET scans with a PET/CT scanner and T1-weighted MR scans. Spatial normalization of MR images was done with a conventional spatial normalization tool (cvMR) and with DARTEL toolbox (dtMR) in statistical parametric mapping software. The CT images were modified in two ways, skull-stripping (ssCT) and intensity transformation (itCT). We normalized PET images with cvMR-, dtMR-, ssCT-, itCT-, and PET-guided methods by using specific templates for each modality and measured striatal SUVR with a VOI template. The SUVR values measured with FreeSurfer-generated VOIs (FSVOI) overlaid on original PET images were also used as a gold standard for comparison. The SUVR values derived from all four structure-guided spatial normalization methods were highly correlated with those measured with FSVOI (P normalization methods provided reliable striatal SUVR values comparable to those obtained with MR-guided methods. CT-guided methods can be useful for analyzing dopamine transporter PET images when MR images are unavailable.

Reliability of the Bony Anatomy in Image-Guided Stereotactic Radiotherapy of Brain Metastases

International Nuclear Information System (INIS)

Guckenberger, Matthias; Baier, Kurt; Guenther, Iris; Richter, Anne; Wilbert, Juergen; Sauer, Otto; Vordermark, Dirk; Flentje, Michael

2007-01-01

Purpose: To evaluate whether the position of brain metastases remains stable between planning and treatment in cranial stereotactic radiotherapy (SRT). Methods and Materials: Eighteen patients with 20 brain metastases were treated with single-fraction (17 lesions) or hypofractionated (3 lesions) image-guided SRT. Median time interval between planning and treatment was 8 days. Before treatment a cone-beam CT (CBCT) and a conventional CT after application of i.v. contrast were acquired. Setup errors using automatic bone registration (CBCT) and manual soft-tissue registration of the brain metastases (conventional CT) were compared. Results: Tumor size was not significantly different between planning and treatment. The three-dimensional setup error (mean ± SD) was 4.0 ± 2.1 mm and 3.5 ± 2.2 mm according to the bony anatomy and the lesion itself, respectively. A highly significant correlation between automatic bone match and soft-tissue registration was seen in all three directions (r ≥ 0.88). The three-dimensional distance between the isocenter according to bone match and soft-tissue registration was 1.7 ± 0.7 mm, maximum 2.8 mm. Treatment of intracranial pressure with steroids did not influence the position of the lesion relative to the bony anatomy. Conclusion: With a time interval of approximately 1 week between planning and treatment, the bony anatomy of the skull proved to be an excellent surrogate for the target position in image-guided SRT

Comparative evaluation of multiple fractions per day radiotherapy and conventional fractionated radiotherapy in squamous cell carcinoma of esophagus

International Nuclear Information System (INIS)

Andrabi, W.H.; Akhtar, S.; Kharadi, M.Y.; Mushtaq, G.; Zargar, S.A.

1999-01-01

Dose fractionated is important in radiotherapy in order to achieve the desired results. There are regimes which are accepted and followed worldwide. Five fractions per week for a full course of treatment is regarded as standard fractionation regimen. Interest has lately been developed to alter this and try regimes like hyper and accelerated fractionations. In the former, smaller doses per fraction than usual are given in several fractions on each treating day, with no change in overall time. In the latter, conventionally sized fractions are given as two or three per day with a shortening of overall time. As the dose fraction in our case is high, we spilt the full course of treatment introducing a gap of one week between the treatment schedules. The results obtained are fairly good in comparison with conventional radiotherapy regimes. (author)

Tcp and NTCP radiobiological models: conventional and hypo fractionated treatments in radiotherapy

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Astudillo V, A.; Paredes G, L. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Resendiz G, G.; Posadas V, A. [Hospital Angeles Lomas, Av. Vialidad de la Barranca s/n, Col. Valle de las Palmas, 52763 Huixquilucan de Degallado, Estado de Mexico (Mexico); Mitsoura, E. [Universidad Autonoma del Estado de Mexico, Facultad de Medicina, Paseo Tollocan, Esq. Jesus Carranza s/n, Col. Moderna de la Cruz, 50180 Toluca, Estado de Mexico (Mexico); Rodriguez L, A.; Flores C, J. M., E-mail: armando.astudillo@inin.gob.mx [Hospital Medica Sur, Puente de Piedra 150, Col. Toriello Guerra, 14050 Tlalpan, Mexico D. F. (Mexico)

2015-10-15

The hypo and conventional fractionated schedules performance were compared in terms of the tumor control and the normal tissue complications. From the records of ten patients, treated for adenocarcinoma and without mastectomy, the dose-volume histogram was used. Using radiobiological models the probabilities for tumor control and normal tissue complications were calculated. For both schedules the tumor control was approximately the same. However, the damage in the normal tissue was larger in conventional fractionated schedule. This is important because patients assistance time to their fractions (15 fractions/25 fractions) can be optimized. Thus, the hypo fractionated schedule has suitable characteristics to be implemented. (Author)

Tcp and NTCP radiobiological models: conventional and hypo fractionated treatments in radiotherapy

International Nuclear Information System (INIS)

Astudillo V, A.; Paredes G, L.; Resendiz G, G.; Posadas V, A.; Mitsoura, E.; Rodriguez L, A.; Flores C, J. M.

2015-10-01

The hypo and conventional fractionated schedules performance were compared in terms of the tumor control and the normal tissue complications. From the records of ten patients, treated for adenocarcinoma and without mastectomy, the dose-volume histogram was used. Using radiobiological models the probabilities for tumor control and normal tissue complications were calculated. For both schedules the tumor control was approximately the same. However, the damage in the normal tissue was larger in conventional fractionated schedule. This is important because patients assistance time to their fractions (15 fractions/25 fractions) can be optimized. Thus, the hypo fractionated schedule has suitable characteristics to be implemented. (Author)

Image-guided radiation therapy: physician's perspectives

International Nuclear Information System (INIS)

Gupta, T.; Anand Narayan, C.

2012-01-01

The evolution of radiotherapy has been ontogenetically linked to medical imaging. Over the years, major technological innovations have resulted in substantial improvements in radiotherapy planning, delivery, and verification. The increasing use of computed tomography imaging for target volume delineation coupled with availability of computer-controlled treatment planning and delivery systems have progressively led to conformation of radiation dose to the target tissues while sparing surrounding normal tissues. Recent advances in imaging technology coupled with improved treatment delivery allow near-simultaneous soft-tissue localization of tumor and repositioning of patient. The integration of various imaging modalities within the treatment room for guiding radiation delivery has vastly improved the management of geometric uncertainties in contemporary radiotherapy practice ushering in the paradigm of image-guided radiation therapy (IGRT). Image-guidance should be considered a necessary and natural corollary to high-precision radiotherapy that was long overdue. Image-guided radiation therapy not only provides accurate information on patient and tumor position on a quantitative scale, it also gives an opportunity to verify consistency of planned and actual treatment geometry including adaptation to daily variations resulting in improved dose delivery. The two main concerns with IGRT are resource-intensive nature of delivery and increasing dose from additional imaging. However, increasing the precision and accuracy of radiation delivery through IGRT is likely to reduce toxicity with potential for dose escalation and improved tumor control resulting in favourable therapeutic index. The radiation oncology community needs to leverage this technology to generate high-quality evidence to support widespread adoption of IGRT in contemporary radiotherapy practice. (author)

Functional Image-Guided Radiotherapy Planning in Respiratory-Gated Intensity-Modulated Radiotherapy for Lung Cancer Patients With Chronic Obstructive Pulmonary Disease

Energy Technology Data Exchange (ETDEWEB)

Kimura, Tomoki, E-mail: tkkimura@hiroshima-u.ac.jp [Department of Radiation Oncology, Hiroshima University, Graduate School of Biomedical Sciences, Hiroshima City (Japan); Nishibuchi, Ikuno; Murakami, Yuji; Kenjo, Masahiro; Kaneyasu, Yuko; Nagata, Yasushi [Department of Radiation Oncology, Hiroshima University, Graduate School of Biomedical Sciences, Hiroshima City (Japan)

2012-03-15

Purpose: To investigate the incorporation of functional lung image-derived low attenuation area (LAA) based on four-dimensional computed tomography (4D-CT) into respiratory-gated intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT) in treatment planning for lung cancer patients with chronic obstructive pulmonary disease (COPD). Methods and Materials: Eight lung cancer patients with COPD were the subjects of this study. LAA was generated from 4D-CT data sets according to CT values of less than than -860 Hounsfield units (HU) as a threshold. The functional lung image was defined as the area where LAA was excluded from the image of the total lung. Two respiratory-gated radiotherapy plans (70 Gy/35 fractions) were designed and compared in each patient as follows: Plan A was an anatomical IMRT or VMAT plan based on the total lung; Plan F was a functional IMRT or VMAT plan based on the functional lung. Dosimetric parameters (percentage of total lung volume irradiated with {>=}20 Gy [V20], and mean dose of total lung [MLD]) of the two plans were compared. Results: V20 was lower in Plan F than in Plan A (mean 1.5%, p = 0.025 in IMRT, mean 1.6%, p = 0.044 in VMAT) achieved by a reduction in MLD (mean 0.23 Gy, p = 0.083 in IMRT, mean 0.5 Gy, p = 0.042 in VMAT). No differences were noted in target volume coverage and organ-at-risk doses. Conclusions: Functional IGRT planning based on LAA in respiratory-guided IMRT or VMAT appears to be effective in preserving a functional lung in lung cancer patients with COPD.

CT-guided intracavitary radiotherapy for cervical cancer: Comparison of conventional point A plan with clinical target volume-based three-dimensional plan using dose-volume parameters

International Nuclear Information System (INIS)

Shin, Kyung Hwan; Kim, Tae Hyun; Cho, Jung Keun; Kim, Joo-Young; Park, Sung Yong; Park, Sang-Yoon; Kim, Dae Yong; Chie, Eui Kyu; Pyo, Hong Ryull; Cho, Kwan Ho

2006-01-01

Purpose: To perform an intracavitary radiotherapy (ICR) plan comparison between the conventional point A plan (conventional plan) and computed tomography (CT)-guided clinical target volume-based plan (CTV plan) by analysis of the quantitative dose-volume parameters and irradiated volumes of organs at risk in patients with cervical cancer. Methods and Materials: Thirty plans for 192 Ir high-dose-rate ICR after 30-40-Gy external beam radiotherapy were investigated. CT images were acquired at the first ICR session with artifact-free applicators in place. The gross tumor volume, clinical target volume (CTV), point A, and International Commission on Radiation Units and Measurements Report 38 rectal and bladder points were defined on reconstructed CT images. A fractional 100% dose was prescribed to point A in the conventional plan and to the outermost point to cover all CTVs in the CTV plan. The reference volume receiving 100% of the prescribed dose (V ref ), and the dose-volume parameters of the coverage index, conformal index, and external volume index were calculated from the dose-volume histogram. The bladder, rectal point doses, and percentage of volumes receiving 50%, 80%, and 100% of the prescribed dose were also analyzed. Results: Conventional plans were performed, and patients were categorized on the basis of whether the 100% isodose line of point A prescription dose fully encompassed the CTV (Group 1, n = 20) or not (Group 2, n = 10). The mean gross tumor volume (11.6 cm 3 ) and CTV (24.9 cm 3 ) of Group 1 were smaller than the corresponding values (23.7 and 44.7 cm 3 , respectively) for Group 2 (p = 0.003). The mean V ref for all patients was 129.6 cm 3 for the conventional plan and 97.0 cm 3 for the CTV plan (p = 0.003). The mean V ref in Group 1 decreased markedly with the CTV plan (p < 0.001). For the conventional and CTV plans in all patients, the mean coverage index, conformal index, and external volume index were 0.98 and 1.0, 0.23 and 0.34, and 3.86 and

Transthoracic CT-guided biopsy with multiplanar reconstruction image improves diagnostic accuracy of solitary pulmonary nodules

International Nuclear Information System (INIS)

Ohno, Yoshiharu; Hatabu, Hiroto; Takenaka, Daisuke; Imai, Masatake; Ohbayashi, Chiho; Sugimura, Kazuro

2004-01-01

Objective: To evaluate the utility of multiplanar reconstruction (MPR) image for CT-guided biopsy and determine factors of influencing diagnostic accuracy and the pneumothorax rate. Materials and methods: 390 patients with 396 pulmonary nodules underwent transthoracic CT-guided aspiration biopsy (TNAB) and transthoracic CT-guided cutting needle core biopsy (TCNB) as follows: 250 solitary pulmonary nodules (SPNs) underwent conventional CT-guided biopsy (conventional method), 81 underwent CT-fluoroscopic biopsy (CT-fluoroscopic method) and 65 underwent conventional CT-guided biopsy in combination with MPR image (MPR method). Success rate, overall diagnostic accuracy, pneumothorax rate and total procedure time were compared in each method. Factors affecting diagnostic accuracy and pneumothorax rate of CT-guided biopsy were statistically evaluated. Results: Success rates (TNAB: 100.0%, TCNB: 100.0%) and overall diagnostic accuracies (TNAB: 96.9%, TCNB: 97.0%) of MPR were significantly higher than those using the conventional method (TNAB: 87.6 and 82.4%, TCNB: 86.3 and 81.3%) (P<0.05). Diagnostic accuracy were influenced by biopsy method, lesion size, and needle path length (P<0.05). Pneumothorax rate was influenced by pathological diagnostic method, lesion size, number of punctures and FEV1.0% (P<0.05). Conclusion: The use of MPR for CT-guided lung biopsy is useful for improving diagnostic accuracy with no significant increase in pneumothorax rate or total procedure time

Split-mouth comparison of the accuracy of computer-generated and conventional surgical guides.

Science.gov (United States)

Farley, Nathaniel E; Kennedy, Kelly; McGlumphy, Edwin A; Clelland, Nancy L

2013-01-01

Recent clinical studies have shown that implant placement is highly predictable with computer-generated surgical guides; however, the reliability of these guides has not been compared to that of conventional guides clinically. This study aimed to compare the accuracy of reproducing planned implant positions with computer-generated and conventional surgical guides using a split-mouth design. Ten patients received two implants each in symmetric locations. All implants were planned virtually using a software program and information from cone beam computed tomographic scans taken with scan appliances in place. Patients were randomly selected for computer-aided design/computer-assisted manufacture (CAD/CAM)-guided implant placement on their right or left side. Conventional guides were used on the contralateral side. Patients underwent operative cone beam computed tomography postoperatively. Planned and actual implant positions were compared using three-dimensional analyses capable of measuring volume overlap as well as differences in angles and coronal and apical positions. Results were compared using a mixed-model repeated-measures analysis of variance and were further analyzed using a Bartlett test for unequal variance (α = .05). Implants placed with CAD/CAM guides were closer to the planned positions in all eight categories examined. However, statistically significant differences were shown only for coronal horizontal distances. It was also shown that CAD/CAM guides had less variability than conventional guides, which was statistically significant for apical distance. Implants placed using CAD/CAM surgical guides provided greater accuracy in a lateral direction than conventional guides. In addition, CAD/CAM guides were more consistent in their deviation from the planned locations than conventional guides.

Fractional Order PIλDμ Control for Maglev Guiding System

Science.gov (United States)

Hu, Qing; Hu, Yuwei

To effectively suppress the external disturbances and parameter perturbation problem of the maglev guiding system, and improve speed and robustness, the electromagnetic guiding system is exactly linearized using state feedback method, Fractional calculus theory is introduced, the order of integer order PID control was extended to the field of fractional, then fractional order PIλDμ Controller was presented, Due to the extra two adjustable parameters compared with traditional PID controller, fractional order PIλDμ controllers were expected to show better control performance. The results of the computer simulation show that the proposed controller suppresses the external disturbances and parameter perturbation of the system effectively; the system response speed was increased; at the same time, it had flexible structure and stronger robustness.

SAFT-UT utilities: Guide to SAFT-UT principles and conventions

International Nuclear Information System (INIS)

Hall, T.E.

1987-10-01

This guide, the Guide to SAFT-UT (Synthetic Aperture Focusing Technique-Ultrasonic Testing), Principles and Conventions, is intended to provide the user with an overall background for practical implementation of SAFT-UT and the associated software utilities. It is not intended to exhaustively cover each related item, but rather to supply information from theory and experience that will assist the serious user in exploiting the robust nature of the SAFT technology. Chapter 1 gives an introductory overview from a historical perspective, emphasizing the need to maintain data integrity throughout the SAFT-UT imaging process. Chapter 2 includes a theoretical description of the Three SAFT-UT configurations currently being supported (single transducer pulse-echo, TSAFT, and TSAFT-2). A general description of the software tools is given in Chapter 3. It describes the major utilities and the general use of each one. Chapter 4 deals with the system resolution and sampling demands of SAFT-UT. A discussion of the strengths and limitations of the SAFT technique is provided in Chapter 5. The scanning conventions assumed throughout the implementation of the SAFT-UT utilities are detailed in Chapter 6. Chapter 7 lists an exhaustive supply of references for the user desiring to investigate the SAFT technology further. 26 refs., 19 figs

Automated landmark-guided deformable image registration.

Science.gov (United States)

Kearney, Vasant; Chen, Susie; Gu, Xuejun; Chiu, Tsuicheng; Liu, Honghuan; Jiang, Lan; Wang, Jing; Yordy, John; Nedzi, Lucien; Mao, Weihua

2015-01-07

The purpose of this work is to develop an automated landmark-guided deformable image registration (LDIR) algorithm between the planning CT and daily cone-beam CT (CBCT) with low image quality. This method uses an automated landmark generation algorithm in conjunction with a local small volume gradient matching search engine to map corresponding landmarks between the CBCT and the planning CT. The landmarks act as stabilizing control points in the following Demons deformable image registration. LDIR is implemented on graphics processing units (GPUs) for parallel computation to achieve ultra fast calculation. The accuracy of the LDIR algorithm has been evaluated on a synthetic case in the presence of different noise levels and data of six head and neck cancer patients. The results indicate that LDIR performed better than rigid registration, Demons, and intensity corrected Demons for all similarity metrics used. In conclusion, LDIR achieves high accuracy in the presence of multimodality intensity mismatch and CBCT noise contamination, while simultaneously preserving high computational efficiency.

Automated landmark-guided deformable image registration

International Nuclear Information System (INIS)

Kearney, Vasant; Chen, Susie; Gu, Xuejun; Chiu, Tsuicheng; Liu, Honghuan; Jiang, Lan; Wang, Jing; Yordy, John; Nedzi, Lucien; Mao, Weihua

2015-01-01

The purpose of this work is to develop an automated landmark-guided deformable image registration (LDIR) algorithm between the planning CT and daily cone-beam CT (CBCT) with low image quality. This method uses an automated landmark generation algorithm in conjunction with a local small volume gradient matching search engine to map corresponding landmarks between the CBCT and the planning CT. The landmarks act as stabilizing control points in the following Demons deformable image registration. LDIR is implemented on graphics processing units (GPUs) for parallel computation to achieve ultra fast calculation. The accuracy of the LDIR algorithm has been evaluated on a synthetic case in the presence of different noise levels and data of six head and neck cancer patients. The results indicate that LDIR performed better than rigid registration, Demons, and intensity corrected Demons for all similarity metrics used. In conclusion, LDIR achieves high accuracy in the presence of multimodality intensity mismatch and CBCT noise contamination, while simultaneously preserving high computational efficiency. (paper)

Serial histopathological changes in irradiated guinea pig lung receiving conventional fractionated and hyperfractionated irradiation

International Nuclear Information System (INIS)

Itoh, Satoshi; Inomata, Taisuke; Ogawa, Yasuhiro; Yoshida, Shoji; Sonobe, Hiroshi; Ohtsuki, Yuji

1999-01-01

The purpose of this study is to determine serial histopathological differences in guinea pig lungs receiving the same total dose as clinically used between conventional fractionated and hyperfractionated irradiation. The guinea pigs received 80 Gy in 40 daily fractions of 2 Gy each (conventional fractionation), 80 Gy in 80 fractions of 1 Gy each twice a day (hyperfractionation), 81 Gy in 27 daily fractions of 3 Gy each (conventional fractionation), or 81 Gy in 54 fractions of 1.5 Gy each twice a day (hyperfractionation). We evaluated the histopathological changes of irradiated guinea pig lungs at 1, 2, 3, 6, 9, and 12 months after irradiation. The guinea pig lungs that received 81 Gy in 27 daily fractions showed histopathological changes of inflammation including formation of lymph follicles after 6 months. The lungs which received 81 Gy in 54 fractions showed similar but slightly less pronounced changes than those that received 81 Gy in 27 daily fractions. The guinea pig lungs of other groups showed no histopathological changes during the observation period. In hyperfractionated irradiation the damage to the guinea pig lung is quantitatively less than that occurring as a result of conventional fractionated irradiation of the same total dose. (author)

Serial histopathological changes in irradiated guinea pig lung receiving conventional fractionated and hyperfractionated irradiation

Energy Technology Data Exchange (ETDEWEB)

Itoh, Satoshi; Inomata, Taisuke; Ogawa, Yasuhiro; Yoshida, Shoji; Sonobe, Hiroshi; Ohtsuki, Yuji [Kochi Medical School, Nankoku (Japan)

1999-05-01

The purpose of this study is to determine serial histopathological differences in guinea pig lungs receiving the same total dose as clinically used between conventional fractionated and hyperfractionated irradiation. The guinea pigs received 80 Gy in 40 daily fractions of 2 Gy each (conventional fractionation), 80 Gy in 80 fractions of 1 Gy each twice a day (hyperfractionation), 81 Gy in 27 daily fractions of 3 Gy each (conventional fractionation), or 81 Gy in 54 fractions of 1.5 Gy each twice a day (hyperfractionation). We evaluated the histopathological changes of irradiated guinea pig lungs at 1, 2, 3, 6, 9, and 12 months after irradiation. The guinea pig lungs that received 81 Gy in 27 daily fractions showed histopathological changes of inflammation including formation of lymph follicles after 6 months. The lungs which received 81 Gy in 54 fractions showed similar but slightly less pronounced changes than those that received 81 Gy in 27 daily fractions. The guinea pig lungs of other groups showed no histopathological changes during the observation period. In hyperfractionated irradiation the damage to the guinea pig lung is quantitatively less than that occurring as a result of conventional fractionated irradiation of the same total dose. (author)

A small animal image guided irradiation system study using 3D dosimeters

International Nuclear Information System (INIS)

Qian, Xin; Wuu, Cheng-Shie; Admovics, John

2015-01-01

In a high resolution image-guided small animal irradiation platform, a cone beam computed tomography (CBCT) is integrated with an irradiation unit for precise targeting. Precise quality assurance is essential for both imaging and irradiation components. The conventional commissioning techniques with films face major challenges due to alignment uncertainty and labour intensive film preparation and scanning. In addition, due to the novel design of this platform the mouse stage rotation for CBCT imaging is perpendicular to the gantry rotation for irradiation. Because these two rotations are associated with different mechanical systems, discrepancy between rotation isocenters exists. In order to deliver x-ray precisely, it is essential to verify coincidence of the imaging and the irradiation isocenters. A 3D PRESAGE dosimeter can provide an excellent tool for checking dosimetry and verifying coincidence of irradiation and imaging coordinates in one system. Dosimetric measurements were performed to obtain beam profiles and percent depth dose (PDD). Isocentricity and coincidence of the mouse stage and gantry rotations were evaluated with starshots acquired using PRESAGE dosimeters. A single PRESAGE dosimeter can provide 3 -D information in both geometric and dosimetric uncertainty, which is crucial for translational studies

Preoperative intensity-modulated and image-guided radiotherapy with a simultaneous integrated boost in locally advanced rectal cancer: Report on late toxicity and outcome

International Nuclear Information System (INIS)

Engels, Benedikt; Platteaux, Nele; Van den Begin, Robbe; Gevaert, Thierry; Sermeus, Alexandra; Storme, Guy; Verellen, Dirk; De Ridder, Mark

2014-01-01

Background and purpose: The addition of chemotherapy to preoperative radiotherapy has been established as the standard of care for patients with cT3-4 rectal cancer. As an alternative strategy, we explored intensity-modulated and image-guided radiotherapy (IMRT–IGRT) with a simultaneous integrated boost (SIB) in a prospective phase II study. Here, we report outcome and late toxicity after a median follow-up of 54 months. Methods and materials: A total of 108 patients were treated preoperatively with IMRT–IGRT, delivering a dose of 46 Gy in fractions of 2 Gy. Patients (n = 57) displaying an anticipated circumferential resection margin (CRM) of less than 2 mm based on magnetic resonance imaging received a SIB to the tumor up to a total dose of 55.2 Gy. Results: The absolute incidence of grade ⩾3 late gastrointestinal and urinary toxicity was 9% and 4%, respectively, with a 13% rate of any grade ⩾3 late toxicity. The actuarial 5-year local control (LC), progression-free survival (PFS) and overall survival (OS) were 97%, 57%, and 68%. On multivariate analysis, R1 resection and pN2 disease were associated with significantly impaired OS. Conclusions: The use of preoperative IMRT–IGRT with a SIB resulted in a high 5-year LC rate and non-negligible late toxicity

Diffuse reflectance imaging: a tool for guided biopsy

Science.gov (United States)

Jayanthi, Jayaraj L.; Subhash, Narayanan; Manju, Stephen; Nisha, Unni G.; Beena, Valappil T.

2012-01-01

Accurate diagnosis of premalignant or malignant oral lesions depends on the quality of the biopsy, adequate clinical information and correct interpretation of the biopsy results. The major clinical challenge is to precisely locate the biopsy site in a clinically suspicious lesion. Dips due to oxygenated hemoglobin absorption have been noticed at 545 and 575 nm in the diffusely reflected white light spectra of oral mucosa and the intensity ratio R545/R575 has been found suited for early detection of oral pre-cancers. A multi-spectral diffuse reflectance (DR) imaging system has been developed consisting of an electron multiplying charge coupled device (EMCCD) camera and a liquid crystal tunable filter for guiding the clinician to an optimal biopsy site. Towards this DR images were recorded from 27 patients with potentially malignant lesions on their tongue (dorsal, lateral and ventral sides) and from 44 healthy controls at 545 and 575 nm with the DR imaging system. False colored ratio image R545/R575 of the lesion provides a visual discerning capability that helps in locating the most malignant site for biopsy. Histopathological report of guided biopsy showed that out of the 27 patients 16 were cancers, 9 pre-cancers and 2 lichen planus. In this clinical trial DR imaging has correctly guided 25 biopsy sites, yielding a sensitivity of 93% and a specificity of 98%, thereby establishing the potential of DR imaging as a tool for guided biopsy.

Efficacy and toxicity of conventionally fractionated pelvic radiation with a hypo fractionated simultaneous versus conventionally fractionated sequential boost for patients with high-risk prostate cancer

International Nuclear Information System (INIS)

McDonald, Andrew M.; Jacob, Rojymon; Dobelbower, Michael C.; Kim, Robert Y.; Fiveash, John B.

2013-01-01

Purpose: To determine if high-risk prostate cancer responds differently to hypo fractionation. Material and methods: One hundred and fifty-seven men with NCCN high-risk (T3, PSA 20, or Gleason 8) clinically localized prostate cancer treated between 1998 and 2010 met the inclusion criteria for the analysis. Eighty-two were treated with conventional WPRT with a conventionally fractionated sequential boost to the prostate (cRT), with the prostate receiving 75-77 Gy in 1.8 - 2.0 Gy fractions. Seventy-five were treated with pelvic IMRT with a hypo fractionated simultaneous boost to the prostate (hRT), with the prostate receiving 70 Gy in 2.5 Gy fractions. The dose to the pelvic lymph nodes was 45 Gy in the cRT group and 50.4 Gy in the hRT group, both at 1.8 Gy per fraction. Ninety-two percent received neoadjuvant hormonal ablation therapy, typically beginning two months prior to the start of RT. Results: Median follow-up was 6.5 years for men receiving cRT and 3.7 years for those receiving hRT. The actuarial rate of biochemical control at four years was 88% for cRT and 94% for hRT (p=0.82). The rates of early rectal and urinary grade ≥2 toxicities were 35% (29 of 82) and 49% (40 of 82) for the cRT group and 36% (27 of 75) and 44% (33 of 75) for the hRT group. The actuarial rate of late grade 2 rectal toxicity at four years was 25% for the cRT group and 13% for the hRT group (p=0.037). The rate of late grade 3 rectal complications was 4% (3 of 82) for patients receiving cRT and 1% (1 of 75) for patients receiving hRT. Conclusion: Initial follow-up indicates equivalent biochemical control between regimens. Patients receiving hRT experienced fewer late rectal complications

Particle image velocimetry a practical guide

CERN Document Server

Raffel, Marcus; Wereley, Steve T; Kompenhans, Jürgen

2007-01-01

The development of Particle Image Velocimetry (PIV), a measurement technique, which allows for capturing velocity information of whole ?ow ?elds in fractions of a second, has begun in the eighties of the last century. In 1998, when this book has been published ?rstly, the PIV technique emerged from laboratories to applications in fundamental and industrial research, in par- lel to the transition from photo-graphicalto video recording techniques. Thus this book, whose objective was and is to serve as a practical guide to the PIV technique, found strong interest within the increasing group of us

MR image-guided portal verification for brain treatment field

International Nuclear Information System (INIS)

Yin, F.-F.; Gao, Q.H.; Xie, H.; Nelson, D.F.; Yu, Y.; Kwok, W.E.; Totterman, S.; Schell, M.C.; Rubin, P.

1996-01-01

Purpose/Objective: Although MR images have been extensively used for the treatment planning of radiation therapy of cancers, especially for brain cancers, they are not effectively used for the portal verification due to lack of bone/air information in MR images and geometric distortions. Typically, MR images are utilized through correlation with CT images, and this procedure is usually very labor and time consuming. For many brain cancer patients to be treated using conventional external beam radiation, MR images with proper distortion correction provide sufficient information for treatment planning and dose calculation, and a projection images may be generated for each specific treatment port and to be used as a reference image for treatment verification. The question is how to transfer anatomical features in MR images to the projection image as landmarks which could be correlated automatically to those in the portal image. The goal of this study is to generate digitally reconstructed projection images from MR brain images with some important anatomical features (brain contour, skull and gross tumor) as well as their relative locations to be used as references for the development of computerized portal verification scheme. Materials/Methods: Compared to conventional digital reconstructed radiograph from CT images, generation of digitally reconstructed projection images from MR images is heavily involved with pixel manipulation of MR images to correlate information from two types of images (MR, portal x-ray images) which are produced based on totally different imaging principles. Initially a wavelet based multi-resolution adaptive thresholding method is used to segment the skull slice-by-slice in MR brain axial images, and identified skull pixels are re-assigned to relatively higher intensities so that projection images will have comparable grey-level information as that in typical brain portal images. Both T1- and T2-weighted images are utilized to eliminate fat

Artificial neural network based gynaecological image-guided adaptive brachytherapy treatment planning correction of intra-fractional organs at risk dose variation.

Science.gov (United States)

Jaberi, Ramin; Siavashpour, Zahra; Aghamiri, Mahmoud Reza; Kirisits, Christian; Ghaderi, Reza

2017-12-01

Intra-fractional organs at risk (OARs) deformations can lead to dose variation during image-guided adaptive brachytherapy (IGABT). The aim of this study was to modify the final accepted brachytherapy treatment plan to dosimetrically compensate for these intra-fractional organs-applicators position variations and, at the same time, fulfilling the dosimetric criteria. Thirty patients with locally advanced cervical cancer, after external beam radiotherapy (EBRT) of 45-50 Gy over five to six weeks with concomitant weekly chemotherapy, and qualified for intracavitary high-dose-rate (HDR) brachytherapy with tandem-ovoid applicators were selected for this study. Second computed tomography scan was done for each patient after finishing brachytherapy treatment with applicators in situ. Artificial neural networks (ANNs) based models were used to predict intra-fractional OARs dose-volume histogram parameters variations and propose a new final plan. A model was developed to estimate the intra-fractional organs dose variations during gynaecological intracavitary brachytherapy. Also, ANNs were used to modify the final brachytherapy treatment plan to compensate dosimetrically for changes in 'organs-applicators', while maintaining target dose at the original level. There are semi-automatic and fast responding models that can be used in the routine clinical workflow to reduce individually IGABT uncertainties. These models can be more validated by more patients' plans to be able to serve as a clinical tool.

Artificial neural network based gynaecological image-guided adaptive brachytherapy treatment planning correction of intra-fractional organs at risk dose variation

Directory of Open Access Journals (Sweden)

Ramin Jaberi

2017-12-01

Full Text Available Purpose : Intra-fractional organs at risk (OARs deformations can lead to dose variation during image-guided adaptive brachytherapy (IGABT. The aim of this study was to modify the final accepted brachytherapy treatment plan to dosimetrically compensate for these intra-fractional organs-applicators position variations and, at the same time, fulfilling the dosimetric criteria. Material and methods : Thirty patients with locally advanced cervical cancer, after external beam radiotherapy (EBRT of 45-50 Gy over five to six weeks with concomitant weekly chemotherapy, and qualified for intracavitary high-dose-rate (HDR brachytherapy with tandem-ovoid applicators were selected for this study. Second computed tomography scan was done for each patient after finishing brachytherapy treatment with applicators in situ. Artificial neural networks (ANNs based models were used to predict intra-fractional OARs dose-volume histogram parameters variations and propose a new final plan. Results : A model was developed to estimate the intra-fractional organs dose variations during gynaecological intracavitary brachytherapy. Also, ANNs were used to modify the final brachytherapy treatment plan to compensate dosimetrically for changes in ‘organs-applicators’, while maintaining target dose at the original level. Conclusions : There are semi-automatic and fast responding models that can be used in the routine clinical workflow to reduce individually IGABT uncertainties. These models can be more validated by more patients’ plans to be able to serve as a clinical tool.

Image Structure-Preserving Denoising Based on Difference Curvature Driven Fractional Nonlinear Diffusion

Directory of Open Access Journals (Sweden)

Xuehui Yin

2015-01-01

Full Text Available The traditional integer-order partial differential equations and gradient regularization based image denoising techniques often suffer from staircase effect, speckle artifacts, and the loss of image contrast and texture details. To address these issues, in this paper, a difference curvature driven fractional anisotropic diffusion for image noise removal is presented, which uses two new techniques, fractional calculus and difference curvature, to describe the intensity variations in images. The fractional-order derivatives information of an image can deal well with the textures of the image and achieve a good tradeoff between eliminating speckle artifacts and restraining staircase effect. The difference curvature constructed by the second order derivatives along the direction of gradient of an image and perpendicular to the gradient can effectively distinguish between ramps and edges. Fourier transform technique is also proposed to compute the fractional-order derivative. Experimental results demonstrate that the proposed denoising model can avoid speckle artifacts and staircase effect and preserve important features such as curvy edges, straight edges, ramps, corners, and textures. They are obviously superior to those of traditional integral based methods. The experimental results also reveal that our proposed model yields a good visual effect and better values of MSSIM and PSNR.

Guiding of short, intense laser pulses through solid guides and preformed plasma channels

International Nuclear Information System (INIS)

Borghesi, M.; Mackinnon, A.J.; Gaillard, R.; Malka, G.; Vickers, C.; Willi, O.; Blanchot, N.; Miquel, J.L.; Canaud, B.; Davies, J.R.; Malka, G.; Offenberger, A.A.

2000-01-01

In a series of experiments carried out at the Rutherford Appleton Laboratory, Chilton (UK) and at the Commissariat a l'Energie Atomique, Limeil (France), various techniques of guiding ultra-intense laser pulses over distances exceeding the natural diffraction length were investigated. Efficient guiding was demonstrated both through density channels formed in an underdense plasma by an intense prepulse and through solid guides (hollow capillary tubes). Indication of collimated fast electron propagation though solid targets has also been obtained. (authors)

Image-guided regularization level set evolution for MR image segmentation and bias field correction.

Science.gov (United States)

Wang, Lingfeng; Pan, Chunhong

2014-01-01

Magnetic resonance (MR) image segmentation is a crucial step in surgical and treatment planning. In this paper, we propose a level-set-based segmentation method for MR images with intensity inhomogeneous problem. To tackle the initialization sensitivity problem, we propose a new image-guided regularization to restrict the level set function. The maximum a posteriori inference is adopted to unify segmentation and bias field correction within a single framework. Under this framework, both the contour prior and the bias field prior are fully used. As a result, the image intensity inhomogeneity can be well solved. Extensive experiments are provided to evaluate the proposed method, showing significant improvements in both segmentation and bias field correction accuracies as compared with other state-of-the-art approaches. Copyright © 2014 Elsevier Inc. All rights reserved.

Diagnostic imaging in intensive care patients

International Nuclear Information System (INIS)

Afione, Cristina; Binda, Maria del C.

2004-01-01

Purpose: To determine the role of imaging diagnostic methods in the location of infection causes of unknown origin in the critical care patient. Material and methods: A comprehensive medical literature search has been done. Recommendations for the diagnostic imaging of septic focus in intensive care patients are presented for each case, with analysis based on evidence. The degree of evidence utilized has been that of Oxford Center for Evidence-based Medicine. Results: Nosocomial infection is the most frequent complication in the intensive care unit (25 to 33%) with high sepsis incidence rate. In order to locate the infection focus, imaging methods play an important role, as a diagnostic tool and to guide therapeutic procedures. The most frequent causes of infection are: ventilation associated pneumonia, sinusitis, intra-abdominal infections and an acute acalculous cholecystitis. This paper analyses the diagnostic imaging of hospital infection, with the evaluation of choice methods for each one and proposes an algorithm to assess the septic patient. Conclusion: There are evidences, with different degrees of recommendation, for the use of diagnostic imaging methods for infectious focuses in critical care patients. The studies have been selected based on their diagnostic precision, on the capacity of the medical team and on the availability of resources, considering the risk-benefit balance for the best safety of the patient. (author)

Guided color consistency optimization for image mosaicking

Science.gov (United States)

Xie, Renping; Xia, Menghan; Yao, Jian; Li, Li

2018-01-01

This paper studies the problem of color consistency correction for sequential images with diverse color characteristics. Existing algorithms try to adjust all images to minimize color differences among images under a unified energy framework, however, the results are prone to presenting a consistent but unnatural appearance when the color difference between images is large and diverse. In our approach, this problem is addressed effectively by providing a guided initial solution for the global consistency optimization, which avoids converging to a meaningless integrated solution. First of all, to obtain the reliable intensity correspondences in overlapping regions between image pairs, we creatively propose the histogram extreme point matching algorithm which is robust to image geometrical misalignment to some extents. In the absence of the extra reference information, the guided initial solution is learned from the major tone of the original images by searching some image subset as the reference, whose color characteristics will be transferred to the others via the paths of graph analysis. Thus, the final results via global adjustment will take on a consistent color similar to the appearance of the reference image subset. Several groups of convincing experiments on both the synthetic dataset and the challenging real ones sufficiently demonstrate that the proposed approach can achieve as good or even better results compared with the state-of-the-art approaches.

Image-guided, intensity-modulated radiation therapy (IG-IMRT) for skull base chordoma and chondrosarcoma: preliminary outcomes.

Science.gov (United States)

Sahgal, Arjun; Chan, Michael W; Atenafu, Eshetu G; Masson-Cote, Laurence; Bahl, Gaurav; Yu, Eugene; Millar, Barbara-Ann; Chung, Caroline; Catton, Charles; O'Sullivan, Brian; Irish, Jonathan C; Gilbert, Ralph; Zadeh, Gelareh; Cusimano, Michael; Gentili, Fred; Laperriere, Normand J

2015-06-01

We report our preliminary outcomes following high-dose image-guided intensity modulated radiotherapy (IG-IMRT) for skull base chordoma and chondrosarcoma. Forty-two consecutive IG-IMRT patients, with either skull base chordoma (n = 24) or chondrosarcoma (n = 18) treated between August 2001 and December 2012 were reviewed. The median follow-up was 36 months (range, 3-90 mo) in the chordoma cohort, and 67 months (range, 15-125) in the chondrosarcoma cohort. Initial surgery included biopsy (7% of patients), subtotal resection (57% of patients), and gross total resection (36% of patients). The median IG-IMRT total doses in the chondrosarcoma and chordoma cohorts were 70 Gy and 76 Gy, respectively, delivered with 2 Gy/fraction. For the chordoma and chondrosarcoma cohorts, the 5-year overall survival and local control rates were 85.6% and 65.3%, and 87.8% and 88.1%, respectively. In total, 10 patients progressed locally: 8 were chordoma patients and 2 chondrosarcoma patients. Both chondrosarcoma failures were in higher-grade tumors (grades 2 and 3). None of the 8 patients with grade 1 chondrosarcoma failed, with a median follow-up of 77 months (range, 34-125). There were 8 radiation-induced late effects-the most significant was a radiation-induced secondary malignancy occurring 6.7 years following IG-IMRT. Gross total resection and age were predictors of local control in the chordoma and chondrosarcoma patients, respectively. We report favorable survival, local control and adverse event rates following high dose IG-IMRT. Further follow-up is needed to confirm long-term efficacy. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Functional image-guided stereotactic body radiation therapy planning for patients with hepatocellular carcinoma

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Tsegmed, Uranchimeg [Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Kimura, Tomoki, E-mail: tkkimura@hiroshima-u.ac.jp [Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Nakashima, Takeo [Division of Radiation Therapy, Hiroshima University Hospital, Hiroshima (Japan); Nakamura, Yuko; Higaki, Toru [Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Imano, Nobuki; Doi, Yoshiko; Kenjo, Masahiro; Ozawa, Shuichi; Murakami, Yuji [Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Awai, Kazuo [Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Nagata, Yasushi [Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan)

2017-07-01

The aim of the current planning study is to evaluate the ability of gadoxetate disodium-enhanced magnetic resonance imaging (EOB-MRI)–guided stereotactic body radiation therapy (SBRT) planning by using intensity-modulated radiation therapy (IMRT) techniques in sparing the functional liver tissues during SBRT for hepatocellular carcinoma. In this study, 20 patients with hepatocellular carcinoma were enrolled. Functional liver tissues were defined according to quantitative liver-spleen contrast ratios ≥ 1.5 on a hepatobiliary phase scan. Functional images were fused with the planning computed tomography (CT) images; the following 2 SBRT plans were designed using a “step-and-shoot” static IMRT technique for each patient: (1) an anatomical SBRT plan optimization based on the total liver; and (2) a functional SBRT plan based on the functional liver. The total prescribed dose was 48 gray (Gy) in 4 fractions. Dosimetric parameters, including dose to 95% of the planning target volume (PTV D{sub 95%}), percentages of total and functional liver volumes, which received doses from 5 to 30 Gy (V5 to V30 and fV5 to fV30), and mean doses to total and functional liver (MLD and fMLD, respectively) of the 2 plans were compared. Compared with anatomical plans, functional image-guided SBRT plans reduced MLD (mean: plan A, 5.5 Gy; and plan F, 5.1 Gy; p < 0.0001) and fMLD (mean: plan A, 5.4 Gy; and plan F, 4.9 Gy; p < 0.0001), as well as V5 to V30 and fV5 to fV30. No differences were noted in PTV coverage and nonhepatic organs at risk (OARs) doses. In conclusion, EOB-MRI–guided SBRT planning using the IMRT technique may preserve functional liver tissues in patients with hepatocellular carcinoma (HCC).

First Clinical Release of an Online, Adaptive, Aperture-Based Image-Guided Radiotherapy Strategy in Intensity-Modulated Radiotherapy to Correct for Inter- and Intrafractional Rotations of the Prostate

International Nuclear Information System (INIS)

Deutschmann, Heinz; Kametriser, Gerhard; Steininger, Philipp; Scherer, Philipp; Schöller, Helmut; Gaisberger, Christoph; Mooslechner, Michaela; Mitterlechner, Bernhard; Weichenberger, Harald; Fastner, Gert; Wurstbauer, Karl; Jeschke, Stephan; Forstner, Rosemarie; Sedlmayer, Felix

2012-01-01

Purpose: We developed and evaluated a correction strategy for prostate rotations using direct adaptation of segments in intensity-modulated radiotherapy (IMRT). Method and Materials: Implanted fiducials (four gold markers) were used to determine interfractional translations, rotations, and dilations of the prostate. We used hybrid imaging: The markers were automatically detected in two pretreatment planar X-ray projections; their actual position in three-dimensional space was reconstructed from these images at first. The structure set comprising prostate, seminal vesicles, and adjacent rectum wall was transformed accordingly in 6 degrees of freedom. Shapes of IMRT segments were geometrically adapted in a class solution forward-planning approach, derived within seconds on-site and treated immediately. Intrafractional movements were followed in MV electronic portal images captured on the fly. Results: In 31 of 39 patients, for 833 of 1013 fractions (supine, flat couch, knee support, comfortably full bladder, empty rectum, no intraprostatic marker migrations >2 mm of more than one marker), the online aperture adaptation allowed safe reduction of margins clinical target volume–planning target volume (prostate) down to 5 mm when only interfractional corrections were applied: Dominant L-R rotations were found to be 5.3° (mean of means), standard deviation of means ±4.9°, maximum at 30.7°. Three-dimensional vector translations relative to skin markings were 9.3 ± 4.4 mm (maximum, 23.6 mm). Intrafractional movements in 7.7 ± 1.5 min (maximum, 15.1 min) between kV imaging and last beam’s electronic portal images showed further L-R rotations of 2.5° ± 2.3° (maximum, 26.9°), and three-dimensional vector translations of 3.0 ±3.7 mm (maximum, 10.2 mm). Addressing intrafractional errors could further reduce margins to 3 mm. Conclusion: We demonstrated the clinical feasibility of an online adaptive image-guided, intensity-modulated prostate protocol on a standard

First clinical release of an online, adaptive, aperture-based image-guided radiotherapy strategy in intensity-modulated radiotherapy to correct for inter- and intrafractional rotations of the prostate.

Science.gov (United States)

Deutschmann, Heinz; Kametriser, Gerhard; Steininger, Philipp; Scherer, Philipp; Schöller, Helmut; Gaisberger, Christoph; Mooslechner, Michaela; Mitterlechner, Bernhard; Weichenberger, Harald; Fastner, Gert; Wurstbauer, Karl; Jeschke, Stephan; Forstner, Rosemarie; Sedlmayer, Felix

2012-08-01

We developed and evaluated a correction strategy for prostate rotations using direct adaptation of segments in intensity-modulated radiotherapy (IMRT). Implanted fiducials (four gold markers) were used to determine interfractional translations, rotations, and dilations of the prostate. We used hybrid imaging: The markers were automatically detected in two pretreatment planar X-ray projections; their actual position in three-dimensional space was reconstructed from these images at first. The structure set comprising prostate, seminal vesicles, and adjacent rectum wall was transformed accordingly in 6 degrees of freedom. Shapes of IMRT segments were geometrically adapted in a class solution forward-planning approach, derived within seconds on-site and treated immediately. Intrafractional movements were followed in MV electronic portal images captured on the fly. In 31 of 39 patients, for 833 of 1013 fractions (supine, flat couch, knee support, comfortably full bladder, empty rectum, no intraprostatic marker migrations >2 mm of more than one marker), the online aperture adaptation allowed safe reduction of margins clinical target volume-planning target volume (prostate) down to 5 mm when only interfractional corrections were applied: Dominant L-R rotations were found to be 5.3° (mean of means), standard deviation of means ±4.9°, maximum at 30.7°. Three-dimensional vector translations relative to skin markings were 9.3 ± 4.4 mm (maximum, 23.6 mm). Intrafractional movements in 7.7 ± 1.5 min (maximum, 15.1 min) between kV imaging and last beam's electronic portal images showed further L-R rotations of 2.5° ± 2.3° (maximum, 26.9°), and three-dimensional vector translations of 3.0 ±3.7 mm (maximum, 10.2 mm). Addressing intrafractional errors could further reduce margins to 3 mm. We demonstrated the clinical feasibility of an online adaptive image-guided, intensity-modulated prostate protocol on a standard linear accelerator to correct 6 degrees of freedom of

Improvement in toxicity in high risk prostate cancer patients treated with image-guided intensity-modulated radiotherapy compared to 3D conformal radiotherapy without daily image guidance.

Science.gov (United States)

Sveistrup, Joen; af Rosenschöld, Per Munck; Deasy, Joseph O; Oh, Jung Hun; Pommer, Tobias; Petersen, Peter Meidahl; Engelholm, Svend Aage

2014-02-04

Image-guided radiotherapy (IGRT) facilitates the delivery of a very precise radiation dose. In this study we compare the toxicity and biochemical progression-free survival between patients treated with daily image-guided intensity-modulated radiotherapy (IG-IMRT) and 3D conformal radiotherapy (3DCRT) without daily image guidance for high risk prostate cancer (PCa). A total of 503 high risk PCa patients treated with radiotherapy (RT) and endocrine treatment between 2000 and 2010 were retrospectively reviewed. 115 patients were treated with 3DCRT, and 388 patients were treated with IG-IMRT. 3DCRT patients were treated to 76 Gy and without daily image guidance and with 1-2 cm PTV margins. IG-IMRT patients were treated to 78 Gy based on daily image guidance of fiducial markers, and the PTV margins were 5-7 mm. Furthermore, the dose-volume constraints to both the rectum and bladder were changed with the introduction of IG-IMRT. The 2-year actuarial likelihood of developing grade > = 2 GI toxicity following RT was 57.3% in 3DCRT patients and 5.8% in IG-IMRT patients (p analysis, 3DCRT was associated with a significantly increased risk of developing grade > = 2 GI toxicity compared to IG-IMRT (p analysis there was no difference in biochemical progression-free survival between 3DCRT and IG-IMRT. The difference in toxicity can be attributed to the combination of the IMRT technique with reduced dose to organs-at-risk, daily image guidance and margin reduction.

Conventional imaging in paediatric uroradiology

International Nuclear Information System (INIS)

Riccabona, M.; Lindbichler, F.; Sinzig, M.

2002-01-01

Objective: To briefly describe basic conventional imaging in paediatric uroradiology. Method: The state of the art performance of standard imaging techniques (intravenous urography (IVU), voiding cystourethrography (VCU), and ultrasound (US)) is described, with emphasis on technical aspects, indications, and patient preparation such as adequate hydration. Only basic applications as used in routine clinical work are included. Result and conclusion: Conventional imaging methods are irreplaceable. They cover the majority of daily clinical routine queries, with consecutive indication of more sophisticated modalities in those patients who need additional imaging for establishing the final diagnosis or outlining therapeutic options

Conventional imaging in paediatric uroradiology

Energy Technology Data Exchange (ETDEWEB)

Riccabona, M. E-mail: michael.riccabona@kfunigraz.ac.at; Lindbichler, F.; Sinzig, M

2002-08-01

Objective: To briefly describe basic conventional imaging in paediatric uroradiology. Method: The state of the art performance of standard imaging techniques (intravenous urography (IVU), voiding cystourethrography (VCU), and ultrasound (US)) is described, with emphasis on technical aspects, indications, and patient preparation such as adequate hydration. Only basic applications as used in routine clinical work are included. Result and conclusion: Conventional imaging methods are irreplaceable. They cover the majority of daily clinical routine queries, with consecutive indication of more sophisticated modalities in those patients who need additional imaging for establishing the final diagnosis or outlining therapeutic options.

Analytical incorporation of fractionation effects in probabilistic treatment planning for intensity-modulated proton therapy.

Science.gov (United States)

Wahl, Niklas; Hennig, Philipp; Wieser, Hans-Peter; Bangert, Mark

2018-04-01

We show that it is possible to explicitly incorporate fractionation effects into closed-form probabilistic treatment plan analysis and optimization for intensity-modulated proton therapy with analytical probabilistic modeling (APM). We study the impact of different fractionation schemes on the dosimetric uncertainty induced by random and systematic sources of range and setup uncertainty for treatment plans that were optimized with and without consideration of the number of treatment fractions. The APM framework is capable of handling arbitrarily correlated uncertainty models including systematic and random errors in the context of fractionation. On this basis, we construct an analytical dose variance computation pipeline that explicitly considers the number of treatment fractions for uncertainty quantitation and minimization during treatment planning. We evaluate the variance computation model in comparison to random sampling of 100 treatments for conventional and probabilistic treatment plans under different fractionation schemes (1, 5, 30 fractions) for an intracranial, a paraspinal and a prostate case. The impact of neglecting the fractionation scheme during treatment planning is investigated by applying treatment plans that were generated with probabilistic optimization for 1 fraction in a higher number of fractions and comparing them to the probabilistic plans optimized under explicit consideration of the number of fractions. APM enables the construction of an analytical variance computation model for dose uncertainty considering fractionation at negligible computational overhead. It is computationally feasible (a) to simultaneously perform a robustness analysis for all possible fraction numbers and (b) to perform a probabilistic treatment plan optimization for a specific fraction number. The incorporation of fractionation assumptions for robustness analysis exposes a dose to uncertainty trade-off, i.e., the dose in the organs at risk is increased for a

Image-Guided Hypofractionated Radiotherapy in Low-Risk Prostate Cancer Patients

Directory of Open Access Journals (Sweden)

Maurizio Valeriani

2014-01-01

Full Text Available Aim. To evaluate efficacy and toxicity of image-guided hypofractionated radiotherapy (HFRT in the treatment of low-risk prostate cancer. Outcomes and toxicities of this series of patients were compared to another group of 32 low-risk patients treated with conventional fractionation (CFRT. Methods. Fifty-nine patients with low-risk prostate cancer were analysed. Total dose for the prostate and proximal seminal vesicles was 60 Gy delivered in 20 fractions. Results. The median follow-up was 30 months. The actuarial 4-year overall survival, biochemical free survival, and disease specific survival were 100%, 97.4%, and 97.4%, respectively. Acute grade 1-2 gastrointestinal (GI and genitourinary (GU toxicity rates were 11.9% and 40.7%, respectively. Grade 1 GI and GU late toxicity rates were 8.5% and 13.6%, respectively. No grade ≥2 late toxicities were recorded. Acute grade 2-3 GU toxicity resulted significantly lower (P=0.04 in HFRT group compared to the CFRT group. The cumulative 4-year incidence of grade 1-2 GU toxicity was significantly higher (P<0.001 for HFRT patients. Conclusions. Our study demonstrated that hypofractionated regimen provided excellent biochemical control in favorable risk prostate cancer patients. The incidence of GI and GU toxicity was low. However, HFRT presented higher cumulative incidence of low-grade late GU toxicity than CFRT.

Reinforcing the role of the conventional C-arm--a novel method for simplified distal interlocking.

Science.gov (United States)

Windolf, Markus; Schroeder, Josh; Fliri, Ladina; Dicht, Benno; Liebergall, Meir; Richards, R Geoff

2012-01-25

The common practice for insertion of distal locking screws of intramedullary nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure of the patient and the surgical personnel. A new concept is introduced utilizing information from within conventional radiographic images to help accurately guide the surgeon to place the interlocking bolt into the interlocking hole. The newly developed technique was compared to conventional freehand in an operating room (OR) like setting on human cadaveric lower legs in terms of operating time and radiation exposure. The proposed concept (guided freehand), generally based on the freehand gold standard, additionally guides the surgeon by means of visible landmarks projected into the C-arm image. A computer program plans the correct drilling trajectory by processing the lens-shaped hole projections of the interlocking holes from a single image. Holes can be drilled by visually aligning the drill to the planned trajectory. Besides a conventional C-arm, no additional tracking or navigation equipment is required.Ten fresh frozen human below-knee specimens were instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland). The implants were distally locked by performing the newly proposed technique as well as the conventional freehand technique on each specimen. An orthopedic resident surgeon inserted four distal screws per procedure. Operating time, number of images and radiation time were recorded and statistically compared between interlocking techniques using non-parametric tests. A 58% reduction in number of taken images per screw was found for the guided freehand technique (7.4 ± 3.4) (mean ± SD) compared to the freehand technique (17.6 ± 10.3) (p < 0.001). Total radiation time (all 4 screws) was 55% lower for the guided freehand technique compared to conventional freehand (p = 0.001). Operating time per screw (from first

SU-E-J-181: Magnetic Resonance Image-Guided Radiation Therapy Workflow: Initial Clinical Experience

International Nuclear Information System (INIS)

Green, O; Kashani, R; Santanam, L; Wooten, H; Li, H; Rodriguez, V; Hu, Y; Mutic, S; Hand, T; Victoria, J; Steele, C

2014-01-01

Purpose: The aims of this work are to describe the workflow and initial clinical experience treating patients with an MRI-guided radiotherapy (MRIGRT) system. Methods: Patient treatments with a novel MR-IGRT system started at our institution in mid-January. The system consists of an on-board 0.35-T MRI, with IMRT-capable delivery via doubly-focused MLCs on three 60 Co heads. In addition to volumetric MR-imaging, real-time planar imaging is performed during treatment. So far, eleven patients started treatment (six finished), ranging from bladder to lung SBRT. While the system is capable of online adaptive radiotherapy and gating, a conventional workflow was used to start, consisting of volumetric imaging for patient setup using visible tumor, evaluation of tumor motion outside of PTV on cine images, and real-time imaging. Workflow times were collected and evaluated to increase efficiency and evaluate feasibility of adding the adaptive and gating features while maintaining a reasonable patient throughput. Results: For the first month, physicians attended every fraction to provide guidance on identifying the tumor and an acceptable level of positioning and anatomical deviation. Average total treatment times (including setup) were reduced from 55 to 45 min after physician presence was no longer required and the therapists had learned to align patients based on soft-tissue imaging. Presently, the source strengths were at half maximum (7.7K Ci each), therefore beam-on times will be reduced after source replacement. Current patient load is 10 per day, with increase to 25 anticipated in the near future. Conclusion: On-board, real-time MRI-guided RT has been incorporated into clinical use. Treatment times were kept to reasonable lengths while including volumetric imaging, previews of tumor movement, and physician evaluation. Workflow and timing is being continuously evaluated to increase efficiency. In near future, adaptive and gating capabilities of the system will be

Changes in different organic matter fractions during conventional treatment and advanced treatment

Institute of Scientific and Technical Information of China (English)

Chao Chen; Xiaojian Zhang; Lingxia Zhu; Wenjie He; Hongda Han

2011-01-01

XAD-8 resin isolation of organic matter in water was used to divide organic matter into the hydrophobic and hydrophilic fractions.A pilot plant was used to investigate the change in both fractions during conventional and advanced treatment processes.The treatment of hydrophobic organics (HPO), rather than hydrophilic organicas (HPI), should carry greater emphasis due to HPO's higher trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP).The removal of hydrophobic matter and its transmission into hydrophilic matter reduced ultimate DBP yield during the disinfection process.The results showed that sand filtration, ozonation, and biological activated carbon (BAC) filtration had distinct influences on the removal of both organic fractions.Additionally, the combination of processes changed the organic fraction proportions present during treatment.The use of ozonation and BAC maximized organic matter removal efficiency, especially for the hydrophobic fraction.In sum, the combination of pre-ozonation,conventional treatment, and O3-BAC removed 48％ of dissolved organic carbon (DOC), 60％ of HPO, 30％ of HPI, 63％ of THMFP,and 85％ of HAAFP.The use of conventional treatment and O3-BAC without pre-ozonation had a comparable performance, removing 51％ of DOC, 56％ of HPO, 45％ of HPI, 61％ of THMFP, and 72％ of HAAFP.The effectiveness of this analysis method indicated that resin isolation and fractionation should be standardized as an applicable test to help assess water treatment process efficiency.

Quality of intensive care chest imaging

International Nuclear Information System (INIS)

Adam, G.; Wein, B.; Keulers, P.; Stargardt, A.; Guenther, R.W.

1989-01-01

The authors have evaluated the image quality of a stimulable phosphorous plate system in intensive care chest radiography. Four radiologists examined 308 chest radiographs (200 conventional, 108 digital) according to the following criteria: visibility of catheters, tubes (artificial objects), bronchi, central and peripheral vessels, diaphragm, trachea, and retrocardial lung parenchyma. Detectability of these structures was classified as good, poor, or impossible to see. In addition, optical density was measured in the region of liver, heart, and lung. Results were evaluated by Student and υ test

Prospective Trial of High-Dose Reirradiation Using Daily Image Guidance With Intensity-Modulated Radiotherapy for Recurrent and Second Primary Head-and-Neck Cancer

International Nuclear Information System (INIS)

Chen, Allen M.; Farwell, D. Gregory; Luu, Quang; Cheng, Suzan; Donald, Paul J.; Purdy, James A.

2011-01-01

Purpose: To report a single-institutional experience using intensity-modulated radiotherapy with daily image-guided radiotherapy for the reirradiation of recurrent and second cancers of the head and neck. Methods and Materials: Twenty-one consecutive patients were prospectively treated with intensity-modulated radiotherapy from February 2006 to March 2009 to a median dose of 66 Gy (range, 60-70 Gy). None of these patients received concurrent chemotherapy. Daily helical megavoltage CT scans were obtained before each fraction as part of an image-guided radiotherapy registration protocol for patient alignment. Results: The 1- and 2-year estimates of in-field control were 72% and 65%, respectively. A total of 651 daily megavoltage CT scans were obtained. The mean systematic shift to account for interfraction motion was 1.38 ± 1.25 mm, 1.79 ± 1.45 mm, and 1.98 ± 1.75 mm for the medial-lateral, superior-inferior, and anterior-posterior directions, respectively. Pretreatment shifts of >3 mm occurred in 19% of setups in the medial-lateral, 27% in the superior-inferior, and 33% in the anterior-posterior directions, respectively. There were no treatment-related fatalities or hospitalizations. Complications included skin desquamation, odynophagia, otitis externa, keratitis, naso-lacrimal duct stenosis, and brachial plexopathy. Conclusions: Intensity-modulated radiotherapy with daily image guidance results in effective disease control with relatively low morbidity and should be considered for selected patients with recurrent and second primary cancers of the head and neck.

A retrospective comparison of outcome and toxicity of preoperative image-guided intensity-modulated radiotherapy versus conventional pelvic radiotherapy for locally advanced rectal carcinoma

International Nuclear Information System (INIS)

Huang, Chun-Ming; Huang, Ming-Yii; Tsai, Hsiang-Lin; Huang, Ching-Wen; Ma, Cheng-Jen; Lin, Chih-Hung; Huang, Chih-Jen; Wang, Jaw-Yuan

2017-01-01

The aim of the study was to compare clinical outcomes and toxicity between 3D conformal radiotherapy (3DCRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) administered through helical tomotherapy in locally advanced rectal cancer (LARC) patients receiving preoperative chemoradiotherapy. We reviewed 144 patients with Stage II–III rectal cancer receiving preoperative fluoropyrimidine-based chemoradiotherapy followed by radical resection. Tumor responses following chemoradiotherapy were evaluated using the Dworak tumor regression grade (TRG). Of the 144 patients, 45 received IG-IMRT and 99 received 3DCRT. A significant reduction in Grade 3 or 4 acute gastrointestinal toxicity (IG-IMRT, 6.7%; 3DCRT, 15.1%; P = 0.039) was observed by IG-IMRT. The pathologic complete response (pCR) rate did not differ between the IG-IMRT and the 3DCRT group (17.8% vs 15.1%, P = 0.52). Patients in the IG-IMRT group had the trend of favorable tumor regressions (TRG 3 or 4) compared with those in the 3DCRT group (66.7% vs 43.5%, P = 0.071). The median follow-up was 53 months (range, 18–95 months) in the 3DCRT group and 43 months (range, 17–69 months) in the IG-IMRT group. Four-year overall, disease-free, and local failure–free survival rates of the IG-IMRT and 3DCRT groups were 81.6% and 67.9% (P = 0.12), 53.8% and 51.8% (P = 0.51), and 88% and 75.1% (P = 0.031), respectively. LARC patients treated with preoperative IG-IMRT achieved lower acute gastrointestinal adverse effects and a higher local control rate than those treated with 3DCRT, but there was no prominent difference in distant metastasis rate and overall survival between two treatment modalities.

A Dosimetric Evaluation of Conventional Helmet Field Irradiation Versus Two-Field Intensity-Modulated Radiotherapy Technique

International Nuclear Information System (INIS)

Yu, James B.; Shiao, Stephen L.; Knisely, Jonathan

2007-01-01

Purpose: To compare dosimetric differences between conventional two-beam helmet field irradiation (external beam radiotherapy, EBRT) of the brain and a two-field intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: Ten patients who received helmet field irradiation at our institution were selected for study. External beam radiotherapy portals were planned per usual practice. Intensity-modulated radiotherapy fields were created using the identical field angles as the EBRT portals. Each brain was fully contoured along with the spinal cord to the bottom of the C2 vertebral body. This volume was then expanded symmetrically by 0.5 cm to construct the planning target volume. An IMRT plan was constructed using uniform optimization constraints. For both techniques, the nominal prescribed dose was 3,000 cGy in 10 fractions of 300 cGy using 6-MV photons. Comparative dose-volume histograms were generated for each patient and analyzed. Results: Intensity-modulated radiotherapy improved dose uniformity over EBRT for whole brain radiotherapy. The mean percentage of brain receiving >105% of dose was reduced from 29.3% with EBRT to 0.03% with IMRT. The mean maximum dose was reduced from 3,378 cGy (113%) for EBRT to 3,162 cGy (105%) with IMRT. The mean percent volume receiving at least 98% of the prescribed dose was 99.5% for the conventional technique and 100% for IMRT. Conclusions: Intensity-modulated radiotherapy reduces dose inhomogeneity, particularly for the midline frontal lobe structures where hot spots occur with conventional two-field EBRT. More study needs to be done addressing the clinical implications of optimizing dose uniformity and its effect on long-term cognitive function in selected long-lived patients

MR image-guided portal verification for brain treatment field

International Nuclear Information System (INIS)

Yin Fangfang; Gao Qinghuai; Xie Huchen; Nelson, Diana F.; Yu Yan; Kwok, W. Edmund; Totterman, Saara; Schell, Michael C.; Rubin, Philip

1998-01-01

Purpose: To investigate a method for the generation of digitally reconstructed radiographs directly from MR images (DRR-MRI) to guide a computerized portal verification procedure. Methods and Materials: Several major steps were developed to perform an MR image-guided portal verification procedure. Initially, a wavelet-based multiresolution adaptive thresholding method was used to segment the skin slice-by-slice in MR brain axial images. Some selected anatomical structures, such as target volume and critical organs, were then manually identified and were reassigned to relatively higher intensities. Interslice information was interpolated with a directional method to achieve comparable display resolution in three dimensions. Next, a ray-tracing method was used to generate a DRR-MRI image at the planned treatment position, and the ray tracing was simply performed on summation of voxels along the ray. The skin and its relative positions were also projected to the DRR-MRI and were used to guide the search of similar features in the portal image. A Canny edge detector was used to enhance the brain contour in both portal and simulation images. The skin in the brain portal image was then extracted using a knowledge-based searching technique. Finally, a Chamfer matching technique was used to correlate features between DRR-MRI and portal image. Results: The MR image-guided portal verification method was evaluated using a brain phantom case and a clinical patient case. Both DRR-CT and DRR-MRI were generated using CT and MR phantom images with the same beam orientation and then compared. The matching result indicated that the maximum deviation of internal structures was less than 1 mm. The segmented results for brain MR slice images indicated that a wavelet-based image segmentation technique provided a reasonable estimation for the brain skin. For the clinical patient case with a given portal field, the MR image-guided verification method provided an excellent match between

Comparing treatment outcomes of fractional flow reserve-guided and angiography-guided percutaneous coronary intervention in patients with multi-vessel coronary artery diseases: a systematic review and meta-analysis.

Science.gov (United States)

Xiu, Jiancheng; Chen, Gangbin; Zheng, Hua; Wang, Yuegang; Chen, Haibin; Liu, Xuewei; Wu, Juefei; Bin, Jianping

2016-02-01

Fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) is used to assess the need for angioplasty in vessels with intermediate blockages. The treatment outcomes of FFR-guided vs. conventional angiography-guided PCI were evaluated in patients with multi-vessel coronary artery disease (CAD). Prospective and retrospective studies comparing FFR-guided vs. angiography-guided PCI in patients with multi-vessel CAD were identified from medical databases by two independent reviewers using the terms "percutaneous coronary intervention, fractional flow reserve, angiography, coronary heart disease, major adverse cardiac events (MACE) and myocardial infarction". The primary outcome was the number of stents placed, and the secondary outcomes were procedure time, mortality, myocardial infarction (MI) and MACE rates. Seven studies (three retrospective and four prospective), which included 49,517 patients, were included in this review. A total of 4,755 patients underwent FFR, while 44,697 received angiography-guided PCI. The mean patient age ranged from 58 to 71.7 years. The average number of stents used in FFR patients ranged from 0.3-1.9, and in angiography-guided PCI patients ranged from 0.7-2.7. Analysis indicated there was a greater number of stents placed in the angiography-guided group compared with the FFR group (pooled difference in means: -0.64, 95% confidence interval [CI]: -0.81 to -0.47, P < 0.001). There were no differences in the secondary outcomes between the two groups. Both procedures produce similar clinical outcomes, but the fewer number of stents used with FFR may have clinical as was as cost implications.

Multi-centre experience of implementing image-guided intensity-modulated radiotherapy using the TomoTherapy platform

International Nuclear Information System (INIS)

Dean, J.C.; Tudor, G.S.J.; Mott, J.H.; Dunlop, P.R.; Morris, S.L.; Harron, E.C.; Christian, J.A.; Sanghera, P.; Elsworthy, M.; Burnet, N.G.

2013-01-01

Use of image guided (IG) intensity modulated radiotherapy (IMRT) is increasing, and helical tomotherapy provides an effective, integrated solution. Practical experience of implementation, shared at a recent UK TomoTherapy Users' meeting, may help centres introducing these techniques using TomoTherapy or other platforms. Seven centres participated, with data shared from 6, varying from 2500 - 4800 new patients per year. Case selection of patients “most likely” to benefit from IG-IMRT was managed in all centres by multi-professional groups comprising clinical oncologists, physicists, treatment planners and radiographers. Radical treatments ranged from 94% to 100%. The proportions of tumour types varied substantially: head and neck: range 0%–100% (mean of centres 50%), prostate: 3%–96% (mean of centres 28%). Head and neck cases were considered most likely to benefit from IMRT, prostate cases from IGRT, or IG-IMRT if pelvic nodes were being treated. IMRT was also selected for complex target volumes, to avoid field junctions, for technical treatment difficulties, and retreatments. Across the centres, every patient was imaged every day, with positional correction before treatment. In one centre, for prostate patients including pelvic treatment, the pelvis was also imaged weekly. All centres had designed a ‘ramp up’ of patient numbers, which was similar in 5. One centre, treating 96% prostate patients, started with 3 and increased to 36 patients per day within 3 months. The variation in case mix implies wide applicability of IG-IMRT. Daily on-line IGRT with IMRT can be routinely implemented into busy departments

MR image reconstruction via guided filter.

Science.gov (United States)

Huang, Heyan; Yang, Hang; Wang, Kang

2018-04-01

Magnetic resonance imaging (MRI) reconstruction from the smallest possible set of Fourier samples has been a difficult problem in medical imaging field. In our paper, we present a new approach based on a guided filter for efficient MRI recovery algorithm. The guided filter is an edge-preserving smoothing operator and has better behaviors near edges than the bilateral filter. Our reconstruction method is consist of two steps. First, we propose two cost functions which could be computed efficiently and thus obtain two different images. Second, the guided filter is used with these two obtained images for efficient edge-preserving filtering, and one image is used as the guidance image, the other one is used as a filtered image in the guided filter. In our reconstruction algorithm, we can obtain more details by introducing guided filter. We compare our reconstruction algorithm with some competitive MRI reconstruction techniques in terms of PSNR and visual quality. Simulation results are given to show the performance of our new method.

The functional relevance of diffusion tensor imaging in comparison to conventional MRI in patients with cervical compressive myelopathy

Energy Technology Data Exchange (ETDEWEB)

Yang, Young-Mi; Oh, Jae-Keun; Song, Ji-Sun [Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Spine Center, Anyang-si, Gyeonggi-do (Korea, Republic of); Yoo, Woo-Kyoung [Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Department of Physical Medicine and Rehabilitation, Anyang-si (Korea, Republic of); Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Hallym Institute for Translational Genomics and Bioinformatics, Anyang-si (Korea, Republic of); Yoo, Je Hyun; Kwak, Yoon Hae [Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Department of Orthopaedic surgery, Anyang-si (Korea, Republic of); Kim, Seok Woo [Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Spine Center, Anyang-si, Gyeonggi-do (Korea, Republic of); Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Department of Orthopaedic surgery, Anyang-si (Korea, Republic of)

2017-11-15

To determine the functional relevance of diffusion tensor imaging (DTI) metrics and conventional MRI (signal intensity change in T2, compression ratio) by measuring the correlation of these parameters with clinical outcome measured by the modified Japanese Orthopedic Association (mJOA) score. A total of 20 cervical myelopathy (CM) patients participated in this prospective cohort study. The severities of CM were assessed using the mJOA score. Conventional MRIs (T2-weighted images) measuring the signal changes of spinal cords and the degree of compression at the lesion level and DTI metrics [fractional anisotropy (FA), apparent diffusion coefficient (ADC)] at each lesion and below each lesion (C7/T1) level were acquired using a 3-T Achieva MRI. These parameters were correlated with the mJOA scores to determine the functional relevance. Ninety percent of CM patients showed signal changes and 30 % of patients noted a more than 40% canal compression ratio in conventional MRIs at the lesion level; however, these findings were not correlated with the mJOA score (p < 0.05). In contrast, FA values on DTI showed high sensitivity to CM (100%), which was well correlated with the mJOA score (p = 0.034, r = 0.475) below the lesion level (C7/T1). This study showed a meaningful symptomatic correlation between mJOA scores and FA values below the lesion levels in CM patients. It could give us more understanding of the pathological changes in spinal cords matched with various clinical findings in CM patients than the results from conventional MRI. (orig.)

Fractional Flow Reserve-guided Percutaneous Coronary Intervention: Standing the Test of Time

Directory of Open Access Journals (Sweden)

Frederik M. Zimmermann, MD

2016-05-01

Full Text Available Percutaneous coronary intervention (PCI improves symptoms and prognosis in ischemia-inducing, functionally significant, coronary lesions. Use of fractional flow reserve allows physicians to investigate the ischemia-inducing potential of a specific lesion and can be used to guide coronary revascularization, especially in multivessel coronary artery disease. Fractional flow reserve-guided PCI has been extensively investigated. Results show that deferral of stenting in non-significant lesions is safe, whereas deferral of stenting in functionally significant lesions worsens outcome. FFR-guided PCI improves outcome in multivessel disease over angiography-guided PCI. Until recently, there was little known about the long-term outcome of FFR-guided revascularization and its validity in acute coronary syndromes. This review aims to address the new evidence regarding long-term appropriateness of FFR-guided PCI, the need for hyperemia to evaluate functional severity, and the use of FFR in acute coronary syndromes.

Acute Toxicity After Image-Guided Intensity Modulated Radiation Therapy Compared to 3D Conformal Radiation Therapy in Prostate Cancer Patients

Energy Technology Data Exchange (ETDEWEB)

Wortel, Ruud C.; Incrocci, Luca [Department of Radiation Oncology, Erasmus Medical Center Cancer Institute, Rotterdam (Netherlands); Pos, Floris J.; Lebesque, Joos V.; Witte, Marnix G.; Heide, Uulke A. van der; Herk, Marcel van [Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam (Netherlands); Heemsbergen, Wilma D., E-mail: w.heemsbergen@nki.nl [Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam (Netherlands)

2015-03-15

Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows significant dose reductions to organs at risk in prostate cancer patients. However, clinical data identifying the benefits of IG-IMRT in daily practice are scarce. The purpose of this study was to compare dose distributions to organs at risk and acute gastrointestinal (GI) and genitourinary (GU) toxicity levels of patients treated to 78 Gy with either IG-IMRT or 3D-CRT. Methods and Materials: Patients treated with 3D-CRT (n=215) and IG-IMRT (n=260) receiving 78 Gy in 39 fractions within 2 randomized trials were selected. Dose surface histograms of anorectum, anal canal, and bladder were calculated. Identical toxicity questionnaires were distributed at baseline, prior to fraction 20 and 30 and at 90 days after treatment. Radiation Therapy Oncology Group (RTOG) grade ≥1, ≥2, and ≥3 endpoints were derived directly from questionnaires. Univariate and multivariate binary logistic regression analyses were applied. Results: The median volumes receiving 5 to 75 Gy were significantly lower (all P<.001) with IG-IMRT for anorectum, anal canal, and bladder. The mean dose to the anorectum was 34.4 Gy versus 47.3 Gy (P<.001), 23.6 Gy versus 44.6 Gy for the anal canal (P<.001), and 33.1 Gy versus 43.2 Gy for the bladder (P<.001). Significantly lower grade ≥2 toxicity was observed for proctitis, stool frequency ≥6/day, and urinary frequency ≥12/day. IG-IMRT resulted in significantly lower overall RTOG grade ≥2 GI toxicity (29% vs 49%, respectively, P=.002) and overall GU grade ≥2 toxicity (38% vs 48%, respectively, P=.009). Conclusions: A clinically meaningful reduction in dose to organs at risk and acute toxicity levels was observed in IG-IMRT patients, as a result of improved technique and tighter margins. Therefore reduced late toxicity levels can be expected as well; additional research is needed to quantify such reductions.

Real-time intensity based 2D/3D registration using kV-MV image pairs for tumor motion tracking in image guided radiotherapy

Science.gov (United States)

Furtado, H.; Steiner, E.; Stock, M.; Georg, D.; Birkfellner, W.

2014-03-01

Intra-fractional respiratorymotion during radiotherapy is one of themain sources of uncertainty in dose application creating the need to extend themargins of the planning target volume (PTV). Real-time tumormotion tracking by 2D/3D registration using on-board kilo-voltage (kV) imaging can lead to a reduction of the PTV. One limitation of this technique when using one projection image, is the inability to resolve motion along the imaging beam axis. We present a retrospective patient study to investigate the impact of paired portal mega-voltage (MV) and kV images, on registration accuracy. We used data from eighteen patients suffering from non small cell lung cancer undergoing regular treatment at our center. For each patient we acquired a planning CT and sequences of kV and MV images during treatment. Our evaluation consisted of comparing the accuracy of motion tracking in 6 degrees-of-freedom(DOF) using the anterior-posterior (AP) kV sequence or the sequence of kV-MV image pairs. We use graphics processing unit rendering for real-time performance. Motion along cranial-caudal direction could accurately be extracted when using only the kV sequence but in AP direction we obtained large errors. When using kV-MV pairs, the average error was reduced from 3.3 mm to 1.8 mm and the motion along AP was successfully extracted. The mean registration time was of 190+/-35ms. Our evaluation shows that using kVMV image pairs leads to improved motion extraction in 6 DOF. Therefore, this approach is suitable for accurate, real-time tumor motion tracking with a conventional LINAC.

Contrast-guided image interpolation.

Science.gov (United States)

Wei, Zhe; Ma, Kai-Kuang

2013-11-01

In this paper a contrast-guided image interpolation method is proposed that incorporates contrast information into the image interpolation process. Given the image under interpolation, four binary contrast-guided decision maps (CDMs) are generated and used to guide the interpolation filtering through two sequential stages: 1) the 45(°) and 135(°) CDMs for interpolating the diagonal pixels and 2) the 0(°) and 90(°) CDMs for interpolating the row and column pixels. After applying edge detection to the input image, the generation of a CDM lies in evaluating those nearby non-edge pixels of each detected edge for re-classifying them possibly as edge pixels. This decision is realized by solving two generalized diffusion equations over the computed directional variation (DV) fields using a derived numerical approach to diffuse or spread the contrast boundaries or edges, respectively. The amount of diffusion or spreading is proportional to the amount of local contrast measured at each detected edge. The diffused DV fields are then thresholded for yielding the binary CDMs, respectively. Therefore, the decision bands with variable widths will be created on each CDM. The two CDMs generated in each stage will be exploited as the guidance maps to conduct the interpolation process: for each declared edge pixel on the CDM, a 1-D directional filtering will be applied to estimate its associated to-be-interpolated pixel along the direction as indicated by the respective CDM; otherwise, a 2-D directionless or isotropic filtering will be used instead to estimate the associated missing pixels for each declared non-edge pixel. Extensive simulation results have clearly shown that the proposed contrast-guided image interpolation is superior to other state-of-the-art edge-guided image interpolation methods. In addition, the computational complexity is relatively low when compared with existing methods; hence, it is fairly attractive for real-time image applications.

Image guided prostate cancer treatments

Energy Technology Data Exchange (ETDEWEB)

Bard, Robert L. [Bard Cancer Center, Biofoundation for Angiogenesis Research and Development, New York, NY (United States); Fuetterer, Jurgen J. [Radboud Univ. Nijmegen, Medical Centre (Netherlands). Dept. of Radiology; Sperling, Dan (ed.) [Sperling Prostate Center, Alpha 3TMRI, New York, NY (United States)

2014-07-01

Systematic overview of the application of ultrasound and MRI in the diagnosis and treatment of diseases of the lower urinary tract. Detailed information on image-guided therapies, including focused ultrasound, photodynamic therapy, and microwave and laser ablation. Numerous high-quality illustrations based on high-end equipment. Represents the state of the art in Non Invasive Imaging and Minimally Invasive Ablation Treatment (MIAT). Image-Guided Prostate Cancer Treatments is a comprehensive reference and practical guide on the technology and application of ultrasound and MRI in the male pelvis, with special attention to the prostate. The book is organized into three main sections, the first of which is devoted to general aspects of imaging and image-guided treatments. The second section provides a systematic overview of the application of ultrasound and MRI to the diagnosis and treatment of diseases of the lower urinary tract. Performance of the ultrasound and MRI studies is explained, and the normal and abnormal pathological anatomy is reviewed. Correlation with the ultrasound in the same plane is provided to assist in understanding the MRI sequences. Biopsy and interventional procedures, ultrasound-MRI fusion techniques, and image-guided therapies, including focused ultrasound, photodynamic therapy, microwave and laser ablation, are all fully covered. The third section focuses on securing treatment effectiveness and the use of follow-up imaging to ensure therapeutic success and detect tumor recurrence at an early stage, which is vital given that prompt focal treatment of recurrence is very successful. Here, particular attention is paid to the role of Doppler ultrasound and DCE-MRI technologies. This book, containing a wealth of high-quality illustrations based on high-end equipment, will acquaint beginners with the basics of prostate ultrasound and MRI, while more advanced practitioners will learn new skills, means of avoiding pitfalls, and ways of effectively

Evaluation of image-guided helical tomotherapy for the retreatment of spinal metastasis

International Nuclear Information System (INIS)

Mahan, Stephen L.; Ramsey, Chester R.; Scaperoth, Daniel D.; Chase, Daniel J.; Byrne, Thomas E.

2005-01-01

Introduction: Patients with vertebral metastasis that receive radiation therapy are typically treated to the spinal cord tolerance dose. As such, it is difficult to successfully deliver a second course of radiation therapy for patients with overlapping treatment volumes. In this study, an image-guided helical tomotherapy system was evaluated for the retreatment of previously irradiated vertebral metastasis. Methods and Materials: Helical tomotherapy dose gradients and maximum cord doses were measured in a cylindrical phantom for geometric test cases with separations between the planning target volume (PTV) and the spinal cord organ at risk (OAR) of 2 mm, 4 mm, 6 mm, 8 mm, and 10 mm. Megavoltage computed tomography (CT) images were examined for their ability to localize spinal anatomy for positioning purposes by repeat imaging of the cervical spine in an anthropomorphic phantom. In addition to the phantom studies, 8 patients with cord compressions that had received previous radiation therapy were retreated to a mean dose of 28 Gy using conventional fractionation. Results and Discussion: Megavoltage CT images were capable of positioning an anthropomorphic phantom to within ±1.2 mm (2σ) superior-inferiorly and within ±0.6 mm (2σ) anterior-posteriorly and laterally. Dose gradients of 10% per mm were measured in phantom while PTV uniformity indices of less than 11% were maintained. The calculated maximum cord dose was 25% of the prescribed dose for a 10-mm PTV-to-OAR separation and 71% of the prescribed dose for a PTV-to-OAR separation of 2 mm. Eight patients total have been treated without radiation-induced myelopathy or any other adverse effects from treatment. Conclusions: A technique has been evaluated for the retreatment of vertebral metastasis using image-guided helical tomotherapy. Phantom and patient studies indicated that a tomotherapy system is capable of delivering dose gradients of 10% per mm and positioning the patient within 1.2 mm without the use of

Image Retrieval Algorithm Based on Discrete Fractional Transforms

Science.gov (United States)

Jindal, Neeru; Singh, Kulbir

2013-06-01

The discrete fractional transforms is a signal processing tool which suggests computational algorithms and solutions to various sophisticated applications. In this paper, a new technique to retrieve the encrypted and scrambled image based on discrete fractional transforms has been proposed. Two-dimensional image was encrypted using discrete fractional transforms with three fractional orders and two random phase masks placed in the two intermediate planes. The significant feature of discrete fractional transforms benefits from its extra degree of freedom that is provided by its fractional orders. Security strength was enhanced (1024!)4 times by scrambling the encrypted image. In decryption process, image retrieval is sensitive for both correct fractional order keys and scrambling algorithm. The proposed approach make the brute force attack infeasible. Mean square error and relative error are the recital parameters to verify validity of proposed method.

Direct imaging of phase objects enables conventional deconvolution in bright field light microscopy.

Directory of Open Access Journals (Sweden)

Carmen Noemí Hernández Candia

Full Text Available In transmitted optical microscopy, absorption structure and phase structure of the specimen determine the three-dimensional intensity distribution of the image. The elementary impulse responses of the bright field microscope therefore consist of separate absorptive and phase components, precluding general application of linear, conventional deconvolution processing methods to improve image contrast and resolution. However, conventional deconvolution can be applied in the case of pure phase (or pure absorptive objects if the corresponding phase (or absorptive impulse responses of the microscope are known. In this work, we present direct measurements of the phase point- and line-spread functions of a high-aperture microscope operating in transmitted bright field. Polystyrene nanoparticles and microtubules (biological polymer filaments serve as the pure phase point and line objects, respectively, that are imaged with high contrast and low noise using standard microscopy plus digital image processing. Our experimental results agree with a proposed model for the response functions, and confirm previous theoretical predictions. Finally, we use the measured phase point-spread function to apply conventional deconvolution on the bright field images of living, unstained bacteria, resulting in improved definition of cell boundaries and sub-cellular features. These developments demonstrate practical application of standard restoration methods to improve imaging of phase objects such as cells in transmitted light microscopy.

Image-guided radiotherapy for effective radiotherapy delivery

CERN Document Server

Karlsson, Ulf Lennart

2016-01-01

Image-guided radiotherapy (IGRT) is a new radiotherapy technology that combines the rapid dose fall off associated with intensity-modulated radiotherapy (IMRT) and daily tumor imaging allowing for high precision tumor dose delivery and effective sparing of surrounding normal organs. The new radiation technology requires close collaboration between radiologists, nuclear medicine specialists, and radiation oncologists to avoid marginal miss. Modern diagnostic imaging such as positron emission tomography (PET) scans, positron emission tomography with Computed Tomograpgy (PET-CT), and magnetic resonance imaging (MRI) allows the radiation oncologist to target the positive tumor with high accuracy. As the tumor is well visualized during radiation treatment, the margins required to avoid geographic miss can be safely reduced , thus sparing the normal organs from excessive radiation. When the tumor is located close to critical radiosensitive structures such as the spinal cord, IGRT can deliver a high dose of radiatio...

Encouraging Early Clinical Outcomes With Helical Tomotherapy–Based Image-Guided Intensity-Modulated Radiation Therapy for Residual, Recurrent, and/or Progressive Benign/Low-Grade Intracranial Tumors: A Comprehensive Evaluation

International Nuclear Information System (INIS)

Gupta, Tejpal; Wadasadawala, Tabassum; Master, Zubin; Phurailatpam, Reena; Pai-Shetty, Rajershi; Jalali, Rakesh

2012-01-01

Purpose: To report early clinical outcomes of helical tomotherapy (HT)-based image-guided intensity-modulated radiation therapy (IMRT) in brain tumors of varying shape, size, and location. Materials and Methods: Patients with residual, recurrent, and/or progressive low-grade intracranial and skull-base tumors were treated on a prospective protocol of HT-based IMRT and followed clinicoradiologically. Standardized metrics were used for plan evaluation and outcome analysis. Results: Twenty-seven patients with 30 lesions were treated to a median radiotherapy dose of 54 Gy in 30 fractions. All HT plans resulted in excellent target volume coverage with steep dose-gradients. The mean (standard deviation) dose homogeneity index and conformity index was 0.07 (0.05) and 0.71 (0.08) respectively. At first response assessment, 20 of 30 lesions were stable, whereas 9 showed partial regression. One patient with a recurrent clival chordoma though neurologically stable showed imaging-defined progression, whereas another patient with stable disease on serial imaging had sustained neurologic worsening. With a median follow-up of 19 months (interquartile range, 11–26 months), the 2-year clinicoradiological progression-free survival and overall survival was 93.3% and 100% respectively. Conclusions: Careful selection of radiotherapy technique is warranted for benign/low-grade brain tumors to achieve durable local control with minimum long-term morbidity. Large or complex-shaped tumors benefit most from IMRT. Our early clinical experience of HT-based IMRT for brain tumors has been encouraging.

Encouraging Early Clinical Outcomes With Helical Tomotherapy-Based Image-Guided Intensity-Modulated Radiation Therapy for Residual, Recurrent, and/or Progressive Benign/Low-Grade Intracranial Tumors: A Comprehensive Evaluation

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Gupta, Tejpal [Department of Radiation Oncology, ACTREC/TMH, Tata Memorial Centre, Kharghar, Navi Mumbai (India); Wadasadawala, Tabassum; Master, Zubin; Phurailatpam, Reena; Pai-Shetty, Rajershi; Jalali, Rakesh [Department of Radiation Oncology, ACTREC/TMH, Tata Memorial Centre, Kharghar, Navi Mumbai (India)

2012-02-01

Purpose: To report early clinical outcomes of helical tomotherapy (HT)-based image-guided intensity-modulated radiation therapy (IMRT) in brain tumors of varying shape, size, and location. Materials and Methods: Patients with residual, recurrent, and/or progressive low-grade intracranial and skull-base tumors were treated on a prospective protocol of HT-based IMRT and followed clinicoradiologically. Standardized metrics were used for plan evaluation and outcome analysis. Results: Twenty-seven patients with 30 lesions were treated to a median radiotherapy dose of 54 Gy in 30 fractions. All HT plans resulted in excellent target volume coverage with steep dose-gradients. The mean (standard deviation) dose homogeneity index and conformity index was 0.07 (0.05) and 0.71 (0.08) respectively. At first response assessment, 20 of 30 lesions were stable, whereas 9 showed partial regression. One patient with a recurrent clival chordoma though neurologically stable showed imaging-defined progression, whereas another patient with stable disease on serial imaging had sustained neurologic worsening. With a median follow-up of 19 months (interquartile range, 11-26 months), the 2-year clinicoradiological progression-free survival and overall survival was 93.3% and 100% respectively. Conclusions: Careful selection of radiotherapy technique is warranted for benign/low-grade brain tumors to achieve durable local control with minimum long-term morbidity. Large or complex-shaped tumors benefit most from IMRT. Our early clinical experience of HT-based IMRT for brain tumors has been encouraging.

Image-guided system versus manual marking for toric intraocular lens alignment in cataract surgery

NARCIS (Netherlands)

Webers, V.S.C.; Bauer, N.J.C.; Visser, N.; Berendschot, T.T.J.M.; van den Biggelaar, F.J.H.M.; Nuijts, R.M.M.A.

2017-01-01

Purpose To compare the accuracy of toric intraocular lens (IOL) alignment using the Verion Image-Guided System versus a conventional manual ink-marking procedure. Setting University Eye Clinic Maastricht, Maastricht, the Netherlands. Design Prospective randomized clinical trial. Methods Eyes with

HDR Pathological Image Enhancement Based on Improved Bias Field Correction and Guided Image Filter

Directory of Open Access Journals (Sweden)

Qingjiao Sun

2016-01-01

Full Text Available Pathological image enhancement is a significant topic in the field of pathological image processing. This paper proposes a high dynamic range (HDR pathological image enhancement method based on improved bias field correction and guided image filter (GIF. Firstly, a preprocessing including stain normalization and wavelet denoising is performed for Haematoxylin and Eosin (H and E stained pathological image. Then, an improved bias field correction model is developed to enhance the influence of light for high-frequency part in image and correct the intensity inhomogeneity and detail discontinuity of image. Next, HDR pathological image is generated based on least square method using low dynamic range (LDR image, H and E channel images. Finally, the fine enhanced image is acquired after the detail enhancement process. Experiments with 140 pathological images demonstrate the performance advantages of our proposed method as compared with related work.

A Dosimetric Comparison between Conventional Fractionated and Hypofractionated Image-guided Radiation Therapies for Localized Prostate Cancer

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Ming Li

2016-01-01

Conclusions: To deliver the hypofractionated radiotherapy in prostate cancer, VMAT significantly increased PTV D95% dose and decreased the dose of radiation delivered to adjacent normal tissues comparing to 7-field, step-and-shoot IMRT. Daily online image-guidance and better management of bladder and rectum could make a more precise treatment delivery.

Reinforcing the role of the conventional C-arm - a novel method for simplified distal interlocking

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Windolf Markus

2012-01-01

Full Text Available Abstract Background The common practice for insertion of distal locking screws of intramedullary nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure of the patient and the surgical personnel. A new concept is introduced utilizing information from within conventional radiographic images to help accurately guide the surgeon to place the interlocking bolt into the interlocking hole. The newly developed technique was compared to conventional freehand in an operating room (OR like setting on human cadaveric lower legs in terms of operating time and radiation exposure. Methods The proposed concept (guided freehand, generally based on the freehand gold standard, additionally guides the surgeon by means of visible landmarks projected into the C-arm image. A computer program plans the correct drilling trajectory by processing the lens-shaped hole projections of the interlocking holes from a single image. Holes can be drilled by visually aligning the drill to the planned trajectory. Besides a conventional C-arm, no additional tracking or navigation equipment is required. Ten fresh frozen human below-knee specimens were instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland. The implants were distally locked by performing the newly proposed technique as well as the conventional freehand technique on each specimen. An orthopedic resident surgeon inserted four distal screws per procedure. Operating time, number of images and radiation time were recorded and statistically compared between interlocking techniques using non-parametric tests. Results A 58% reduction in number of taken images per screw was found for the guided freehand technique (7.4 ± 3.4 (mean ± SD compared to the freehand technique (17.6 ± 10.3 (p p = 0.001. Operating time per screw (from first shot to screw tightened was on average 22% reduced by guided freehand (p = 0

Color image guided depth image super resolution using fusion filter

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He, Jin; Liang, Bin; He, Ying; Yang, Jun

2018-04-01

Depth cameras are currently playing an important role in many areas. However, most of them can only obtain lowresolution (LR) depth images. Color cameras can easily provide high-resolution (HR) color images. Using color image as a guide image is an efficient way to get a HR depth image. In this paper, we propose a depth image super resolution (SR) algorithm, which uses a HR color image as a guide image and a LR depth image as input. We use the fusion filter of guided filter and edge based joint bilateral filter to get HR depth image. Our experimental results on Middlebury 2005 datasets show that our method can provide better quality in HR depth images both numerically and visually.

Image-Guided Cancer Nanomedicine

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Dong-Hyun Kim

2018-01-01

Full Text Available Multifunctional nanoparticles with superior imaging properties and therapeutic effects have been extensively developed for the nanomedicine. However, tumor-intrinsic barriers and tumor heterogeneity have resulted in low in vivo therapeutic efficacy. The poor in vivo targeting efficiency in passive and active targeting of nano-therapeutics along with the toxicity of nanoparticles has been a major problem in nanomedicine. Recently, image-guided nanomedicine, which can deliver nanoparticles locally using non-invasive imaging and interventional oncology techniques, has been paid attention as a new opportunity of nanomedicine. This short review will discuss the existing challenges in nanomedicine and describe the prospects for future image-guided nanomedicine.

Image-guided automatic triggering of a fractional CO2 laser in aesthetic procedures.

Science.gov (United States)

Wilczyński, Sławomir; Koprowski, Robert; Wiernek, Barbara K; Błońska-Fajfrowska, Barbara

2016-09-01

Laser procedures in dermatology and aesthetic medicine are associated with the need for manual laser triggering. This leads to pulse overlapping and side effects. Automatic laser triggering based on image analysis can provide a secure fit to each successive doses of radiation. A fractional CO2 laser was used in the study. 500 images of the human skin of healthy subjects were acquired. Automatic triggering was initiated by an application together with a camera which tracks and analyses the skin in visible light. The tracking algorithm uses the methods of image analysis to overlap images. After locating the characteristic points in analysed adjacent areas, the correspondence of graphs is found. The point coordinates derived from the images are the vertices of graphs with respect to which isomorphism is sought. When the correspondence of graphs is found, it is possible to overlap the neighbouring parts of the image. The proposed method of laser triggering owing to the automatic image fitting method allows for 100% repeatability. To meet this requirement, there must be at least 13 graph vertices obtained from the image. For this number of vertices, the time of analysis of a single image is less than 0.5s. The proposed method, applied in practice, may help reduce the number of side effects during dermatological laser procedures resulting from laser pulse overlapping. In addition, it reduces treatment time and enables to propose new techniques of treatment through controlled, precise laser pulse overlapping. Copyright © 2016 Elsevier Ltd. All rights reserved.

Automatic prostate localization on cone-beam CT scans for high precision image-guided radiotherapy

NARCIS (Netherlands)

Smitsmans, Monique H. P.; de Bois, Josien; Sonke, Jan-Jakob; Betgen, Anja; Zijp, Lambert J.; Jaffray, David A.; Lebesque, Joos V.; van Herk, Marcel

2005-01-01

PURPOSE: Previously, we developed an automatic three-dimensional gray-value registration (GR) method for fast prostate localization that could be used during online or offline image-guided radiotherapy. The method was tested on conventional computed tomography (CT) scans. In this study, the

Immobilization and positioning systems for treatment of patients with image-guided radiation therapy and intensity modulated radiation therapy)

International Nuclear Information System (INIS)

Hueso Bernad, M. Nuria; Suarez Dieguez, Raquel; Roures Ramos, M. Teresa; Broseta Tormos, M.Mercedes; Tirado Porcar, Miriam M; Del Castillo Arres, Jose; Franch Martinez, Silvia

2009-01-01

For adequate reproduction of daily patient positioning during treatment we use a 3-coordinate system alignment. The first set of axes would be the system of light (laser). - The second coordinate system is recognized by marks on the skin patient and / or immobilization systems. The third set of alignment refers to alignment of coordinates volume to try to locate the isocenter use Guided Radiotherapy Imaging when applied technologies with Intensity Modulated Radiotherapy treatment fields tend to be very small so it made individual protection and immobilization systems such as thermoplastic masks, vacuum sealed bags exterotaxicos conjugated systems and immobilization systems carbon fiber results by combining these immobilization and positioning systems can ensure effective treatment volume to be treated. There is no perfect immobilization system. However the choice of pool of qualified stun makes treatment more precise. (author)

Imaging breast adipose and fibroglandular tissue molecular signatures by using hybrid MRI-guided near-infrared spectral tomography

Science.gov (United States)

Brooksby, Ben; Pogue, Brian W.; Jiang, Shudong; Dehghani, Hamid; Srinivasan, Subhadra; Kogel, Christine; Tosteson, Tor D.; Weaver, John; Poplack, Steven P.; Paulsen, Keith D.

2006-06-01

Magnetic resonance (MR)-guided near-infrared spectral tomography was developed and used to image adipose and fibroglandular breast tissue of 11 normal female subjects, recruited under an institutional review board-approved protocol. Images of hemoglobin, oxygen saturation, water fraction, and subcellular scattering were reconstructed and show that fibroglandular fractions of both blood and water are higher than in adipose tissue. Variation in adipose and fibroglandular tissue composition between individuals was not significantly different across the scattered and dense breast categories. Combined MR and near-infrared tomography provides fundamental molecular information about these tissue types with resolution governed by MR T1 images. hemoglobin | magnetic resonance imaging | water | fat | oxygen saturation

Preliminary results of a new workflow for MRI/CT-based image-guided brachytherapy in cervical carcinoma.

Science.gov (United States)

Nemoto, Miho Watanabe; Iwai, Yuma; Togasaki, Gentaro; Kurokawa, Marie; Harada, Rintarou; Kobayashi, Hiroki; Uno, Takashi

2017-12-01

We propose a method of image-guided brachytherapy (IGBT) that combines MRI-based target volume delineation for the first fraction with CT datasets of subsequent fractions, using an automatic, applicator-based co-registration, and report our preliminary experience. The MRI of the first fraction was used for the first brachytherapy planning. For each subsequent brachytherapy fraction, after the same applicator insertion, a new CT scan with the applicator in place was obtained. The MR image set was registered to the subsequent brachytherapy treatment planning CT using the applicator for rigid body registration. To demonstrate the registration quality, we used here the Dice index as a measurement of tandem delineation overlap between CT and MRI. The median Dice index was 0.879 (range 0.610-0.932), which indicated that the contours on CT and MRI fitted well. With this combination method, the median D90 of HR CTV and the calculated D2 cm 3 of the bladder, rectum, and sigmoid in each fraction were 7.2 (4.0-10.4), 5.9 (2.3-7.7), 4.0 (1.9-6.7), and 3.8 (0.6-7.2) Gy, respectively. Our described method of MRI-guided IGBT offers a practical option for the benefits of target delineation.

Radiation resistivity of pure-silica core image guide

International Nuclear Information System (INIS)

Hayami, H.; Ishitani, T.; Kishihara, O.; Suzuki, K.

1988-01-01

Radiation resistivity of pure-silica core image guides were investigated in terms of incremental spectral loss and quality of pictures transmitted through the image guides. Radiation-induced spectral losses were measured so as to clarify the dependences of radiation resistivity on such parameters as core materials (OH and Cl contents), picture element dimensions, (core packing density and cladding thickness), number of picture elements and drawing conditions. As the results, an image guide with OH-and Cl-free pure-silica core, 30-45% in core packing density, and 1.8 ∼ 2.2 μm in cladding thickness showed the lowest loss. The parameters to design this image guide were almost the same as those to obtain a image guide with good picture quality. Radiation resistivity of the image guide was not dependent on drawing conditions and number of picture elements, indicating that the image guide has large allowable in production conditions and that reliable quality is constantly obtained in production. Radiation resistivity under high total doses was evaluated using the image guide with the lowest radiation-induced loss. Maximum usable lengths of the image guide for practical use under specific high total doses and maximum allowable total doses for the image guide in specific lengths were extrapolated. Picture quality in terms of radiation-induced degradation in color fidelity in the pictures transmitted through image guides was quantitatively evaluated in the chromaticity diagram based on the CIE standard colorimetric system and in the color specification charts according to three attributes of colors. The image guide with the least spectral incremental loss gives the least radiation-induced degradation in color fidelity in the pictures as well. (author)

Feasibility of real-time magnetic resonance imaging-guided endomyocardial biopsies: An in-vitro study.

Science.gov (United States)

Lossnitzer, Dirk; Seitz, Sebastian A; Krautz, Birgit; Schnackenburg, Bernhard; André, Florian; Korosoglou, Grigorios; Katus, Hugo A; Steen, Henning

2015-07-26

To investigate if magnetic resonance (MR)-guided biopsy can improve the performance and safety of such procedures. A novel MR-compatible bioptome was evaluated in a series of in-vitro experiments in a 1.5T magnetic resonance imaging (MRI) system. The bioptome was inserted into explanted porcine and bovine hearts under real-time MR-guidance employing a steady state free precession sequence. The artifact produced by the metal element at the tip and the signal voids caused by the bioptome were visually tracked for navigation and allowed its constant and precise localization. Cardiac structural elements and the target regions for the biopsy were clearly visible. Our method allowed a significantly better spatial visualization of the bioptoms tip compared to conventional X-ray guidance. The specific device design of the bioptome avoided inducible currents and therefore subsequent heating. The novel MR-compatible bioptome provided a superior cardiovascular magnetic resonance (imaging) soft-tissue visualization for MR-guided myocardial biopsies. Not at least the use of MRI guidance for endomyocardial biopsies completely avoided radiation exposure for both patients and interventionalists. MRI-guided endomyocardial biopsies provide a better than conventional X-ray guided navigation and could therefore improve the specificity and reproducibility of cardiac biopsies in future studies.

Image-guided and adaptive radiotherapy

International Nuclear Information System (INIS)

Louvel, G.; Chajon, E.; Henry, O.; Cazoulat, G.; Le Maitre, A.; Simon, A.; Bensadoun, R.J.; Crevoisier, R. de

2012-01-01

Image-guided radiotherapy (IGRT) aims to take into account anatomical variations occurring during irradiation by visualization of anatomical structures. It may consist of a rigid registration of the tumour by moving the patient, in case of prostatic irradiation for example. IGRT associated with intensity-modulated radiotherapy (IMRT) is strongly recommended when high-dose is delivered in the prostate, where it seems to reduce rectal and bladder toxicity. In case of significant anatomical deformations, as in head and neck tumours (tumour shrinking and decrease in volume of the salivary glands), re-planning appears to be necessary, corresponding to the adaptive radiotherapy. This should ideally be 'monitored' and possibly triggered based on a calculation of cumulative dose, session after session, compared to the initial planning dose, corresponding to the concept of dose-guided adaptive radiotherapy. The creation of 'planning libraries' based on predictable organ positions (as in cervical cancer) is another way of adaptive radiotherapy. All of these strategies still appear very complex and expensive and therefore require stringent validation before being routinely applied. (authors)

Value of MR contrast media in image-guided body interventions.

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Saeed, Maythem; Wilson, Mark

2012-01-28

In the past few years, there have been multiple advances in magnetic resonance (MR) instrumentation, in vivo devices, real-time imaging sequences and interventional procedures with new therapies. More recently, interventionists have started to use minimally invasive image-guided procedures and local therapies, which reduce the pain from conventional surgery and increase drug effectiveness, respectively. Local therapy also reduces the systemic dose and eliminates the toxic side effects of some drugs to other organs. The success of MR-guided procedures depends on visualization of the targets in 3D and precise deployment of ablation catheters, local therapies and devices. MR contrast media provide a wealth of tissue contrast and allows 3D and 4D image acquisitions. After the development of fast imaging sequences, the clinical applications of MR contrast media have been substantially expanded to include pre- during- and post-interventions. Prior to intervention, MR contrast media have the potential to localize and delineate pathologic tissues of vital organs, such as the brain, heart, breast, kidney, prostate, liver and uterus. They also offer other options such as labeling therapeutic agents or cells. During intervention, these agents have the capability to map blood vessels and enhance the contrast between the endovascular guidewire/catheters/devices, blood and tissues as well as direct therapies to the target. Furthermore, labeling therapeutic agents or cells aids in visualizing their delivery sites and tracking their tissue distribution. After intervention, MR contrast media have been used for assessing the efficacy of ablation and therapies. It should be noted that most image-guided procedures are under preclinical research and development. It can be concluded that MR contrast media have great value in preclinical and some clinical interventional procedures. Future applications of MR contrast media in image-guided procedures depend on their safety, tolerability

Adjuvant radiotherapy for cutaneous melanoma: Comparing hypofractionation to conventional fractionation

International Nuclear Information System (INIS)

Chang, Daniel T.; Amdur, Robert J.; Morris, Christopher G. M.S.; Mendenhall, William M.

2006-01-01

Purpose: To examine locoregional control after adjuvant radiotherapy (RT) for cutaneous melanoma and compare outcomes between conventional fractionation and hypofractionation. Methods and Materials: Between January 1980 and June 2004, 56 patients with high-risk disease were treated with adjuvant RT. Indications for RT included: recurrent disease, cervical lymph node involvement, lymph nodes >3 cm, more than three lymph nodes involved, extracapsular extension, gross residual disease, close or positive margins, or satellitosis. Hypofractionation was used in 41 patients (73%) and conventional fractionation was used in 15 patients (27%). Results: The median age was 61 years (21->90). The median follow-up among living patients was 4.4 years (range, 0.6-14.4 years). The primary site was located in the head and neck in 49 patients (87%) and below the clavicles in 7 patients (13%). There were 7 in-field locoregional failures (12%), 3 out-of-field regional failures (5%), and 24 (43%) distant failures. The 5-year in-field locoregional control (ifLRC) and freedom from distant metastases (FFDM) rates were 87% and 43%, respectively. The 5-year cause-specific (CSS) and overall survival (OS) was 57% and 46%, respectively. The only factor associated with ifLRC was satellitosis (p = 0.0002). Nodal involvement was the only factor associated with FFDM (p = 0.0007), CSS (p = 0.0065), and OS (p = 0.016). Two patients (4%) who experienced severe late complications, osteoradionecrosis of the temporal bone and radiation plexopathy, and both received hypofractionation (5%). Conclusions: Although surgery and adjuvant RT provides excellent locoregional control, distant metastases remain the major cause of mortality. Hypofractionation and conventional fractionation are equally efficacious

Image-guided intensity-modulated radiotherapy for prostate cancer: Dose constraints for the anterior rectal wall to minimize rectal toxicity

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Peterson, Jennifer L., E-mail: peterson.jennifer2@mayo.edu [Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL (United States); Buskirk, Steven J. [Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL (United States); Heckman, Michael G.; Diehl, Nancy N. [Section of Biostatistics, Mayo Clinic Florida, Jacksonville, FL (United States); Bernard, Johnny R. [Section of Biostatistics, Mayo Clinic Florida, Jacksonville, FL (United States); Department of Radiation Oncology, Southern Ohio Medical Center, Portsmouth, OH (United States); Tzou, Katherine S.; Casale, Henry E.; Bellefontaine, Louis P.; Serago, Christopher; Kim, Siyong; Vallow, Laura A.; Daugherty, Larry C.; Ko, Stephen J. [Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL (United States)

2014-04-01

Rectal adverse events (AEs) are a major concern with definitive radiotherapy (RT) treatment for prostate cancer. The anterior rectal wall is at the greatest risk of injury as it lies closest to the target volume and receives the highest dose of RT. This study evaluated the absolute volume of anterior rectal wall receiving a high dose to identify potential ideal dose constraints that can minimize rectal AEs. A total of 111 consecutive patients with Stage T1c to T3a N0 M0 prostate cancer who underwent image-guided intensity-modulated RT at our institution were included. AEs were graded according to the Common Terminology Criteria for Adverse Events, version 4.0. The volume of anterior rectal wall receiving 5 to 80 Gy in 2.5-Gy increments was determined. Multivariable Cox regression models were used to identify cut points in these volumes that led to an increased risk of early and late rectal AEs. Early AEs occurred in most patients (88%); however, relatively few of them (13%) were grade ≥2. At 5 years, the cumulative incidence of late rectal AEs was 37%, with only 5% being grade ≥2. For almost all RT doses, we identified a threshold of irradiated absolute volume of anterior rectal wall above which there was at least a trend toward a significantly higher rate of AEs. Most strikingly, patients with more than 1.29, 0.73, or 0.45 cm{sup 3} of anterior rectal wall exposed to radiation doses of 67.5, 70, or 72.5 Gy, respectively, had a significantly increased risk of late AEs (relative risks [RR]: 2.18 to 2.72; p ≤ 0.041) and of grade ≥ 2 early AEs (RR: 6.36 to 6.48; p = 0.004). Our study provides evidence that definitive image-guided intensity-modulated radiotherapy (IG-IMRT) for prostate cancer is well tolerated and also identifies dose thresholds for the absolute volume of anterior rectal wall above which patients are at greater risk of early and late complications.

Image-guided intensity-modulated radiotherapy for prostate cancer: Dose constraints for the anterior rectal wall to minimize rectal toxicity

International Nuclear Information System (INIS)

Peterson, Jennifer L.; Buskirk, Steven J.; Heckman, Michael G.; Diehl, Nancy N.; Bernard, Johnny R.; Tzou, Katherine S.; Casale, Henry E.; Bellefontaine, Louis P.; Serago, Christopher; Kim, Siyong; Vallow, Laura A.; Daugherty, Larry C.; Ko, Stephen J.

2014-01-01

Rectal adverse events (AEs) are a major concern with definitive radiotherapy (RT) treatment for prostate cancer. The anterior rectal wall is at the greatest risk of injury as it lies closest to the target volume and receives the highest dose of RT. This study evaluated the absolute volume of anterior rectal wall receiving a high dose to identify potential ideal dose constraints that can minimize rectal AEs. A total of 111 consecutive patients with Stage T1c to T3a N0 M0 prostate cancer who underwent image-guided intensity-modulated RT at our institution were included. AEs were graded according to the Common Terminology Criteria for Adverse Events, version 4.0. The volume of anterior rectal wall receiving 5 to 80 Gy in 2.5-Gy increments was determined. Multivariable Cox regression models were used to identify cut points in these volumes that led to an increased risk of early and late rectal AEs. Early AEs occurred in most patients (88%); however, relatively few of them (13%) were grade ≥2. At 5 years, the cumulative incidence of late rectal AEs was 37%, with only 5% being grade ≥2. For almost all RT doses, we identified a threshold of irradiated absolute volume of anterior rectal wall above which there was at least a trend toward a significantly higher rate of AEs. Most strikingly, patients with more than 1.29, 0.73, or 0.45 cm 3 of anterior rectal wall exposed to radiation doses of 67.5, 70, or 72.5 Gy, respectively, had a significantly increased risk of late AEs (relative risks [RR]: 2.18 to 2.72; p ≤ 0.041) and of grade ≥ 2 early AEs (RR: 6.36 to 6.48; p = 0.004). Our study provides evidence that definitive image-guided intensity-modulated radiotherapy (IG-IMRT) for prostate cancer is well tolerated and also identifies dose thresholds for the absolute volume of anterior rectal wall above which patients are at greater risk of early and late complications

MRT letter: Guided filtering of image focus volume for 3D shape recovery of microscopic objects.

Science.gov (United States)

Mahmood, Muhammad Tariq

2014-12-01

In this letter, a shape from focus (SFF) method is proposed that utilizes the guided image filtering to enhance the image focus volume efficiently. First, image focus volume is computed using a conventional focus measure. Then each layer of image focus volume is filtered using guided filtering. In this work, the all-in-focus image, which can be obtained from the initial focus volume, is used as guidance image. Finally, improved depth map is obtained from the filtered image focus volume by maximizing the focus measure along the optical axis. The proposed SFF method is efficient and provides better depth maps. The improved performance is highlighted by conducting several experiments using image sequences of simulated and real microscopic objects. The comparative analysis demonstrates the effectiveness of the proposed SFF method. © 2014 Wiley Periodicals, Inc.

Intensity Variation Normalization for Finger Vein Recognition Using Guided Filter Based Singe Scale Retinex.

Science.gov (United States)

Xie, Shan Juan; Lu, Yu; Yoon, Sook; Yang, Jucheng; Park, Dong Sun

2015-07-14

Finger vein recognition has been considered one of the most promising biometrics for personal authentication. However, the capacities and percentages of finger tissues (e.g., bone, muscle, ligament, water, fat, etc.) vary person by person. This usually causes poor quality of finger vein images, therefore degrading the performance of finger vein recognition systems (FVRSs). In this paper, the intrinsic factors of finger tissue causing poor quality of finger vein images are analyzed, and an intensity variation (IV) normalization method using guided filter based single scale retinex (GFSSR) is proposed for finger vein image enhancement. The experimental results on two public datasets demonstrate the effectiveness of the proposed method in enhancing the image quality and finger vein recognition accuracy.

Regularized Fractional Power Parameters for Image Denoising Based on Convex Solution of Fractional Heat Equation

Directory of Open Access Journals (Sweden)

Hamid A. Jalab

2014-01-01

Full Text Available The interest in using fractional mask operators based on fractional calculus operators has grown for image denoising. Denoising is one of the most fundamental image restoration problems in computer vision and image processing. This paper proposes an image denoising algorithm based on convex solution of fractional heat equation with regularized fractional power parameters. The performances of the proposed algorithms were evaluated by computing the PSNR, using different types of images. Experiments according to visual perception and the peak signal to noise ratio values show that the improvements in the denoising process are competent with the standard Gaussian filter and Wiener filter.

Daily organ tracking in intensity-modulated radiotherapy of prostate cancer using an electronic portal imaging device with a dose saving acquisition mode

International Nuclear Information System (INIS)

Vetterli, Daniel; Thalmann, Sandrine; Behrensmeier, Frank; Kemmerling, Ludger; Born, Ernst J.; Mini, Roberto; Greiner, Richard H.; Aebersold, Daniel M.

2006-01-01

Background and purpose: Daily use of conventional electronic portal imaging devices (EPID) for organ tracking is limited due to the relatively high dose required for high quality image acquisition. We studied the use of a novel dose saving acquisition mode (RadMode) allowing to take images with one monitor unit per image in prostate cancer patients undergoing intensity-modulated radiotherapy (IMRT) and tracking of implanted fiducial gold markers. Patients and methods: Twenty five patients underwent implantation of three fiducial gold markers prior to the planning CT. Before each treatment of a course of 37 fractions, orthogonal localization images from the antero-posterior and from the lateral direction were acquired. Portal images of both the setup procedure and the five IMRT treatment beams were analyzed. Results: On average, four localization images were needed for a correct patient setup, resulting in four monitor units extra dose per fraction. The mean extra dose delivered to the patient was thereby increased by 1.2%. The procedure was precise enough to reduce the mean displacements prior to treatment to ≤0.3 mm. Conclusions: The use of a new dose saving acquisition mode enables to perform daily EPID-based prostate tracking with a cumulative extra dose of below 1 Gy. This concept is efficiently used in IMRT-treated patients, where separation of setup beams from treatment beams is mandatory

Clinical efficacy and safety of surface imaging guided radiosurgery (SIG-RS) in the treatment of benign skull base tumors.

Science.gov (United States)

Lau, Steven K M; Patel, Kunal; Kim, Teddy; Knipprath, Erik; Kim, Gwe-Ya; Cerviño, Laura I; Lawson, Joshua D; Murphy, Kevin T; Sanghvi, Parag; Carter, Bob S; Chen, Clark C

2017-04-01

Frameless, surface imaging guided radiosurgery (SIG-RS) is a novel platform for stereotactic radiosurgery (SRS) wherein patient positioning is monitored in real-time through infra-red camera tracking of facial topography. Here we describe our initial clinical experience with SIG-RS for the treatment of benign neoplasms of the skull base. We identified 48 patients with benign skull base tumors consecutively treated with SIG-RS at a single institution between 2009 and 2011. Patients were diagnosed with meningioma (n = 22), vestibular schwannoma (n = 20), or nonfunctional pituitary adenoma (n = 6). Local control and treatment-related toxicity were retrospectively assessed. Median follow-up was 65 months (range 61-72 months). Prescription doses were 12-13 Gy in a single fraction (n = 18), 8 Gy × 3 fractions (n = 6), and 5 Gy × 5 fractions (n = 24). Actuarial tumor control rate at 5 years was 98%. No grade ≥3 treatment-related toxicity was observed. Grade ≤2 toxicity was associated with symptomatic lesions (p = 0.049) and single fraction treatment (p = 0.005). SIG-RS for benign skull base tumors produces clinical outcomes comparable to conventional frame-based SRS techniques while enhancing patient comfort.

High signal intensity of fat on fast spin echo imaging

International Nuclear Information System (INIS)

Ogura, Akio; Yamazaki, Masaru; Hongoh, Takaharu; Inoue, Hiroshi; Ishikuro, Akihiro

2000-01-01

The fast spin echo (FSE) technique of producing T 2 -weighted images in greatly reduced imaging times has recently been used for routine clinical study. FSE images show contrast that is very similar in most tissues to that of conventional SE images. However, fat shows a high signal intensity that is influenced by j-coupling and the magnetization transfer effect. The purpose of this study was to assess whether the higher signal intensity of fat is different among MRI systems and to examine the effects of j-coupling and magnetization transfer on the high signal intensity of fat on FSE. The contrast in signal intensity between fat and water was measured for various echo train lengths (ETL) with and without multislicing on FSE using a contrast phantom. Measurements were obtained with four different MRI systems. In addition, the effective T 2 values of fat were calculated for the above conditions. Results indicated that contrast for fat and water was reduced with increased ETL and by using multislicing and was different among the four MRI systems. The effective T 2 values of fat were extended for increased ETL and were not dependent on multislicing. They also differed among the four MRI systems. The extent of effective T 2 values was affected by j-coupling. In this study, it was indicated that the degree of the high signal intensity of fat on FSE differed for different MRI systems. In addition, the reasons for the high signal intensity of fat on FSE were related to the effects of j-coupling and magnetization transfer. (author)

Intense-proton-beam transport through an insulator beam guide

International Nuclear Information System (INIS)

Hanamori, Susumu; Kawata, Shigeo; Kikuchi, Takashi; Fujita, Akira; Chiba, Yasunobu; Hikita, Taisuke; Kato, Shigeru

1998-01-01

In this paper we study intense-proton-beam transport through an insulator guide. In our previous papers (Jpn. J. Appl. Phys. 34 (1995) L520, Jpn. J. Appl. Phys. 35 (1996) L1127) we proposed a new system for intense-electron-beam transport using an insulator guide. In contrast to the electron beam, an intense-proton beam tends to generate a virtual anode, because of the large proton mass. The virtual anode formation at the initial stage is prevented by prefilled plasma in this system. During and after this, electrons are extracted from the plasma generated at the insulator surface by the proton beam space charge and expand over the transport area. The proton beam charge is effectively neutralized by the electrons. Consequently, the proton beam propagates efficiently through the insulator beam guide. The electron extraction is self-regulated by the net space charge of the proton beam. (author)

Evaluation of intra- and inter-fraction movement of the cervix during intensity modulated radiation therapy

International Nuclear Information System (INIS)

Haripotepornkul, Nora H.; Nath, Sameer K.; Scanderbeg, Daniel; Saenz, Cheryl; Yashar, Catheryn M.

2011-01-01

Background and purpose: To assess the degree of intra- and inter-fraction cervical motion throughout a course of intensity modulated radiation therapy (IMRT) for cervical cancer patients. Materials and methods: A retrospective study of 10 women with stage 1B1-3B cervical cancer diagnosed from September 2007 to July 2008 was conducted. All patients were treated with chemoradiation using IMRT followed by intracavitary brachytherapy. Pretreatment, patients had 2 seeds placed at a depth of 10 mm into the cervix. On-Board Imaging (OBI) was used to obtain anterior/posterior (AP) and lateral X-rays before and after each treatment. OBI images were rigidly aligned to baseline digitally reconstructed radiographs (DRRs), and movement of cervical seeds was determined in the lateral, vertical, and AP directions. Mean differences in cervical seed position and standard error of the mean (SEM) were calculated. Results: A total of 922 images were reviewed, with approximately 90 images per patient. The mean intra-fractional movement in cervical seed position in the lateral, vertical, and AP directions were 1.6 mm (SD ± 2.0), 2.6 mm (SD ± 2.4), and 2.9 mm (SD ± 2.7), respectively, with a range from 0 to 15 mm for each direction. The mean inter-fractional movement in the lateral, vertical, and AP directions were 1.9 mm (SD ± 1.9), 4.1 mm (SD ± 3.2), and 4.2 mm (SD ± 3.5), respectively, with a range from 0 to 18 mm for each direction. Conclusions: This is the first study to assess intra- and inter-fractional movement of the cervix using daily imaging before and after each fraction. Within and between radiation treatments, cervical motion averages approximately 3 mm in any given direction. However, maximal movement of the cervix can be as far as 18 mm from baseline. This wide range of motion needs to be accounted for when generating planning treatment volumes.

Improvement in toxicity in high risk prostate cancer patients treated with image-guided intensity-modulated radiotherapy compared to 3D conformal radiotherapy without daily image guidance

International Nuclear Information System (INIS)

Sveistrup, Joen; Rosenschöld, Per Munck af; Deasy, Joseph O; Oh, Jung Hun; Pommer, Tobias; Petersen, Peter Meidahl; Engelholm, Svend Aage

2014-01-01

Image-guided radiotherapy (IGRT) facilitates the delivery of a very precise radiation dose. In this study we compare the toxicity and biochemical progression-free survival between patients treated with daily image-guided intensity-modulated radiotherapy (IG-IMRT) and 3D conformal radiotherapy (3DCRT) without daily image guidance for high risk prostate cancer (PCa). A total of 503 high risk PCa patients treated with radiotherapy (RT) and endocrine treatment between 2000 and 2010 were retrospectively reviewed. 115 patients were treated with 3DCRT, and 388 patients were treated with IG-IMRT. 3DCRT patients were treated to 76 Gy and without daily image guidance and with 1–2 cm PTV margins. IG-IMRT patients were treated to 78 Gy based on daily image guidance of fiducial markers, and the PTV margins were 5–7 mm. Furthermore, the dose-volume constraints to both the rectum and bladder were changed with the introduction of IG-IMRT. The 2-year actuarial likelihood of developing grade > = 2 GI toxicity following RT was 57.3% in 3DCRT patients and 5.8% in IG-IMRT patients (p < 0.001). For GU toxicity the numbers were 41.8% and 29.7%, respectively (p = 0.011). On multivariate analysis, 3DCRT was associated with a significantly increased risk of developing grade > = 2 GI toxicity compared to IG-IMRT (p < 0.001, HR = 11.59 [CI: 6.67-20.14]). 3DCRT was also associated with an increased risk of developing GU toxicity compared to IG-IMRT. The 3-year actuarial biochemical progression-free survival probability was 86.0% for 3DCRT and 90.3% for IG-IMRT (p = 0.386). On multivariate analysis there was no difference in biochemical progression-free survival between 3DCRT and IG-IMRT. The difference in toxicity can be attributed to the combination of the IMRT technique with reduced dose to organs-at-risk, daily image guidance and margin reduction

Complexity and accuracy of image registration methods in SPECT-guided radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Yin, L S; Duzenli, C; Moiseenko, V [Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada); Tang, L; Hamarneh, G [Computing Science, Simon Fraser University, 9400 TASC1, Burnaby, BC, V5A 1S6 (Canada); Gill, B [Medical Physics, Vancouver Cancer Centre, BC Cancer Agency, 600 West 10th Ave, Vancouver, BC, V5Z 4E6 (Canada); Celler, A; Shcherbinin, S [Department of Radiology, University of British Columbia, 828 West 10th Ave, Vancouver, BC, V5Z 1L8 (Canada); Fua, T F; Thompson, A; Sheehan, F [Radiation Oncology, Vancouver Cancer Centre, BC Cancer Agency, 600 West 10th Ave, Vancouver, BC, V5Z 4E6 (Canada); Liu, M [Radiation Oncology, Fraser Valley Cancer Centre, BC Cancer Agency, 13750 9th Ave, Surrey, BC, V3V 1Z2 (Canada)], E-mail: lyin@bccancer.bc.ca

2010-01-07

The use of functional imaging in radiotherapy treatment (RT) planning requires accurate co-registration of functional imaging scans to CT scans. We evaluated six methods of image registration for use in SPECT-guided radiotherapy treatment planning. Methods varied in complexity from 3D affine transform based on control points to diffeomorphic demons and level set non-rigid registration. Ten lung cancer patients underwent perfusion SPECT-scans prior to their radiotherapy. CT images from a hybrid SPECT/CT scanner were registered to a planning CT, and then the same transformation was applied to the SPECT images. According to registration evaluation measures computed based on the intensity difference between the registered CT images or based on target registration error, non-rigid registrations provided a higher degree of accuracy than rigid methods. However, due to the irregularities in some of the obtained deformation fields, warping the SPECT using these fields may result in unacceptable changes to the SPECT intensity distribution that would preclude use in RT planning. Moreover, the differences between intensity histograms in the original and registered SPECT image sets were the largest for diffeomorphic demons and level set methods. In conclusion, the use of intensity-based validation measures alone is not sufficient for SPECT/CT registration for RTTP. It was also found that the proper evaluation of image registration requires the use of several accuracy metrics.

Bioassay-guided fractionation of Melastoma malabathricum Linn. leaf solid phase extraction fraction and its anticoagulant activity.

Science.gov (United States)

Khoo, Li Teng; Abdullah, Janna Ong; Abas, Faridah; Tohit, Eusni Rahayu Mohd; Hamid, Muhajir

2015-02-24

The aims of this study were to examine the bioactive component(s) responsible for the anticoagulant activity of M. malabathricum Linn. leaf hot water crude extract via bioassay-guided fractionation and to evaluate the effect of bioactive component(s) on the intrinsic blood coagulation pathway. The active anticoagulant fraction of F3 was subjected to a series of chromatographic separation and spectroscopic analyses. Furthermore, the effect of the bioactive component(s) on the intrinsic blood coagulation pathway was studied through immediate and time incubation mixing studies. Through Activated Partial Thromboplastin Time (APTT) assay-guided fractionation, Subfraction B was considered the most potent anticoagulant fraction. Characterisation of Subfraction B indicated that anticoagulant activity could partly be due to the presence of cinnamic acid and a cinnamic acid derivative. APTT assays for both the immediate and time incubation mixing were corrected back into normal clotting time range (35.4-56.3 s). In conclusion, cinnamic acid and cinnamic acid derivative from Subfraction B were the first such compounds to be discovered from M. malabathricum Linn. leaf hot water crude extract that possess anticoagulant activity. This active anticoagulant Subfraction B prolonged blood clotting time by causing factor(s) deficiency in the intrinsic blood coagulation pathway.

Urethrogram-directed Stereotactic Body Radiation Therapy (SBRT for Clinically Localized Prostate Cancer in Patients with Contraindications to Magnetic Resonance Imaging

Directory of Open Access Journals (Sweden)

Ima ePaydar

2015-09-01

Full Text Available Purpose: Magnetic resonance imaging (MRI-directed stereotactic body radiation therapy (SBRT has been established as a safe and effective treatment for prostate cancer. For patients with contraindications to MRI, CT-urethrogram is an alternative imaging approach to identify the location of the prostatic apex to guide treatment. This study sought to evaluate the safety of urethrogram-directed SBRT for prostate cancer.Methods: Between February 2009 and January 2014, 31 men with clinically localized prostate cancer were treated definitively with urethrogram-directed SBRT with or without supplemental intensity modulated radiation therapy (IMRT at Georgetown University Hospital. SBRT was delivered either as a primary treatment of 35-36.25 Gray (Gy in 5 fractions or as a boost of 19.5 Gy in 3 fractions followed by supplemental conventionally fractionated intensity modulated radiation therapy (45-50.4 Gy. Toxicities were recorded and scored using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v.4.0.Results: The median patient age was 70 years with a median prostate volume of 38 cc. The median follow-up was 3.7 years. The patients were elderly (Median age = 70, and comorbidities were common (Carlson Comorbidity Index > 2 in 36%. 71% of patients utilized alpha agonists prior to treatment, and 9.7% had prior procedures for benign prostatic hyperplasia (BPH. The 3-year actuarial incidence rates of > Grade 3 GU toxicity and > Grade 2 GI toxicity were 3.2% and 9.7%, respectively. There were no Grade 4 or 5 toxicities.Conclusions: MRI is the preferred imaging modality to guide prostate SBRT treatment. However, urethrogram-directed SBRT is a safe alternative for the treatment of patients with prostate cancer who are unable to undergo MRI.

Clinical application of image-guided radiotherapy, IGRT (on the Varian OBI platform)

International Nuclear Information System (INIS)

Sorcini, B.; Tilikidis, A.

2006-01-01

Image-guided radiation therapy (IGRT) can be used to measure and correct positional errors for target and critical structures immediately prior to or during treatment delivery. Some of the most recent available methods applied for target localization are: trans-abdominal ultrasound, implanted markers with in room MV or kV X-rays, optical surface tracking systems, implantable electromagnetic markers, in room CT such as kVCT on rail, kilo-voltage or mega-voltage cone-beam CT (CBCT) and helical megavoltage CT. The verification of the accurate treatment position in conjunction with detailed anatomical information before every fraction can be essential for the outcome of the treatment. In this paper we present the on-board imager (OBI, Varian Medical Systems, Palo Alto, CA) that has been in routine clinical use at the Karolinska University Hospital since June 2004. The OBI has been used for on-line set-up correction of prostate patients using internal gold markers. Displacements of these markers can be monitored radiographically during the treatment course and the registered marker shifts act as a surrogate for prostate motion. For this purpose, on-board kV-kV seems to be an ideal system in terms of image quality. The CBCT function of OBI was installed in March 2005 at our department. It focuses on localizing tumors based on internal anatomy, not just on the conventional external marks or tattoos. The CBCT system provides the capacity for soft tissue imaging in the treatment position and real-time radiographic monitoring during treatment delivery. (authors)

Toxicity after post-prostatectomy image-guided intensity-modulated radiotherapy using Australian guidelines.

Science.gov (United States)

Chin, Stephen; Aherne, Noel J; Last, Andrew; Assareh, Hassan; Shakespeare, Thomas P

2017-12-01

We evaluated single institution toxicity outcomes after post-prostatectomy radiotherapy (PPRT) via image-guided intensity-modulated radiation therapy (IG-IMRT) with implanted fiducial markers following national eviQ guidelines, for which late toxicity outcomes have not been published. Prospectively collected toxicity data were retrospectively reviewed for 293 men who underwent 64-66 Gy IG-IMRT to the prostate bed between 2007 and 2015. Median follow-up after PPRT was 39 months. Baseline grade ≥2 genitourinary (GU), gastrointestinal (GI) and sexual toxicities were 20.5%, 2.7% and 43.7%, respectively, reflecting ongoing toxicity after radical prostatectomy. Incidence of new (compared to baseline) acute grade ≥2 GU and GI toxicity was 5.8% and 10.6%, respectively. New late grade ≥2 GU, GI and sexual toxicity occurred in 19.1%, 4.7% and 20.2%, respectively. However, many patients also experienced improvements in toxicities. For this reason, prevalence of grade ≥2 GU, GI and sexual toxicities 4 years after PPRT was similar to or lower than baseline (21.7%, 2.6% and 17.4%, respectively). There were no grade ≥4 toxicities. Post-prostatectomy IG-IMRT using Australian contouring guidelines appears to have tolerable acute and late toxicity. The 4-year prevalence of grade ≥2 GU and GI toxicity was virtually unchanged compared to baseline, and sexual toxicity improved over baseline. This should reassure radiation oncologists following these guidelines. Late toxicity rates of surgery and PPRT are higher than following definitive IG-IMRT, and this should be taken into account if patients are considering surgery and likely to require PPRT. © 2017 The Royal Australian and New Zealand College of Radiologists.

Intensity Variation Normalization for Finger Vein Recognition Using Guided Filter Based Singe Scale Retinex

Directory of Open Access Journals (Sweden)

Shan Juan Xie

2015-07-01

Full Text Available Finger vein recognition has been considered one of the most promising biometrics for personal authentication. However, the capacities and percentages of finger tissues (e.g., bone, muscle, ligament, water, fat, etc. vary person by person. This usually causes poor quality of finger vein images, therefore degrading the performance of finger vein recognition systems (FVRSs. In this paper, the intrinsic factors of finger tissue causing poor quality of finger vein images are analyzed, and an intensity variation (IV normalization method using guided filter based single scale retinex (GFSSR is proposed for finger vein image enhancement. The experimental results on two public datasets demonstrate the effectiveness of the proposed method in enhancing the image quality and finger vein recognition accuracy.

Curved-straight neutron guide system with uniform spatial intensity distribution

International Nuclear Information System (INIS)

Mildner, D.F.R.; Cook, J.C.

2008-01-01

The spatial intensity distribution of neutrons emerging from a curved guide is asymmetric, and straight guide sections are sometimes appended to curved guides to make the intensity distribution more nearly uniform. For idealized uniform illumination and in the perfect reflectivity approximation, the spatial-angular acceptance at the exit of the combination can be made exactly uniform for a range of long wavelengths by using a sufficiently long straight section, together with a curved guide whose outer wall coating has a critical angle slightly greater than those of the other guide walls. We refer to this as a 'phase space tailoring guide' where the coatings on the inner wall and straight section are used to define the required divergence at the end of the guide. Increasing the critical angle of the outer wall of the curved section reduces the characteristic wavelength of the curved guide as well as the wavelength at which ideal uniformity can be obtained. The outer wall coating need only be of sufficiently high critical angle to fill the transmittable phase space area of the straight guide uniformly to adequately short wavelength

Appearances of diffuse excessive high signal intensity (DEHSI) on MR imaging following preterm birth

International Nuclear Information System (INIS)

Hart, Anthony R.; Smith, Michael F.; Rigby, Alan S.; Wallis, Lauren I.; Whitby, Elspeth H.

2010-01-01

Diffuse damage to the periventricular white matter has recently been suggested to be a cause of the cognitive deficits seen following preterm birth. It is unclear whether this form of injury can be visualised on MR imaging, but one group has described diffuse excessive high signal intensity (DEHSI) as a possible form of diffuse white matter injury. This finding is dependant on window imaging and the subjective assessment of the reviewer, but little data have been published on the degree of subjectivity on its appearance among raters. To assess the subjectivity of DEHSI on conventional and ultrafast T2-weighted MR imaging following preterm birth. An observational study of 40 preterm infants who had MR imaging of the brain around term-equivalent age, including conventional fast spin-echo (FSE) and ultrafast single-shot fast spin-echo (SSFSE) T2-weighted sequences in the axial plane. Images were anonymised and scored twice by four observers for the presence of DEHSI. Inter- and intra-observer agreement were calculated. Sixty-five percent of conventional and 100% of the ultrafast images were of diagnostic quality. DEHSI was noted in between 0% and 69.2% of conventional images and 27.5-90% of the ultrafast images. Inter- and intra-observer agreement ranged from none to moderate. The visual appearances of DEHSI on conventional FSE and ultrafast SSFSE T2-W images are highly subjective, limiting its clinical application. (orig.)

Appearances of diffuse excessive high signal intensity (DEHSI) on MR imaging following preterm birth

Energy Technology Data Exchange (ETDEWEB)

Hart, Anthony R. [Sheffield Teaching Hospital NHS Foundation Trust, Department of Neonatology, Jessop Wing, Sheffield (United Kingdom); University of Sheffield, Academic Unit of Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom); University of Sheffield, Department of Academic Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom); Smith, Michael F. [Sheffield Teaching Hospital NHS Foundation Trust, Department of Neonatology, Jessop Wing, Sheffield (United Kingdom); Rigby, Alan S. [University of Hull, Postgraduate Medical Centre, Castle Hill Hospital, East Yorkshire (United Kingdom); Wallis, Lauren I.; Whitby, Elspeth H. [University of Sheffield, Academic Unit of Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom)

2010-08-15

Diffuse damage to the periventricular white matter has recently been suggested to be a cause of the cognitive deficits seen following preterm birth. It is unclear whether this form of injury can be visualised on MR imaging, but one group has described diffuse excessive high signal intensity (DEHSI) as a possible form of diffuse white matter injury. This finding is dependant on window imaging and the subjective assessment of the reviewer, but little data have been published on the degree of subjectivity on its appearance among raters. To assess the subjectivity of DEHSI on conventional and ultrafast T2-weighted MR imaging following preterm birth. An observational study of 40 preterm infants who had MR imaging of the brain around term-equivalent age, including conventional fast spin-echo (FSE) and ultrafast single-shot fast spin-echo (SSFSE) T2-weighted sequences in the axial plane. Images were anonymised and scored twice by four observers for the presence of DEHSI. Inter- and intra-observer agreement were calculated. Sixty-five percent of conventional and 100% of the ultrafast images were of diagnostic quality. DEHSI was noted in between 0% and 69.2% of conventional images and 27.5-90% of the ultrafast images. Inter- and intra-observer agreement ranged from none to moderate. The visual appearances of DEHSI on conventional FSE and ultrafast SSFSE T2-W images are highly subjective, limiting its clinical application. (orig.)

Quality of MR thermometry during palliative MR-guided high-intensity focused ultrasound (MR-HIFU) treatment of bone metastases

NARCIS (Netherlands)

Lam, Mie K; Huisman, Merel; Nijenhuis, Robbert J; van den Bosch, Maurice; Viergever, Max A; Moonen, Chrit Tw; Bartels, LW

2015-01-01

BACKGROUND: Magnetic resonance (MR)-guided high-intensity focused ultrasound has emerged as a clinical option for palliative treatment of painful bone metastases, with MR thermometry (MRT) used for treatment monitoring. In this study, the general image quality of the MRT was assessed in terms of

Fractional Hartley transform applied to optical image encryption

Science.gov (United States)

Jimenez, C.; Torres, C.; Mattos, L.

2011-01-01

A new method for image encryption is introduced on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform We encrypt the image by two fractional orders and random phase codes. It has an advantage over Hartley transform, for its fractional orders can also be used as addictional keys, and that, of course, strengthens image security. Only when all of these keys are correct, can the image be well decrypted. Computer simulations are also perfomed to confirm the possibilty of proposed method.

Fractional Hartley transform applied to optical image encryption

Energy Technology Data Exchange (ETDEWEB)

Jimenez, C [Grupo GIFES. Universidad de La Guajira. Riohacha (Colombia); Torres, C; Mattos, L, E-mail: carlosj114@gmail.com [Grupo LOI. Universidad Popular del Cesar. Valledupar (Colombia)

2011-01-01

A new method for image encryption is introduced on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform We encrypt the image by two fractional orders and random phase codes. It has an advantage over Hartley transform, for its fractional orders can also be used as addictional keys, and that, of course, strengthens image security. Only when all of these keys are correct, can the image be well decrypted. Computer simulations are also perfomed to confirm the possibility of proposed method.

Developing Quality Assurance Processes for Image-Guided Adaptive Radiation Therapy

International Nuclear Information System (INIS)

Yan Di

2008-01-01

Quality assurance has long been implemented in radiation treatment as systematic actions necessary to provide adequate confidence that the radiation oncology service will satisfy the given requirements for quality care. The existing reports from the American Association of Physicists in Medicine Task Groups 40 and 53 have provided highly detailed QA guidelines for conventional radiotherapy and treatment planning. However, advanced treatment processes recently developed with emerging high technology have introduced new QA requirements that have not been addressed previously in the conventional QA program. Therefore, it is necessary to expand the existing QA guidelines to also include new considerations. Image-guided adaptive radiation therapy (IGART) is a closed-loop treatment process that is designed to include the individual treatment information, such as patient-specific anatomic variation and delivered dose assessed during the therapy course in treatment evaluation and planning optimization. Clinical implementation of IGART requires high levels of automation in image acquisition, registration, segmentation, treatment dose construction, and adaptive planning optimization, which brings new challenges to the conventional QA program. In this article, clinical QA procedures for IGART are outlined. The discussion focuses on the dynamic or four-dimensional aspects of the IGART process, avoiding overlap with conventional QA guidelines

Image-guided procedures in brain biopsy.

Science.gov (United States)

Fujita, K; Yanaka, K; Meguro, K; Narushima, K; Iguchi, M; Nakai, Y; Nose, T

1999-07-01

Image-guided procedures, such as computed tomography (CT)-guided stereotactic and ultrasound-guided methods, can assist neurosurgeons in localizing the relevant pathology. The characteristics of image-guided procedures are important for their appropriate use, especially in brain biopsy. This study reviewed the results of various image-guided brain biopsies to ascertain the advantages and disadvantages. Brain biopsies assisted by CT-guided stereotactic, ultrasound-guided, Neuronavigator-guided, and the combination of ultrasound and Neuronavigator-guided procedures were carried out in seven, eight, one, and three patients, respectively. Four patients underwent open biopsy without a guiding system. Twenty of 23 patients had a satisfactory diagnosis after the initial biopsy. Three patients failed to have a definitive diagnosis after the initial procedure, one due to insufficient volume sampling after CT-guided procedure, and two due to localization failure by ultrasound because the lesions were nonechogenic. All patients who underwent biopsy using the combination of ultrasound and Neuronavigator-guided methods had a satisfactory result. The CT-guided procedure provided an efficient method of approaching any intracranial target and was appropriate for the diagnosis of hypodense lesions, but tissue sampling was sometimes not sufficient to achieve a satisfactory diagnosis. The ultrasound-guided procedure was suitable for the investigation of hyperdense lesions, but was difficult to localize nonechogenic lesions. The combination of ultrasound and Neuronavigator methods improved the diagnostic accuracy even in nonechogenic lesions such as malignant lymphoma. Therefore, it is essential to choose the most appropriate guiding method for brain biopsy according to the radiological nature of the lesions.

Present and future of the Image Guided Radiotherapy (I.G.R.T.) and its applications in lung cancer treatment

International Nuclear Information System (INIS)

Lefkopoulos, D.; Ferreira, I.; Isambert, A.; Le Pechoux, C.; Mornex, F.

2007-01-01

These last years, the new irradiation techniques as the conformal 3D radiotherapy and the IMRT are strongly correlated with the technological developments in radiotherapy. The rigorous definition of the target volume and the organs at risk required by these irradiation techniques, imposed the development of various image guided patient positioning and target tracking techniques. The availability of these imaging systems inside the treatment room has lead to the exploration of performing real-time adaptive radiation therapy. In this paper we present the different image guided radiotherapy (IGRT) techniques and the adaptive radiotherapy (ART) approaches. IGRT developments are focused in the following areas: 1) biological imaging for better definition of tumor volume; 2) 4D imaging for modeling the intra-fraction organ motion; 3) on-board imaging system or imaging devices registered to the treatment machines for inter-fraction patient localization; and 4) treatment planning and delivery schemes incorporating the information derived from the new imaging techniques. As this paper is included in the 'Cancer Radiotherapie' special volume dedicated to the lung cancers, in the description of the different IGRT techniques we try to present the lung tumors applications when this is possible. (author)

Bio-guided fractionation of methanol extract of Ziziphus mauritiana Lam. (bark and effect of the most active fraction on cancer cell lines

Directory of Open Access Journals (Sweden)

Richard Simo Tagne

2015-04-01

Full Text Available Objective: To investigate the anticancer and antioxidant potential of methanol bark extract of Ziziphus mauritiana (Z. mauritiana, which is used by traditional healers to cure some cases of cancer in Cameroon. Methods: The methanol crude extract of Z. mauritiana has the antiproliferative activity on four cancer cell lines and its antioxidant activity. The extract was partitioned in five different solvents, and each fraction was tested. The effect of the most antiproliferative fraction on cell cycle was determined. Bio-guided fractionation was performed on the fraction with the highest antiproliferative and the highest antioxidant activities. Results: Z. mauritiana methanol extract was active on all tested cells, and showed promising antioxidant activity. All fractions except hexane fraction were active with the dichloromethane fraction being the most active and showed S and G2-M phase arrest (P<0.01 on cell cycle progression of NCI-H460 and MCF-7, respectively. Bio-guided fractionation of the dichloromethane fraction led to lupeol and betulinic acid. The greatest antioxidant activity was recorded with ethyl acetate fraction and its fractionation led to catechin and epigallocatechin. Conclusions: Overall, this study showed that Z. mauritiana barks has benefits as a chemoprevention agent cancer.

Radiation resistivity of pure silica core image guides for industrial fiberscopes

International Nuclear Information System (INIS)

Okamoto, Shinichi; Ohnishi, Tokuhiro; Kanazawa, Tamotsu; Tsuji, Yukio; Hayami, Hiroyuki; Ishitani, Tadayoshi; Akutsu, Takeji; Suzuki, Koichi.

1991-01-01

Industrial fiberscopes incorporating pure silica core image guides have been extensively used for remote visual inspection in radiation fields including nuclear power plants, owing to their superior radiation resistivity. The authors have been intensively conducting R and D on improving radiation resistivity of pure silica core image guides. This paper reports the results of experiments to compare the effects of core materials on radiation resistivity and to investigate the dependence of radiation resistivity on total dose, does rate, and support pipe material. The results confirmed the superior radiation resistivity of the core material containing fluorine at any irradiation condition and indicated the existence of a critical dose rate at which radiation-induced deterioration was stabilized. No difference in radiation resistivity attributable to support layer material was observed. (author)

Compositional-prior-guided image reconstruction algorithm for multi-modality imaging

Science.gov (United States)

Fang, Qianqian; Moore, Richard H.; Kopans, Daniel B.; Boas, David A.

2010-01-01

The development of effective multi-modality imaging methods typically requires an efficient information fusion model, particularly when combining structural images with a complementary imaging modality that provides functional information. We propose a composition-based image segmentation method for X-ray digital breast tomosynthesis (DBT) and a structural-prior-guided image reconstruction for a combined DBT and diffuse optical tomography (DOT) breast imaging system. Using the 3D DBT images from 31 clinically measured healthy breasts, we create an empirical relationship between the X-ray intensities for adipose and fibroglandular tissue. We use this relationship to then segment another 58 healthy breast DBT images from 29 subjects into compositional maps of different tissue types. For each breast, we build a weighted-graph in the compositional space and construct a regularization matrix to incorporate the structural priors into a finite-element-based DOT image reconstruction. Use of the compositional priors enables us to fuse tissue anatomy into optical images with less restriction than when using a binary segmentation. This allows us to recover the image contrast captured by DOT but not by DBT. We show that it is possible to fine-tune the strength of the structural priors by changing a single regularization parameter. By estimating the optical properties for adipose and fibroglandular tissue using the proposed algorithm, we found the results are comparable or superior to those estimated with expert-segmentations, but does not involve the time-consuming manual selection of regions-of-interest. PMID:21258460

Image-guided adaptive gating of lung cancer radiotherapy: a computer simulation study

Energy Technology Data Exchange (ETDEWEB)

Aristophanous, Michalis; Rottmann, Joerg; Park, Sang-June; Berbeco, Ross I [Department of Radiation Oncology, Brigham and Women' s Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Nishioka, Seiko [Department of Radiology, NTT Hospital, Sapporo (Japan); Shirato, Hiroki, E-mail: maristophanous@lroc.harvard.ed [Department of Radiation Medicine, Hokkaido University School of Medicine, Sapporo (Japan)

2010-08-07

The purpose of this study is to investigate the effect that image-guided adaptation of the gating window during treatment could have on the residual tumor motion, by simulating different gated radiotherapy techniques. There are three separate components of this simulation: (1) the 'Hokkaido Data', which are previously measured 3D data of lung tumor motion tracks and the corresponding 1D respiratory signals obtained during the entire ungated radiotherapy treatments of eight patients, (2) the respiratory gating protocol at our institution and the imaging performed under that protocol and (3) the actual simulation in which the Hokkaido Data are used to select tumor position information that could have been collected based on the imaging performed under our gating protocol. We simulated treatments with a fixed gating window and a gating window that is updated during treatment. The patient data were divided into different fractions, each with continuous acquisitions longer than 2 min. In accordance to the imaging performed under our gating protocol, we assume that we have tumor position information for the first 15 s of treatment, obtained from kV fluoroscopy, and for the rest of the fractions the tumor position is only available during the beam-on time from MV imaging. The gating window was set according to the information obtained from the first 15 s such that the residual motion was less than 3 mm. For the fixed gating window technique the gate remained the same for the entire treatment, while for the adaptive technique the range of the tumor motion during beam-on time was measured and used to adapt the gating window to keep the residual motion below 3 mm. The algorithm used to adapt the gating window is described. The residual tumor motion inside the gating window was reduced on average by 24% for the patients with regular breathing patterns and the difference was statistically significant (p-value = 0.01). The magnitude of the residual tumor motion

Optical image encryption with redefined fractional Hartley transform

Science.gov (United States)

Zhao, Daomu; Li, Xinxin; Chen, Linfei

2008-11-01

A new method for optical image encryption is introduced on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform. We encrypt the image by two fractional orders and random phase codes. It has an advantage over Hartley transform, for its fractional orders can also be used as additional keys, and that, of course, strengthens image security. Only when all of these keys are correct, can the image be well decrypted. The optical realization is then proposed and computer simulations are also performed to confirm the possibility of the proposed method.

Acute gastrointestinal and genitourinary toxicity of image-guided intensity modulated radiation therapy for prostate cancer using a daily water-filled endorectal balloon

Directory of Open Access Journals (Sweden)

Deville Curtiland

2012-05-01

Full Text Available Abstract Background Our purpose was to report acute gastrointestinal (GI and genitourinary (GU toxicity rates for prostate cancer patients undergoing image-guided intensity modulated radiation therapy (IG-IMRT with a daily endorectal water-filled balloon (ERBH2O, and assess associations with planning parameters and pretreatment clinical characteristics. Methods The first 100 patients undergoing prostate and proximal seminal vesicle IG-IMRT with indexed-lumen 100 cc ERBH2O to 79.2 Gy in 1.8 Gy fractions at our institution from 12/2008- 12/2010 were assessed. Pretreatment characteristics, organ-at-risk dose volume histograms, and maximum GU and GI toxicities (CTCAE 3.0 were evaluated. Logistic regression models evaluated univariate association between toxicities and dosimetric parameters, and uni- and multivariate association between toxicities and pretreatment characteristics. Results Mean age was 68 (range 51–88. Thirty-two, 49, and 19 patients were low, intermediate, and high-risk, respectively; 40 received concurrent androgen deprivation. No grade 3 or greater toxicities were recorded. Maximum GI toxicity was grade 0, 1, and 2 in 69%, 23%, and 8%, respectively. Infield (defined as 1 cm above/below the CTV rectal mean/median doses, D75, V30, and V40 and hemorrhoid history were associated with grade 2 GI toxicity (Ps  Conclusion Prostate IG-IMRT using a daily ERBH2O shows low rates of acute GI toxicity compared to previous reports of air-filled ERB IMRT when using stringent infield rectum constraints and comparable GU toxicities.

Fast-MICP for frameless image-guided surgery

International Nuclear Information System (INIS)

Lee, Jiann-Der; Huang, Chung-Hsien; Wang, Sheng-Ta; Lin, Chung-Wei; Lee, Shin-Tseng

2010-01-01

Purpose: In image-guided surgery (IGS) systems, image-to-physical registration is critical for reliable anatomical information mapping and spatial guidance. Conventional stereotactic frame-based or fiducial-based approaches provide accurate registration but are not patient-friendly. This study proposes a frameless cranial IGS system that uses computer vision techniques to replace the frame or fiducials with the natural features of the patient. Methods: To perform a cranial surgery with the proposed system, the facial surface of the patient is first reconstructed by stereo vision. Accuracy is ensured by capturing parallel-line patterns projected from a calibrated LCD projector. Meanwhile, another facial surface is reconstructed from preoperative computed tomography (CT) images of the patient. The proposed iterative closest point (ICP)-based algorithm [fast marker-added ICP (Fast-MICP)] is then used to register the two facial data sets, which transfers the anatomical information from the CT images to the physical space. Results: Experimental results reveal that the Fast-MICP algorithm reduces the computational cost of marker-added ICP (J.-D. Lee et al., ''A coarse-to-fine surface registration algorithm for frameless brain surgery,'' in Proceedings of International Conference of the IEEE Engineering in Medicine and Biology Society, 2007, pp. 836-839) to 10% and achieves comparable registration accuracy, which is under 3 mm target registration error (TRE). Moreover, two types of optical-based spatial digitizing devices can be integrated for further surgical navigation. Anatomical information or image-guided surgical landmarks can be projected onto the patient to obtain an immersive augmented reality environment. Conclusion: The proposed frameless IGS system with stereo vision obtains TRE of less than 3 mm. The proposed Fast-MICP registration algorithm reduces registration time by 90% without compromising accuracy.

Fast-MICP for frameless image-guided surgery

Energy Technology Data Exchange (ETDEWEB)

Lee, Jiann-Der; Huang, Chung-Hsien; Wang, Sheng-Ta; Lin, Chung-Wei; Lee, Shin-Tseng [Department of Electrical Engineering, Chang Gung University, Tao-Yuan 333, Taiwan (China); Department of Medical Mechatronics, Chang Gung University, Tao-Yuan 333, Taiwan (China); Department of Neurosurgery and Medical Augmented Reality Research Center, Chang Gung Memorial Hospital, No. 199, Tunghwa Rd., Taipei 105, Taiwan (China)

2010-09-15

Purpose: In image-guided surgery (IGS) systems, image-to-physical registration is critical for reliable anatomical information mapping and spatial guidance. Conventional stereotactic frame-based or fiducial-based approaches provide accurate registration but are not patient-friendly. This study proposes a frameless cranial IGS system that uses computer vision techniques to replace the frame or fiducials with the natural features of the patient. Methods: To perform a cranial surgery with the proposed system, the facial surface of the patient is first reconstructed by stereo vision. Accuracy is ensured by capturing parallel-line patterns projected from a calibrated LCD projector. Meanwhile, another facial surface is reconstructed from preoperative computed tomography (CT) images of the patient. The proposed iterative closest point (ICP)-based algorithm [fast marker-added ICP (Fast-MICP)] is then used to register the two facial data sets, which transfers the anatomical information from the CT images to the physical space. Results: Experimental results reveal that the Fast-MICP algorithm reduces the computational cost of marker-added ICP (J.-D. Lee et al., ''A coarse-to-fine surface registration algorithm for frameless brain surgery,'' in Proceedings of International Conference of the IEEE Engineering in Medicine and Biology Society, 2007, pp. 836-839) to 10% and achieves comparable registration accuracy, which is under 3 mm target registration error (TRE). Moreover, two types of optical-based spatial digitizing devices can be integrated for further surgical navigation. Anatomical information or image-guided surgical landmarks can be projected onto the patient to obtain an immersive augmented reality environment. Conclusion: The proposed frameless IGS system with stereo vision obtains TRE of less than 3 mm. The proposed Fast-MICP registration algorithm reduces registration time by 90% without compromising accuracy.

Strategies for Biologic Image-Guided Dose Escalation: A Review

International Nuclear Information System (INIS)

Sovik, Aste; Malinen, Eirik; Olsen, Dag Rune

2009-01-01

There is increasing interest in how to incorporate functional and molecular information obtained by noninvasive, three-dimensional tumor imaging into radiotherapy. The key issues are to identify radioresistant regions that can be targeted for dose escalation, and to develop radiation dose prescription and delivery strategies providing optimal treatment for the individual patient. In the present work, we review the proposed strategies for biologic image-guided dose escalation with intensity-modulated radiation therapy. Biologic imaging modalities and the derived images are discussed, as are methods for target volume delineation. Different dose escalation strategies and techniques for treatment delivery and treatment plan evaluation are also addressed. Furthermore, we consider the need for response monitoring during treatment. We conclude with a summary of the current status of biologic image-based dose escalation and of areas where further work is needed for this strategy to become incorporated into clinical practice

1.5 T conventional MR-guided iodine-125 interstitial implants for hepatocellular carcinoma: Feasibility and preliminary clinical experience

International Nuclear Information System (INIS)

Lin Zhengyu; Lin Jun; Lin Cong; Li Yinguan; Chen Shaoming; Hu Jianping; Hu Rui; Chen Jin

2012-01-01

Purpose: To evaluate the feasibility and therapeutic efficacy of 1.5 T conventional MR-guided percutaneous interstitial implantation of I-125 radioactive seeds in patients with hepatocellular carcinoma (HCC). Materials and methods: The institutional ethics committee approved this study. After imformed consent was obtained, twenty-three patients suffering from a total of 65 HCC lesions were treated with I-125 seed permanent interstitial implantation under the guidance of a 1.5 T conventional magnetic resonance imaging (MRI) system. The FSE T2WI, T1 FSPGR, FIESTA 2D, 3D Dyn T1WI sequences were used to guide an 18G MR-compatible needle inserted into the lesions to introduce the I-125 seeds. The response evaluation criteria in solid tumors (RECIST) were used to evaluate the curative effect. Results: The needle and I-125 seed were seen clearly on MRI images. The final dose delivered to total decay was 173.46 ± 32.44 Gy (range, 110–270 Gy) as calculated by postoperative TPS. The complete response (CR) was seen in 22 lesions (33.8%), partial response (PR) in 24 lesions (36.9%), stable disease (SD) in 9 lesions (13.8%), and progressive disease (PD) in 10 lesions (15.4%). The post-operative alpha-fetoprotein (AFP) was decreased (t = 3.117, P = 0.005 < 0.05). Two patients were observed a small area of subcapsular bleeding that did not lead to any symptoms or clinical sequelae. Conclusion: MR-guided I-125 implantation for HCC is technically feasible and effective.

Maximum intensity projection MR angiography using shifted image data

International Nuclear Information System (INIS)

Machida, Yoshio; Ichinose, Nobuyasu; Hatanaka, Masahiko; Goro, Takehiko; Kitake, Shinichi; Hatta, Junicchi.

1992-01-01

The quality of MR angiograms has been significantly improved in past several years. Spatial resolution, however, is not sufficient for clinical use. On the other hand, MR image data can be filled at anywhere using Fourier shift theorem, and the quality of multi-planar reformed image has been reported to be improved remarkably using 'shifted data'. In this paper, we have clarified the efficiency of 'shifted data' for maximum intensity projection MR angiography. Our experimental studies and theoretical consideration showd that the quality of MR angiograms has been significantly improved using 'shifted data' as follows; 1) remarkable reduction of mosaic artifact, 2) improvement of spatial continuity for the blood vessels, and 3) reduction of variance for the signal intensity along the blood vessels. In other words, the angiograms looks much 'finer' than conventional ones, although the spatial resolution is not improved theoretically. Furthermore, we found the quality of MR angiograms dose not improve significantly with the 'shifted data' more than twice as dense as ordinal ones. (author)

Parotid gland function following accelerated and conventionally fractionated radiotherapy

International Nuclear Information System (INIS)

Leslie, M.D.; Dische, S.

1991-01-01

The function of parotid glands in patients treated by 3 different schedules of radiotherapy was studied 9 months or more after its conclusion. All had received radiotherapy for a malignancy confined to 1 side of the head and neck region and only the gland on the side of the lesion was in the treatment volume; the contralateral gland acted as an internal control. Saliva was selectively collected from the parotid glands and the stimulated flow rate and pH of the saliva determined. Flow rates were expressed in each case as a percentage of that of the contralateral ('untreated') gland. Twelve glands that had received conventionally fractionated radiotherapy to a dose of 60-66 Gy showed a mean percentage flow of 20 percent and a significant fall in the pH of the saliva produced. Six glands that had received CHART (Continuous Hyperfractionated Accelerated RadioTherapy) and 8 conventionally fractionated radiotherapy to a dose of 35-40 Gy showed mean percentage flows of 57 and 65 percent respectively, with only slight and non-significant falls in saliva pH. The results show that in the treatment of squamous cell carcinoma in the head and neck the use of CHART can lead to considerable less late change in the function of the parotid gland. (author). 26 refs.; 5 figs.; 2 tabs

Imaging technique for the complete edentulous patient treated conventionally or with mini implant overdenture

Science.gov (United States)

Meleşcanu Imre, M; Preoteasa, E; Țâncu, AM; Preoteasa, CT

2013-01-01

Rationale. The imaging methods are more and more used in the clinical process of modern dentistry. Once the implant based treatment alternatives are nowadays seen as being the standard of care in edentulous patients, these techniques must be integrated in the complete denture treatment. Aim. The study presents some evaluation techniques for the edentulous patient treated by conventional dentures or mini dental implants (mini SKY Bredent) overdentures, using the profile teleradiography. These offer data useful for an optimal positioning of the artificial teeth and the mini dental implants, favoring to obtain an esthetic and functional treatment outcome. We proposed also a method to conceive a simple surgical guide that allows the prosthetically driven implants placement. Material and method. Clinical case reports were made, highlighting the importance of cephalometric evaluation on lateral teleradiographs in complete edentulous patients. A clinical case that gradually reports the surgical guide preparation (Bredent silicon radio opaque), in order to place the mini dental implants in the best prosthetic and anatomic conditions, was presented. Conclusions. The profile teleradiograph is a useful tool for the practitioner. It allows establishing the optimal site for implant placement, in a good relation with the overdenture. The conventional denture can be easily and relatively costless transformed in a surgical guide used during implant placement. PMID:23599828

Intermediate-term results of image-guided brachytherapy and high-technology external beam radiotherapy in cervical cancer: Chiang Mai University experience.

Science.gov (United States)

Tharavichitkul, Ekkasit; Chakrabandhu, Somvilai; Wanwilairat, Somsak; Tippanya, Damrongsak; Nobnop, Wannapha; Pukanhaphan, Nantaka; Galalae, Razvan M; Chitapanarux, Imjai

2013-07-01

To evaluate the outcomes of image-guided brachytherapy combined with 3D conformal or intensity modulated external beam radiotherapy (3D CRT/IMRT) in cervical cancer at Chiang Mai University. From 2008 to 2011, forty-seven patients with locally advanced cervical cancer were enrolled in this study. All patients received high-technology (3D CRT/IMRT) whole pelvic radiotherapy with a total dose of 45-46 Gy plus image-guided High-Dose-Rate intracavitary brachytherapy 6.5-7 Gy × 4 fractions to a High-Risk Clinical Target Volume (HR-CTV) according to GEC-ESTRO recommendations. The dose parameters of the HR-CTV for bladder, rectum and sigmoid colon were recorded, as well as toxicity profiles. In addition, the endpoints for local control, disease-free, metastasis-free survival and overall survival were calculated. At the median follow-up time of 26 months, the local control, disease-free survival, and overall survival rates were 97.9%, 85.1%, and 93.6%, respectively. The mean dose of HR-CTV, bladder, rectum and sigmoid were 93.1, 88.2, 69.6, and 72 Gy, respectively. In terms of late toxicity, the incidence of grade 3-4 bladder and rectum morbidity was 2.1% and 2.1%, respectively. A combination of image-guided brachytherapy and IMRT/3D CRT showed very promising results of local control, disease-free survival, metastasis-free survival and overall survival rates. It also caused a low incidence of grade 3-4 toxicity in treated study patients. Copyright © 2013 Elsevier Inc. All rights reserved.

A preliminary diffusional kurtosis imaging study of Parkinson disease: comparison with conventional diffusion tensor imaging

Energy Technology Data Exchange (ETDEWEB)

Kamagata, Koji; Kamiya, Kouhei; Suzuki, Michimasa; Hori, Masaaki; Yoshida, Mariko; Aoki, Shigeki [Juntendo University School of Medicine, Department of Radiology, Bunkyo-ku, Tokyo (Japan); Tomiyama, Hiroyuki; Hatano, Taku; Motoi, Yumiko; Hattori, Nobutaka [Juntendo University School of Medicine, Department of Neurology, Tokyo (Japan); Abe, Osamu [Nihon University School of Medicine, Department of Radiology, Tokyo (Japan); Shimoji, Keigo [National Center of Neurology and Psychiatry Hospital, Department of Radiology, Tokyo (Japan)

2014-03-15

Diffusional kurtosis imaging (DKI) is a more sensitive technique than conventional diffusion tensor imaging (DTI) for assessing tissue microstructure. In particular, it quantifies the microstructural integrity of white matter, even in the presence of crossing fibers. The aim of this preliminary study was to compare how DKI and DTI show white matter alterations in Parkinson disease (PD). DKI scans were obtained with a 3-T magnetic resonance imager from 12 patients with PD and 10 healthy controls matched by age and sex. Tract-based spatial statistics were used to compare the mean kurtosis (MK), mean diffusivity (MD), and fractional anisotropy (FA) maps of the PD patient group and the control group. In addition, a region-of-interest analysis was performed for the area of the posterior corona radiata and superior longitudinal fasciculus (SLF) fiber crossing. FA values in the frontal white matter were significantly lower in PD patients than in healthy controls. Reductions in MK occurred more extensively throughout the brain: in addition to frontal white matter, MK was lower in the parietal, occipital, and right temporal white matter. The MK value of the area of the posterior corona radiata and SLF fiber crossing was also lower in the PD group. DKI detects changes in the cerebral white matter of PD patients more sensitively than conventional DTI. In addition, DKI is useful for evaluating crossing fibers. By providing a sensitive index of brain pathology in PD, DKI may enable improved monitoring of disease progression. (orig.)

Feasibility study of image guided radiotherapy for lung tumor using online and offline cone-beam CT setup verification

International Nuclear Information System (INIS)

Li Hongsheng; Li Baosheng; Lu Jie; Yin Yong; Yu Ningsha; Chen Yiru

2009-01-01

Objective: To investigate the feasibility of online and offline cone-beam CT(CBCT) guided radiotherapy for lung cancer. Methods: Fourteen patients with lung tumor treated by three-dimensional conformal radiotherapy were investigated. Online kV CBCT scan, image registration and setup correction were performed before and immediately after radiotherapy. CBCT online-guided correction data were used to calculate the population-based CTV-PTV margins under the condition of non-correction and correction in every fraction respectively. The numbers of initial images and the population-based CTV-PTV margins after the offline compensation of the system setup error were evaluated with the permission of 0.5 mm and 1.5 mm maximal residue error, respectively. Results: Under the condition of non-correction, the required margins for total error were 5.7 mm, 8.0 mm and 7.8 mm in the left-right (x axis), cranio-caudal (y axis) and anterior-posterior(z axis) directions, respectively. When the tumor was corrected in every fraction, the required margins for intra-fraction error were 2.4 mm, 2.4 mm and 2.3 mm in x,y and z axes, respectively. To correct the systematic setup error, 9 sets of CBCT images for 3.3 mm, 3.7 mm and 3.6 mm PTV margins, and 7 sets of CBCT images for 3.9 mm, 4.3 mm and 4.3 mm PTV margins in x,y and z axes were necessary when 0.5 mm and 1.5 mm maximal residue error were permitted respectively. Conclusions: Both of the online CBCT correction and the offline adaptive correction can markedly reduce the impact of setup error and reduce the required PTV margins accordingly. It is feasible to deliver the online and offline image guided radiation for patients with lung tumor. (authors)

Better compliance with hypofractionation vs. conventional fractionation in adjuvant breast cancer radiotherapy. Results of a single, institutional, retrospective study

International Nuclear Information System (INIS)

Rudat, Volker; Nour, Alaa; Hammoud, Mohamed; Abou Ghaida, Salam

2017-01-01

The aim of the study was to identify factors significantly associated with the occurrence of unintended treatment interruptions in adjuvant breast cancer radiotherapy. Patients treated with postoperative radiotherapy of the breast or chest wall between March 2014 and August 2016 were evaluated. The radiotherapy regimens and techniques applied were either conventional fractionation (CF; 28 daily fractions of 1.8 Gy or 25 fractions of 2.0 Gy) or hypofractionation (HF; 15 daily fractions of 2.67 Gy) with inverse planned intensity-modulated radiotherapy (IMRT) or three-dimensional planned conformal radiotherapy (3DCRT). Logistic regression analysis was used to identify factors associated with noncompliance. Noncompliance was defined as the missing of at least one scheduled radiotherapy fraction. In all, 19 of 140 (13.6%) patients treated with HF and 39 of 146 (26.7%) treated with CF experienced treatment interruptions. Of 23 factors tested, the fractionation regimen emerged as the only independent significant prognostic factor for noncompliance on multivariate analysis (CF; p = 0.007; odds ratio, 2.3; 95% confidence interval, 1.3-4.2). No statistically significant differences concerning the reasons for treatment interruptions could be detected between patients treated with CF or HF. HF is significantly associated with a better patient compliance with the prescribed radiotherapy schedule compared with CF. The data suggest that this finding is basically related to the shorter overall treatment time of HF. (orig.) [de

MO-DE-202-03: Image-Guided Surgery and Interventions in the Advanced Multimodality Image-Guided Operating (AMIGO) Suite

Energy Technology Data Exchange (ETDEWEB)

Kapur, T. [Brigham & Women’s Hospital (United States)

2016-06-15

At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

MO-DE-202-03: Image-Guided Surgery and Interventions in the Advanced Multimodality Image-Guided Operating (AMIGO) Suite

International Nuclear Information System (INIS)

Kapur, T.

2016-01-01

At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

Role of image-guided patient repositioning and online planning in localized prostate cancer IMRT

International Nuclear Information System (INIS)

Lerma, Fritz A.; Liu, Bei; Wang, Zhendong; Yi, Byongyong; Amin, Pradip; Liu, Sandy; Feng Yuanming; Yu, Cedric X.

2009-01-01

Purpose: To determine the expected benefit of image-guided online replanning over image-guided repositioning of localized prostate cancer intensity-modulated radiotherapy (IMRT). Materials and methods: On 10 to 11 CT scans of each of 10 early-stage prostate cancer patients, the prostate, bladder and rectum are manually segmented. Using a 3-mm PTV margin expansion from the CTV, an IMRT plan is made on the first CT scan of each patient. Online repositioning is simulated by recalculating the IMRT plan from the initial CT scan on the subsequent CT scans of each patient. For online replanning, IMRT is replanned twice on all CT scans, using 0-mm and 3-mm margins. The doses from subsequent CT images of each patient are then deformed to the initial CT anatomy using a mesh-based thin-plate B-spline deformation method and are accumulated for DVH and isodose review. Results: Paired t-tests show that online replanning with 3-mm margins significantly increases the prostate volume receiving the prescribed dose over replanning with 0-mm margins (p-value 0.004); gives marginally better target coverage than repositioning with 3-mm margins(p-value 0.06-0.343), and reduces variations in target coverage over repositioning. Fractional volumes of rectum and bladder receiving 75%, 80%, 85%, 90%, and 95% (V75, V80, V85, V90, and V95) of the prescription dose are evaluated. V90 and V95 values for the rectum are 1.6% and 0.7 % for 3-mm margin replanning and 1% and 0.4 % for 0-mm margin replanning, with p-values of 0.010-0.011. No significant differences between repositioning and replanning with 3-mm margins are found for both the rectum and the bladder. Conclusions: Image-guided replanning using 3-mm margins reduces target coverage variations, and maintains comparable rectum and bladder sparing to patient repositioning in localized prostate cancer IMRT. Marginal reductions in doses to rectum and bladder are possible when planning margins are eliminated in the online replanning scenario

Image-guided robotic surgery.

Science.gov (United States)

Marescaux, Jacques; Solerc, Luc

2004-06-01

Medical image processing leads to an improvement in patient care by guiding the surgical gesture. Three-dimensional models of patients that are generated from computed tomographic scans or magnetic resonance imaging allow improved surgical planning and surgical simulation that offers the opportunity for a surgeon to train the surgical gesture before performing it for real. These two preoperative steps can be used intra-operatively because of the development of augmented reality, which consists of superimposing the preoperative three-dimensional model of the patient onto the real intraoperative view. Augmented reality provides the surgeon with a view of the patient in transparency and can also guide the surgeon, thanks to the real-time tracking of surgical tools during the procedure. When adapted to robotic surgery, this tool tracking enables visual serving with the ability to automatically position and control surgical robotic arms in three dimensions. It is also now possible to filter physiologic movements such as breathing or the heart beat. In the future, by combining augmented reality and robotics, these image-guided robotic systems will enable automation of the surgical procedure, which will be the next revolution in surgery.

Cost minimisation analysis: kilovoltage imaging with automated repositioning versus electronic portal imaging in image-guided radiotherapy for prostate cancer.

Science.gov (United States)

Gill, S; Younie, S; Rolfo, A; Thomas, J; Siva, S; Fox, C; Kron, T; Phillips, D; Tai, K H; Foroudi, F

2012-10-01

To compare the treatment time and cost of prostate cancer fiducial marker image-guided radiotherapy (IGRT) using orthogonal kilovoltage imaging (KVI) and automated couch shifts and orthogonal electronic portal imaging (EPI) and manual couch shifts. IGRT treatment delivery times were recorded automatically on either unit. Costing was calculated from real costs derived from the implementation of a new radiotherapy centre. To derive cost per minute for EPI and KVI units the total annual setting up and running costs were divided by the total annual working time. The cost per IGRT fraction was calculated by multiplying the cost per minute by the duration of treatment. A sensitivity analysis was conducted to test the robustness of our analysis. Treatment times without couch shift were compared. Time data were analysed for 8648 fractions, 6057 from KVI treatment and 2591 from EPI treatment from a total of 294 patients. The median time for KVI treatment was 6.0 min (interquartile range 5.1-7.4 min) and for EPI treatment it was 10.0 min (interquartile range 8.3-11.8 min) (P value time for EPI was 8.8 min and for KVI was 5.1 min. Treatment time is less on KVI units compared with EPI units. This is probably due to automation of couch shift and faster evaluation of imaging on KVI units. Annual running costs greatly outweigh initial setting up costs and therefore the cost per fraction was less with KVI, despite higher initial costs. The selection of appropriate IGRT equipment can make IGRT practical within radiotherapy departments. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Trilogy Image-Guided Stereotactic Radiosurgery

International Nuclear Information System (INIS)

Huntzinger, Calvin; Friedman, William; Bova, Frank; Fox, Timothy; Bouchet, Lionel; Boeh, Lester M.B.A.

2007-01-01

Full integration of advanced imaging, noninvasive immobilization, positioning, and motion-management methods into radiosurgery have resulted in fundamental changes in therapeutic strategies and approaches that are leading us to the treatment room of the future. With the introduction of image-guided radiosurgery (IGRS) systems, such as Trilogy TM , physicians have for the first time a practical means of routinely identifying and treating very small lesions throughout the body. Using new imaging processes such as positron emission tomography/computed tomography (PET/CT) scans, clinics may be able to detect these lesions and then eradicate them with image-guided stereotactic radiosurgery treatments. Thus, there is promise that cancer could be turned into a chronic disease, managed through a series of checkups, and Trilogy treatments when metastatic lesions reappear

Image guided percutaneous splenic interventions

International Nuclear Information System (INIS)

Kang, Mandeep; Kalra, Naveen; Gulati, Madhu; Lal, Anupam; Kochhar, Rohit; Rajwanshi, Arvind

2007-01-01

Aim: The objective of this study is to evaluate the efficacy and safety of image-guided percutaneous splenic interventions as diagnostic or therapeutic procedures. Materials and methods: We performed a retrospective review of our interventional records from July 2001 to June 2006. Ninety-five image-guided percutaneous splenic interventions were performed after informed consent in 89 patients: 64 men and 25 women who ranged in age from 5 months to 71 years (mean, 38.4 years) under ultrasound (n = 93) or CT (n = 2) guidance. The procedures performed were fine needle aspiration biopsy of focal splenic lesions (n = 78) and aspiration (n = 10) or percutaneous catheter drainage of a splenic abscess (n = 7). Results: Splenic fine needle aspiration biopsy was successful in 62 (83.78%) of 74 patients with benign lesions diagnosed in 43 (58.1%) and malignancy in 19 (25.67%) patients. The most common pathologies included tuberculosis (26 patients, 35.13%) and lymphoma (14 patients, 18.91%). Therapeutic aspiration or pigtail catheter drainage was successful in all (100%) patients. There were no major complications. Conclusions: Image-guided splenic fine needle aspiration biopsy is a safe and accurate technique that can provide a definitive diagnosis in most patients with focal lesions in the spleen. This study also suggests that image-guided percutaneous aspiration or catheter drainage of splenic abscesses is a safe and effective alternative to surgery

Digital imaging in conventional diagnostic radiology: status and trends

International Nuclear Information System (INIS)

Pfeiler, M.; Marhoff, P.; Schipper, P.

1984-01-01

Digital techniques, i.e. techniques using microcomputers of minicomputers, are getting increasingly common in so-called conventional radiography. These nonreconstructive techniques are referred to here as 'digital, direct-imaging radiography' in order to contrast them with the reconstructive techniques of computerized tomography. Digitalisation of imaging and image processing operation and control will change the jobs of the radiologist and radiological assistants in such manner that only X-ray units with film-foil systems or with X-ray image intensification should be classified as conventional systems. Digital and conventional systems differ in that digital techniques imply the possibility of establishing data pools which may eventually be developed into a digital image interconnection and archiving system. The authors first describe the general system in which the digital imaging systems must be integrated on a medium-term and long-term basis and then proceed to discuss digital imaging and image processing in some more detail. (orig./WU) [de

Preliminary results for positron emission mammography: real-time functional breast imaging in a conventional mammography gantry

International Nuclear Information System (INIS)

Weinberg, I.; Majewski, S.; Weisenberger, A.; Markowitz, A.; Aloj, L.; Majewski, L,; Danforth, D.; Mulshine, J.; Cowan, K.; Zujewski, J.; Chow, C.; Jones, E.; Chang, V.; Berg, W.; Frank, J.

1996-01-01

In order to optimally integrate radiotracer breast imaging within the breast clinic, anatomy and pathology should be easily correlated with functional nuclear medicine breast images. As a first step in the development of a hybrid functional/anatomic breast imaging platform with biopsy capability, a conventional X-ray mammography gantry was modified to image the compressed brest with positron emitters. Phantom studies with the positron emission mammography (PEM) device showed that a 1-cc hot spot could be detected within 5 min. A preliminary clinical trial demonstrated in vivo visualization of primary breast cancer within 4 min. For sites where positron-emitting radionuclides are available, PEM promises to achieve low-cost directed functional examination of breast abnormalities, with potential for achieving X-ray correlation and image-guided biopsy. (orig.)

Real-time registration of 3D to 2D ultrasound images for image-guided prostate biopsy.

Science.gov (United States)

Gillies, Derek J; Gardi, Lori; De Silva, Tharindu; Zhao, Shuang-Ren; Fenster, Aaron

2017-09-01

During image-guided prostate biopsy, needles are targeted at tissues that are suspicious of cancer to obtain specimen for histological examination. Unfortunately, patient motion causes targeting errors when using an MR-transrectal ultrasound (TRUS) fusion approach to augment the conventional biopsy procedure. This study aims to develop an automatic motion correction algorithm approaching the frame rate of an ultrasound system to be used in fusion-based prostate biopsy systems. Two modes of operation have been investigated for the clinical implementation of the algorithm: motion compensation using a single user initiated correction performed prior to biopsy, and real-time continuous motion compensation performed automatically as a background process. Retrospective 2D and 3D TRUS patient images acquired prior to biopsy gun firing were registered using an intensity-based algorithm utilizing normalized cross-correlation and Powell's method for optimization. 2D and 3D images were downsampled and cropped to estimate the optimal amount of image information that would perform registrations quickly and accurately. The optimal search order during optimization was also analyzed to avoid local optima in the search space. Error in the algorithm was computed using target registration errors (TREs) from manually identified homologous fiducials in a clinical patient dataset. The algorithm was evaluated for real-time performance using the two different modes of clinical implementations by way of user initiated and continuous motion compensation methods on a tissue mimicking prostate phantom. After implementation in a TRUS-guided system with an image downsampling factor of 4, the proposed approach resulted in a mean ± std TRE and computation time of 1.6 ± 0.6 mm and 57 ± 20 ms respectively. The user initiated mode performed registrations with in-plane, out-of-plane, and roll motions computation times of 108 ± 38 ms, 60 ± 23 ms, and 89 ± 27 ms, respectively, and corresponding

Real-time 3D-surface-guided head refixation useful for fractionated stereotactic radiotherapy

International Nuclear Information System (INIS)

Li Shidong; Liu Dezhi; Yin Gongjie; Zhuang Ping; Geng, Jason

2006-01-01

Accurate and precise head refixation in fractionated stereotactic radiotherapy has been achieved through alignment of real-time 3D-surface images with a reference surface image. The reference surface image is either a 3D optical surface image taken at simulation with the desired treatment position, or a CT/MRI-surface rendering in the treatment plan with corrections for patient motion during CT/MRI scans and partial volume effects. The real-time 3D surface images are rapidly captured by using a 3D video camera mounted on the ceiling of the treatment vault. Any facial expression such as mouth opening that affects surface shape and location can be avoided using a new facial monitoring technique. The image artifacts on the real-time surface can generally be removed by setting a threshold of jumps at the neighboring points while preserving detailed features of the surface of interest. Such a real-time surface image, registered in the treatment machine coordinate system, provides a reliable representation of the patient head position during the treatment. A fast automatic alignment between the real-time surface and the reference surface using a modified iterative-closest-point method leads to an efficient and robust surface-guided target refixation. Experimental and clinical results demonstrate the excellent efficacy of <2 min set-up time, the desired accuracy and precision of <1 mm in isocenter shifts, and <1 deg. in rotation

Implementation of image-guided intensity-modulated accelerated partial breast irradiation. Three-year results of a phase II clinical study

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Meszaros, Norbert; Major, Tibor; Stelczer, Gabor; Zaka, Zoltan; Takacsi-Nagy, Zoltan; Fodor, Janos; Polgar, Csaba [National Institute of Oncology, Center of Radiotherapy, Budapest (Hungary); Mozsa, Emoke [National Institute of Oncology, Center of Radiotherapy, Budapest (Hungary); Landesklinikum, Department of Radiooncology and Radiotherapy, Wiener Neustadt (Austria); Pukancsik, David [National Institute of Oncology, Department of Breast and Sarcoma Surgery, Budapest (Hungary)

2017-01-15

To report 3-year results of accelerated partial breast irradiation (APBI) using image-guided intensity-modulated radiotherapy (IG-IMRT) following breast conserving surgery (BCS) for low-risk early invasive breast cancer. Between July 2011 and March 2014, 60 patients with low-risk early invasive breast cancer underwent BCS and were enrolled in this phase II prospective study. The total dose was 36.9 Gy (9 fractions of 4.1 Gy, two fractions/day). Patient setup errors were detected in LAT, LONG and VERT directions. Local tumour control, survival results, early and late side effects and cosmetic outcome were assessed. At a median follow-up of 39 months, all patients were alive and neither locoregional nor distant failure occurred. One contralateral breast cancer and two new primary malignancies outside the breast were observed. No grade (G) 3-4 acute toxicity was detected. G1 and G2 erythema occurred in 21 (35%) and 2 (3.3%) patients, respectively; while G1 oedema was observed in 23 (38.8%) cases. G1 and G2 pain was reported by 6 (10%) and 2 (3.3%) patients, respectively. Among the late radiation side effects, G1 pigmentation or telangiectasia, G1 fibrosis and G1 asymptomatic fat necrosis occurred in 10 (16.7%), 7 (11.7%) and 3 (5%) patients, respectively. No ≥ G2 late toxicity was detected. Cosmetic outcome was excellent in 43 (71.7%) and good in 17 (28.3%) patients. IG-IMRT is a reproducible and feasible technique for delivery of external beam APBI following BCS for treatment of low-risk, early-stage invasive breast carcinoma. In order to avoid toxicity, image guidance performed before each radiation fraction is necessary to minimize the PTV. Three-year results are promising, early and late radiation side-effects are minimal, and cosmetic results are excellent to good. (orig.) [German] Evaluierung der 3-Jahres-Ergebnisse der Teilbrustbestrahlung (APBI) mittels bildgefuehrter intensitaetsmodulierter Strahlentherapie (IG-IMRT) nach brusterhaltender Operation (BCS

Magnetic Resonance Image Guided Radiation Therapy for External Beam Accelerated Partial-Breast Irradiation: Evaluation of Delivered Dose and Intrafractional Cavity Motion

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Acharya, Sahaja; Fischer-Valuck, Benjamin W.; Mazur, Thomas R.; Curcuru, Austen; Sona, Karl; Kashani, Rojano; Green, Olga; Ochoa, Laura; Mutic, Sasa; Zoberi, Imran; Li, H. Harold; Thomas, Maria A., E-mail: mthomas@radonc.wustl.edu

2016-11-15

Purpose: To use magnetic resonance image guided radiation therapy (MR-IGRT) for accelerated partial-breast irradiation (APBI) to (1) determine intrafractional motion of the breast surgical cavity; and (2) assess delivered dose versus planned dose. Methods and Materials: Thirty women with breast cancer (stages 0-I) who underwent breast-conserving surgery were enrolled in a prospective registry evaluating APBI using a 0.35-T MR-IGRT system. Clinical target volume was defined as the surgical cavity plus a 1-cm margin (excluding chest wall, pectoral muscles, and 5 mm from skin). No additional margin was added for the planning target volume (PTV). A volumetric MR image was acquired before each fraction, and patients were set up to the surgical cavity as visualized on MR imaging. To determine the delivered dose for each fraction, the electron density map and contours from the computed tomography simulation were transferred to the pretreatment MR image via rigid registration. Intrafractional motion of the surgical cavity was determined by applying a tracking algorithm to the cavity contour as visualized on cine MR. Results: Median PTV volume was reduced by 52% when using no PTV margin compared with a 1-cm PTV margin used conventionally. The mean (± standard deviation) difference between planned and delivered dose to the PTV (V95) was 0.6% ± 0.1%. The mean cavity displacement in the anterior–posterior and superior–inferior directions was 0.6 ± 0.4 mm and 0.6 ± 0.3 mm, respectively. The mean margin required for at least 90% of the cavity to be contained by the margin for 90% of the time was 0.7 mm (5th-95th percentile: 0-2.7 mm). Conclusion: Minimal intrafractional motion was observed, and the mean difference between planned and delivered dose was less than 1%. Assessment of efficacy and cosmesis of this MR-guided APBI approach is under way.

CT reconstruction from few-views with anisotropic edge-guided total variance

International Nuclear Information System (INIS)

Rong, Junyan; Liu, Wenlei; Gao, Peng; Liao, Qimei; Jiao, Chun; Ma, Jianhua; Lu, Hongbing

2016-01-01

To overcome the oversmoothing drawback in the edge areas when reconstructing few-view CT with total variation (TV) minimization, in this paper, we propose an anisotropic edge-guided TV minimization framework for few-view CT reconstruction. In the framework, anisotropic TV is summed with pre-weighted image gradient and then used as the object function for minimizing. It includes edge-guided TV minimization (EGTV) and edge-guided adaptive-weighted TV minimization (EGAwTV) algorithms. For EGTV algorithm, the weights of the TV discretization term are updated by anisotropic edge information detected from the image, whereas the weights for EGAwTV are determined based on edge information and local image-intensity gradients. To solve the minimization problem of the proposed algorithm, a similar TV-based minimization implementation is developed to address the raw data fidelity and other constraints. The evaluation results using both computer simulations with the Shepp-Logan phantom and experimental data from a physical phantom demonstrate that the proposed algorithms exhibit noticeable gains in the merits of spatial resolution compared with the conventional TV and other modified TV algorithms.

Meniscal tears: comparison of half-Fourier technique and conventional MR imaging

International Nuclear Information System (INIS)

Shabana, Wael; Maeseneer, Michel de; Machiels, Freddy; Ridder, Filip de; Osteaux, Michel

2003-01-01

Purpose: To determine whether half-Fourier MR image acquisition technique can provide similar information to that of conventional MR acquisition technique for evaluation of meniscal tears. Materials and methods: We studied 101 menisci in 52 patients who were referred for evaluation of meniscal tears. Sagittal MR images of the knee were obtained for all patients by using proton density and T2-weighted SE sequences on a 1-T clinical system. The half-Fourier technique and conventional technique were used for all patients. All other imaging parameters were identical for both sequences (TR/TE=2400/20,70; 3 mm slice thickness; 200x256 matrix; field of view, 200; one signal acquired). Both sets of images were filmed with standard window and level settings. Images were randomised and interpreted independently by two radiologists for the presence of meniscal tears. Images were also subjectively assessed for image quality using a five-point grading scale. Results: On half-Fourier images, Reader 1 interpreted 23 menisci as torn, compared to 28 for Reader 2. On conventional images, Reader 1 interpreted 24 menisci as torn, compared to 26 for Reader 2. Agreement between interpretation of the conventional and that of the half-Fourier images was 99% for Reader 1, and 98% for Reader 2. Agreement between readers for the half-Fourier images was 95%, and for the conventional images 96%. No statistically significant difference was found in the subjective evaluation of image quality between the conventional and half-Fourier images. Conclusion: The half-Fourier acquisition technique compares favourably with the conventional technique for the evaluation of meniscal tears

Poster — Thur Eve — 13: Inter-Fraction Target Movement in Image-Guided Radiation Therapy of Prostate Cancer

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Cui, Congwu; Zeng, Grace G. [Department of Medical Physics, Carlo Fidani Peel Regional Cancer Center, Trillium Health Partners / Credit Valley Hospital,Mississauga, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada)

2014-08-15

We investigated the setup variations over the treatment courses of 113 patients with intact prostate treated with 78Gy/39fx. Institutional standard bladder and bowel preparation and image guidance protocols were used in CT simulation and treatment. The RapidArc treatment plans were optimized in Varian Eclipse treatment planning system and delivered on Varian 2100X Clinacs equipped with On-Board Imager to localize the target before beam-on. The setup variations were calculated in terms of mean and standard deviation of couch shifts. No correlation was observed between the mean shift and standard deviation over the treatment course and patient age, initial prostate volume and rectum size. The mean shifts in the first and last 5 fractions are highly correlated (P < 10{sup −10}) while the correlation of the standard deviations cannot be determined. The Mann-Kendall tests indicate trends of the mean daily Ant-Post and Sup-Inf shifts of the group. The target is inferior by ∼1mm to the planned position when the treatment starts and moves superiorly, approaching the planned position at 10th fraction, and then gradually moves back inferiorly by ∼1mm in the remain fractions. In the Ant-Post direction, the prostate gradually moves posteriorly during the treatment course from a mean shift of ∼2.5mm in the first fraction to ∼1mm in the last fraction. It may be related to a systematic rectum size change in the progress of treatment. The biased mean shifts in Ant-Post and Sup-Inf direction of most patients suggest systematically larger rectum and smaller bladder during the treatment than at CT simulation.

Hyperdynamic left ventricular ejection fraction in the intensive care unit.

Science.gov (United States)

Paonessa, Joseph R; Brennan, Thomas; Pimentel, Marco; Steinhaus, Daniel; Feng, Mengling; Celi, Leo Anthony

2015-08-07

Limited information exists on the etiology, prevalence, and significance of hyperdynamic left ventricular ejection fraction (HDLVEF) in the intensive care unit (ICU). Our aim in the present study was to compare characteristics and outcomes of patients with HDLVEF with those of patients with normal left ventricular ejection fraction in the ICU using a large, public, deidentified critical care database. We conducted a longitudinal, single-center, retrospective cohort study of adult patients who underwent echocardiography during a medical or surgical ICU admission at the Beth Israel Deaconess Medical Center using the Multiparameter Intelligent Monitoring in Intensive Care II database. The final cohort had 2867 patients, of whom 324 had HDLVEF, defined as an ejection fraction >70%. Patients with an ejection fraction <55% were excluded. Compared with critically ill patients with normal left ventricular ejection fraction, the finding of HDLVEF in critically ill patients was associated with female sex, increased age, and the diagnoses of hypertension and cancer. Patients with HDLVEF had increased 28-day mortality compared with those with normal ejection fraction in multivariate logistic regression analysis adjusted for age, sex, Sequential Organ Failure Assessment score, Elixhauser score for comorbidities, vasopressor use, and mechanical ventilation use (odds ratio 1.38, 95% confidence interval 1.039-1.842, p =0.02). The presence of HDLVEF portended increased 28-day mortality, and may be helpful as a gravity marker for prognosis in patients admitted to the ICU. Further research is warranted to gain a better understanding of how these patients respond to common interventions in the ICU and to determine if pharmacologic modulation of HDLVEF improves outcomes.

Evaluation of Image-Guided Positioning for Frameless Intracranial Radiosurgery

International Nuclear Information System (INIS)

Lamba, Michael; Breneman, John C.; Warnick, Ronald E.

2009-01-01

Purpose: The standard for target alignment and immobilization in intracranial radiosurgery is frame-based alignment and rigid immobilization using a stereotactic head ring. Recent improvements in image-guidance systems have introduced the possibility of image-guided radiosurgery with nonrigid immobilization. We present data on the alignment accuracy and patient stability of a frameless image-guided system. Methods and Materials: Isocenter alignment errors were measured for in vitro studies in an anthropomorphic phantom for both frame-based stereotactic and frameless image-guided alignment. Subsequently, in vivo studies assessed differences between frame-based and image-guided alignment in patients who underwent frame-based intracranial radiosurgery. Finally, intratreatment target stability was determined by image-guided alignment performed before and after image-guided mask immobilized radiosurgery. Results: In vitro hidden target localization errors were comparable for the framed (0.7 ± 0.5 mm) and image-guided (0.6 ± 0.2 mm) techniques. The in vivo differences in alignment were 0.9 ± 0.5 mm (anteroposterior), -0.2 ± 0.4 mm (superoinferior), and 0.3 ± 0.5 mm (lateral). For in vivo stability tests, the mean distance differed between the pre- and post-treatment positions with mask-immobilized radiosurgery by 0.5 ± 0.3 mm. Conclusion: Frame-based and image-guided alignment accuracy in vitro was comparable for the system tested. In vivo tests showed a consistent trend in the difference of alignment in the anteroposterior direction, possibly due to torque to the ring and mounting system with frame-based localization. The mask system as used appeared adequate for patient immobilization.

Tailor-made Surgical Guide Reduces Incidence of Outliers of Cup Placement.

Science.gov (United States)

Hananouchi, Takehito; Saito, Masanobu; Koyama, Tsuyoshi; Sugano, Nobuhiko; Yoshikawa, Hideki

2010-04-01

Malalignment of the cup in total hip arthroplasty (THA) increases the risks of postoperative complications such as neck cup impingement, dislocation, and wear. We asked whether a tailor-made surgical guide based on CT images would reduce the incidence of outliers beyond 10 degrees from preoperatively planned alignment of the cup compared with those without the surgical guide. We prospectively followed 38 patients (38 hips, Group 1) having primary THA with the conventional technique and 31 patients (31 hips, Group 2) using the surgical guide. We designed the guide for Group 2 based on CT images and fixed it to the acetabular edge with a Kirschner wire to indicate the planned cup direction. Postoperative CT images showed the guide reduced the number of outliers compared with the conventional method (Group 1, 23.7%; Group 2, 0%). The surgical guide provided more reliable cup insertion compared with conventional techniques. Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

In-room CT techniques for image-guided radiation therapy

International Nuclear Information System (INIS)

Ma, C.-M. Charlie; Paskalev, Kamen M.S.

2006-01-01

Accurate patient setup and target localization are essential to advanced radiation therapy treatment. Significant improvement has been made recently with the development of image-guided radiation therapy, in which image guidance facilitates short treatment course and high dose per fraction radiotherapy, aiming at improving tumor control and quality of life. Many imaging modalities are being investigated, including x-ray computed tomography (CT), ultrasound imaging, positron emission tomography, magnetic resonant imaging, magnetic resonant spectroscopic imaging, and kV/MV imaging with flat panel detectors. These developments provide unique imaging techniques and methods for patient setup and target localization. Some of them are different; some are complementary. This paper reviews the currently available kV x-ray CT systems used in the radiation treatment room, with a focus on the CT-on-rails systems, which are diagnostic CT scanners moving on rails installed in the treatment room. We will describe the system hardware including configurations, specifications, operation principles, and functionality. We will review software development for image fusion, structure recognition, deformation correction, target localization, and alignment. Issues related to the clinical implementation of in-room CT techniques in routine procedures are discussed, including acceptance testing and quality assurance. Clinical applications of the in-room CT systems for patient setup, target localization, and adaptive therapy are also reviewed for advanced radiotherapy treatments

Analysis of Magnetic Resonance Image Signal Fluctuations Acquired During MR-Guided Radiotherapy.

Science.gov (United States)

Breto, Adrian L; Padgett, Kyle R; Ford, John C; Kwon, Deukwoo; Chang, Channing; Fuss, Martin; Stoyanova, Radka; Mellon, Eric A

2018-03-28

Magnetic resonance-guided radiotherapy (MRgRT) is a new and evolving treatment modality that allows unprecedented visualization of the tumor and surrounding anatomy. MRgRT includes daily 3D magnetic resonance imaging (MRI) for setup and rapidly repeated near real-time MRI scans during treatment for target tracking. One of the more exciting potential benefits of MRgRT is the ability to analyze serial MRIs to monitor treatment response or predict outcomes. A typical radiation treatment (RT) over the span of 10-15 minutes on the MRIdian system (ViewRay, Cleveland, OH) yields thousands of "cine" images, each acquired in 250 ms. This unique data allows for a glimpse in image intensity changes during RT delivery. In this report, we analyze cine images from a single fraction RT of a glioblastoma patient on the ViewRay platform in order to characterize the dynamic signal changes occurring during RT therapy. The individual frames in the cines were saved into DICOM format and read into an MIM image analysis platform (MIM Software, Cleveland, OH) as a time series. The three possible states of the three Cobalt-60 radiation sources-OFF, READY, and ON-were also recorded. An in-house Java plugin for MIM was created in order to perform principal component analysis (PCA) on each of the datasets. The analysis resulted in first PC, related to monotonous signal increase over the course of the treatment fraction. We found several distortion patterns in the data that we postulate result from the perturbation of the magnetic field due to the moving metal parts in the platform while treatment was being administered. The largest variations were detected when all Cobalt-60 sources were OFF. During this phase of the treatment, the gantry and multi-leaf collimators (MLCs) are moving. Conversely, when all Cobalt-60 sources were in the ON position, the image signal fluctuations were minimal, relating to very little mechanical motion. At this phase, the gantry, the MLCs, and sources are fixed

Present status and future of high-precision image guided adaptive brachytherapy for cervix carcinoma

International Nuclear Information System (INIS)

Poetter, Richard; Kirisits, Christian; Fidarova, Elena F.; Dimopoulos, Johan nes C. A.; Berger, Daniel; Tanderup, Kari; Lindegaard, Jacob C.

2008-01-01

Introduction. Image guided adaptive brachytherapy (IGABT) for cervical cancer, using mainly MRI, is an evolving method, increasingly replacing the 2D approach based on conventional radiography. During the complex 4D chain of this procedure image-assistance is provided for disease assessment, provisional treatment planning ('pre-planning'), applicator placement and reconstruction, as well as for contouring, definitive treatment planning and quality control of dose delivery. With IGABT changes of topography adjacent to the applicator, caused by tumour regression, oedema, organ changes and dilation are identified. Thus, the CTV for IGABT is primarily based on the tumour volume at the time of BT and takes into account both time and spatial domains. IGABT requires systematic concepts for target, OAR, biological modelling, DVH analysis, and dose-volume-adaptation. Methods and Results. This report focuses on the advantages and uncertainties, dose-effect relations and clinical results of the IGABT procedure addressing the current status and future perspectives. Uncertainties during the 4D chain of IGABT are mainly related to target contouring, applicator reconstruction, as well as to inter-fraction, intra-fraction and inter-application variability, as caused by tumour response and organ changes. Different from EBRT where set-up uncertainties are compensated by adding a margin to the CTV, no margins to the lateral and anterior-posterior directions can be used for IGABT. Discussion. By 3D treatment planning for IGABT significant improvement of the DVH parameters is achieved compared to 2D library plans. In small tumours the benefit is primarily obtained by a decrease of dose to nearby OAR while in large tumours the use of supplementary interstitial techniques and optimization may double the target volume that can be treated at a therapeutic dose level. The clinical impact of IGABT could recently be demonstrated by the establishment of some correlations between target- and

Deep architecture neural network-based real-time image processing for image-guided radiotherapy.

Science.gov (United States)

Mori, Shinichiro

2017-08-01

To develop real-time image processing for image-guided radiotherapy, we evaluated several neural network models for use with different imaging modalities, including X-ray fluoroscopic image denoising. Setup images of prostate cancer patients were acquired with two oblique X-ray fluoroscopic units. Two types of residual network were designed: a convolutional autoencoder (rCAE) and a convolutional neural network (rCNN). We changed the convolutional kernel size and number of convolutional layers for both networks, and the number of pooling and upsampling layers for rCAE. The ground-truth image was applied to the contrast-limited adaptive histogram equalization (CLAHE) method of image processing. Network models were trained to keep the quality of the output image close to that of the ground-truth image from the input image without image processing. For image denoising evaluation, noisy input images were used for the training. More than 6 convolutional layers with convolutional kernels >5×5 improved image quality. However, this did not allow real-time imaging. After applying a pair of pooling and upsampling layers to both networks, rCAEs with >3 convolutions each and rCNNs with >12 convolutions with a pair of pooling and upsampling layers achieved real-time processing at 30 frames per second (fps) with acceptable image quality. Use of our suggested network achieved real-time image processing for contrast enhancement and image denoising by the use of a conventional modern personal computer. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Image-guided left ventricular lead placement in cardiac resynchronization therapy for patients with heart failure: a meta-analysis.

Science.gov (United States)

Jin, Yan; Zhang, Qi; Mao, Jia-Liang; He, Ben

2015-05-10

Heart failure (HF) is a debilitating condition that affects millions of people worldwide. One means of treating HF is cardiac resynchronization therapy (CRT). Recently, several studies have examined the use of echocardiography (ECHO) in the optimization of left ventricular (LV) lead placement to increase the response to CRT. The objective of this study was to synthesize the available data on the comparative efficacy of image-guided and standard CRT. We searched the PubMed, Cochrane, Embase, and ISI Web of Knowledge databases through April 2014 with the following combinations of search terms: left ventricular lead placement, cardiac resynchronization therapy, image-guided, and echocardiography-guided. Studies meeting all of the inclusion criteria and none of the exclusion criteria were eligible for inclusion. The primary outcome measures were CRT response rate, change in LV ejection fraction (LVEF), and change in LV end systolic volume (LVESV). Secondary outcomes included the rates of all-cause mortality and HF-related hospitalization. Our search identified 103 articles, 3 of which were included in the analysis. In total, 270 patients were randomized to the image-guided CRT and 241, to the standard CRT. The pooled estimates showed a significant benefit for image-guided CRT (CRT response: OR, 2.098, 95 % CI, 1.432-3.072; LVEF: difference in means, 3.457, 95 % CI, 1.910-5.005; LVESV: difference in means, -20.36, 95 % CI, -27.819 - -12.902). Image-guided CRT produced significantly better clinical outcomes than the standard CRT. Additional trials are warranted to validate the use of imaging in the prospective optimization of CRT.

Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

2008-11-15

To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes; Reed, Umbertina Conti; Rosemberg, Sergio

2008-01-01

To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

Image-guided system versus manual marking for toric intraocular lens alignment in cataract surgery.

Science.gov (United States)

Webers, Valentijn S C; Bauer, Noel J C; Visser, Nienke; Berendschot, Tos T J M; van den Biggelaar, Frank J H M; Nuijts, Rudy M M A

2017-06-01

To compare the accuracy of toric intraocular lens (IOL) alignment using the Verion Image-Guided System versus a conventional manual ink-marking procedure. University Eye Clinic Maastricht, Maastricht, the Netherlands. Prospective randomized clinical trial. Eyes with regular corneal astigmatism of at least 1.25 diopters (D) that required cataract surgery and toric IOL implantation (Acrysof SN6AT3-T9) were randomly assigned to the image-guided group or the manual-marking group. The primary outcome was the alignment of the toric IOL based on preoperative images and images taken immediately after surgery. Secondary outcome measures were residual astigmatism, uncorrected distance visual acuity (UDVA), and complications. The study enrolled 36 eyes (24 patients). The mean toric IOL misalignment was significantly less in the image-guided group than in the manual group 1 hour (1.3 degrees ± 1.6 [SD] versus 2.8 ± 1.8 degrees; P = .02) and 3 months (1.7 ± 1.5 degrees versus 3.1 ± 2.1 degrees; P image-guided group and manual group, respectively (P > .05). The mean UDVA was 0.03 ± 0.10 logarithm of minimum angle of resolution (logMAR) and 0.04 ± 0.09 logMAR, respectively (both P > .05). No intraoperative complications occurred during any surgery. The IOL misalignment was significantly less with digital marking than with manual marking; this did not result in a better UDVA or lower residual refractive astigmatism. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Antiplasmodial Properties and Bioassay-Guided Fractionation of Ethyl Acetate Extracts from Carica papaya Leaves

Science.gov (United States)

Melariri, Paula; Campbell, William; Etusim, Paschal; Smith, Peter

2011-01-01

We investigated the antiplasmodial properties of crude extracts from Carica papaya leaves to trace the activity through bioassay-guided fractionation. The greatest antiplasmodial activity was observed in the ethyl acetate crude extract. C. papaya showed a high selectivity for P. falciparum against CHO cells with a selectivity index of 249.25 and 185.37 in the chloroquine-sensitive D10 and chloroquine-resistant DD2 strains, respectively. Carica papaya ethyl acetate extract was subjected to bioassay-guided fractionation to ascertain the most active fraction, which was purified and identified using high-pressure liquid chromatography (HPLC) and GC-MS (Gas chromatography-Mass spectrometry) methods. Linoleic and linolenic acids identified from the ethyl acetate fraction showed IC50 of 6.88 μg/ml and 3.58 μg/ml, respectively. The study demonstrated greater antiplasmodial activity of the crude ethyl acetate extract of Carica papaya leaves with an IC50 of 2.96 ± 0.14 μg/ml when compared to the activity of the fractions and isolated compounds. PMID:22174990

A framework to measure myocardial extracellular volume fraction using dual-phase low dose CT images

International Nuclear Information System (INIS)

Liu, Yixun; Summers, Ronald M.; Yao, Jianhua; Liu, Songtao; Sibley, Christopher T.; Bluemke, David A.; Nacif, Marcelo S.

2013-01-01

Purpose: Myocardial extracellular volume fraction (ECVF) is a surrogate imaging biomarker of diffuse myocardial fibrosis, a hallmark of pathologic ventricular remodeling. Low dose cardiac CT is emerging as a promising modality to detect diffuse interstitial myocardial fibrosis due to its fast acquisition and low radiation; however, the insufficient contrast in the low dose CT images poses great challenge to measure ECVF from the image. Methods: To deal with this difficulty, the authors present a complete ECVF measurement framework including a point-guided myocardial modeling, a deformable model-based myocardium segmentation, nonrigid registration of pre- and post-CT, and ECVF calculation. Results: The proposed method was evaluated on 20 patients by two observers. Compared to the manually delineated reference segmentations, the accuracy of our segmentation in terms of true positive volume fraction (TPVF), false positive volume fraction (FPVF), and average surface distance (ASD), were 92.18% ± 3.52%, 0.31% ± 0.10%, 0.69 ± 0.14 mm, respectively. The interobserver variability measured by concordance correlation coefficient regarding TPVF, FPVF, and ASD were 0.95, 0.90, 0.94, respectively, demonstrating excellent agreement. Bland-Altman method showed 95% limits of agreement between ECVF at CT and ECVF at MR. Conclusions: The proposed framework demonstrates its efficiency, accuracy, and noninvasiveness in ECVF measurement and dramatically advances the ECVF at cardiac CT toward its clinical use

A framework to measure myocardial extracellular volume fraction using dual-phase low dose CT images

Energy Technology Data Exchange (ETDEWEB)

Liu, Yixun; Summers, Ronald M.; Yao, Jianhua, E-mail: JYao@cc.nih.gov [Clinical Image Processing Service, Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, Maryland 20892 (United States); Liu, Songtao; Sibley, Christopher T.; Bluemke, David A. [Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, Maryland 20892-1182 and Molecular Biomedical Imaging Laboratory, National Institute of Biomedical Imaging and Bioengineering, NIH Clinical Center, Bethesda, Maryland 20892 (United States); Nacif, Marcelo S. [Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, Maryland 20892-1182 (United States)

2013-10-15

Purpose: Myocardial extracellular volume fraction (ECVF) is a surrogate imaging biomarker of diffuse myocardial fibrosis, a hallmark of pathologic ventricular remodeling. Low dose cardiac CT is emerging as a promising modality to detect diffuse interstitial myocardial fibrosis due to its fast acquisition and low radiation; however, the insufficient contrast in the low dose CT images poses great challenge to measure ECVF from the image. Methods: To deal with this difficulty, the authors present a complete ECVF measurement framework including a point-guided myocardial modeling, a deformable model-based myocardium segmentation, nonrigid registration of pre- and post-CT, and ECVF calculation. Results: The proposed method was evaluated on 20 patients by two observers. Compared to the manually delineated reference segmentations, the accuracy of our segmentation in terms of true positive volume fraction (TPVF), false positive volume fraction (FPVF), and average surface distance (ASD), were 92.18% ± 3.52%, 0.31% ± 0.10%, 0.69 ± 0.14 mm, respectively. The interobserver variability measured by concordance correlation coefficient regarding TPVF, FPVF, and ASD were 0.95, 0.90, 0.94, respectively, demonstrating excellent agreement. Bland-Altman method showed 95% limits of agreement between ECVF at CT and ECVF at MR. Conclusions: The proposed framework demonstrates its efficiency, accuracy, and noninvasiveness in ECVF measurement and dramatically advances the ECVF at cardiac CT toward its clinical use.

Reliability of conventional shade guides in teeth color determination.

Science.gov (United States)

Todorović, Ana; Todorović, Aleksandar; Gostović, Aleksandra Spadijer; Lazić, Vojkan; Milicić, Biljana; Djurisić, Slobodan

2013-10-01

Color matching in prosthodontic therapy is a very important task because it influences the esthetic value of dental restorations. Visual shade matching represents the most frequently applied method in clinical practice. Instrumental measurements provide objective and quantified data in color assessment of natural teeth and restorations. In instrumental shade analysis, the goal is to achieve the smallest deltaE value possible, indicating the most accurate shade match. The aim of this study was to evaluate the reliability of commercially available ceramic shade guides. VITA Easyshade spectrophotometer (VITA, Germany) was used for instrumental color determination. Utilizing this device, color samples of ten VITA Classical and ten VITA 3D - Master shade guides were analyzed. Each color sample from all shade guides was measured three times and the basic parameters of color quality were examined: deltaL, deltaC, deltaH, deltaE, deltaElc. Based on these parameters spectrophotometer marks the shade matching as good, fair or adjust. After performing 1,248 measurements of ceramic color samples, frequency of evaluations adjust, fair and good were statistically significantly different between VITA Classical and VITA 3D Master shade guides (p = 0.002). There were 27.1% cases scored as adjust, 66.3% as fair and 6.7% as good. In VITA 3D - Master shade guides 30.9% cases were evaluated as adjust, 66.4% as fair and 2.7% cases as good. Color samples from different shade guides, produced by the same manufacturer, show variability in basic color parameters, which once again proves the lack of precision and nonuniformity of the conventional method.

HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy.

Science.gov (United States)

Yan, Sijing; Lu, Min; Ding, Xiaoya; Chen, Fei; He, Xuemei; Xu, Chunyan; Zhou, Hang; Wang, Qi; Hao, Lan; Zou, Jianzhong

2016-08-18

This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic.

Improving CT-guided transthoracic biopsy of mediastinal lesions by diffusion-weighted magnetic resonance imaging

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Guimaraes, Marcos Duarte; TyngI, Chiang Cheng; Bitencourt, Almir Galvao Vieira; Gross, Jefferson Luiz; Zurstrassen, Charles Edouard, E-mail: marcosduarte500@gmail.com [AC Camargo Cancer Center, Sao Paulo, SP (Brazil); Hochhegger, Bruno [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil). Dept. de Radiologia; Benveniste, Marcelo Felipe Kuperman; Odisio, Bruno Calazans [University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Marchiori, Edson [Universidade Federal do Rio de Janeiro (UFRJ), Petropolis, RJ (Brazil)

2014-11-15

Objectives: to evaluate the preliminary results obtained using diffusion-weighted magnetic resonance imaging and the apparent diffusion coefficient for planning computed tomography-guided biopsies of selected mediastinal lesions. Methods: eight patients with mediastinal lesions suspicious for malignancy were referred for computed tomography-guided biopsy. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient measurement were performed to assist in biopsy planning with diffusion/computed tomography fused images. We selected mediastinal lesions that could provide discordant diagnoses depending on the biopsy site, including large heterogeneous masses, lesions associated with lung atelectasis or consolidation, lesions involving large mediastinal vessels and lesions for which the results of biopsy using other methods and histopathological examination were divergent from the clinical and radiological suspicion. Results: in all cases, the biopsy needle was successfully directed to areas of higher signal intensity on diffusion weighted sequences and the lowest apparent diffusion coefficient within the lesion (mean, 0.8 [range, 0.6–1.1]610{sup -3} mm{sup 2}/s), suggesting high cellularity. All biopsies provided adequate material for specific histopathological diagnoses of four lymphomas, two sarcomas and two thymoma s. Conclusion: functional imaging tools, such as diffusion-weighted imaging and the apparent diffusion coefficient, are promising for implementation in noninvasive and imaging-guided procedures. However, additional studies are needed to confirm that mediastinal biopsy can be improved with these techniques. (author)

A study of image-guided radiotherapy of bladder cancer based on lipiodol injection in the bladder wall

International Nuclear Information System (INIS)

Soendergaard, Jimmi; Muren, Ludvig Paul; Elstroem, Ulrik Vindelev; Grau, Cai; Hoeyer, Morten; Oerding Olsen, Kasper

2010-01-01

Purpose. We have tested a procedure of focal injection of the contrast medium Lipiodol as a fiducial marker for image-guided boost of the tumor in bladder cancer radiotherapy (RT). In this study, we have evaluated the feasibility and the safety of the method as well as the inter- and intra-fraction shift of the bladder tumor. Materials and methods. Five patients with muscle invasive urinary bladder cancer were included in the study. Lipiodol was injected during flexible cystoscopy into the submucosa of the bladder wall at the periphery of the tumor or the post resection tumor-bed. Cone-beam CT (CBCT) scans were acquired daily throughout the course of RT. Results. Lipiodol demarcation of the bladder tumor was feasible and safe with only a minimum of side effects related to the procedure. The Lipiodol spots were visible on CT and CBCT scans for the duration of the RT course. More than half of all the treatment fractions required a geometric shift of 5 mm or more to match on the Lipiodol spots. The mean intra-fraction shift (3D) of the tumor was 3 mm, largest in the anterior-posterior and cranial-caudal directions. Conclusion. This study demonstrates that Lipiodol can be injected into the bladder mucosa and subsequently visualized on CT and CBCT as a fiducial marker. The relatively large inter-fraction shifts in the positions of Lipiodol spots compared to the intra-fraction movement indicates that image-guided RT based on radio-opaque markers is important for RT of the bladder cancer tumor.

Change detection for synthetic aperture radar images based on pattern and intensity distinctiveness analysis

Science.gov (United States)

Wang, Xiao; Gao, Feng; Dong, Junyu; Qi, Qiang

2018-04-01

Synthetic aperture radar (SAR) image is independent on atmospheric conditions, and it is the ideal image source for change detection. Existing methods directly analysis all the regions in the speckle noise contaminated difference image. The performance of these methods is easily affected by small noisy regions. In this paper, we proposed a novel change detection framework for saliency-guided change detection based on pattern and intensity distinctiveness analysis. The saliency analysis step can remove small noisy regions, and therefore makes the proposed method more robust to the speckle noise. In the proposed method, the log-ratio operator is first utilized to obtain a difference image (DI). Then, the saliency detection method based on pattern and intensity distinctiveness analysis is utilized to obtain the changed region candidates. Finally, principal component analysis and k-means clustering are employed to analysis pixels in the changed region candidates. Thus, the final change map can be obtained by classifying these pixels into changed or unchanged class. The experiment results on two real SAR images datasets have demonstrated the effectiveness of the proposed method.

The technical feasibility of an image-guided intensity-modulated radiotherapy (IG-IMRT) to perform a hypofractionated schedule in terms of toxicity and local control for patients with locally advanced or recurrent pancreatic cancer

International Nuclear Information System (INIS)

Son, Seok Hyun; Song, Jin Ho; Choi, Byung Ock; Kang, Young-nam; Lee, Myung Ah; Kang, Ki Mun; Jang, Hong Seok

2012-01-01

The purpose of this study was to evaluate the technical feasibility of an image-guided intensity modulated radiotherapy (IG-IMRT) using involved-field technique to perform a hypofractionated schedule for patients with locally advanced or recurrent pancreatic cancer. From May 2009 to November 2011, 12 patients with locally advanced or locally recurrent pancreatic cancer received hypofractionated CCRT using TomoTherapy Hi-Art with concurrent and sequential chemotherapy at Seoul St. Mary’s Hospital, the Catholic University of Korea. The total dose delivered was 45 Gy in 15 fractions or 50 Gy in 20 fractions. The target volume did not include the uninvolved regional lymph nodes. Treatment planning and delivery were performed using the IG-IMRT technique. The follow-up duration was a median of 31.1 months (range: 5.7-36.3 months). Grade 2 or worse acute toxicities developed in 7 patients (58%). Grade 3 or worse gastrointestinal and hematologic toxicity occurred in 0% and 17% of patients, respectively. In the response evaluation, the rates of partial response and stable disease were 58% and 42%, respectively. The rate of local failure was 8% and no regional failure was observed. Distant failure was the main cause of treatment failure. The progression-free survival and overall survival durations were 7.6 and 12.1 months, respectively. The involved-field technique and IG-IMRT delivered via a hypofractionated schedule are feasible for patients with locally advanced or recurrent pancreatic cancer

Comparative evaluation of toric intraocular lens alignment and visual quality with image-guided surgery and conventional three-step manual marking.

Science.gov (United States)

Titiyal, Jeewan S; Kaur, Manpreet; Jose, Cijin P; Falera, Ruchita; Kinkar, Ashutosh; Bageshwar, Lalit Ms

2018-01-01

To compare toric intraocular lens (IOL) alignment assisted by image-guided surgery or manual marking methods and its impact on visual quality. This prospective comparative study enrolled 80 eyes with cataract and astigmatism ≥1.5 D to undergo phacoemulsification with toric IOL alignment by manual marking method using bubble marker (group I, n=40) or Callisto eye and Z align (group II, n=40). Postoperatively, accuracy of alignment and visual quality was assessed with a ray tracing aberrometer. Primary outcome measure was deviation from the target axis of implantation. Secondary outcome measures were visual quality and acuity. Follow-up was performed on postoperative days (PODs) 1 and 30. Deviation from the target axis of implantation was significantly less in group II on PODs 1 and 30 (group I: 5.5°±3.3°, group II: 3.6°±2.6°; p =0.005). Postoperative refractive cylinder was -0.89±0.35 D in group I and -0.64±0.36 D in group II ( p =0.003). Visual acuity was comparable between both the groups. Visual quality measured in terms of Strehl ratio ( p image-guided surgery group. Significant negative correlation was observed between deviation from target axis and visual quality parameters (Strehl ratio and MTF) ( p Image-guided surgery allows precise alignment of toric IOL without need for reference marking. It is associated with superior visual quality which correlates with the precision of IOL alignment.

Acute gastrointestinal and genitourinary toxicity of image-guided intensity modulated radiation therapy for prostate cancer using a daily water-filled endorectal balloon

International Nuclear Information System (INIS)

Deville, Curtiland; Both, Stefan; Bui, Viet; Hwang, Wei-Ting; Tan, Kay-See; Schaer, Mattia; Tochner, Zelig; Vapiwala, Neha

2012-01-01

Our purpose was to report acute gastrointestinal (GI) and genitourinary (GU) toxicity rates for prostate cancer patients undergoing image-guided intensity modulated radiation therapy (IG-IMRT) with a daily endorectal water-filled balloon (ERB H2O ), and assess associations with planning parameters and pretreatment clinical characteristics. The first 100 patients undergoing prostate and proximal seminal vesicle IG-IMRT with indexed-lumen 100 cc ERB H2O to 79.2 Gy in 1.8 Gy fractions at our institution from 12/2008- 12/2010 were assessed. Pretreatment characteristics, organ-at-risk dose volume histograms, and maximum GU and GI toxicities (CTCAE 3.0) were evaluated. Logistic regression models evaluated univariate association between toxicities and dosimetric parameters, and uni- and multivariate association between toxicities and pretreatment characteristics. Mean age was 68 (range 51–88). Thirty-two, 49, and 19 patients were low, intermediate, and high-risk, respectively; 40 received concurrent androgen deprivation. No grade 3 or greater toxicities were recorded. Maximum GI toxicity was grade 0, 1, and 2 in 69%, 23%, and 8%, respectively. Infield (defined as 1 cm above/below the CTV) rectal mean/median doses, D75, V30, and V40 and hemorrhoid history were associated with grade 2 GI toxicity (Ps < 0.05). Maximum acute GU toxicity was grade 0, 1, and 2 for 17%, 41%, and 42% of patients, respectively. Infield bladder V20 (P = 0.03) and pretreatment International Prostate Symptom Scale (IPSS) (P = 0.003) were associated with grade 2 GU toxicity. Prostate IG-IMRT using a daily ERB H2O shows low rates of acute GI toxicity compared to previous reports of air-filled ERB IMRT when using stringent infield rectum constraints and comparable GU toxicities

Image quality of conventional images of dual-layer SPECTRAL CT: a phantom study.

Science.gov (United States)

van Ommen, F; Bennink, E; Vlassenbroek, A; Dankbaar, J W; Schilham, A M R; Viergever, M A; de Jong, H W A M

2018-05-10

Spectral CT using a dual layer detector offers the possibility of retrospectively introducing spectral information to conventional CT images. In theory, the dual-layer technology should not come with a dose or image quality penalty for conventional images. In this study, we evaluate the influence of a dual-layer detector (IQon Spectral CT, Philips) on the image quality of conventional CT images, by comparing these images with those of a conventional but otherwise technically comparable single-layer CT scanner (Brilliance iCT, Philips), by means of phantom experiments. For both CT scanners conventional CT images were acquired using four adult scanning protocols: i) body helical, ii) body axial, iii) head helical and iv) head axial. A CATPHAN 600 phantom was scanned to conduct an assessment of image quality metrics at equivalent (CTDI) dose levels. Noise was characterized by means of noise power spectra (NPS) and standard deviation (SD) of a uniform region, and spatial resolution was evaluated with modulation transfer functions (MTF) of a tungsten wire. In addition, contrast-to-noise ratio (CNR), image uniformity, CT number linearity, slice thickness, slice spacing, and spatial linearity were measured and evaluated. Additional measurements of CNR, resolution and noise were performed in two larger phantoms. The resolution levels at 50%, 10% and 5% MTF of the iCT and IQon showed small but significant differences up to 0.25 lp/cm for body scans, and up to 0.2 lp/cm for head scans in favor of the IQon. The iCT and IQon showed perfect CT linearity for body scans, but for head scans both scanners showed an underestimation of the CT numbers of materials with a high opacity. Slice thickness was slightly overestimated for both scanners. Slice spacing was comparable and reconstructed correctly. In addition, spatial linearity was excellent for both scanners, with a maximum error of 0.11 mm. CNR was higher on the IQon compared to the iCT for both normal and larger phantoms with

Optimization of an Image-Guided Laser-Induced Choroidal Neovascularization Model in Mice.

Directory of Open Access Journals (Sweden)

Yan Gong

Full Text Available The mouse model of laser-induced choroidal neovascularization (CNV has been used in studies of the exudative form of age-related macular degeneration using both the conventional slit lamp and a new image-guided laser system. A standardized protocol is needed for consistent results using this model, which has been lacking. We optimized details of laser-induced CNV using the image-guided laser photocoagulation system. Four lesions with similar size were consistently applied per eye at approximately double the disc diameter away from the optic nerve, using different laser power levels, and mice of various ages and genders. After 7 days, the mice were sacrificed and retinal pigment epithelium/choroid/sclera was flat-mounted, stained with Isolectin B4, and imaged. Quantification of the area of the laser-induced lesions was performed using an established and constant threshold. Exclusion criteria are described that were necessary for reliable data analysis of the laser-induced CNV lesions. The CNV lesion area was proportional to the laser power levels. Mice at 12-16 weeks of age developed more severe CNV than those at 6-8 weeks of age, and the gender difference was only significant in mice at 12-16 weeks of age, but not in those at 6-8 weeks of age. Dietary intake of omega-3 long-chain polyunsaturated fatty acid reduced laser-induced CNV in mice. Taken together, laser-induced CNV lesions can be easily and consistently applied using the image-guided laser platform. Mice at 6-8 weeks of age are ideal for the laser-induced CNV model.

Clinical application of image-guided radiotherapy, IGRT (on the Varian OBI platform); Applications cliniques de la radiotherapie guidee par l'image (RTGI)

Energy Technology Data Exchange (ETDEWEB)

Sorcini, B.; Tilikidis, A. [Karolinska Univ. Hospital, Dept. of Medical Physics, Stockholm (Sweden)

2006-09-15

Image-guided radiation therapy (IGRT) can be used to measure and correct positional errors for target and critical structures immediately prior to or during treatment delivery. Some of the most recent available methods applied for target localization are: trans-abdominal ultrasound, implanted markers with in room MV or kV X-rays, optical surface tracking systems, implantable electromagnetic markers, in room CT such as kVCT on rail, kilo-voltage or mega-voltage cone-beam CT (CBCT) and helical megavoltage CT. The verification of the accurate treatment position in conjunction with detailed anatomical information before every fraction can be essential for the outcome of the treatment. In this paper we present the on-board imager (OBI, Varian Medical Systems, Palo Alto, CA) that has been in routine clinical use at the Karolinska University Hospital since June 2004. The OBI has been used for on-line set-up correction of prostate patients using internal gold markers. Displacements of these markers can be monitored radiographically during the treatment course and the registered marker shifts act as a surrogate for prostate motion. For this purpose, on-board kV-kV seems to be an ideal system in terms of image quality. The CBCT function of OBI was installed in March 2005 at our department. It focuses on localizing tumors based on internal anatomy, not just on the conventional external marks or tattoos. The CBCT system provides the capacity for soft tissue imaging in the treatment position and real-time radiographic monitoring during treatment delivery. (authors)

Image-guided drug delivery: preclinical applications and clinical translation

NARCIS (Netherlands)

Ojha, Tarun; Rizzo, Larissa; Storm, Gerrit; Kiessling, Fabian; Lammers, Twan Gerardus Gertudis Maria

2015-01-01

Image-guided drug delivery refers to the combination of drug targeting and imaging. Preclinically, image-guided drug delivery can be used for several different purposes, including for monitoring biodistribution, target site accumulation, off-target localization, drug release and drug efficacy.

Image-guided positioning and tracking.

Science.gov (United States)

Ruan, Dan; Kupelian, Patrick; Low, Daniel A

2011-01-01

Radiation therapy aims at maximizing tumor control while minimizing normal tissue complication. The introduction of stereotactic treatment explores the volume effect and achieves dose escalation to tumor target with small margins. The use of ablative irradiation dose and sharp dose gradients requires accurate tumor definition and alignment between patient and treatment geometry. Patient geometry variation during treatment may significantly compromise the conformality of delivered dose and must be managed properly. Setup error and interfraction/intrafraction motion are incorporated in the target definition process by expanding the clinical target volume to planning target volume, whereas the alignment between patient and treatment geometry is obtained with an adaptive control process, by taking immediate actions in response to closely monitored patient geometry. This article focuses on the monitoring and adaptive response aspect of the problem. The term "image" in "image guidance" will be used in a most general sense, to be inclusive of some important point-based monitoring systems that can be considered as degenerate cases of imaging. Image-guided motion adaptive control, as a comprehensive system, involves a hierarchy of decisions, each of which balances simplicity versus flexibility and accuracy versus robustness. Patient specifics and machine specifics at the treatment facility also need to be incorporated into the decision-making process. Identifying operation bottlenecks from a system perspective and making informed compromises are crucial in the proper selection of image-guidance modality, the motion management mechanism, and the respective operation modes. Not intended as an exhaustive exposition, this article focuses on discussing the major issues and development principles for image-guided motion management systems. We hope these information and methodologies will facilitate conscientious practitioners to adopt image-guided motion management systems

MO-DE-210-03: Ultrasound imaging is an attractive method for image guided radiation treatment (IGRT), by itself or to complement other imaging modalities

International Nuclear Information System (INIS)

Ding, K.

2015-01-01

Ultrasound imaging is an attractive method for image guided radiation treatment (IGRT), by itself or to complement other imaging modalities. It is inexpensive, portable and provides good soft tissue contrast. For challenging soft tissue targets such as pancreatic cancer, ultrasound imaging can be used in combination with pre-treatment MRI and/or CT to transfer important anatomical features for target localization at time of treatment. The non-invasive and non-ionizing nature of ultrasound imaging is particularly powerful for intra-fraction localization and monitoring. Recognizing these advantages, efforts are being made to incorporate novel robotic approaches to position and manipulate the ultrasound probe during irradiation. These recent enabling developments hold potential to bring ultrasound imaging to a new level of IGRT applications. However, many challenges, not limited to image registration, robotic deployment, probe interference and image acquisition rate, need to be addressed to realize the full potential of IGRT with ultrasound imaging. Learning Objectives: Understand the benefits and limitations in using ultrasound to augment MRI and/or CT for motion monitoring during radiation therapy delivery. Understanding passive and active robotic approaches to implement ultrasound imaging for intra-fraction monitoring. Understand issues of probe interference with radiotherapy treatment. Understand the critical clinical workflow for effective and reproducible IGRT using ultrasound guidance. The work of X.L. is supported in part by Elekta; J.W. and K.D. is supported in part by a NIH grant R01 CA161613 and by Elekta; D.H. is support in part by a NIH grant R41 CA174089

MO-DE-210-03: Ultrasound imaging is an attractive method for image guided radiation treatment (IGRT), by itself or to complement other imaging modalities

Energy Technology Data Exchange (ETDEWEB)

Ding, K. [Johns Hopkins University: Development of Intra-Fraction Soft Tissue Monitoring with Ultrasound Imaging (United States)

2015-06-15

Ultrasound imaging is an attractive method for image guided radiation treatment (IGRT), by itself or to complement other imaging modalities. It is inexpensive, portable and provides good soft tissue contrast. For challenging soft tissue targets such as pancreatic cancer, ultrasound imaging can be used in combination with pre-treatment MRI and/or CT to transfer important anatomical features for target localization at time of treatment. The non-invasive and non-ionizing nature of ultrasound imaging is particularly powerful for intra-fraction localization and monitoring. Recognizing these advantages, efforts are being made to incorporate novel robotic approaches to position and manipulate the ultrasound probe during irradiation. These recent enabling developments hold potential to bring ultrasound imaging to a new level of IGRT applications. However, many challenges, not limited to image registration, robotic deployment, probe interference and image acquisition rate, need to be addressed to realize the full potential of IGRT with ultrasound imaging. Learning Objectives: Understand the benefits and limitations in using ultrasound to augment MRI and/or CT for motion monitoring during radiation therapy delivery. Understanding passive and active robotic approaches to implement ultrasound imaging for intra-fraction monitoring. Understand issues of probe interference with radiotherapy treatment. Understand the critical clinical workflow for effective and reproducible IGRT using ultrasound guidance. The work of X.L. is supported in part by Elekta; J.W. and K.D. is supported in part by a NIH grant R01 CA161613 and by Elekta; D.H. is support in part by a NIH grant R41 CA174089.

Implementation of an image guided intensity-modulated protocol for post-prostatectomy radiotherapy: planning data and acute toxicity outcomes.

Science.gov (United States)

Chua, Benjamin; Min, Myo; Wood, Maree; Edwards, Sarah; Hoffmann, Matthew; Greenham, Stuart; Kovendy, Andrew; McKay, Michael J; Shakespeare, Thomas P

2013-08-01

There is substantial interest in implementation of image-guided intensity-modulated radiotherapy (IG-IMRT) in the post-prostatectomy setting. We describe our implementation of IG-IMRT, and examine how often published organ-at-risk (OAR) constraints were met. Furthermore, we evaluate the incidence of acute genitourinary and gastrointestinal toxicities when patients were treated according to our protocol. Patients were eligible if they received post-prostatectomy radiotherapy (PPRT). Planning data were collected prospectively, and toxicity assessments were collected before, during and after treatment. Seventy-five eligible patients received either 64 Gy (19%) or 66 Gy (81%) in a single phase to the prostate bed. Suggested rectal dose-constraints of V40Gy < 60% and V60Gy < 40% were met in 64 (85%) and 75 (100%) patients, respectively. IMRT-specific rectal dose-constraints of V40Gy < 35% and V65Gy < 17% were achieved in 5 (7%) and 57 (76%) of patients. Bladder dose-constraint (V50Gy < 50%) was met in 58 (77%) patients. Two patients (3%) experienced new grade 3 genitourinary toxicity and one patient (1%) experienced new grade 3 gastroinestinal toxicity. All grade 3 toxicities had improved by 3-month review. Overall deterioration in urinary and gastrointestinal symptoms occurred in 33 (44%) and 35 (47%) of patients respectively. We report on our implementation of PPRT which takes into account nationally adopted guidelines, with a margin reduction supported by use of daily image guidance. Non-IMRT OAR constraints were met in most cases. IMRT-specific constraints were less often achieved despite margin reductions, suggesting the need for review of guidelines. Severe toxicity was rare, and most patients did not experience deterioration in urinary or bowel function attributable to radiotherapy. © 2013 The Authors. Journal of Medical Imaging and Radiation Oncology © 2013 The Royal Australian and New Zealand College of Radiologists.

Transient Splenial Lesion of Corpus Callosum Associated with Antiepileptic Drug: Conventional and Diffusion-weighted Magnetic Resonance Images

Energy Technology Data Exchange (ETDEWEB)

Hakyemez, B.; Erdogan, C.; Yildirim, N.; Gokalp, G.; Parlak, M. [Uludag Univ. Medical School, Bursa (Turkey). Dept. of Radiology

2005-11-01

Transient focal lesions of splenium of corpus callosum can be seen as a component of many central nervous system diseases, including antiepileptic drug toxicity. The conventional magnetic resonance (MR) findings of the disease are characteristic and include ovoid lesions with high signal intensity at T2-weighted MRI. Limited information exists about the diffusion-weighted MRI characteristics of these lesions vanishing completely after a period of time. We examined the conventional, FLAIR, and diffusion-weighted MR images of a patient complaining of depressive mood and anxiety disorder after 1 year receiving antiepileptic medication.

Double oblique MR images of the shoulder. Comparison with conventional images

International Nuclear Information System (INIS)

Sasaki, Taisuke; Saito, Yoko; Yodono, Hiraku; Miura, Hiroyuki; Shinohara, Atsushi; Abe, Shuichiro

1998-01-01

Because the scapula is not only slanted on transverse sections but also inclines on sagittal sections, we now perform shoulder MR imaging using double oblique images (DOI), which are planes perpendicular or parallel to the long axis of the scapula obtained with oblique sagittal scout imaging. The purpose of this study was to evaluate the usefulness of double oblique shoulder MR imaging. MR images of shoulders with operatively or arthroscopically proven lesions (20 cases) that had been examined on both conventional images (CI) and DOI were retrospectively reviewed. DOI were compared with CI not only in terms of diagnostic performance but also in their ability to identify the details of shoulder anatomy. All MR studies were done with a shoulder coil on a high-field (1.5 T) unit. Although the accuracy of DOI in diagnosing shoulder disorders such as rotator cuff tear and labrum injury was not as good as that of CI, DOI were better for identifying or discriminating muscles and tendons of the rotator cuff, labralbicipital junction and anterior band of the inferior gleno-humeral ligament, and for recognizing the correct position of the glenoid labrum. MR double oblique imaging of the shoulder provides more detailed information about shoulder anatomy and disorders than conventional imaging. (author)

Target coverage in image-guided stereotactic body radiotherapy of liver tumors.

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Wunderink, Wouter; Méndez Romero, Alejandra; Vásquez Osorio, Eliana M; de Boer, Hans C J; Brandwijk, René P; Levendag, Peter C; Heijmen, Ben J M

2007-05-01

To determine the effect of image-guided procedures (with computed tomography [CT] and electronic portal images before each treatment fraction) on target coverage in stereotactic body radiotherapy for liver patients using a stereotactic body frame (SBF) and abdominal compression. CT guidance was used to correct for day-to-day variations in the tumor's mean position in the SBF. By retrospectively evaluating 57 treatment sessions, tumor coverage, as obtained with the clinically applied CT-guided protocol, was compared with that of alternative procedures. The internal target volume-plus (ITV(+)) was introduced to explicitly include uncertainties in tumor delineations resulting from CT-imaging artifacts caused by residual respiratory motion. Tumor coverage was defined as the volume overlap of the ITV(+), derived from a tumor delineated in a treatment CT scan, and the planning target volume. Patient stability in the SBF, after acquisition of the treatment CT scan, was evaluated by measuring the displacement of the bony anatomy in the electronic portal images relative to CT. Application of our clinical protocol (with setup corrections following from manual measurements of the distances between the contours of the planning target volume and the daily clinical target volume in three orthogonal planes, multiple two-dimensional) increased the frequency of nearly full (> or = 99%) ITV(+) coverage to 77% compared with 63% without setup correction. An automated three-dimensional method further improved the frequency to 96%. Patient displacements in the SBF were generally small (design, patient stability in the SBF should be verified with portal imaging.

Concurrent image-guided intensity modulated radiotherapy and chemotherapy following neoadjuvant chemotherapy for locally advanced nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Shueng, Pei-Wei; Hsieh, Chen-Hsi; Shen, Bing-Jie; Wu, Le-Jung; Liao, Li-Jen; Hsiao, Chi-Huang; Lin, Yu-Chin; Cheng, Po-Wen; Lo, Wu-Chia; Jen, Yee-Min

2011-01-01

To evaluate the experience of induction chemotherapy followed by concurrent chemoradiationwith helical tomotherapy (HT) for nasopharyngeal carcinoma (NPC). Between August 2006 and December 2009, 28 patients with pathological proven nonmetastatic NPC were enrolled. All patients were staged as IIB-IVB. Patients were first treated with 2 to 3 cycles of induction chemotherapy with EP-HDFL (Epirubicin, Cisplatin, 5-FU, and Leucovorin). After induction chemotherapy, weekly based PFL was administered concurrent with HT. Radiation consisted of 70 Gy to the planning target volumes of the primary tumor plus any positive nodal disease using 2 Gy per fraction. After completion of induction chemotherapy, the response rates for primary and nodal disease were 96.4% and 80.8%, respectively. With a median follow-up after 33 months (Range, 13-53 months), there have been 2 primary and 1 nodal relapse after completion of radiotherapy. The estimated 3-year progression-free rates for local, regional, locoregional and distant metastasis survival rate were 92.4%, 95.7%, 88.4%, and 78.0%, respectively. The estimated 3-year overall survival was 83.5%. Acute grade 3, 4 toxicities for xerostomia and dermatitis were only 3.6% and 10.7%, respectively. HT for locoregionally advanced NPC is feasible and effective in regard to locoregional control with high compliance, even after neoadjuvant chemotherapy. None of out-field or marginal failure noted in the current study confirms the potential benefits of treating NPC patients by image-guided radiation modality. A long-term follow-up study is needed to confirm these preliminary findings

Real-space imaging of fractional quantum Hall liquids

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Hayakawa, Junichiro; Muraki, Koji; Yusa, Go

2013-01-01

Electrons in semiconductors usually behave like a gas--as independent particles. However, when confined to two dimensions under a perpendicular magnetic field at low temperatures, they condense into an incompressible quantum liquid. This phenomenon, known as the fractional quantum Hall (FQH) effect, is a quantum-mechanical manifestation of the macroscopic behaviour of correlated electrons that arises when the Landau-level filling factor is a rational fraction. However, the diverse microscopic interactions responsible for its emergence have been hidden by its universality and macroscopic nature. Here, we report real-space imaging of FQH liquids, achieved with polarization-sensitive scanning optical microscopy using trions (charged excitons) as a local probe for electron spin polarization. When the FQH ground state is spin-polarized, the triplet/singlet intensity map exhibits a spatial pattern that mirrors the intrinsic disorder potential, which is interpreted as a mapping of compressible and incompressible electron liquids. In contrast, when FQH ground states with different spin polarization coexist, domain structures with spontaneous quasi-long-range order emerge, which can be reproduced remarkably well from the disorder patterns using a two-dimensional random-field Ising model. Our results constitute the first reported real-space observation of quantum liquids in a class of broken symmetry state known as the quantum Hall ferromagnet.

Comparative effects of Facebook and conventional media on body image dissatisfaction.

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Cohen, Rachel; Blaszczynski, Alex

2015-01-01

Appearance comparison has consistently been shown to engender body image dissatisfaction. To date, most studies have demonstrated this relationship between appearance comparison and body image dissatisfaction in the context of conventional media images depicting the thin-ideal. Social comparison theory posits that people are more likely to compare themselves to similar others. Since social media forums such as Facebook involve one's peers, the current study aimed to determine whether the relationship between appearance comparison and body image dissatisfaction would be stronger for those exposed to social media images, compared to conventional media images. A sample of 193 female first year university students were randomly allocated to view a series of either Facebook or conventional media thin-ideal images. Participants completed questionnaires assessing pre- and post- image exposure measures of thin-ideal internalisation, appearance comparison, self-esteem, Facebook use and eating disorder risk. Type of exposure was not found to moderate the relationship between appearance comparison and changes in body image dissatisfaction. When analysed according to exposure type, appearance comparison only significantly predicted body image dissatisfaction change for those exposed to Facebook, but not conventional media. Facebook use was found to predict higher baseline body image dissatisfaction and was associated with higher eating disorder risk. The findings suggest the importance of extending the body image dissatisfaction literature by taking into account emerging social media formats. It is recommended that interventions for body image dissatisfaction and eating disorders consider appearance comparison processes elicited by thin-ideal content on social media forums, such as Facebook, in addition to conventional media.

Panoramic images of conventional radiographs: digital panoramic dynamic images

International Nuclear Information System (INIS)

Schultze, M.

2001-01-01

The benefits of digital technic s to od ontology are evident. Instant images, the possibility to handle them, the reduction of exposition time to radiations, better quality image, better quality information, Stocking them in a compact disc, occupying very little space, allows an easy transport and duplication, as well as the possibility to transfer and save it in an electronica l support.This kind of communication allows the transmission of digital images and every other type of data, instantaneously and no matter distances or geographical borders. Anyway, we should point out that conventional and digital technic s reveal the same information contents

MR-Guided High-Intensity Focused Ultrasound Ablation of Breast Cancer with a Dedicated Breast Platform

International Nuclear Information System (INIS)

Merckel, Laura G.; Bartels, Lambertus W.; Köhler, Max O.; Bongard, H. J. G. Desirée van den; Deckers, Roel; Mali, Willem P. Th. M.; Binkert, Christoph A.; Moonen, Chrit T.; Gilhuijs, Kenneth G. A.; Bosch, Maurice A. A. J. van den

2013-01-01

Optimizing the treatment of breast cancer remains a major topic of interest. In current clinical practice, breast-conserving therapy is the standard of care for patients with localized breast cancer. Technological developments have fueled interest in less invasive breast cancer treatment. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a completely noninvasive ablation technique. Focused beams of ultrasound are used for ablation of the target lesion without disrupting the skin and subcutaneous tissues in the beam path. MRI is an excellent imaging method for tumor targeting, treatment monitoring, and evaluation of treatment results. The combination of HIFU and MR imaging offers an opportunity for image-guided ablation of breast cancer. Previous studies of MR-HIFU in breast cancer patients reported a limited efficacy, which hampered the clinical translation of this technique. These prior studies were performed without an MR-HIFU system specifically developed for breast cancer treatment. In this article, a novel and dedicated MR-HIFU breast platform is presented. This system has been designed for safe and effective MR-HIFU ablation of breast cancer. Furthermore, both clinical and technical challenges are discussed, which have to be solved before MR-HIFU ablation of breast cancer can be implemented in routine clinical practice.

Algorithms for testing of fractional dynamics: a practical guide to ARFIMA modelling

International Nuclear Information System (INIS)

Burnecki, Krzysztof; Weron, Aleksander

2014-01-01

In this survey paper we present a systematic methodology which demonstrates how to identify the origins of fractional dynamics. We consider three mechanisms which lead to it, namely fractional Brownian motion, fractional Lévy stable motion and an autoregressive fractionally integrated moving average (ARFIMA) process but we concentrate on the ARFIMA modelling. The methodology is based on statistical tools for identification and validation of the fractional dynamics, in particular on an ARFIMA parameter estimator, an ergodicity test, a self-similarity index estimator based on sample p-variation and a memory parameter estimator based on sample mean-squared displacement. A complete list of algorithms needed for this is provided in appendices A–F. Finally, we illustrate the methodology on various empirical data and show that ARFIMA can be considered as a universal model for fractional dynamics. Thus, we provide a practical guide for experimentalists on how to efficiently use ARFIMA modelling for a large class of anomalous diffusion data. (paper)

Treating locally advanced lung cancer with a 1.5T MR-Linac - Effects of the magnetic field and irradiation geometry on conventionally fractionated and isotoxic dose-escalated radiotherapy.

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Bainbridge, Hannah E; Menten, Martin J; Fast, Martin F; Nill, Simeon; Oelfke, Uwe; McDonald, Fiona

2017-11-01

This study investigates the feasibility and potential benefits of radiotherapy with a 1.5T MR-Linac for locally advanced non-small cell lung cancer (LA NSCLC) patients. Ten patients with LA NSCLC were retrospectively re-planned six times: three treatment plans were created according to a protocol for conventionally fractionated radiotherapy and three treatment plans following guidelines for isotoxic target dose escalation. In each case, two plans were designed for the MR-Linac, either with standard (∼7mm) or reduced (∼3mm) planning target volume (PTV) margins, while one conventional linac plan was created with standard margins. Treatment plan quality was evaluated using dose-volume metrics or by quantifying dose escalation potential. All generated treatment plans fulfilled their respective planning constraints. For conventionally fractionated treatments, MR-Linac plans with standard margins had slightly increased skin dose when compared to conventional linac plans. Using reduced margins alleviated this issue and decreased exposure of several other organs-at-risk (OAR). Reduced margins also enabled increased isotoxic target dose escalation. It is feasible to generate treatment plans for LA NSCLC patients on a 1.5T MR-Linac. Margin reduction, facilitated by an envisioned MRI-guided workflow, enables increased OAR sparing and isotoxic target dose escalation for the respective treatment approaches. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Feasibility of ultrasound-guided high intensity focused ultrasound ablating uterine fibroids with hyperintense on T2-weighted MR imaging

International Nuclear Information System (INIS)

Zhao, Wen-Peng; Chen, Jin-Yun; Zhang, Lian; Li, Quan; Qin, Juan

2013-01-01

Purpose: To retrospectively investigate whether uterine fibroids with hyperintense on pretreatment T2-weighted magnetic resonance imaging (MRI) could be treated with ultrasound-guided high intensity focused ultrasound (USgHIFU). Materials and methods: 282 patients with 282 symptomatic uterine fibroids who underwent USgHIFU treatment were retrospectively analyzed. Based on the signal intensity of T2-weighted MRI, uterine fibroids were classified as hypointense, isointense and hyperintense. Hyperintense fibroids were subjectively further subdivided into heterogeneous hyperintense, slightly homogeneous hyperintense and markedly homogeneous hyperintense based on the signal intensity of fibroid relative to myometrium and endometrium on T2-weighted MRI. Enhanced MRI was performed within one month after HIFU treatment. Non-perfused volume (NPV, indicative of successful ablation) ratio, treatment time, treatment efficiency, energy effect ratio and adverse events were recorded. Results: The median volume of uterine fibroids was 70.3 cm 3 (interquartile range, 41.1–132.5 cm 3 ). The average NPV ratio, defined as non-perfused volume divided by the fibroid volume after HIFU treatment, was 76.8 ± 19.0% (range, 0–100%) in the 282 patients. It was 86.3 ± 11.9% (range, 40.9–100.0%) in the group with hypointense fibroids, 77.1 ± 16.5% (range, 32.2–100.0%) in isointense fibroids, and 67.6 ± 23.9% (range, 0–100.0%) in hyperintense fibroids. The lowest NPV ratio, lowest treatment efficiency, more treatment time, more sonication energy and pain scores were observed in the slightly homogeneous hyperintense fibroids, and the NPV ratio was 55.8 ± 26.7% (range, 0–83.9%) in this subgroup. Conclusion: Based on our results, the heterogeneous and markedly homogeneous hyperintense fibroids were suitable for USgHIFU, and only the slightly homogeneous hyperintense fibroids should be excluded

Long-term decision regret after post-prostatectomy image-guided intensity-modulated radiotherapy.

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Shakespeare, Thomas P; Chin, Stephen; Manuel, Lucy; Wen, Shelly; Hoffman, Matthew; Wilcox, Shea W; Aherne, Noel J

2017-02-01

Decision regret (DR) may occur when a patient believes their outcome would have been better if they had decided differently about their management. Although some studies investigate DR after treatment for localised prostate cancer, none report DR in patients undergoing surgery and post-prostatectomy radiotherapy. We evaluated DR in this group of patients overall, and for specific components of therapy. We surveyed 83 patients, with minimum 5 years follow-up, treated with radical prostatectomy (RP) and post-prostatectomy image-guided intensity-modulated radiotherapy (IG-IMRT) to 64-66 Gy following www.EviQ.org.au protocols. A validated questionnaire identified DR if men either indicated that they would have been better off had they chosen another treatment, or they wished they could change their mind about treatment. There was an 85.5% response rate, with median follow-up post-IMRT 78 months. Adjuvant IG-IMRT was used in 28% of patients, salvage in 72% and ADT in 48%. A total of 70% of patients remained disease-free. Overall, 16.9% of patients expressed DR for treatment, with fourfold more regret for the RP component of treatment compared to radiotherapy (16.9% vs 4.2%, P = 0.01). DR for androgen deprivation was 14.3%. Patients were regretful of surgery due to toxicity, not being adequately informed about radiotherapy as an alternative, positive margins and surgery costs (83%, 33%, 25% and 8% of regretful patients respectively). Toxicity caused DR in the three radiotherapy-regretful and four ADT-regretful patients. Patients were twice as regretful overall, and of surgery, for salvage vs adjuvant approaches (both 19.6% vs 10.0%). Decision regret after RP and post-prostatectomy IG-IMRT is uncommon, although patients regret RP more than post-operative IG-IMRT. This should reassure urologists referring patients for post-prostatectomy IG-IMRT, particularly in the immediate adjuvant setting. Other implications include appropriate patient selection for RP (and

Prospective Evaluation of Dual-Energy Imaging in Patients Undergoing Image Guided Radiation Therapy for Lung Cancer: Initial Clinical Results

International Nuclear Information System (INIS)

Sherertz, Tracy; Hoggarth, Mark; Luce, Jason; Block, Alec M.; Nagda, Suneel; Harkenrider, Matthew M.; Emami, Bahman; Roeske, John C.

2014-01-01

Purpose: A prospective feasibility study was conducted to investigate the utility of dual-energy (DE) imaging compared to conventional x-ray imaging for patients undergoing kV-based image guided radiation therapy (IGRT) for lung cancer. Methods and Materials: An institutional review board-approved feasibility study enrolled patients with lung cancer undergoing IGRT and was initiated in September 2011. During daily setup, 2 sequential respiration-gated x-ray images were obtained using an on-board imager. Imaging was composed of 1 standard x-ray image at 120 kVp (1 mAs) and a second image obtained at 60 kVp (4 mAs). Weighted logarithmic subtraction of the 2 images was performed offline to create a soft tissue-selective DE image. Conventional and DE images were evaluated by measuring relative contrast and contrast-to-noise ratios (CNR) and also by comparing spatial localization, using both approaches. Imaging dose was assessed using a calibrated ion chamber. Results: To date, 10 patients with stage IA to IIIA lung cancer were enrolled and 57 DE images were analyzed. DE subtraction resulted in complete suppression of overlying bone in all 57 DE images, with an average improvement in relative contrast of 4.7 ± 3.3 over that of 120 kVp x-ray images (P<.0002). The improvement in relative contrast with DE imaging was seen for both smaller (gross tumor volume [GTV] ≤5 cc) and larger tumors (GTV >5 cc), with average relative contrast improvement ratios of 3.4 ± 4.1 and 5.4 ± 3.6, respectively. Moreover, the GTV was reliably localized in 95% of the DE images versus 74% of the single energy (SE images, (P=.004). Mean skin dose per DE image set was 0.44 ± 0.03 mGy versus 0.43 ± 0.03 mGy, using conventional kV imaging parameters. Conclusions: Initial results of this feasibility study suggest that DE thoracic imaging may enhance tumor localization in lung cancer patients receiving kV-based IGRT without increasing imaging dose

Fast lesion mapping during HIFU treatment using harmonic motion imaging guided focused ultrasound (HMIgFUS) in vitro and in vivo

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Han, Yang; Wang, Shutao; Payen, Thomas; Konofagou, Elisa

2017-04-01

The successful clinical application of high intensity focused ultrasound (HIFU) ablation depends on reliable monitoring of the lesion formation. Harmonic motion imaging guided focused ultrasound (HMIgFUS) is an ultrasound-based elasticity imaging technique, which monitors HIFU ablation based on the stiffness change of the tissue instead of the echo intensity change in conventional B-mode monitoring, rendering it potentially more sensitive to lesion development. Our group has shown that predicting the lesion location based on the radiation force-excited region is feasible during HMIgFUS. In this study, the feasibility of a fast lesion mapping method is explored to directly monitor the lesion map during HIFU. The harmonic motion imaging (HMI) lesion map was generated by subtracting the reference HMI image from the present HMI peak-to-peak displacement map, as streamed on the computer display. The dimensions of the HMIgFUS lesions were compared against gross pathology. Excellent agreement was found between the lesion depth (r 2  =  0.81, slope  =  0.90), width (r 2  =  0.85, slope  =  1.12) and area (r 2  =  0.58, slope  =  0.75). In vivo feasibility was assessed in a mouse with a pancreatic tumor. These findings demonstrate that HMIgFUS can successfully map thermal lesions and monitor lesion development in real time in vitro and in vivo. The HMIgFUS technique may therefore constitute a novel clinical tool for HIFU treatment monitoring.

Ultrasonic image analysis and image-guided interventions.

Science.gov (United States)

Noble, J Alison; Navab, Nassir; Becher, H

2011-08-06

The fields of medical image analysis and computer-aided interventions deal with reducing the large volume of digital images (X-ray, computed tomography, magnetic resonance imaging (MRI), positron emission tomography and ultrasound (US)) to more meaningful clinical information using software algorithms. US is a core imaging modality employed in these areas, both in its own right and used in conjunction with the other imaging modalities. It is receiving increased interest owing to the recent introduction of three-dimensional US, significant improvements in US image quality, and better understanding of how to design algorithms which exploit the unique strengths and properties of this real-time imaging modality. This article reviews the current state of art in US image analysis and its application in image-guided interventions. The article concludes by giving a perspective from clinical cardiology which is one of the most advanced areas of clinical application of US image analysis and describing some probable future trends in this important area of ultrasonic imaging research.

Image-guided pleural biopsy: diagnostic yield and complications

International Nuclear Information System (INIS)

Benamore, R.E.; Scott, K.; Richards, C.J.; Entwisle, J.J.

2006-01-01

Background: Pleural biopsy and cytology are standard procedures for the investigation of pleural disease. Recent medical literature has suggested that image-guided pleural biopsy shows improved sensitivity for the diagnosis of pleural malignancy, when compared with the more commonly performed reverse bevel needle biopsy such as Abrams' needle. In our centre there has been an increasing trend towards performing image-guided pleural biopsies, and to our knowledge there is no large published series documenting the complication rate and diagnostic yield. Methods: The radiology and pathology databases were searched for all image-guided [computed tomography (CT) and ultrasound (US)] pleural biopsies from January 2001 to December 2004. All imaging and histology were reviewed, and final diagnostic information about patients was obtained from the respiratory multidisciplinary team database and patient notes. A record was made of complications following biopsy, presence of pleura in the biopsy, and adequacy of tissue for histological diagnosis. Results: A total of 82 patients underwent 85 image-guided pleural biopsies over a 4-year period. 80 cases were performed under CT and five under US guidance. The rate of new pneumothorax detected by chest radiography was 4.7%. No patient required a chest drain or blood transfusion to treat complications. In 10 (12%) cases, there was inadequate tissue to reach a confident histological diagnosis and in eight (9%) of these, no pleura was present. Assuming all suspicious and inadequate biopsies are treated as benign, which is the worst case scenario, image-guided pleural biopsy has a sensitivity and specificity of 76% and 100%, respectively, for the diagnosis of malignant disease. Conclusions: Image-guided pleural biopsy is a safe procedure with few associated complications and has a higher sensitivity than previously published series for reverse cutting needle biopsy in the diagnosis of malignant pleural disease

Image-guided pleural biopsy: diagnostic yield and complications

Energy Technology Data Exchange (ETDEWEB)

Benamore, R.E. [Department of Radiology and Department of Histopathology, Glenfield Hospital, University Hospitals of Leicester NHS Trust, Leicester (United Kingdom)]. E-mail: rachelbenamore@doctors.org.uk; Scott, K. [Department of Radiology and Department of Histopathology, Glenfield Hospital, University Hospitals of Leicester NHS Trust, Leicester (United Kingdom); Richards, C.J. [Department of Radiology and Department of Histopathology, Glenfield Hospital, University Hospitals of Leicester NHS Trust, Leicester (United Kingdom); Entwisle, J.J. [Department of Radiology and Department of Histopathology, Glenfield Hospital, University Hospitals of Leicester NHS Trust, Leicester (United Kingdom)

2006-08-15

Background: Pleural biopsy and cytology are standard procedures for the investigation of pleural disease. Recent medical literature has suggested that image-guided pleural biopsy shows improved sensitivity for the diagnosis of pleural malignancy, when compared with the more commonly performed reverse bevel needle biopsy such as Abrams' needle. In our centre there has been an increasing trend towards performing image-guided pleural biopsies, and to our knowledge there is no large published series documenting the complication rate and diagnostic yield. Methods: The radiology and pathology databases were searched for all image-guided [computed tomography (CT) and ultrasound (US)] pleural biopsies from January 2001 to December 2004. All imaging and histology were reviewed, and final diagnostic information about patients was obtained from the respiratory multidisciplinary team database and patient notes. A record was made of complications following biopsy, presence of pleura in the biopsy, and adequacy of tissue for histological diagnosis. Results: A total of 82 patients underwent 85 image-guided pleural biopsies over a 4-year period. 80 cases were performed under CT and five under US guidance. The rate of new pneumothorax detected by chest radiography was 4.7%. No patient required a chest drain or blood transfusion to treat complications. In 10 (12%) cases, there was inadequate tissue to reach a confident histological diagnosis and in eight (9%) of these, no pleura was present. Assuming all suspicious and inadequate biopsies are treated as benign, which is the worst case scenario, image-guided pleural biopsy has a sensitivity and specificity of 76% and 100%, respectively, for the diagnosis of malignant disease. Conclusions: Image-guided pleural biopsy is a safe procedure with few associated complications and has a higher sensitivity than previously published series for reverse cutting needle biopsy in the diagnosis of malignant pleural disease.

Combustion characteristics of intensively cleaned coal fractions. Effect of mineral matter

Energy Technology Data Exchange (ETDEWEB)

Rubiera, F.; Arenillas, A.; Fuente, E.; Pis, J.J. [Inst. Nacional de Carbon, Oviedo (Spain); Ivatt, S. [ETSU, Harwell, Didcot (United Kingdom)

1997-12-31

The purpose of this work has been to assess the effect that intensive coal cleaning exerts on the combustion behaviour of different density-separated coal fractions. Samples with ash contents varying from 39% for the raw coal, to 2% for the cleanest fraction were obtained after density separation. Temperature-programmed combustion and isothermal gasification in air were used to measure the reactivities of the parent coal and the cleaned fractions. Coal and char reactivities increased with increasing ash content of the samples. Thermal analysis-mass spectrometry of the low-temperature ashes was also carried out in order to study the reactions of coal minerals under combustion conditions. (orig.)

Automatic block-matching registration to improve lung tumor localization during image-guided radiotherapy

Science.gov (United States)

Robertson, Scott Patrick

To improve relatively poor outcomes for locally-advanced lung cancer patients, many current efforts are dedicated to minimizing uncertainties in radiotherapy. This enables the isotoxic delivery of escalated tumor doses, leading to better local tumor control. The current dissertation specifically addresses inter-fractional uncertainties resulting from patient setup variability. An automatic block-matching registration (BMR) algorithm is implemented and evaluated for the purpose of directly localizing advanced-stage lung tumors during image-guided radiation therapy. In this algorithm, small image sub-volumes, termed "blocks", are automatically identified on the tumor surface in an initial planning computed tomography (CT) image. Each block is independently and automatically registered to daily images acquired immediately prior to each treatment fraction. To improve the accuracy and robustness of BMR, this algorithm incorporates multi-resolution pyramid registration, regularization with a median filter, and a new multiple-candidate-registrations technique. The result of block-matching is a sparse displacement vector field that models local tissue deformations near the tumor surface. The distribution of displacement vectors is aggregated to obtain the final tumor registration, corresponding to the treatment couch shift for patient setup correction. Compared to existing rigid and deformable registration algorithms, the final BMR algorithm significantly improves the overlap between target volumes from the planning CT and registered daily images. Furthermore, BMR results in the smallest treatment margins for the given study population. However, despite these improvements, large residual target localization errors were noted, indicating that purely rigid couch shifts cannot correct for all sources of inter-fractional variability. Further reductions in treatment uncertainties may require the combination of high-quality target localization and adaptive radiotherapy.

A hybrid biomechanical intensity based deformable image registration of lung 4DCT

International Nuclear Information System (INIS)

Samavati, Navid; Velec, Michael; Brock, Kristy

2015-01-01

Deformable image registration (DIR) has been extensively studied over the past two decades due to its essential role in many image-guided interventions (IGI). IGI demands a highly accurate registration that maintains its accuracy across the entire region of interest. This work evaluates the improvement in accuracy and consistency by refining the results of Morfeus, a biomechanical model-based DIR algorithm.A hybrid DIR algorithm is proposed based on, a biomechanical model–based DIR algorithm and a refinement step based on a B-spline intensity-based algorithm. Inhale and exhale reconstructions of four-dimensional computed tomography (4DCT) lung images from 31 patients were initially registered using the biomechanical DIR by modeling contact surface between the lungs and the chest cavity. The resulting deformations were then refined using the intensity-based algorithm to reduce any residual uncertainties. Important parameters in the intensity-based algorithm, including grid spacing, number of pyramids, and regularization coefficient, were optimized on 10 randomly-chosen patients (out of 31). Target registration error (TRE) was calculated by measuring the Euclidean distance of common anatomical points on both images after registration. For each patient a minimum of 30 points/lung were used.Grid spacing of 8 mm, 5 levels of grid pyramids, and regularization coefficient of 3.0 were found to provide optimal results on 10 randomly chosen patients. Overall the entire patient population (n = 31), the hybrid method resulted in mean ± SD (90th%) TRE of 1.5 ± 1.4 (2.9) mm compared to 3.1 ± 1.9 (5.6) using biomechanical DIR and 2.6 ± 2.5 (6.1) using intensity-based DIR alone.The proposed hybrid biomechanical modeling intensity based algorithm is a promising DIR technique which could be used in various IGI procedures. The current investigation shows the efficacy of this approach for the registration of 4DCT images of the lungs with average accuracy of 1.5�

Review of fluorescence guided surgery systems: identification of key performance capabilities beyond indocyanine green imaging

Science.gov (United States)

DSouza, Alisha V.; Lin, Huiyun; Henderson, Eric R.; Samkoe, Kimberley S.; Pogue, Brian W.

2016-01-01

Abstract. There is growing interest in using fluorescence imaging instruments to guide surgery, and the leading options for open-field imaging are reviewed here. While the clinical fluorescence-guided surgery (FGS) field has been focused predominantly on indocyanine green (ICG) imaging, there is accelerated development of more specific molecular tracers. These agents should help advance new indications for which FGS presents a paradigm shift in how molecular information is provided for resection decisions. There has been a steady growth in commercially marketed FGS systems, each with their own differentiated performance characteristics and specifications. A set of desirable criteria is presented to guide the evaluation of instruments, including: (i) real-time overlay of white-light and fluorescence images, (ii) operation within ambient room lighting, (iii) nanomolar-level sensitivity, (iv) quantitative capabilities, (v) simultaneous multiple fluorophore imaging, and (vi) ergonomic utility for open surgery. In this review, United States Food and Drug Administration 510(k) cleared commercial systems and some leading premarket FGS research systems were evaluated to illustrate the continual increase in this performance feature base. Generally, the systems designed for ICG-only imaging have sufficient sensitivity to ICG, but a fraction of the other desired features listed above, with both lower sensitivity and dynamic range. In comparison, the emerging research systems targeted for use with molecular agents have unique capabilities that will be essential for successful clinical imaging studies with low-concentration agents or where superior rejection of ambient light is needed. There is no perfect imaging system, but the feature differences among them are important differentiators in their utility, as outlined in the data and tables here. PMID:27533438

Review of fluorescence guided surgery systems: identification of key performance capabilities beyond indocyanine green imaging

Science.gov (United States)

DSouza, Alisha V.; Lin, Huiyun; Henderson, Eric R.; Samkoe, Kimberley S.; Pogue, Brian W.

2016-08-01

There is growing interest in using fluorescence imaging instruments to guide surgery, and the leading options for open-field imaging are reviewed here. While the clinical fluorescence-guided surgery (FGS) field has been focused predominantly on indocyanine green (ICG) imaging, there is accelerated development of more specific molecular tracers. These agents should help advance new indications for which FGS presents a paradigm shift in how molecular information is provided for resection decisions. There has been a steady growth in commercially marketed FGS systems, each with their own differentiated performance characteristics and specifications. A set of desirable criteria is presented to guide the evaluation of instruments, including: (i) real-time overlay of white-light and fluorescence images, (ii) operation within ambient room lighting, (iii) nanomolar-level sensitivity, (iv) quantitative capabilities, (v) simultaneous multiple fluorophore imaging, and (vi) ergonomic utility for open surgery. In this review, United States Food and Drug Administration 510(k) cleared commercial systems and some leading premarket FGS research systems were evaluated to illustrate the continual increase in this performance feature base. Generally, the systems designed for ICG-only imaging have sufficient sensitivity to ICG, but a fraction of the other desired features listed above, with both lower sensitivity and dynamic range. In comparison, the emerging research systems targeted for use with molecular agents have unique capabilities that will be essential for successful clinical imaging studies with low-concentration agents or where superior rejection of ambient light is needed. There is no perfect imaging system, but the feature differences among them are important differentiators in their utility, as outlined in the data and tables here.

Dosimetric consequences of translational and rotational errors in frame-less image-guided radiosurgery

Directory of Open Access Journals (Sweden)

Guckenberger Matthias

2012-04-01

Full Text Available Abstract Background To investigate geometric and dosimetric accuracy of frame-less image-guided radiosurgery (IG-RS for brain metastases. Methods and materials Single fraction IG-RS was practiced in 72 patients with 98 brain metastases. Patient positioning and immobilization used either double- (n = 71 or single-layer (n = 27 thermoplastic masks. Pre-treatment set-up errors (n = 98 were evaluated with cone-beam CT (CBCT based image-guidance (IG and were corrected in six degrees of freedom without an action level. CBCT imaging after treatment measured intra-fractional errors (n = 64. Pre- and post-treatment errors were simulated in the treatment planning system and target coverage and dose conformity were evaluated. Three scenarios of 0 mm, 1 mm and 2 mm GTV-to-PTV (gross tumor volume, planning target volume safety margins (SM were simulated. Results Errors prior to IG were 3.9 mm ± 1.7 mm (3D vector and the maximum rotational error was 1.7° ± 0.8° on average. The post-treatment 3D error was 0.9 mm ± 0.6 mm. No differences between double- and single-layer masks were observed. Intra-fractional errors were significantly correlated with the total treatment time with 0.7mm±0.5mm and 1.2mm±0.7mm for treatment times ≤23 minutes and >23 minutes (p5% in 14% of the patients. A 1 mm safety margin fully compensated intra-fractional patient motion. Conclusions IG-RS with online correction of translational errors achieves high geometric and dosimetric accuracy. Intra-fractional errors decrease target coverage and conformity unless compensated with appropriate safety margins.

Preservation of the endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound ablation of submucosal uterine fibroids

International Nuclear Information System (INIS)

Kim, Young-sun; Kim, Tae-Joong; Lee, Jeong-Won; Kim, Byoung-Gie; Lim, Hyo Keun; Rhim, Hyunchul; Jung, Sin-Ho; Ahn, Joong Hyun

2017-01-01

To evaluate the integrity of endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) ablation of submucosal uterine fibroids based on contrast-enhanced MRI findings, and to identify the risk factors for endometrial impairment. In total, 117 submucosal fibroids (diameter: 5.9 ± 3.0 cm) in 101 women (age: 43.6 ± 4.4 years) treated with MR-HIFU ablation were retrospectively analysed. Endometrial integrity was assessed with contrast-enhanced T1-weighted images at immediate (n = 101), 3-month (n = 62) and 12-month (n = 15) follow-ups. Endometrial impairment was classified into grades 0 (continuous endometrium), 1 (pin-point, full-thickness discontinuity), 2 (between grade 1 and 3), or 3 (full-thickness discontinuity >1 cm). Risk factors were assessed with generalized estimating equation (GEE) analysis. Among 117 fibroids, grades 0, 1, 2 and 3 endometrial impairments were observed at initial examination in 56.4%, 24.8%, 13.7% and 4.3%, respectively. Among 37 fibroid cases of endometrial impairment for which follow-ups were conducted, 30 showed improvements at 3- and/or 12-month follow-up. GEE analysis revealed the degree of endometrial protrusion was significantly associated with severity of endometrial injury (P < 0.0001). After MR-HIFU ablation of submucosal fibroids, endometrial enhancement was preserved intact or minimally impaired in most cases. Impaired endometrium, which is more common after treating endometrially-protruded fibroids, may recover spontaneously. (orig.)

Preservation of the endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound ablation of submucosal uterine fibroids

Energy Technology Data Exchange (ETDEWEB)

Kim, Young-sun [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Uterine Fibroid Integrated Management Center, MINT Intervention Hospital, Department of Radiology, Seoul (Korea, Republic of); Kim, Tae-Joong; Lee, Jeong-Won; Kim, Byoung-Gie [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Obstetrics and Gynecology, Seoul (Korea, Republic of); Lim, Hyo Keun [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); SAIHST, Sungkyunkwan University, Department of Health Sciences and Technology, Seoul (Korea, Republic of); Rhim, Hyunchul [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Jung, Sin-Ho [SAIHST, Sungkyunkwan University, Department of Health Sciences and Technology, Seoul (Korea, Republic of); Samsung Medical Center, Department of Biostatistics and Clinical Epidemiology, Seoul (Korea, Republic of); Ahn, Joong Hyun [Samsung Biomedical Research Institute, Samsung Medical Center, Biostatistics Team, Seoul (Korea, Republic of)

2017-09-15

To evaluate the integrity of endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) ablation of submucosal uterine fibroids based on contrast-enhanced MRI findings, and to identify the risk factors for endometrial impairment. In total, 117 submucosal fibroids (diameter: 5.9 ± 3.0 cm) in 101 women (age: 43.6 ± 4.4 years) treated with MR-HIFU ablation were retrospectively analysed. Endometrial integrity was assessed with contrast-enhanced T1-weighted images at immediate (n = 101), 3-month (n = 62) and 12-month (n = 15) follow-ups. Endometrial impairment was classified into grades 0 (continuous endometrium), 1 (pin-point, full-thickness discontinuity), 2 (between grade 1 and 3), or 3 (full-thickness discontinuity >1 cm). Risk factors were assessed with generalized estimating equation (GEE) analysis. Among 117 fibroids, grades 0, 1, 2 and 3 endometrial impairments were observed at initial examination in 56.4%, 24.8%, 13.7% and 4.3%, respectively. Among 37 fibroid cases of endometrial impairment for which follow-ups were conducted, 30 showed improvements at 3- and/or 12-month follow-up. GEE analysis revealed the degree of endometrial protrusion was significantly associated with severity of endometrial injury (P < 0.0001). After MR-HIFU ablation of submucosal fibroids, endometrial enhancement was preserved intact or minimally impaired in most cases. Impaired endometrium, which is more common after treating endometrially-protruded fibroids, may recover spontaneously. (orig.)

Surgical neuro navigator guided by preoperative magnetic resonance images, based on a magnetic position sensor

International Nuclear Information System (INIS)

Perini, Ana Paula; Siqueira, Rogerio Bulha; Carneiro, Antonio Adilton Oliveira; Oliveira, Lucas Ferrari de; Machado, Helio Rubens

2009-01-01

Image guided neurosurgery enables the neurosurgeon to navigate inside the patient's brain using pre-operative images as a guide and a tracking system, during a surgery. Following a calibration procedure, three-dimensional position and orientation of surgical instruments may be transmitted to computer. The spatial information is used to access a region of interest, in the pre-operative images, displaying them to the neurosurgeon during the surgical procedure. However, when a craniotomy is involved and the lesion is removed, movements of brain tissue can be a significant source of error in these conventional navigation systems. The architecture implemented in this work intends the development of a system to surgical planning and orientation guided by ultrasound image. For surgical orientation, the software developed allows the extraction of slices from the volume of the magnetic resonance images (MRI) with orientation supplied by a magnetic position sensor (Polhemus R ). The slices extracted with this software are important because they show the cerebral area that the neurosurgeon is observing during the surgery, and besides they can be correlated with the intra-operative ultrasound images to detect and to correct the deformation of brain tissue during the surgery. Also, a tool for per-operative navigation was developed, providing three orthogonal planes through the image volume. In the methodology used for the software implementation, the Python tm programming language and the Visualization Toolkit (VTK) graphics library were used. The program to extract slices of the MRI volume allowed the application of transformations in the volume, using coordinates supplied by the position sensor. (author)

Objective-guided image annotation.

Science.gov (United States)

Mao, Qi; Tsang, Ivor Wai-Hung; Gao, Shenghua

2013-04-01

Automatic image annotation, which is usually formulated as a multi-label classification problem, is one of the major tools used to enhance the semantic understanding of web images. Many multimedia applications (e.g., tag-based image retrieval) can greatly benefit from image annotation. However, the insufficient performance of image annotation methods prevents these applications from being practical. On the other hand, specific measures are usually designed to evaluate how well one annotation method performs for a specific objective or application, but most image annotation methods do not consider optimization of these measures, so that they are inevitably trapped into suboptimal performance of these objective-specific measures. To address this issue, we first summarize a variety of objective-guided performance measures under a unified representation. Our analysis reveals that macro-averaging measures are very sensitive to infrequent keywords, and hamming measure is easily affected by skewed distributions. We then propose a unified multi-label learning framework, which directly optimizes a variety of objective-specific measures of multi-label learning tasks. Specifically, we first present a multilayer hierarchical structure of learning hypotheses for multi-label problems based on which a variety of loss functions with respect to objective-guided measures are defined. And then, we formulate these loss functions as relaxed surrogate functions and optimize them by structural SVMs. According to the analysis of various measures and the high time complexity of optimizing micro-averaging measures, in this paper, we focus on example-based measures that are tailor-made for image annotation tasks but are seldom explored in the literature. Experiments show consistency with the formal analysis on two widely used multi-label datasets, and demonstrate the superior performance of our proposed method over state-of-the-art baseline methods in terms of example-based measures on four

Evaluation of multiple image-based modalities for image-guided radiation therapy (IGRT) of prostate carcinoma: A prospective study

International Nuclear Information System (INIS)

Mayyas, Essa; Chetty, Indrin J.; Chetvertkov, Mikhail; Wen, Ning; Neicu, Toni; Nurushev, Teamor; Ren Lei; Pradhan, Deepak; Movsas, Benjamin; Elshaikh, Mohamed A.; Lu Mei; Stricker, Hans

2013-01-01

Purpose: Setup errors and prostate intrafraction motion are main sources of localization uncertainty in prostate cancer radiation therapy. This study evaluates four different imaging modalities 3D ultrasound (US), kV planar images, cone-beam computed tomography (CBCT), and implanted electromagnetic transponders (Calypso/Varian) to assess inter- and intrafraction localization errors during intensity-modulated radiation therapy based treatment of prostate cancer. Methods: Twenty-seven prostate cancer patients were enrolled in a prospective IRB-approved study and treated to a total dose of 75.6 Gy (1.8 Gy/fraction). Overall, 1100 fractions were evaluated. For each fraction, treatment targets were localized using US, kV planar images, and CBCT in a sequence defined to determine setup offsets relative to the patient skin tattoos, intermodality differences, and residual errors for each patient and patient cohort. Planning margins, following van Herk's formalism, were estimated based on error distributions. Calypso-based localization was not available for the first eight patients, therefore centroid positions of implanted gold-seed markers imaged prior to and immediately following treatment were used as a motion surrogate during treatment. For the remaining 19 patients, Calypso transponders were used to assess prostate intrafraction motion. Results: The means (μ), and standard deviations (SD) of the systematic (Σ) and random errors (σ) of interfraction prostate shifts (relative to initial skin tattoo positioning), as evaluated using CBCT, kV, and US, averaged over all patients and fractions, were: [μ CBCT = (−1.2, 0.2, 1.1) mm, Σ CBCT = (3.0, 1.4, 2.4) mm, σ CBCT = (3.2, 2.2, 2.5) mm], [μ kV = (−2.9, −0.4, 0.5) mm, Σ kV = (3.4, 3.1, 2.6) mm, σ kV = (2.9, 2.0, 2.4) mm], and [μ US = (−3.6, −1.4, 0.0) mm, Σ US = (3.3, 3.5, 2.8) mm, σ US = (4.1, 3.8, 3.6) mm], in the anterior–posterior (A/P), superior–inferior (S/I), and the left–right (L

Evaluation of multiple image-based modalities for image-guided radiation therapy (IGRT) of prostate carcinoma: A prospective study

Energy Technology Data Exchange (ETDEWEB)

Mayyas, Essa; Chetty, Indrin J.; Chetvertkov, Mikhail; Wen, Ning; Neicu, Toni; Nurushev, Teamor; Ren Lei; Pradhan, Deepak; Movsas, Benjamin; Elshaikh, Mohamed A. [Department of Radiation Oncology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, Michigan 48202 (United States); Lu Mei [Department of Public Health Sciences, Henry Ford Health System, 2799 West Grand Boulevard, Detroit Michigan 48202 (United States); Stricker, Hans [Department of Urology, Henry Ford Health System, 2799 West Grand Boulevard, Detroit Michigan 48202 (United States)

2013-04-15

Purpose: Setup errors and prostate intrafraction motion are main sources of localization uncertainty in prostate cancer radiation therapy. This study evaluates four different imaging modalities 3D ultrasound (US), kV planar images, cone-beam computed tomography (CBCT), and implanted electromagnetic transponders (Calypso/Varian) to assess inter- and intrafraction localization errors during intensity-modulated radiation therapy based treatment of prostate cancer. Methods: Twenty-seven prostate cancer patients were enrolled in a prospective IRB-approved study and treated to a total dose of 75.6 Gy (1.8 Gy/fraction). Overall, 1100 fractions were evaluated. For each fraction, treatment targets were localized using US, kV planar images, and CBCT in a sequence defined to determine setup offsets relative to the patient skin tattoos, intermodality differences, and residual errors for each patient and patient cohort. Planning margins, following van Herk's formalism, were estimated based on error distributions. Calypso-based localization was not available for the first eight patients, therefore centroid positions of implanted gold-seed markers imaged prior to and immediately following treatment were used as a motion surrogate during treatment. For the remaining 19 patients, Calypso transponders were used to assess prostate intrafraction motion. Results: The means ({mu}), and standard deviations (SD) of the systematic ({Sigma}) and random errors ({sigma}) of interfraction prostate shifts (relative to initial skin tattoo positioning), as evaluated using CBCT, kV, and US, averaged over all patients and fractions, were: [{mu}{sub CBCT}= (-1.2, 0.2, 1.1) mm, {Sigma}{sub CBCT}= (3.0, 1.4, 2.4) mm, {sigma}{sub CBCT}= (3.2, 2.2, 2.5) mm], [{mu}{sub kV}= (-2.9, -0.4, 0.5) mm, {Sigma}{sub kV}= (3.4, 3.1, 2.6) mm, {sigma}{sub kV}= (2.9, 2.0, 2.4) mm], and [{mu}{sub US}= (-3.6, -1.4, 0.0) mm, {Sigma}{sub US}= (3.3, 3.5, 2.8) mm, {sigma}{sub US}= (4.1, 3.8, 3.6) mm], in the anterior

Dosimetric consequences of translational and rotational errors in frame-less image-guided radiosurgery

International Nuclear Information System (INIS)

Guckenberger, Matthias; Roesch, Johannes; Baier, Kurt; Sweeney, Reinhart A; Flentje, Michael

2012-01-01

To investigate geometric and dosimetric accuracy of frame-less image-guided radiosurgery (IG-RS) for brain metastases. Single fraction IG-RS was practiced in 72 patients with 98 brain metastases. Patient positioning and immobilization used either double- (n = 71) or single-layer (n = 27) thermoplastic masks. Pre-treatment set-up errors (n = 98) were evaluated with cone-beam CT (CBCT) based image-guidance (IG) and were corrected in six degrees of freedom without an action level. CBCT imaging after treatment measured intra-fractional errors (n = 64). Pre- and post-treatment errors were simulated in the treatment planning system and target coverage and dose conformity were evaluated. Three scenarios of 0 mm, 1 mm and 2 mm GTV-to-PTV (gross tumor volume, planning target volume) safety margins (SM) were simulated. Errors prior to IG were 3.9 mm ± 1.7 mm (3D vector) and the maximum rotational error was 1.7° ± 0.8° on average. The post-treatment 3D error was 0.9 mm ± 0.6 mm. No differences between double- and single-layer masks were observed. Intra-fractional errors were significantly correlated with the total treatment time with 0.7mm±0.5mm and 1.2mm±0.7mm for treatment times ≤23 minutes and >23 minutes (p<0.01), respectively. Simulation of RS without image-guidance reduced target coverage and conformity to 75% ± 19% and 60% ± 25% of planned values. Each 3D set-up error of 1 mm decreased target coverage and dose conformity by 6% and 10% on average, respectively, with a large inter-patient variability. Pre-treatment correction of translations only but not rotations did not affect target coverage and conformity. Post-treatment errors reduced target coverage by >5% in 14% of the patients. A 1 mm safety margin fully compensated intra-fractional patient motion. IG-RS with online correction of translational errors achieves high geometric and dosimetric accuracy. Intra-fractional errors decrease target coverage and conformity unless compensated with appropriate

Systematic measurements of whole-body imaging dose distributions in image-guided radiation therapy

International Nuclear Information System (INIS)

Hälg, Roger A.; Besserer, Jürgen; Schneider, Uwe

2012-01-01

Purpose: The full benefit of the increased precision of contemporary treatment techniques can only be exploited if the accuracy of the patient positioning is guaranteed. Therefore, more and more imaging modalities are used in the process of the patient setup in clinical routine of radiation therapy. The improved accuracy in patient positioning, however, results in additional dose contributions to the integral patient dose. To quantify this, absorbed dose measurements from typical imaging procedures involved in an image-guided radiation therapy treatment were measured in an anthropomorphic phantom for a complete course of treatment. The experimental setup, including the measurement positions in the phantom, was exactly the same as in a preceding study of radiotherapy stray dose measurements. This allows a direct combination of imaging dose distributions with the therapy dose distribution. Methods: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The dose distributions from imaging devices used with treatment machines from the manufacturers Accuray, Elekta, Siemens, and Varian and from computed tomography scanners from GE Healthcare were determined and the resulting effective dose was calculated. The list of investigated imaging techniques consisted of cone beam computed tomography (kilo- and megavoltage), megavoltage fan beam computed tomography, kilo- and megavoltage planar imaging, planning computed tomography with and without gating methods and planar scout views. Results: A conventional 3D planning CT resulted in an effective dose additional to the treatment stray dose of less than 1 mSv outside of the treated volume, whereas a 4D planning CT resulted in a 10 times larger dose. For a daily setup of the patient with two planar kilovoltage images or with a fan beam CT at the TomoTherapy unit, an additional effective dose outside of the treated volume of less than 0.4 mSv and 1

High-resolution imaging of coronary calcifications by intense low-energy fluoroscopic X-ray obtained from synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Ohtsuka, S.; Sugishita, Y.; Takeda, T.; Itai, Y.; Tada, J.; Hyodo, K.; Ando, M. [Inst. of Clinical Medicine, Univ. of Tsukuba, Ibaraki (Japan). Dept. of Cardiology

2000-07-01

In order to obtain an intense monochromatic low-energy X-ray from synchrotron radiation (SR) and apply it to detect coronary calcifications, the SR beam was reflected with a silicon crystal to be expanded (150 mm in height and 80 mm in width) and to be monochromatized at an energy level of 37 keV. The X-ray was intermittently irradiated to obtain dynamic imaging of 30 images/s. Images were recorded by a digital fluorography system. The low-energy X-ray from SR sharply visualized calcification of coronary arteries, while conventional X-ray could not visualize coronary calcification. The intense monochromatic low-energy X-ray from SR is sensitive, has high-resolution for imaging coronary calcification and may serve as a screening method for coronary artery disease.

Study on Fuzzy Adaptive Fractional Order PIλDμ Control for Maglev Guiding System

Science.gov (United States)

Hu, Qing; Hu, Yuwei

The mathematical model of the linear elevator maglev guiding system is analyzed in this paper. For the linear elevator needs strong stability and robustness to run, the integer order PID was expanded to the fractional order, in order to improve the steady state precision, rapidity and robustness of the system, enhance the accuracy of the parameter in fractional order PIλDμ controller, the fuzzy control is combined with the fractional order PIλDμ control, using the fuzzy logic achieves the parameters online adjustment. The simulations reveal that the system has faster response speed, higher tracking precision, and has stronger robustness to the disturbance.

TU-A-304-01: Introduction and Workflow of Image-Guided SBRT

International Nuclear Information System (INIS)

Salter, B.

2015-01-01

Increased use of SBRT and hypo fractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide updated knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT or IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state-of-art imaging and planning techniques. Learning Objectives: Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA. Update on the use of multi-dimensional (3D and 4D) and multi-modality (CT, beam-level X-ray imaging, pre- and on-treatment 3D/4D MRI, PET, robotic ultrasound, etc.) for reliable guidance of SBRT. Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT. Discuss treatment planning and quality assurance issues specific to SBRT. Research grant from Varian Medical Systems

TU-A-304-01: Introduction and Workflow of Image-Guided SBRT

Energy Technology Data Exchange (ETDEWEB)

Salter, B. [University of Utah Huntsman Cancer Institute (United States)

2015-06-15

Increased use of SBRT and hypo fractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide updated knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT or IMRT, and technical advancements in QA of SBRT (in particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state-of-art imaging and planning techniques. Learning Objectives: Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA. Update on the use of multi-dimensional (3D and 4D) and multi-modality (CT, beam-level X-ray imaging, pre- and on-treatment 3D/4D MRI, PET, robotic ultrasound, etc.) for reliable guidance of SBRT. Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT. Discuss treatment planning and quality assurance issues specific to SBRT. Research grant from Varian Medical Systems.

Arthritis: Conventional and Advanced Radiological Imaging

Directory of Open Access Journals (Sweden)

Adviye Ergun

2014-06-01

Full Text Available Arthritides are acute or chronic inflammation of one or more joints. The most common types of arthritis are osteoarthritis and rheumatoid arthritis, but there are more than 100 different forms. Right and early diagnosis is extremely important for the prevention of eventual structural and functional disability of the affected joint. Imaging findings, especially those of advanced level imaging, play a major role in diagnosis and monitor the progression of arthritis or its response to therapy. The objective of the review is to discuss the findings of conventional and advanced radiological imaging of most common arthritides and to present a simplified approach for their radiological evaluation.

How can global conventions for biodiversity and ecosystem services guide local conservation actions?

NARCIS (Netherlands)

Geijzendorffer, Ilse R.; van Teeffelen, Astrid; Allison, Hilary; Braun, Daniela; Horgan, K.; Iturrate-Garcia, Maitane; Santos, Maria João; Pellissier, Loïc; Prieur-Richard, Anne-Helene; Quatrini, Simone; Sakai, Shoko; Zuppinger-Dingley, Debra

2017-01-01

With global science-policy conventions for biodiversity and ecosystem services in place, much effort goes into monitoring and reporting on the progress toward policy targets. As conservation actions happen locally, can such global monitoring and reporting efforts effectively guide conservation

Positron range in PET imaging: non-conventional isotopes

International Nuclear Information System (INIS)

Jødal, L; Le Loirec, C; Champion, C

2014-01-01

In addition to conventional short-lived radionuclides, longer-lived isotopes are becoming increasingly important to positron emission tomography (PET). The longer half-life both allows for circumvention of the in-house production of radionuclides, and expands the spectrum of physiological processes amenable to PET imaging, including processes with prohibitively slow kinetics for investigation with short-lived radiotracers. However, many of these radionuclides emit ‘high-energy’ positrons and gamma rays which affect the spatial resolution and quantitative accuracy of PET images. The objective of the present work is to investigate the positron range distribution for some of these long-lived isotopes. Based on existing Monte Carlo simulations of positron interactions in water, the probability distribution of the line of response displacement have been empirically described by means of analytic displacement functions. Relevant distributions have been derived for the isotopes 22 Na, 52 Mn, 89 Zr, 45 Ti, 51 Mn, 94m Tc, 52m Mn, 38 K, 64 Cu, 86 Y, 124 I, and 120 I. It was found that the distribution functions previously found for a series of conventional isotopes (Jødal et al 2012 Phys. Med. Bio. 57 3931–43), were also applicable to these non-conventional isotopes, except that for 120 I, 124 I, 89 Zr, 52 Mn, and 64 Cu, parameters in the formulae were less well predicted by mean positron energy alone. Both conventional and non-conventional range distributions can be described by relatively simple analytic expressions. The results will be applicable to image-reconstruction software to improve the resolution. (paper)

Different styles of image-guided radiotherapy

NARCIS (Netherlands)

van Herk, Marcel

2007-01-01

To account for geometric uncertainties during radiotherapy, safety margins are applied. In many cases, these margins overlap organs at risk, thereby limiting dose escalation. The aim of image-guided radiotherapy is to improve the accuracy by imaging tumors and critical structures on the machine just

Image quality characteristics for virtual monoenergetic images using dual-layer spectral detector CT: Comparison with conventional tube-voltage images.

Science.gov (United States)

Sakabe, Daisuke; Funama, Yoshinori; Taguchi, Katsuyuki; Nakaura, Takeshi; Utsunomiya, Daisuke; Oda, Seitaro; Kidoh, Masafumi; Nagayama, Yasunori; Yamashita, Yasuyuki

2018-05-01

To investigate the image quality characteristics for virtual monoenergetic images compared with conventional tube-voltage image with dual-layer spectral CT (DLCT). Helical scans were performed using a first-generation DLCT scanner, two different sizes of acrylic cylindrical phantoms, and a Catphan phantom. Three different iodine concentrations were inserted into the phantom center. The single-tube voltage for obtaining virtual monoenergetic images was set to 120 or 140 kVp. Conventional 120- and 140-kVp images and virtual monoenergetic images (40-200-keV images) were reconstructed from slice thicknesses of 1.0 mm. The CT number and image noise were measured for each iodine concentration and water on the 120-kVp images and virtual monoenergetic images. The noise power spectrum (NPS) was also calculated. The iodine CT numbers for the iodinated enhancing materials were similar regardless of phantom size and acquisition method. Compared with the iodine CT numbers of the conventional 120-kVp images, those for the monoenergetic 40-, 50-, and 60-keV images increased by approximately 3.0-, 1.9-, and 1.3-fold, respectively. The image noise values for each virtual monoenergetic image were similar (for example, 24.6 HU at 40 keV and 23.3 HU at 200 keV obtained at 120 kVp and 30-cm phantom size). The NPS curves of the 70-keV and 120-kVp images for a 1.0-mm slice thickness over the entire frequency range were similar. Virtual monoenergetic images represent stable image noise over the entire energy spectrum and improved the contrast-to-noise ratio than conventional tube voltage using the dual-layer spectral detector CT. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Intensity of the production organisation in organic and conventional dairy farms

Directory of Open Access Journals (Sweden)

Urszula Malaga-Toboła

2013-03-01

Full Text Available This paper presents a comparative analysis of the intensity of the production organization between dairy farms conducting agricultural activity in organic and conventional production systems. Study groups of farms were located in the southern (fifteen organic farms, central and eastern part of Poland (fifteen conventional farms. The study was conducted in the form of a directed interview in the marketing year 2010/2011. Area, structure of land use and crop, livestock and the size of plant and animal in the production global and commodity were specified. The analysis showed a lot of differences between the two systems of production, from the area of farm and structure of land use and finally the production outputs. Basic statistical analysis was also conducted. It showed a significant negative correlation between the area of agricultural land and a positive correlation between the livestock and intensity of organisation of production. However, the correlation coefficients between the studied variables in the analysed farm groups differed from each other.

Imaging of the digital arteries: Digital subtraction angiography versus conventional angiography

International Nuclear Information System (INIS)

Menanteau, B.P.; Treutenaere, J.M.; Marcus, C.; Ladam, V.; Gausserand, F.

1986-01-01

The authors report their experience with the use of digital subtraction angiography (DSA) and conventional angiography of the hand. Of the 95 patients in the study group, 80 underwent conventional angiography and 15 underwent DSA. They analyzed the studies with regard to the type and amount of contrast agent used, the number of radiographs needed, and the diagnostic quality of the images. Conventional angiography often requires general anesthesia, magnification, and pharmaco-angiographic techniques to improve the image-based diagnosis. In comparison with conventional angiography, intraarterial DSA is characterized by improved contrast sensitivity and inferior spatial resolution. However, DSA provides images as acceptable as those of conventional angiography. Smaller catheters can be used, and the examination is performed under local anesthesia. The authors conclude that intraarterial DSA is now the technique of choice for examining patients with chronic ischemia of the hand

MO-DE-202-02: Advances in Image Registration and Reconstruction for Image-Guided Neurosurgery

Energy Technology Data Exchange (ETDEWEB)

Siewerdsen, J. [Johns Hopkins University (United States)

2016-06-15

At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

MO-DE-202-02: Advances in Image Registration and Reconstruction for Image-Guided Neurosurgery

International Nuclear Information System (INIS)

Siewerdsen, J.

2016-01-01

At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

Positioning device for MRI-guided high intensity focused ultrasound system

Energy Technology Data Exchange (ETDEWEB)

Damianou, Christakis [Frederick Institute of Technology (FIT), Limassol (Cyprus); MEDSONIC, LTD, Limassol (Cyprus); Ioannides, Kleanthis [Polikliniki Igia, Limassol (Cyprus); Milonas, Nicos [Frederick Institute of Technology (FIT), Limassol (Cyprus)

2008-04-15

A prototype magnetic resonance imaging (MRI)- compatible positioning device was used to move an MRI-guided high intensity focused ultrasound (HIFU) transducer. The positioning device has three user-controlled degrees of freedom that allow access to various targeted lesions. The positioning device was designed and fabricated using construction materials selected for compatibility with high magnetic fields and fast switching magnetic field gradients encountered inside MRI scanners. The positioning device incorporates only MRI compatible materials such as piezoelectric motors, plastic sheets, brass screws, plastic pulleys and timing belts. The HIFU/MRI system includes the multiple subsystems (a) HIFU system, (b) MR imaging, (c) Positioning device (robot) and associate drivers, (d) temperature measurement, (e) cavitation detection, (f) MRI compatible camera, and (g) Soft ware. The MRI compatibility of the system was successfully demonstrated in a clinical high-field MRI scanner. The ability of the robot to accurately move the transducer thus creating discrete and overlapping lesions in biological tissue was tested successfully. A simple, cost effective, portable positioning device has been developed which can be used in virtually any clinical MRI scanner since it can be sited on the scanner's table. The propagation of HIFU can use either a lateral or superior-inferior approach. Discrete and large lesions were created successfully with reproducible results. (orig.)

Multiscale infrared and visible image fusion using gradient domain guided image filtering

Science.gov (United States)

Zhu, Jin; Jin, Weiqi; Li, Li; Han, Zhenghao; Wang, Xia

2018-03-01

For better surveillance with infrared and visible imaging, a novel hybrid multiscale decomposition fusion method using gradient domain guided image filtering (HMSD-GDGF) is proposed in this study. In this method, hybrid multiscale decomposition with guided image filtering and gradient domain guided image filtering of source images are first applied before the weight maps of each scale are obtained using a saliency detection technology and filtering means with three different fusion rules at different scales. The three types of fusion rules are for small-scale detail level, large-scale detail level, and base level. Finally, the target becomes more salient and can be more easily detected in the fusion result, with the detail information of the scene being fully displayed. After analyzing the experimental comparisons with state-of-the-art fusion methods, the HMSD-GDGF method has obvious advantages in fidelity of salient information (including structural similarity, brightness, and contrast), preservation of edge features, and human visual perception. Therefore, visual effects can be improved by using the proposed HMSD-GDGF method.

Image-guided surgery and therapy: current status and future directions

Science.gov (United States)

Peters, Terence M.

2001-05-01

Image-guided surgery and therapy is assuming an increasingly important role, particularly considering the current emphasis on minimally-invasive surgical procedures. Volumetric CT and MR images have been used now for some time in conjunction with stereotactic frames, to guide many neurosurgical procedures. With the development of systems that permit surgical instruments to be tracked in space, image-guided surgery now includes the use of frame-less procedures, and the application of the technology has spread beyond neurosurgery to include orthopedic applications and therapy of various soft-tissue organs such as the breast, prostate and heart. Since tracking systems allow image- guided surgery to be undertaken without frames, a great deal of effort has been spent on image-to-image and image-to- patient registration techniques, and upon the means of combining real-time intra-operative images with images acquired pre-operatively. As image-guided surgery systems have become increasingly sophisticated, the greatest challenges to their successful adoption in the operating room of the future relate to the interface between the user and the system. To date, little effort has been expended to ensure that the human factors issues relating to the use of such equipment in the operating room have been adequately addressed. Such systems will only be employed routinely in the OR when they are designed to be intuitive, unobtrusive, and provide simple access to the source of the images.

Recent advances in near-infrared fluorescence-guided imaging surgery using indocyanine green.

Science.gov (United States)

Namikawa, Tsutomu; Sato, Takayuki; Hanazaki, Kazuhiro

2015-12-01

Near-infrared (NIR) fluorescence imaging has better tissue penetration, allowing for the effective rejection of excitation light and detection deep inside organs. Indocyanine green (ICG) generates NIR fluorescence after illumination by an NIR ray, enabling real-time intraoperative visualization of superficial lymphatic channels and vessels transcutaneously. The HyperEye Medical System (HEMS) can simultaneously detect NIR rays under room light to provide color imaging, which enables visualization under bright light. Thus, NIR fluorescence imaging using ICG can provide for excellent diagnostic accuracy in detecting sentinel lymph nodes in cancer and microvascular circulation in various ischemic diseases, to assist us with intraoperative decision making. Including HEMS in this system could further improve the sentinel lymph node mapping and intraoperative identification of blood supply in reconstructive organs and ischemic diseases, making it more attractive than conventional imaging. Moreover, the development of new laparoscopic imaging systems equipped with NIR will allow fluorescence-guided surgery in a minimally invasive setting. Future directions, including the conjugation of NIR fluorophores to target specific cancer markers might be realistic technology with diagnostic and therapeutic benefits.

Magnetic Resonance Imaging-Guided Intracavitary Brachytherapy for Cancer of the Cervix

International Nuclear Information System (INIS)

Zwahlen, Daniel; Jezioranski, John; Chan, Philip; Haider, Masoom A.; Cho, Young-Bin; Yeung, Ivan; Levin, Wilfred; Manchul, Lee; Fyles, Anthony; Milosevic, Michael

2009-01-01

Purpose: To determine the feasibility and benefits of optimized magnetic resonance imaging (MRI)-guided brachytherapy (BT) for cancer of the cervix. Methods and Materials: A total of 20 patients with International Federation of Gynecology and Obstetrics Stage IB-IV cervical cancer had an MRI-compatible intrauterine BT applicator inserted after external beam radiotherapy. MRI scans were acquired, and the gross tumor volume at diagnosis and at BT, the high-risk (HR) and intermediate-risk clinical target volume (CTV), and rectal, sigmoid, and bladder walls were delineated. Pulsed-dose-rate BT was planned and delivered in a conventional manner. Optimized MRI-based plans were developed and compared with the conventional plans. Results: The HR CTV and intermediate-risk CTV were adequately treated (the percentage of volume treated to ≥100% of the intended dose was >95%) in 70% and 85% of the patients with the conventional plans, respectively, and in 75% and 95% of the patients with the optimized plans, respectively. The minimal dose to the contiguous 2 cm 3 of the rectal, sigmoid, and bladder wall volume was 16 ± 6.2, 25 ± 8.7, and 31 ± 9.2 Gy, respectively. With MRI-guided BT optimization, it was possible to maintain coverage of the HR-CTV and reduce the dose to the normal tissues, especially in patients with small tumors at BT. In these patients, the HR percentage of volume treated to ≥100% of the intended dose approached 100% in all cases, and the minimal dose to the contiguous 2-cm 3 of the rectum, sigmoid, and bladder was 12-32% less than with conventional BT planning. Conclusion: MRI-based BT for cervical cancer has the potential to optimize primary tumor dosimetry and reduce the dose to critical normal tissues, particularly in patients with small tumors.

Physics of fractional imaging in biomedicine.

Science.gov (United States)

Sohail, Ayesha; Bég, O A; Li, Zhiwu; Celik, Sebahattin

2018-03-12

The mathematics of imaging is a growing field of research and is evolving rapidly parallel to evolution in the field of imaging. Imaging, which is a sub-field of biomedical engineering, considers novel approaches to visualize biological tissues with the general goal of improving health. "Medical imaging research provides improved diagnostic tools in clinical settings and supports the development of drugs and other therapies. The data acquisition and diagnostic interpretation with minimum error are the important technical aspects of medical imaging. The image quality and resolution are really important in portraying the internal aspects of patient's body. Although there are several user friendly resources for processing image features, such as enhancement, colour manipulation and compression, the development of new processing methods is still worthy of efforts. In this article we aim to present the role of fractional calculus in imaging with the aid of practical examples. Copyright © 2018 Elsevier Ltd. All rights reserved.

Diffusion Tensor Imaging of Heterotopia: Changes of Fractional Anisotropy during Radial Migration of Neurons

Science.gov (United States)

Kim, Jinna

2010-01-01

Purpose Diffusion tensor imaging provides better understanding of pathophysiology of congenital anomalies, involving central nervous system. This study was aimed to specify the pathogenetic mechanism of heterotopia, proved by diffusion tensor imaging, and establish new findings of heterotopia on fractional anisotropy maps. Materials and Methods Diffusion-weighted imaging data from 11 patients (M : F = 7 : 4, aged from 1 to 22 years, mean = 12.3 years) who visited the epilepsy clinic and received a routine seizure protocol MRI exam were retrospectively analyzed. Fractional anisotropy (FA) maps were generated from diffusion tensor imaging of 11 patients with heterotopia. Regions of interests (ROI) were placed in cerebral cortex, heterotopic gray matter and deep gray matter, including putamen. ANOVA analysis was performed for comparison of different gray matter tissues. Results Heterotopic gray matter showed signal intensities similar to normal gray matter on T1 and T2 weighted MRI. The measured FA of heterotopic gray matter was higher than that of cortical gray matter (0.236 ± 0.011 vs. 0.169 ± 0.015, p < 0.01, one way ANOVA), and slightly lower than that of deep gray matter (0.236 ± 0.011 vs. 0.259 ± 0.016, p < 0.01). Conclusion Increased FA of heterotopic gray matter suggests arrested neuron during radial migration and provides better understanding of neurodevelopment. PMID:20499428

Improvement in dose escalation using off-line and on-line image feedback in the intensity modulated beam design for prostate cancer treatment

International Nuclear Information System (INIS)

Yan, D.; Birkner, M.; Nuesslin, F.; Wong, J.; Martinez, A.

2001-01-01

Purpose: To test the capability of dose escalation in the IMRT process where the organ/patient temporal geometric variation, measured using either off-line or on-line treatment CT and portal images, are adapted for the optimal design of intensity modulated beam. Materials and Methods: Retrospective study was performed on five prostate cancer patients with multiple CT scans (14∼17/patient) and daily portal images obtained during the treatment course. These images were used to determine the displacements of each subvolume in the organs of interest caused by the daily patient setup and internal organ motion/deformation. The temporal geometric information was processed in order of treatment time and fed into an inverse planning system. The inverse planning engine was specifically implemented to adapt the design of intensity modulated beam to the temporal subvolume displacement and patient internal density changes. Three image feedback strategies were applied to each patient and evaluated with respect to the capability of safe dose escalation. The first one is off-line image feedback, which designs the beam intensity based on the patient images measured within the first week of treatment. The second is an on-line 'the target of the day' strategy, which designs the beam intensity in daily bases by using 'the image of the day' alone. The last one is also the on-line based. However, it designs the instantaneous beam intensity based on also dose distribution in each organ of interest received prior to the current treatment. For each of the treatment strategies, the minimum dose delivered to the CTV was determined by applying the identical normal tissue constraints of partial dose/volumes. This minimum dose was used to represent the treatment dose for each patient. Results: The off-line strategy appears feasible after 5 days of image feedback. The average treatment dose among the patients can be 10% higher than the one in the conventional IMRT treatment where the inverse

Image super-resolution reconstruction based on regularization technique and guided filter

Science.gov (United States)

Huang, De-tian; Huang, Wei-qin; Gu, Pei-ting; Liu, Pei-zhong; Luo, Yan-min

2017-06-01

In order to improve the accuracy of sparse representation coefficients and the quality of reconstructed images, an improved image super-resolution algorithm based on sparse representation is presented. In the sparse coding stage, the autoregressive (AR) regularization and the non-local (NL) similarity regularization are introduced to improve the sparse coding objective function. A group of AR models which describe the image local structures are pre-learned from the training samples, and one or several suitable AR models can be adaptively selected for each image patch to regularize the solution space. Then, the image non-local redundancy is obtained by the NL similarity regularization to preserve edges. In the process of computing the sparse representation coefficients, the feature-sign search algorithm is utilized instead of the conventional orthogonal matching pursuit algorithm to improve the accuracy of the sparse coefficients. To restore image details further, a global error compensation model based on weighted guided filter is proposed to realize error compensation for the reconstructed images. Experimental results demonstrate that compared with Bicubic, L1SR, SISR, GR, ANR, NE + LS, NE + NNLS, NE + LLE and A + (16 atoms) methods, the proposed approach has remarkable improvement in peak signal-to-noise ratio, structural similarity and subjective visual perception.

Quality assurance for image-guided radiotherapy

International Nuclear Information System (INIS)

Marinello, Ginette

2008-01-01

The topics discussed include, among others, the following: Quality assurance program; Image guided radiotherapy; Commissioning and quality assurance; Check of agreement between visual and displayed scales; quality controls: electronic portal imaging device (EPID), MV-kV and kV-kV, cone-beam CT (CBCT), patient doses. (P.A.)

Radiologists' leading position in image-guided therapy

NARCIS (Netherlands)

Helmberger, Thomas; Martí-Bonmatí, Luis; Pereira, Philippe; Gillams, Alice; Martínez, Jose; Lammer, Johannes; Malagari, Katarina; Gangi, Afshin; de Baere, Thierry; Adam, E. Jane; Rasch, Coen; Budach, Volker; Reekers, Jim A.

2013-01-01

Image-guided diagnostic and therapeutic procedures are related to, or performed under, some kind of imaging. Such imaging may be direct inspection (as in open surgery) or indirect inspection as in endoscopy or laparoscopy. Common to all these techniques is the transformation of optical and visible

Diagnostic imaging of Klippel-Feil syndrome: conventional radiography, CT and MR imaging. Case report

International Nuclear Information System (INIS)

Jochens, R.; Schubeus, P.; Steinkamp, H.J.; Menzhausen, L.; Felix, R.

1993-01-01

In two patients with Klippel-Feil syndrome, type II radiographic findings of the malformation are shown in the cervical spine and the craniocervical junction. Conventional X-rays of the cervical spine in the AP and lateral view and conventional tomography as well as CT of the cervical spine were obtained in both patients. One of the two patients additionally underwent MR imaging. Findings of the different imaging modalities are compared with each other. (orig.) [de

Image-guided stereotactic surgery using ultrasonography and reconstructive three-dimensional CT-imaging system

International Nuclear Information System (INIS)

Kawamura, Hirotsune; Iseki, Hiroshi; Umezawa, Yoshihiro

1991-01-01

A new simulation and navigation system utilizing three-dimensional CT images has been developed for image-guided stereotactic surgery. Preoperative CT images are not always useful in predicting the intraoperative location of lesions, for cerebral lesions are easily displaced or distorted by gravity, brain retraction, and/or CSF aspiration during operative procedure. This new system, however, has the advantage that the intraoperative locations of intracranial lesions or the anatomical structures of the brain can be precisely confirmed during stereotactic surgery. Serial CT images were obtained from a patient whose head had been fixed to the ISEKI CT-guided stereotactic frame. The data of serial CT images were saved on a floppy disc and then transferred to the work station (IRIS) using the off line. In order to find the best approach angle for ultrasound-guided stereotactic surgery, three-dimenstional CT images were reconstructed using the work station. The site of the craniotomy or the angle of the trajectory of the ultrasound probe was measured preoperatively based on the three-dimensional CT images. Then, in the operating room, the patient's head was fixed to the ISEKI frame with the subframe at the same position as before according to the measurement of the CT images. In a case of cystic glioma, the predicable ultrasonograms from three-dimensional reconstructive CT images were ascertained to correspond well to the actual ultrasound images during ultrasound-guided stereotactic surgery. Therefore, the new simulation and navigation system can be judged to be a powerful operative supporting modality for correcting the locations of cerebral lesions; it allows one to perform stereotactic surgery more accurately and less invasively. (author)

Image quality in conventional chest radiography. Evaluation using the postprocessing tool Diamond View

International Nuclear Information System (INIS)

Niemann, Tilo; Reisinger, Clemens; Rau, Philipp; Schwarz, Jochen; Ruis-Lopez, Laura; Bongartz, Georg

2010-01-01

The objective of this work was to evaluate the influence of the postprocessing tool Diamond View (Siemens AG Medical Solutions, Germany) on image quality in conventional chest radiography. Evaluation of image quality remains a challenge in conventional radiography. Based on the European Commission quality criteria we evaluated the improvement of image quality when applying the new postprocessing tool Diamond View (Siemens AG Medical solutions, Germany) to conventional chest radiographs. Three different readers prospectively evaluated 102 digital image pairs of chest radiographs. Statistical analysis was performed with a p value <0.05 considered as significant. Images were evaluated on basis of the modified imaging Quality Criteria by the Commission of the European Communities. Each of the 11 image quality criteria was evaluated separately using a five point classification. Statistical analysis showed an overall tendency for improved image quality for Diamond View (DV) for all criteria. Significant differences could be found in most of the criteria. In conclusion DV improves image quality in conventional chest radiographs.

Scaled signal intensity of uterine fibroids based on T2-weighted MR images: a potential objective method to determine the suitability for magnetic resonance-guided focused ultrasound surgery of uterine fibroids.

Science.gov (United States)

Park, Hyun; Yoon, Sang-Wook; Sokolov, Amit

2015-12-01

Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive method to treat uterine fibroids. To help determine the patient suitability for MRgFUS, we propose a new objective measure: the scaled signal intensity (SSI) of uterine fibroids in T2 weighted MR images (T2WI). Forty three uterine fibroids in 40 premenopausal women were included in this retrospective study. SSI of each fibroid was measured from the screening T2WI by standardizing its mean signal intensity to a 0-100 scale, using reference intensities of rectus abdominis muscle (0) and subcutaneous fat (100). Correlation between the SSI and the non-perfused volume (NPV) ratio (a measure for treatment success) was calculated. Pre-treatment SSI showed a significant inverse-correlation with post treatment NPV ratio (p < 0.05). When dichotomizing NPV ratio at 45 %, the optimal cut off value of the SSI was found to be 16.0. A fibroid with SSI value 16.0 or less can be expected to have optimal responses. The SSI of uterine fibroids in T2WI can be suggested as an objective parameter to help in patient selection for MRgFUS. • Signal intensity of fibroid in MR images predicts treatment response to MRgFUS. • Signal intensity is standardized into scaled form using adjacent tissues as references. • Fibroids with SSI less than 16.0 are expected to have optimal responses.

Feasibility and efficacy of helical intensity-modulated radiotherapy for stage III non-small cell lung cancer in comparison with conventionally fractionated 3D-CRT.

Science.gov (United States)

He, Jian; Huang, Yan; Chen, Yixing; Shi, Shiming; Ye, Luxi; Hu, Yong; Zhang, Jianying; Zeng, Zhaochong

2016-05-01

The standard treatment for stage III non-small-cell lung cancer (NSCLC) is still 60 Gy in conventional fractions combined with concurrent chemotherapy; however, the resulting local controls are disappointing. The aim of this study was to compare and assess the feasibility and efficacy of hypofractionated chemoradiotherapy using helical tomotherapy (HT) with conventional fractionation as opposed to using three-dimensional conformal radiotherapy (3D-CRT) for stage III NSCLC. Sixty-nine patients with stage III (AJCC 7th edition) NSCLC who underwent definitive radiation treatment at our institution between July 2011 and November 2013 were reviewed and analyzed retrospectively. A dose of 60 Gy in 20 fractions was delivered in the HT group (n=34), whereas 60 Gy in 30 fractions in the 3D-CRT group (n=35). Primary endpoints were toxicity, overall response rate, overall survival (OS) and progression-free survival (PFS). The median follow-up period was 26.4 months. V20 (P=0.005), V30 (P=0.001), V40 (P=0.004), mean lung dose (P=0.000) and max dose of spinal cord (P=0.005) were significantly lower in the HT group than in the 3D-CRT group. There was no significant difference in the incidences of acute radiation pneumonitis (RP) ≥ grade 2 between the two groups, whereas the incidences of acute radiation esophagitis ≥ grade 2 were significantly lower in the HT group than in the 3D-CRT group (P=0.027). Two-year overall response rate was significantly higher in the HT group than in the 3D-CRT group (P=0.015). One- and 2-year OS rates were significantly higher in the HT group (95.0% and 68.7%, respectively) than in the 3D-CRT group (85.5% and 47.6%, respectively; P=0.0236). One- and 2-year PFS rates were significantly higher in the HT group (57.8% and 26.3%, respectively) than in the 3D-CRT group (32.7% and 11.4%, respectively; P=0.0351). Univariate analysis indicated that performance status (PS), T stage and radiotherapy technique were significant prognostic factors for both OS

Intensity modulated radiotherapy (IMRT) in bilateral retinoblastoma

International Nuclear Information System (INIS)

Atalar, Banu; Ozyar, Enis; Gunduz, Kaan; Gungor, Gorkem

2010-01-01

External beam radiotherapy (EBRT) for retinoblastoma has traditionally been done with conventional radiotherapy techniques which resulted high doses to the surrounding normal tissues. A 20 month-old girl with group D bilateral retinoblastoma underwent intensity modulated radiotherapy (IMRT) to both eyes after failing chemoreduction and focal therapies including cryotherapy and transpupillary thermotherapy. In this report, we discuss the use of IMRT as a method for reducing doses to adjacent normal tissues while delivering therapeutic doses to the tumour tissues compared with 3-dimensional conformal radiotherapy (3DCRT). At one year follow-up, the patient remained free of any obvious radiation complications. Image guided IMRT provides better dose distribution than 3DCRT in retinoblastoma eyes, delivering the therapeutic dose to the tumours and minimizing adjacent tissue damage

Target Coverage in Image-Guided Stereotactic Body Radiotherapy of Liver Tumors

International Nuclear Information System (INIS)

Wunderink, Wouter; Romero, Alejandra Mendez; Osorio, Eliana M. Vasquez; Boer, Hans C.J. de; Brandwijk, Rene P.; Levendag, Peter C.; Heijmen, Ben

2007-01-01

Purpose: To determine the effect of image-guided procedures (with computed tomography [CT] and electronic portal images before each treatment fraction) on target coverage in stereotactic body radiotherapy for liver patients using a stereotactic body frame (SBF) and abdominal compression. CT guidance was used to correct for day-to-day variations in the tumor's mean position in the SBF. Methods and Materials: By retrospectively evaluating 57 treatment sessions, tumor coverage, as obtained with the clinically applied CT-guided protocol, was compared with that of alternative procedures. The internal target volume-plus (ITV + ) was introduced to explicitly include uncertainties in tumor delineations resulting from CT-imaging artifacts caused by residual respiratory motion. Tumor coverage was defined as the volume overlap of the ITV + , derived from a tumor delineated in a treatment CT scan, and the planning target volume. Patient stability in the SBF, after acquisition of the treatment CT scan, was evaluated by measuring the displacement of the bony anatomy in the electronic portal images relative to CT. Results: Application of our clinical protocol (with setup corrections following from manual measurements of the distances between the contours of the planning target volume and the daily clinical target volume in three orthogonal planes, multiple two-dimensional) increased the frequency of nearly full (≥99%) ITV + coverage to 77% compared with 63% without setup correction. An automated three-dimensional method further improved the frequency to 96%. Patient displacements in the SBF were generally small (≤2 mm, 1 standard deviation), but large craniocaudal displacements (maximal 7.2 mm) were occasionally observed. Conclusion: Daily, CT-assisted patient setup may substantially improve tumor coverage, especially with the automated three-dimensional procedure. In the present treatment design, patient stability in the SBF should be verified with portal imaging

Backscattering analysis of high frequency ultrasonic imaging for ultrasound-guided breast biopsy

Science.gov (United States)

Cummins, Thomas; Akiyama, Takahiro; Lee, Changyang; Martin, Sue E.; Shung, K. Kirk

2017-03-01

A new ultrasound-guided breast biopsy technique is proposed. The technique utilizes conventional ultrasound guidance coupled with a high frequency embedded ultrasound array located within the biopsy needle to improve the accuracy in breast cancer diagnosis.1 The array within the needle is intended to be used to detect micro- calcifications indicative of early breast cancers such as ductal carcinoma in situ (DCIS). Backscattering analysis has the potential to characterize tissues to improve localization of lesions. This paper describes initial results of the application of backscattering analysis of breast biopsy tissue specimens and shows the usefulness of high frequency ultrasound for the new biopsy related technique. Ultrasound echoes of ex-vivo breast biopsy tissue specimens were acquired by using a single-element transducer with a bandwidth from 41 MHz to 88 MHz utilizing a UBM methodology, and the backscattering coefficients were calculated. These values as well as B-mode image data were mapped in 2D and matched with each pathology image for the identification of tissue type for the comparison to the pathology images corresponding to each plane. Microcalcifications were significantly distinguished from normal tissue. Adenocarcinoma was also successfully differentiated from adipose tissue. These results indicate that backscattering analysis is able to quantitatively distinguish tissues into normal and abnormal, which should help radiologists locate abnormal areas during the proposed ultrasound-guided breast biopsy with high frequency ultrasound.

In vivo optoacoustic temperature imaging for image-guided cryotherapy of prostate cancer

Science.gov (United States)

Petrova, E. V.; Brecht, H. P.; Motamedi, M.; Oraevsky, A. A.; Ermilov, S. A.

2018-03-01

The objective of this study is to demonstrate in vivo the feasibility of optoacoustic temperature imaging during cryotherapy of prostate cancer. We developed a preclinical prototype optoacoustic temperature imager that included pulsed optical excitation at a wavelength of 805 nm, a modified clinical transrectal ultrasound probe, a parallel data acquisition system, image processing and visualization software. Cryotherapy of a canine prostate was performed in vivo using a commercial clinical system, Cryocare® CS, with an integrated ultrasound imaging. The universal temperature-dependent optoacoustic response of blood was employed to convert reconstructed optoacoustic images to temperature maps. Optoacoustic imaging of temperature during prostate cryotherapy was performed in the longitudinal view over a region of 30 mm (long)  ×  10 mm (deep) that covered the rectum, the Denonvilliers fascia, and the posterior portion of the treated gland. The transrectal optoacoustic images showed high-contrast vascularized regions, which were used for quantitative estimation of local temperature profiles. The constructed temperature maps and their temporal dynamics were consistent with the arrangement of the cryoprobe and readouts of the thermal needle sensors. The temporal profiles of the readouts from the thermal needle sensors and the temporal profile estimated from the normalized optoacoustic intensity of the selected vascularized region showed significant resemblance, except for the initial overshoot, that may be explained as a result of the physiological thermoregulatory compensation. The temperature was mapped with errors not exceeding  ±2 °C (standard deviation) consistent with the clinical requirements for monitoring cryotherapy of the prostate. In vivo results showed that the optoacoustic temperature imaging is a promising non-invasive technique for real-time imaging of tissue temperature during cryotherapy of prostate cancer, which can be combined

Preoperative magnetic resonance imaging protocol for endoscopic cranial base image-guided surgery.

Science.gov (United States)

Grindle, Christopher R; Curry, Joseph M; Kang, Melissa D; Evans, James J; Rosen, Marc R

2011-01-01

Despite the increasing utilization of image-guided surgery, no radiology protocols for obtaining magnetic resonance (MR) imaging of adequate quality are available in the current literature. At our institution, more than 300 endonasal cranial base procedures including pituitary, extended pituitary, and other anterior skullbase procedures have been performed in the past 3 years. To facilitate and optimize preoperative evaluation and assessment, there was a need to develop a magnetic resonance protocol. Retrospective Technical Assessment was performed. Through a collaborative effort between the otolaryngology, neurosurgery, and neuroradiology departments at our institution, a skull base MR image-guided (IGS) protocol was developed with several ends in mind. First, it was necessary to generate diagnostic images useful for the more frequently seen pathologies to improve work flow and limit the expense and inefficiency of case specific MR studies. Second, it was necessary to generate sequences useful for IGS, preferably using sequences that best highlight that lesion. Currently, at our institution, all MR images used for IGS are obtained using this protocol as part of preoperative planning. The protocol that has been developed allows for thin cut precontrast and postcontrast axial cuts that can be used to plan intraoperative image guidance. It also obtains a thin cut T2 axial series that can be compiled separately for intraoperative imaging, or may be fused with computed tomographic images for combined modality. The outlined protocol obtains image sequences effective for diagnostic and operative purposes for image-guided surgery using both T1 and T2 sequences. Copyright © 2011 Elsevier Inc. All rights reserved.

Image-guided robotic radiosurgery for spinal metastases

International Nuclear Information System (INIS)

Gibbs, Iris C.; Kamnerdsupaphon, Pimkhuan; Ryu, Mi-Ryeong; Dodd, Robert; Kiernan, Michaela; Chang, Steven D.; Adler, John R.

2007-01-01

Background and Purpose: To determine the effectiveness and safety of image-guided robotic radiosurgery for spinal metastases. Materials/Methods: From 1996 to 2005, 74 patients with 102 spinal metastases were treated using the CyberKnife TM at Stanford University. Sixty-two (84%) patients were symptomatic. Seventy-four percent (50/68) of previously treated patients had prior radiation. Using the CyberKnife TM , 16-25 Gy in 1-5 fractions was delivered. Patients were followed clinically and radiographically for at least 3 months or until death. Results: With mean follow-up of 9 months (range 0-33 months), 36 patients were alive and 38 were dead at last follow-up. No death was treatment related. Eighty-four (84%) percent of symptomatic patients experienced improvement or resolution of symptoms after treatment. Three patients developed treatment-related spinal injury. Analysis of dose-volume parameters and clinical parameters failed to identify predictors of spinal cord injury. Conclusions: Robotic radiosurgery is effective and generally safe for spinal metastases even in previously irradiated patients

Implementation of an image guided intensity-modulated protocol for post-prostatectomy radiotherapy: planning data and acute toxicity outcomes

International Nuclear Information System (INIS)

Chua, Benjamin; Min, Myo; Wood, Maree; Edwards, Sarah; Hoffmann, Matthew; Greenham, Stuart; Kovendy, Andrew; McKay, Michael J.; Shakespeare, Thomas P.

2013-01-01

There is substantial interest in implementation of image-guided intensity-modulated radiotherapy (IG-IMRT) in the post-prostatectomy setting. We describe our implementation of IG-IMRT, and examine how often published organ-at-risk (OAR) constraints were met. Furthermore, we evaluate the incidence of acute genitourinary and gastrointestinal toxicities when patients were treated according to our protocol. Patients were eligible if they received post-prostatectomy radiotherapy (PPRT). Planning data were collected prospectively, and toxicity assessments were collected before, during and after treatment. Seventy-five eligible patients received either 64Gy (19%) or 66Gy (81%) in a single phase to the prostate bed. Suggested rectal dose-constraints of V40Gy<60% and V60Gy<40% were met in 64 (85%) and 75 (100%) patients, respectively. IMRT-specific rectal dose-constraints of V40Gy<35% and V65Gy<17% were achieved in 5 (7%) and 57 (76%) of patients. Bladder dose-constraint (V50Gy<50%) was met in 58 (77%) patients. Two patients (3%) experienced new grade 3 genitourinary toxicity and one patient (1%) experienced new grade 3 gastrointestinal toxicity. All grade 3 toxicities had improved by 3-month review. Overall deterioration in urinary and gastrointestinal symptoms occurred in 33 (44%) and 35 (47%) of patients respectively. We report on our implementation of PPRT which takes into account nationally adopted guidelines, with a margin reduction supported by use of daily image guidance. Non-IMRT OAR constraints were met in most cases. IMRT-specific constraints were less often achieved despite margin reductions, suggesting the need for review of guidelines. Severe toxicity was rare, and most patients did not experience deterioration in urinary or bowel function attributable to radiotherapy.

Phantom evaluation of a commercially available three modality image guided radiation therapy system

International Nuclear Information System (INIS)

Ploquin, Nicolas; Rangel, Alejandra; Dunscombe, Peter

2008-01-01

The authors describe a detailed evaluation of the capabilities of imaging and image registration systems available with Varian linear accelerators for image guided radiation therapy (IGRT). Specifically, they present modulation transfer function curves for megavoltage planar, kilovoltage (kV) planar, and cone beam computed tomography imaging systems and compare these with conventional computed tomography. While kV planar imaging displayed the highest spatial resolution, all IGRT imaging techniques were assessed as adequate for their intended purpose. They have also characterized the image registration software available for use in conjunction with these imaging systems through a comprehensive phantom study involving translations in three orthogonal directions. All combinations of imaging systems and image registration software were found to be accurate, although the planar kV imaging system with automatic registration was generally superior, with both accuracy and precision of the order of 1 mm, under the conditions tested. Based on their phantom study, the attainable accuracy for rigid body translations using any of the features available with Varian equipment will more likely be limited by the resolution of the couch readouts than by inherent limitations in the imaging systems and image registration software. Overall, the accuracy and precision of currently available IGRT technology exceed published experience with the accuracy and precision of contouring for planning.

Image-Guided Robotic Stereotactic Body Radiation Therapy for Liver Metastases: Is There a Dose Response Relationship?

International Nuclear Information System (INIS)

Vautravers-Dewas, Claire; Dewas, Sylvain; Bonodeau, Francois; Adenis, Antoine; Lacornerie, Thomas; Penel, Nicolas; Lartigau, Eric; Mirabel, Xavier

2011-01-01

Purpose: To evaluate the outcome, tolerance, and toxicity of stereotactic body radiotherapy, using image-guided robotic radiation delivery, for the treatment of patients with unresectable liver metastases. Methods and Material: Patients were treated with real-time respiratory tracking between July 2007 and April 2009. Their records were retrospectively reviewed. Metastases from colorectal carcinoma and other primaries were not necessarily confined to liver. Toxicity was evaluated using National Cancer Institute Common Criteria for Adverse Events version 3.0. Results: Forty-two patients with 62 metastases were treated with two dose levels of 40 Gy in four Dose per Fraction (23) and 45 Gy in three Dose per Fraction (13). Median follow-up was 14.3 months (range, 3-23 months). Actuarial local control for 1 and 2 years was 90% and 86%, respectively. At last follow-up, 41 (66%) complete responses and eight (13%) partial responses were observed. Five lesions were stable. Nine lesions (13%) were locally progressed. Overall survival was 94% at 1 year and 48% at 2 years. The most common toxicity was Grade 1 or 2 nausea. One patient experienced Grade 3 epidermitis. The dose level did not significantly contribute to the outcome, toxicity, or survival. Conclusion: Image-guided robotic stereotactic body radiation therapy is feasible, safe, and effective, with encouraging local control. It provides a strong alternative for patients who cannot undergo surgery.

Effect of rectal enema on intrafraction prostate movement during image-guided radiotherapy.

Science.gov (United States)

Choi, Youngmin; Kwak, Dong-Won; Lee, Hyung-Sik; Hur, Won-Joo; Cho, Won-Yeol; Sung, Gyung Tak; Kim, Tae-Hyo; Kim, Soo-Dong; Yun, Seong-Guk

2015-04-01

Rectal volume and movement are major factors that influence prostate location. The aim of this study was to assess the effect of a rectal enema on intrafraction prostate motion. The data from 12 patients with localised prostate cancer were analysed. Each patient underwent image-guided radiotherapy (RT), receiving a total dose of 70 Gy in 28 fractions. Rectal enemas were administered to all of the patients before each RT fraction. The location of the prostate was determined by implanting three fiducial markers under the guidance of transrectal ultrasound. Each patient underwent preparation for IGRT twice before an RT fraction and in the middle of the fraction. The intrafraction displacement of the prostate was calculated by comparing fiducial marker locations before and in the middle of an RT fraction. The rectal enemas were well tolerated by patients. The mean intrafraction prostate movement in 336 RT fractions was 1.11 ± 0.77 mm (range 0.08-7.20 mm). Intrafraction motions of 1, 2 and 3 mm were observed in 56.0%, 89.0% and 97.6% of all RT fractions, respectively. The intrafraction movements on supero-inferior and anteroposterior axes were larger than on the right-to-left axes (P movement, calculated using the van Herk formula (2.5Σ + 0.7σ), was 1.50 mm. A daily rectal enema before each RT fraction was tolerable and yielded little intrafraction prostate displacement. We think the use of rectal enemas is a feasible method to reduce prostate movement during RT. © 2014 The Royal Australian and New Zealand College of Radiologists.

Effect of rectal enema on intrafraction prostate movement during image-guided radiotherapy

International Nuclear Information System (INIS)

Choi, Youngmin; Kwak, Dong-Won; Lee, Hyung-Sik; Hur, Won-Jooh; Cho, Won-Yeol; Sung, Gyung Tak; Kim, Tae-Hyo; Kim, Soo-Dong; Yun, Seong-Guk

2015-01-01

Rectal volume and movement are major factors that influence prostate location. The aim of this study was to assess the effect of a rectal enema on intrafraction prostate motion. The data from 12 patients with localised prostate cancer were analysed. Each patient underwent image-guided radiotherapy (RT), receiving a total dose of 70 Gy in 28 fractions. Rectal enemas were administered to all of the patients before each RT fraction. The location of the prostate was determined by implanting three fiducial markers under the guidance of transrectal ultrasound. Each patient underwent preparation for IGRT twice before an RT fraction and in the middle of the fraction. The intrafraction displacement of the prostate was calculated by comparing fiducial marker locations before and in the middle of an RT fraction. The rectal enemas were well tolerated by patients. The mean intrafraction prostate movement in 336 RT fractions was 1.11 ± 0.77 mm (range 0.08–7.20 mm). Intrafraction motions of 1, 2 and 3 mm were observed in 56.0%, 89.0% and 97.6% of all RT fractions, respectively. The intrafraction movements on supero-inferior and anteroposterior axes were larger than on the right-to-left axes (P < 0.05). The CTV-to-PTV margin necessary to allow for movement, calculated using the van Herk formula (2.5Σ + 0.7σ), was 1.50 mm. A daily rectal enema before each RT fraction was tolerable and yielded little intrafraction prostate displacement. We think the use of rectal enemas is a feasible method to reduce prostate movement during RT.

Leptomeningeal high signal intensity (ivy sign) on fluid-attenuated inversion-recovery (FLAIR) MR images in moyamoya disease

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, Hirokazu [Department of Diagnostic Radiology, School of Medicine, Keio University, Tokyo 1608582 (Japan)]. E-mail: hirokazu_fujiwara@ybb.ne.jp; Momoshima, Suketaka [Department of Diagnostic Radiology, School of Medicine, Keio University, Tokyo 1608582 (Japan); Kuribayashi, Sachio [Department of Diagnostic Radiology, School of Medicine, Keio University, Tokyo 1608582 (Japan)

2005-08-01

Purpose: There are a few reports on leptomeningeal high signal intensity (LMHI: ivy sign) on fluid-attenuated inversion-recovery (FLAIR) images in moyamoya disease, but the feature of this finding has not been completely understood. The purpose of this study was to characterize LMHI on FLAIR images in moyamoya disease and to assess usefulness of this finding in the diagnosis of moyamoya disease in conventional MR imaging. Material and methods: MR imaging of 28 patients with moyamoya disease was retrospectively reviewed. The grade of LMHI on FLAIR images was classified as 'absent,' 'minimal,' 'moderate' and 'marked.' Fifty-four hemispheres of 28 patients (2 patients had unilateral disease) were assessed for the frequency of visualization and distribution of LMHI. The correlations between LMHI on FLAIR images, moyamoya vessels on T1- and T2-weighted images and MR angiography findings were also analyzed. Results: Moderate and marked LMHI was seen in 31 out of 54 hemispheres (57%). LMHI was seen more prominently in the frontal and parietal lobes than in the temporal and occipital lobes. Although there was a tendency for LMHI on FLAIR images to be prominent in groups with moderate and marked moyamoya vessels on T1- and T2-weighted images, there was no significant correlation. More prominent LMHI was observed in the hemispheres in which cortical branches of the middle cerebral arteries were poorly visualized on MR angiography. Conclusion: Leptomeningeal high signal intensity (ivy sign) on FLAIR images is predominantly seen in the frontal and parietal lobes. Because this sign can be seen in patients with unremarkable moyamoya vessels, LMHI is a useful sign in conventional MR imaging for the diagnosis of moyamoya disease.

Imaging in hematology. Part 1: Ultrasonography and conventional radiology

International Nuclear Information System (INIS)

Zhechev, Y.

2003-01-01

Applications of conventional ultrasonography techniques (B-mode or real time) in oncohematology are presented. The newer adaptations (in particular colour Doppler) provide incremental advantages that support their inclusion in the imaging techniques available to modern hematology. Conventional radiologic studies include chest and bone X-ray, gastrointestinal contrast examination and bipedal lymphangiography

Fractional flow reserve versus angiography for guiding percutaneous coronary intervention

DEFF Research Database (Denmark)

Tonino, Pim A L; De Bruyne, Bernard; Pijls, Nico H J

2009-01-01

of maximal blood flow in a stenotic artery to normal maximal flow), in addition to angiography, improves outcomes. METHODS: In 20 medical centers in the United States and Europe, we randomly assigned 1005 patients with multivessel coronary artery disease to undergo PCI with implantation of drug......BACKGROUND: In patients with multivessel coronary artery disease who are undergoing percutaneous coronary intervention (PCI), coronary angiography is the standard method for guiding the placement of the stent. It is unclear whether routine measurement of fractional flow reserve (FFR; the ratio...

Accelerated Fractional Ventilation Imaging with Hyperpolarized Gas MRI

Science.gov (United States)

Emami, Kiarash; Xu, Yinan; Hamedani, Hooman; Profka, Harrilla; Kadlecek, Stephen; Xin, Yi; Ishii, Masaru; Rizi, Rahim R.

2013-01-01

PURPOSE To investigate the utility of accelerated imaging to enhance multi-breath fractional ventilation (r) measurement accuracy using HP gas MRI. Undersampling shortens the breath-hold time, thereby reducing the O2-induced signal decay and allows subjects to maintain a more physiologically relevant breathing pattern. Additionally it may improve r estimation accuracy by reducing RF destruction of HP gas. METHODS Image acceleration was achieved by using an 8-channel phased array coil. Undersampled image acquisition was simulated in a series of ventilation images and images were reconstructed for various matrix sizes (48–128) using GRAPPA. Parallel accelerated r imaging was also performed on five mechanically ventilated pigs. RESULTS Optimal acceleration factor was fairly invariable (2.0–2.2×) over the range of simulated resolutions. Estimation accuracy progressively improved with higher resolutions (39–51% error reduction). In vivo r values were not significantly different between the two methods: 0.27±0.09, 0.35±0.06, 0.40±0.04 (standard) versus 0.23±0.05, 0.34±0.03, 0.37±0.02 (accelerated); for anterior, medial and posterior slices, respectively, whereas the corresponding vertical r gradients were significant (P fractional ventilation measurement with HP gas MRI. PMID:23400938

Gamma Imaging-Guided Minimally Invasive Breast Biopsy: Initial Clinical Experience.

Science.gov (United States)

Brem, Rachel F; Mehta, Anita K; Rapelyea, Jocelyn A; Akin, Esma A; Bazoberry, Adriana M; Velasco, Christel D

2018-03-01

The purpose of this study was to evaluate our initial experience with gamma imaging-guided vacuum-assisted breast biopsy in women with abnormal findings. A retrospective review of patients undergoing breast-specific gamma imaging (BSGI), also known as molecular breast imaging (MBI), between April 2011 and October 2015 found 117 nonpalpable mammographically and sonographically occult lesions for which gamma imaging-guided biopsies were recommended. Biopsy was performed with a 9-gauge vacuum-assisted device with subsequent placement of a titanium biopsy site marker. Medical records and pathologic findings were evaluated. Of the 117 biopsies recommended, 104 were successful and 13 were canceled. Of the 104 performed biopsies, 32 (30.8%) had abnormal pathologic findings. Of those 32 biopsies, nine (28.1%) found invasive cancers, six (18.8%) found ductal carcinoma in situ (DCIS), and 17 (53.1%) found high-risk lesions. Of the 17 high-risk lesions, there were three (17.6%) lobular carcinomas in situ, five (29.4%) atypical ductal hyperplasias, two (11.8%) atypical lobular hyperplasias, one (5.9%) flat epithelial atypia, and six (35.3%) papillomas. Two cases of atypical ductal hyperplasia were upgraded to DCIS at surgery. The overall cancer detection rate for gamma imaging-guided biopsy was 16.3%. In this study, gamma imaging-guided biopsy had a positive predictive value of total successful biopsies of 16.3% for cancer and 30.8% for cancer and high-risk lesions. Gamma imaging-guided biopsy is a viable approach to sampling BSGI-MBI-detected lesions without sonographic or mammographic correlate. Our results compare favorably to those reported for MRI-guided biopsy.

MR imaging-guided cryoablation of metastatic brain tumours: initial experience in six patients

International Nuclear Information System (INIS)

Li, Chengli; Wu, Lebin; Song, Jiqing; Liu, Ming; Lv, Yubo; Sequeiros, Roberto Blanco

2010-01-01

The objective was to evaluate the initial experience and safety of magnetic resonance imaging (MRI)-guided transcranial cryoablation in cystic metastatic brain tumours. Seven cystic metastatic brain tumours in six patients were treated with cryoablation. The approval from the local ethics committee and individual patient consent were acquired before the study. Before the procedure the tumours were detected with conventional CT or MRI. The procedure was performed under local anaesthesia and conscious sedation. A 0.23-T open MRI system with optical tracking was used for procedural planning, instrument guidance and procedural monitoring of the ice ball formation. An MR-compatible, argon-based cryoablation system was used. The schedule of follow-up imaging ranged from 12 days to 12 months. Seven treatment sessions were performed. All the cryoprobes were successfully inserted into the target with one pass. All the patients tolerated the procedure well without experiencing any neurological deficits during the treatment phase or during the immediate post-treatment period. One patient died 12 days after cryoablation. MR-guided and monitored metastasis brain tumour cryoablation is technically feasible and may represent an alternative treatment in selected patients. (orig.)

A Single-Institution Experience in Percutaneous Image-Guided Biopsy of Malignant Pleural Mesothelioma

International Nuclear Information System (INIS)

Welch, B. T.; Eiken, P. W.; Atwell, T. D.; Peikert, T.; Yi, E. S.; Nichols, F.; Schmit, G. D.

2017-01-01

PurposeMesothelioma has been considered a difficult pathologic diagnosis to achieve via image-guided core needle biopsy. The purpose of this study was to assess the diagnostic sensitivity of percutaneous image-guided biopsy for diagnosis of pleural mesothelioma.Materials and MethodsRetrospective review was performed to identify patients with a confirmed diagnosis of pleural mesothelioma and who underwent image-guided needle biopsy between January 1, 2002, and January 1, 2016. Thirty-two patients with pleural mesothelioma were identified and included for analysis in 33 image-guided biopsy procedures. Patient, procedural, and pathologic characteristics were recorded. Complications were characterized via standardized nomenclature [Common Terminology for Clinically Adverse Events (CTCAE)].ResultsPercutaneous image-guided biopsy was associated with an overall sensitivity of 81%. No CTCAE clinically significant complications were observed. No image-guided procedures were complicated by pneumothorax or necessitated chest tube placement. No patients had tumor seeding of the biopsy tract.ConclusionPercutaneous image-guided biopsy can achieve high sensitivity for pathologic diagnosis of pleural mesothelioma with a low procedural complication rate, potentially obviating need for surgical biopsy.

A Single-Institution Experience in Percutaneous Image-Guided Biopsy of Malignant Pleural Mesothelioma

Energy Technology Data Exchange (ETDEWEB)

Welch, B. T., E-mail: Welch.brian@mayo.edu; Eiken, P. W.; Atwell, T. D. [Mayo Clinic, Department of Radiology (United States); Peikert, T. [Mayo Clinic, Department of Pulmonary and Critical Care Medicine (United States); Yi, E. S. [Mayo Clinic, Department of Pathology (United States); Nichols, F. [Mayo Clinic, Department of Thoracic Surgery (United States); Schmit, G. D. [Mayo Clinic, Department of Radiology (United States)

2017-06-15

PurposeMesothelioma has been considered a difficult pathologic diagnosis to achieve via image-guided core needle biopsy. The purpose of this study was to assess the diagnostic sensitivity of percutaneous image-guided biopsy for diagnosis of pleural mesothelioma.Materials and MethodsRetrospective review was performed to identify patients with a confirmed diagnosis of pleural mesothelioma and who underwent image-guided needle biopsy between January 1, 2002, and January 1, 2016. Thirty-two patients with pleural mesothelioma were identified and included for analysis in 33 image-guided biopsy procedures. Patient, procedural, and pathologic characteristics were recorded. Complications were characterized via standardized nomenclature [Common Terminology for Clinically Adverse Events (CTCAE)].ResultsPercutaneous image-guided biopsy was associated with an overall sensitivity of 81%. No CTCAE clinically significant complications were observed. No image-guided procedures were complicated by pneumothorax or necessitated chest tube placement. No patients had tumor seeding of the biopsy tract.ConclusionPercutaneous image-guided biopsy can achieve high sensitivity for pathologic diagnosis of pleural mesothelioma with a low procedural complication rate, potentially obviating need for surgical biopsy.

Physics Potential of Very Intense Conventional Neutrino Beams

CERN Document Server

Gómez-Cadenas, J J; Burguet-Castell, J; Casper, David William; DOnega, M; Gilardoni, S S; Hernández, Pilar; Mezzetto, Mauro

2001-01-01

The physics potential of high intensity conventional beams is explored. We consider a low energy super beam which could be produced by a proposed new accelerator at CERN, the Super Proton Linac. Water Cherenkov and liquid oil scintillator detectors are studied as possible candidates for a neutrino oscillation experiment which could improve our current knowledge of the atmospheric parameters and measure or severely constrain the parameter connecting the atmospheric and solar realms. It is also shown that a very large water detector could eventually observe leptonic CP violation. The reach of such an experiment to the neutrino mixing parameters would lie in-between the next generation of neutrino experiments (MINOS, OPERA, etc) and a future neutrino factory.

The establishment of Digital Image Capture System(DICS) using conventional simulator

International Nuclear Information System (INIS)

Oh, Tae Sung; Park, Jong Il; Byun, Young Sik; Shin, Hyun Kyoh

2004-01-01

The simulator is used to determine patient field and ensure the treatment field, which encompasses the required anatomy during patient normal movement such as during breathing. The latest simulator provide real time display of still, fluoroscopic and digitalized image, but conventional simulator is not yet. The purpose of this study is to introduce digital image capture system(DICS) using conventional simulator and clinical case using digital captured still and fluoroscopic image. We connect the video signal cable to the video terminal in the back up of simulator monitor, and connect the video jack to the A/D converter. After connection between the converter jack and computer, We can acquire still image and record fluoroscopic image with operating image capture program. The data created with this system can be used in patient treatment, and modified for verification by using image processing software. (j.e. photoshop, paintshop) DICS was able to establish easy and economical procedure. DCIS image was helpful for simulation. DICS imaging was powerful tool in the evaluation of the department specific patient positioning. Because the commercialized simulator based of digital capture is very expensive, it is not easily to establish DICS simulator in the most hospital. DICS using conventional simulator enable to utilize the practical use of image equal to high cost digitalized simulator and to research many clinical cases in case of using other software program.

Dose to radiation therapists from activation at high-energy accelerators used for conventional and intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Rawlinson, J. Alan; Islam, Mohammad K.; Galbraith, Duncan M.

2002-01-01

The increased beam-on times which characterize intensity-modulated radiation therapy (IMRT) could lead to an increase in the dose received by radiation therapists due to induced activity. To examine this, gamma ray spectrometry was used to identify the major isotopes responsible for activation at a representative location in the treatment room of an 18 MV accelerator (Varian Clinac 21EX). These were found to be 28 Al, 56 Mn, and 24 Na. The decay of the dose rate measured at this location following irradiation was analyzed in terms of the known half-lives to yield saturation dose rates of 9.6, 12.4, and 6.2 μSv/h, respectively. A formalism was developed to estimate activation dose (μSv/week) due to successive patient irradiation cycles, characterized by the number of 18 MV fractions per week, F, the number of MU per fraction, M, the in-room time between fractions, t d (min), and the treatment delivery time t r ' (min). The results are represented by the sum of two formulas, one for the dose from 28 Al≅1.8x10 -3 F M (1-e -0.3t r ' )/t r ' and one for the dose from the other isotopes ≅1.1x10 -6 F 1.7 Mt d . For conventional therapy doses are about 60 μ Sv/week for an 18 MV workload of 60 000 MU/week. Irradiation for QA purposes can significantly increase the dose. For IMRT as currently practiced, lengthy treatment delivery times limit the number of fractions that can be delivered per week and hence limit the dose to values similar to those in conventional therapy. However for an IMRT regime designed to maximize patient throughput, doses up to 330 μSv/week could be expected. To reduce dose it is recommended that IMRT treatments should be delivered at energies lower than 18 MV, that in multienergy IMRT, high-energy treatments should be scheduled in the latter part of the day, and that equipment manufacturers should strive to minimize activation in the design of high-energy accelerators

Image guided versus palpation guided core needle biopsy of palpable breast masses: a prospective study

Directory of Open Access Journals (Sweden)

Smriti Hari

2016-01-01

Interpretation & conclusions: Our results showed that in palpable breast masses, image guided biopsy was superior to palpation guided biopsy in terms of sensitivity, false negative rate and repeat biopsy rates.

Large-field image intensifiers versus conventional chest radiography: ROC study with simulated interstitial disease

International Nuclear Information System (INIS)

Winter, L.H.L.; Chakraborty, D.P.; Waes, P.F.G.M.

1988-01-01

Two image intensifier tubes have recently been introduced whose large imaging area makes them suitable for chest imaging (Phillips Pulmodiagnost TLX slit II and Siemens TX 57 large entrance field II). Both modalities present a 10 x 10-cm hard copy image to the radiologist. A receiver operating characteristic (ROC) curve study with simulated interstitial disease was performed to compare the image quality of these image intensifiers with conventional chest images. The relative ranking in terms of decreasing ROC areas was Siemens, conventional, and Philips. Compared with conventional imaging, none of the differences in ROC curve area were statistically significant at the 5% level

Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation

International Nuclear Information System (INIS)

Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Wong, John; Iordachita, Iulian; Siewerdsen, Jeffrey

2015-01-01

The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal (‘tubular’ geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal (‘pancake’ geometry). The small animal radiation research platform developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Not withstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e. pancake and tubular geometry

Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation.

Science.gov (United States)

Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

2015-07-07

The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal ('tubular' geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal ('pancake' geometry). The small animal radiation research platform developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Not withstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e. pancake and tubular geometry, respectively.

Hypofractionated Prostate Radiotherapy with or without Conventionally Fractionated Nodal Irradiation: Clinical Toxicity Observations and Retrospective Daily Dosimetry.

Science.gov (United States)

McDonald, Andrew M; Bishop, Justin M; Jacob, Rojymon; Dobelbower, Michael C; Kim, Robert Y; Yang, Eddy S; Smith, Heather; Wu, Xingen; Fiveash, John B

2012-01-01

Purpose. To evaluate toxicity associated with the addition of elective nodal irradiation (ENI) to a hypofractionated regimen for the treatment of prostate cancer. Methods and Materials. Fifty-seven patients received pelvic image-guided IMRT to 50.4 Gy in 28 fractions with a hypofractionated simultaneous boost to the prostate to 70 Gy. Thirty-one patients received prostate-only treatment to 70 Gy in 28 fractions. Results. Median followup was 41.1 months. Early grade ≥2 urinary toxicity rates were 49% (28 of 57) for patients receiving ENI and 58% (18 of 31) for those not (P = 0.61). Early grade ≥2 rectal toxicity rates were 40% (23 of 57) and 23% (7 of 31), respectively (P = 0.09). The addition of ENI resulted in a 21% actuarial rate of late grade ≥2 rectal toxicity at 4 years, compared to 0% for patients treated to the prostate only (P = 0.02). Retrospective daily dosimetry of patients experiencing late rectal toxicity revealed an average increase of 2.67% of the rectal volume receiving 70 Gy compared to the original plan. Conclusions. The addition of ENI resulted in an increased risk of late rectal toxicity. Grade ≥2 late rectal toxicity was associated with worse daily rectal dosimetry compared to the treatment plan.

Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation

Directory of Open Access Journals (Sweden)

Terrence T. Kim

2016-01-01

Full Text Available We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy.

Diffusion-weighted MR imaging in biopsy-proven Creutzfeldt-Jakob disease

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyo Cheol; Chang, Kee Hyun; Song In Chan; Lee, Sang Hyun; Kwon, Bae Ju; Han, Moon Hee; Kim, Sang Yun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

2001-12-01

To compare conventional and diffusion-weighted MR imaging in terms of their depiction of the abnormalities occurring in Creutzfeldt-Jakob disease. We retrospectively analyzed the findings of conventional (T2-weighted and fluid-attenuated inversion recovery) and diffusion-weighted MR imaging in four patients with biopsy-proven Creutzfeldt-Jakob disease. The signal intensity of the lesion was classified by visual assessment as markedly high, slightly high, or isointense, relative to normal brain parenchyma. Both conventional and diffusion-weighted MR images demonstrated bilateral high signal intensity in the basal ganglia in all four patients. Cortical lesions were observed on diffusion-weighted MR images in all four, and on fluidattenuated inversion recovery MR images in one, but in no patient on T2-weighted images. Conventional MR images showed slightly high signal intensity in all lesions, while diffusion-weighted images showed markedly high signal intensity in most. Diffusion-weighted MR imaging is more sensitive than its conventional counterpart in the depiction of Creutzfeldt-Jakob disease, and permits better detection of the lesion in both the cerebral cortices and basal ganglia.

Diffusion-weighted MR imaging in biopsy-proven Creutzfeldt-Jakob disease

International Nuclear Information System (INIS)

Kim, Hyo Cheol; Chang, Kee Hyun; Song In Chan; Lee, Sang Hyun; Kwon, Bae Ju; Han, Moon Hee; Kim, Sang Yun

2001-01-01

To compare conventional and diffusion-weighted MR imaging in terms of their depiction of the abnormalities occurring in Creutzfeldt-Jakob disease. We retrospectively analyzed the findings of conventional (T2-weighted and fluid-attenuated inversion recovery) and diffusion-weighted MR imaging in four patients with biopsy-proven Creutzfeldt-Jakob disease. The signal intensity of the lesion was classified by visual assessment as markedly high, slightly high, or isointense, relative to normal brain parenchyma. Both conventional and diffusion-weighted MR images demonstrated bilateral high signal intensity in the basal ganglia in all four patients. Cortical lesions were observed on diffusion-weighted MR images in all four, and on fluidattenuated inversion recovery MR images in one, but in no patient on T2-weighted images. Conventional MR images showed slightly high signal intensity in all lesions, while diffusion-weighted images showed markedly high signal intensity in most. Diffusion-weighted MR imaging is more sensitive than its conventional counterpart in the depiction of Creutzfeldt-Jakob disease, and permits better detection of the lesion in both the cerebral cortices and basal ganglia

Endovascular image-guided interventions (EIGIs)

International Nuclear Information System (INIS)

Rudin, Stephen; Bednarek, Daniel R.; Hoffmann, Kenneth R.

2008-01-01

Minimally invasive interventions are rapidly replacing invasive surgical procedures for the most prevalent human disease conditions. X-ray image-guided interventions carried out using the insertion and navigation of catheters through the vasculature are increasing in number and sophistication. In this article, we offer our vision for the future of this dynamic field of endovascular image-guided interventions in the form of predictions about (1) improvements in high-resolution detectors for more accurate guidance, (2) the implementation of high-resolution region of interest computed tomography for evaluation and planning, (3) the implementation of dose tracking systems to control patient radiation risk, (4) the development of increasingly sophisticated interventional devices, (5) the use of quantitative treatment planning with patient-specific computer fluid dynamic simulations, and (6) the new expanding role of the medical physicist. We discuss how we envision our predictions will come to fruition and result in the universal goal of improved patient care.

Bioactivity-guided fractionation for anti-inflammatory and analgesic properties and constituents of Xanthium strumarium L.

Science.gov (United States)

Han, T; Li, H-L; Zhang, Q-Y; Han, P; Zheng, H-C; Rahman, K; Qin, L-P

2007-12-01

The aim of this study was to fractionate an extract of Xanthium strumarium L. (EXS) and to investigate the anti-inflammatory and analgesic properties of the extract and its fractions. The ethanol extract of X. strumarium (EXS) was fractionated on the basis of polarity. Among the different fractions, the n-butanol fraction showed the highest anti-inflammatory activity in the croton-oil-induced ear edema test and furthermore reduced the number of writhings induced by acetic acid in mice in a dose-dependent manner. This indicates that the n-butanol fraction of X. strumarium possesses potent analgesic effects which are likely to be mediated by its anti-inflammatory activity. Bioassay-guided fractionation of EXS led to the isolation and identification of ten caffeoylquinic acids and three heterocyclics by HPLC-DAD-MS(n) from the active n-butanol fraction, implying that the active compounds are polar in nature. The isolated caffeoylquinic acids could partially explain the antinociceptive effect of X. strumarium polar extract.

4D radiobiological modelling of the interplay effect in conventionally and hypofractionated lung tumour IMRT.

Science.gov (United States)

Selvaraj, J; Uzan, J; Baker, C; Nahum, A

2015-01-01

To study the impact of the interplay between respiration-induced tumour motion and multileaf collimator leaf movements in intensity-modulated radiotherapy (IMRT) as a function of number of fractions, dose rate on population mean tumour control probability ([Formula: see text]) using an in-house developed dose model. Delivered dose was accumulated in a voxel-by-voxel basis inclusive of tumour motion over the course of treatment. The effect of interplay on dose and [Formula: see text] was studied for conventionally and hypofractionated treatments using digital imaging and communications in medicine data sets. Moreover, the effect of dose rate on interplay was also studied for single-fraction treatments. Simulations were repeated several times to obtain [Formula: see text] for each plan. The average variation observed in mean dose to the target volumes were -0.76% ± 0.36% for the 20-fraction treatment and -0.26% ± 0.68% and -1.05% ± 0.98% for the three- and single-fraction treatments, respectively. For the 20-fraction treatment, the drop in [Formula: see text] was -1.05% ± 0.39%, whereas for the three- and single-fraction treatments, it was -2.80% ± 1.68% and -4.00% ± 2.84%, respectively. By reducing the dose rate from 600 to 300 MU min(-1) for the single-fraction treatments, the drop in [Formula: see text] was reduced by approximately 1.5%. The effect of interplay on [Formula: see text] is negligible for conventionally fractionated treatments, whereas considerable drop in [Formula: see text] is observed for the three- and single-fraction treatments. Reduced dose rate could be used in hypofractionated treatments to reduce the interplay effect. A novel in silico dose model is presented to determine the impact of interplay effect in IMRT treatments on [Formula: see text].

Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

International Nuclear Information System (INIS)

Siewerdsen, Jeffrey H.

2011-01-01

The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions-for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical

Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

Energy Technology Data Exchange (ETDEWEB)

Siewerdsen, Jeffrey H., E-mail: jeff.siewerdsen@jhu.edu [Department of Biomedical Engineering, Johns Hopkins University, Traylor Building, Room 718, 720 Rutland Avenue, Baltimore, MD 21205 (United States)

2011-08-21

The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions-for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical

Intravoxel Incoherent Motion Diffusion Weighted MR Imaging for Monitoring the Instantly Therapeutic Efficacy of Radiofrequency Ablation in Rabbit VX2 Tumors without Evident Links between Conventional Perfusion Weighted Images.

Directory of Open Access Journals (Sweden)

Ziyi Guo

Full Text Available To investigate the intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI as a potential valuable marker to monitor the therapy responses of VX2 to radiofrequency ablation (RF Ablation.The institutional animal care and use committee approved this study. In 10 VX2 tumor-bearing rabbits, IVIM-DWI examinations were performed with a 3.0T imaging unit by using 16 b values from 0 to 800 sec/mm2. The true diffusion coefficient (D, pseudodiffusion coefficient (D* and perfusion fraction (f of tumors were compared between before and instantly after RF Ablation treatment. The differences of D, D* and f and conventional perfusion parameters (from perfusion CT and dynamic enhanced magnetic resonance imaging, DCE-MRI in the coagulation necrosis area, residual unablated area, untreated area, and normal control had been calculated by compared t-test. The correlation between f or D* with perfusion weighted CT including blood flow, BF (milliliter per 100 mL/min, blood volume, BV (milliliter per 100 mL/min, and capillary permeability-surface area, PMB (as a fraction or from DCE-MRI: transfer constant (Ktrans, extra-vascular extra-cellular volume fraction (Ve and reflux constant (Kep values had been analyzed by region-of-interest (ROI methods to calculate Pearson's correlation coefficients.In the ablated necrosis areas, f and D* significantly decreased and D significantly increased, compared with residual unblazed areas or untreated control groups and normal control groups (P < 0.001. The IVIM-DWI derived f parameters showed significant increases in the residual unablated tumor area. There was no significant correlations between f or D* and conventional perfusion parameters.The IVIM-DW derived f, D and D* parameters have the potential to indicate therapy response immediately after RF Ablation treatment, while no significant correlations with classical tumor perfusion metrics were derived from DCE-MRI and perfusion-CT measurements.

Late Side Effects After Image Guided Intensity Modulated Radiation Therapy Compared to 3D-Conformal Radiation Therapy for Prostate Cancer: Results From 2 Prospective Cohorts

Energy Technology Data Exchange (ETDEWEB)

Wortel, Ruud C.; Incrocci, Luca [Department of Radiation Oncology, Erasmus Medical Center Cancer Institute, Rotterdam (Netherlands); Pos, Floris J.; Heide, Uulke A. van der; Lebesque, Joos V. [Department of Radiation Oncology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Aluwini, Shafak [Department of Radiation Oncology, Erasmus Medical Center Cancer Institute, Rotterdam (Netherlands); Witte, Marnix G. [Department of Radiation Oncology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Heemsbergen, Wilma D., E-mail: w.heemsbergen@nki.nl [Department of Radiation Oncology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

2016-06-01

Purpose: Technical developments in the field of external beam radiation therapy (RT) enabled the clinical introduction of image guided intensity modulated radiation therapy (IG-IMRT), which improved target conformity and allowed reduction of safety margins. Whether this had an impact on late toxicity levels compared to previously applied three-dimensional conformal radiation therapy (3D-CRT) is currently unknown. We analyzed late side effects after treatment with IG-IMRT or 3D-CRT, evaluating 2 prospective cohorts of men treated for localized prostate cancer to investigate the hypothesized reductions in toxicity. Methods and Materials: Patients treated with 3D-CRT (n=189) or IG-IMRT (n=242) to 78 Gy in 39 fractions were recruited from 2 Dutch randomized trials with identical toxicity scoring protocols. Late toxicity (>90 days after treatment) was derived from self-assessment questionnaires and case report forms, according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG-EORTC) scoring criteria. Grade ≥2 endpoints included gastrointestinal (GI) rectal bleeding, increased stool frequency, discomfort, rectal incontinence, proctitis, and genitourinary (GU) obstruction, increased urinary frequency, nocturia, urinary incontinence, and dysuria. The Cox proportional hazards regression model was used to compare grade ≥2 toxicities between both techniques, adjusting for other modifying factors. Results: The 5-year cumulative incidence of grade ≥2 GI toxicity was 24.9% for IG-IMRT and 37.6% following 3D-CRT (adjusted hazard ratio [HR]: 0.59, P=.005), with significant reductions in proctitis (HR: 0.37, P=.047) and increased stool frequency (HR: 0.23, P<.001). GU grade ≥2 toxicity levels at 5 years were comparable with 46.2% and 36.4% following IG-IMRT and 3D-CRT, respectively (adjusted HR: 1.19, P=.33). Other strong predictors (P<.01) of grade ≥2 late toxicity were baseline complaints, acute toxicity, and age

Late Side Effects After Image Guided Intensity Modulated Radiation Therapy Compared to 3D-Conformal Radiation Therapy for Prostate Cancer: Results From 2 Prospective Cohorts

International Nuclear Information System (INIS)

Wortel, Ruud C.; Incrocci, Luca; Pos, Floris J.; Heide, Uulke A. van der; Lebesque, Joos V.; Aluwini, Shafak; Witte, Marnix G.; Heemsbergen, Wilma D.

2016-01-01

Purpose: Technical developments in the field of external beam radiation therapy (RT) enabled the clinical introduction of image guided intensity modulated radiation therapy (IG-IMRT), which improved target conformity and allowed reduction of safety margins. Whether this had an impact on late toxicity levels compared to previously applied three-dimensional conformal radiation therapy (3D-CRT) is currently unknown. We analyzed late side effects after treatment with IG-IMRT or 3D-CRT, evaluating 2 prospective cohorts of men treated for localized prostate cancer to investigate the hypothesized reductions in toxicity. Methods and Materials: Patients treated with 3D-CRT (n=189) or IG-IMRT (n=242) to 78 Gy in 39 fractions were recruited from 2 Dutch randomized trials with identical toxicity scoring protocols. Late toxicity (>90 days after treatment) was derived from self-assessment questionnaires and case report forms, according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG-EORTC) scoring criteria. Grade ≥2 endpoints included gastrointestinal (GI) rectal bleeding, increased stool frequency, discomfort, rectal incontinence, proctitis, and genitourinary (GU) obstruction, increased urinary frequency, nocturia, urinary incontinence, and dysuria. The Cox proportional hazards regression model was used to compare grade ≥2 toxicities between both techniques, adjusting for other modifying factors. Results: The 5-year cumulative incidence of grade ≥2 GI toxicity was 24.9% for IG-IMRT and 37.6% following 3D-CRT (adjusted hazard ratio [HR]: 0.59, P=.005), with significant reductions in proctitis (HR: 0.37, P=.047) and increased stool frequency (HR: 0.23, P<.001). GU grade ≥2 toxicity levels at 5 years were comparable with 46.2% and 36.4% following IG-IMRT and 3D-CRT, respectively (adjusted HR: 1.19, P=.33). Other strong predictors (P<.01) of grade ≥2 late toxicity were baseline complaints, acute toxicity, and age

Finite-mode analysis by means of intensity information in fractional optical systems

NARCIS (Netherlands)

Alieva, T.; Bastiaans, M.J.

2002-01-01

It is shown how a coherent optical signal that contains only a finite number of Hermite-Gauss modes, can be reconstructed from the knowledge of its Radon-Wigner transform -- associated with the intensity distribution in a fractional Fourier transform optical system -- at only two transversal points.

Body-mounted robotic instrument guide for image-guided cryotherapy of renal cancer

Science.gov (United States)

Hata, Nobuhiko; Song, Sang-Eun; Olubiyi, Olutayo; Arimitsu, Yasumichi; Fujimoto, Kosuke; Kato, Takahisa; Tuncali, Kemal; Tani, Soichiro; Tokuda, Junichi

2016-01-01

Purpose: Image-guided cryotherapy of renal cancer is an emerging alternative to surgical nephrectomy, particularly for those who cannot sustain the physical burden of surgery. It is well known that the outcome of this therapy depends on the accurate placement of the cryotherapy probe. Therefore, a robotic instrument guide may help physicians aim the cryotherapy probe precisely to maximize the efficacy of the treatment and avoid damage to critical surrounding structures. The objective of this paper was to propose a robotic instrument guide for orienting cryotherapy probes in image-guided cryotherapy of renal cancers. The authors propose a body-mounted robotic guide that is expected to be less susceptible to guidance errors caused by the patient’s whole body motion. Methods: Keeping the device’s minimal footprint in mind, the authors developed and validated a body-mounted, robotic instrument guide that can maintain the geometrical relationship between the device and the patient’s body, even in the presence of the patient’s frequent body motions. The guide can orient the cryotherapy probe with the skin incision point as the remote-center-of-motion. The authors’ validation studies included an evaluation of the mechanical accuracy and position repeatability of the robotic instrument guide. The authors also performed a mock MRI-guided cryotherapy procedure with a phantom to compare the advantage of robotically assisted probe replacements over a free-hand approach, by introducing organ motions to investigate their effects on the accurate placement of the cryotherapy probe. Measurements collected for performance analysis included accuracy and time taken for probe placements. Multivariate analysis was performed to assess if either or both organ motion and the robotic guide impacted these measurements. Results: The mechanical accuracy and position repeatability of the probe placement using the robotic instrument guide were 0.3 and 0.1 mm, respectively, at a depth

Deep inspiration breath-hold radiotherapy for lung cancer: impact on image quality and registration uncertainty in cone beam CT image guidance

DEFF Research Database (Denmark)

Josipovic, Mirjana; Persson, Gitte F; Bangsgaard, Jens Peter

2016-01-01

OBJECTIVE: We investigated the impact of deep inspiration breath-hold (DIBH) and tumour baseline shifts on image quality and registration uncertainty in image-guided DIBH radiotherapy (RT) for locally advanced lung cancer. METHODS: Patients treated with daily cone beam CT (CBCT)-guided free...... for the craniocaudal direction in FB, where it was >3 mm. On the 31st fraction, the intraobserver uncertainty increased compared with the second fraction. This increase was more pronounced in FB. Image quality scores improved in DIBH compared with FB for all parameters in all patients. Simulated tumour baseline shifts...... ≤2 mm did not affect the CBCT image quality considerably. CONCLUSION: DIBH CBCT improved image quality and reduced registration uncertainty in the craniocaudal direction in image-guided RT of locally advanced lung cancer. Baseline shifts ≤2 mm in DIBH during CBCT acquisition did not affect image...

An assessment of the magnitude of intra-fraction movement of head-and-neck IMRT cases and its implication on the action-level of the imaging protocol

International Nuclear Information System (INIS)

Pang, Pei Ping Eric; Hendry, Julie; Cheah, Shie Lee; Soong, Yoke Lim; Fong, Kam Weng; Wee, Tien Seng Joseph; Tan, Wee Kiat Terence; Nei, Wen Long; Wang, Fuqiang; Wong, Ru Xin; Ng, Wee Loon; Chen, John

2014-01-01

Background and purpose: A planning margin ⩽3 mm is employed in some head-and-neck IMRT cases due to the proximity of critical structures. This study aims to explore the need to redefine the action-level in the head-and-neck imaging protocol in consideration of the intra-fraction movement. Material and methods: This is a local study of 18 patients treated using the same immobilisation system and setup protocol. Post-treatment orthogonal pair of kilovoltage X-ray images was acquired on the first three days of treatment. 106 sets of pre- and post-treatment kV X-ray images acquired over 53 fractions were analysed against the treatment planning DRR for calculation of intra-fraction movement. Results: Individual mean intra-fraction movement in all directions ranged from −1.8 to 1.1 mm. Population mean (median) intra-fraction movement in the x-, y-, and z-planes were −0.1 mm (0 mm), −0.3 mm (−0.3 mm) and −0.2 mm (−0.2 mm) respectively. Intra-fraction movement in all three dimensions, x-, y- and z-planes were considered statistically significant (p < 0.05). 7 out of 53 fractions (13.2%) were highlighted as the combined magnitude of the intra-fraction motion with the uncorrected pre-treatment setup errors had exceeded the boundaries of given margins. Conclusions: 3 mm-AL was not adequate to account for intra-fraction movement when the CTV–PTV margin was ⩽3 mm and should be excluded from the routine imaging protocol and daily image-guided radiotherapy should be employed. Adjusting the action-level to 2 mm would allow a more confident approach in delivery of the prescribed dose in head-and-neck IMRT cases

Histopathological changes in the irradiated normal organs of guinea pigs with conventional fractionation and hyperfractionation

International Nuclear Information System (INIS)

Inomata, Taisuke; Itoh, Satoshi; Tsuboi, Nobuaki

1998-01-01

Guinea pigs were divided into groups according to four irradiation schedules : 2 Gy/3 Gy x 1/day, five fractions/week, total 80 Gy/81 Gy (A/C group) and 1.0 Gy/1.5 Gy x 2/day, ten fractions/week, total 80 Gy/81 Gy (B/D group). The A group and the C group pathologically caused severe damage in the kidney six and three months after irradiation, respectively. In the B group pathological analysis suggested that only slight-to-moderate changes were occurred in the Bowman's capsule. The D group caused slight damage in the kidney six months after irradiation. Hyperfractionation (B/D group) used in this protocol can clearly reduce radiation damage in the kidney of guinea pigs as compared with conventional fractionation (A/C group). (author)

Reduction of Dose Delivered to Organs at Risk in Prostate Cancer Patients via Image-Guided Radiation Therapy

International Nuclear Information System (INIS)

Pawlowski, Jason M.; Yang, Eddy S.; Malcolm, Arnold W.; Coffey, Charles W.; Ding, George X.

2010-01-01

Purpose: To determine whether image guidance can improve the dose delivered to target organs and organs at risk (OARs) for prostate cancer patients treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: Eight prostate cancer patients were treated with IMRT to 76 Gy at 2 Gy per fraction. Daily target localization was performed via alignment of three intraprostatic fiducials and weekly kV-cone beam computed tomography (CBCT) scans. The prostate and OARs were manually contoured on each CBCT by a single physician. Daily patient setup shifts were obtained by comparing alignment of skin tattoos with the treatment position based on fiducials. Treatment fields were retrospectively applied to CBCT scans. The dose distributions were calculated using actual treatment plans (an 8-mm PTV margin everywhere except for 6-mm posteriorly) with and without image guidance shifts. Furthermore, the feasibility of margin reduction was evaluated by reducing planning margins to 4 mm everywhere except for 3 mm posteriorly. Results: For the eight treatment plans on the 56 CBCT scans, the average doses to 98% of the prostate (D98) were 102% (range, 99-104%) and 99% (range, 45-104%) with and without image guidance, respectively. Using margin reduction, the average D98s were 100% (range, 84-104%) and 92% (range, 40-104%) with and without image guidance, respectively. Conclusions: Currently, margins used in IMRT plans are adequate to deliver a dose to the prostate with conventional patient positioning using skin tattoos or bony anatomy. The use of image guidance may facilitate significant reduction of planning margins. Future studies to assess the efficacy of decreasing margins and improvement of treatment-related toxicities are warranted.

Self-guiding of high-intensity laser pulses for laser wake field acceleration

International Nuclear Information System (INIS)

Umstader, D.; Liu, X.

1992-01-01

A means of self-guiding an ultrashort and high-intensity laser pulse is demonstrated both experimentally and numerically. Its relevance to the laser wake field accelerator concept is discussed. Self-focusing and multiple foci formation are observed when a high peak power (P>100 GW), 1 μm, subpicosecond laser is focused onto various gases (air or hydrogen). It appears to result from the combined effects of self-focusing by the gas, and de-focusing both by diffraction and the plasma formed in the central high-intensity region. Quasi-stationary computer simulations show the same multiple foci behavior as the experiments. The results suggest much larger nonlinear electronic susceptibilities of a gas near or undergoing ionization in the high field of the laser pulse. Although self-guiding of a laser beam by this mechanism appears to significantly extend its high-intensity focal region, small-scale self-focusing due to beam non-uniformity is currently a limitation

Evaluating imaging-pathology concordance and discordance after ultrasound-guided breast biopsy

Science.gov (United States)

2018-01-01

Ultrasound (US)-guided breast biopsy has become the main method for diagnosing breast pathology, and it has a high diagnostic accuracy, approaching that of open surgical biopsy. However, methods for confirming adequate lesion retrieval after US-guided biopsy are relatively limited and false-negative results are unavoidable. Determining imaging-pathology concordance after US-guided biopsy is essential for validating the biopsy result and providing appropriate management. In this review article, we briefly present the results of US-guided breast biopsy; describe general aspects to consider when establishing imaging-pathology concordance; and review the various categories of imaging-pathology correlations and corresponding management strategies. PMID:29169231

Fractional flow reserve versus angiography for guiding percutaneous coronary intervention in patients with multivessel coronary artery disease: 2-year follow-up of the FAME (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) study

DEFF Research Database (Denmark)

Pijls, Nico H J; Fearon, William F; Tonino, Pim A L

2010-01-01

The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD).......The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD)....

Spatial Specificity in Spatiotemporal Encoding and Fourier Imaging

Science.gov (United States)

Goerke, Ute

2015-01-01

Purpose Ultrafast imaging techniques based on spatiotemporal-encoding (SPEN), such as RASER (rapid acquisition with sequential excitation and refocusing), is a promising new class of sequences since they are largely insensitive to magnetic field variations which cause signal loss and geometric distortion in EPI. So far, attempts to theoretically describe the point-spread-function (PSF) for the original SPEN-imaging techniques have yielded limited success. To fill this gap a novel definition for an apparent PSF is proposed. Theory Spatial resolution in SPEN-imaging is determined by the spatial phase dispersion imprinted on the acquired signal by a frequency-swept excitation or refocusing pulse. The resulting signal attenuation increases with larger distance from the vertex of the quadratic phase profile. Methods Bloch simulations and experiments were performed to validate theoretical derivations. Results The apparent PSF quantifies the fractional contribution of magnetization to a voxel’s signal as a function of distance to the voxel. In contrast, the conventional PSF represents the signal intensity at various locations. Conclusion The definition of the conventional PSF fails for SPEN-imaging since only the phase of isochromats, but not the amplitude of the signal varies. The concept of the apparent PSF is shown to be generalizable to conventional Fourier- imaging techniques. PMID:26712657

A randomized trial comparing hypofractionated and conventionally fractionated three-dimensional external-beam radiotherapy for localized prostate adenocarcinoma. A report on acute toxicity

Energy Technology Data Exchange (ETDEWEB)

Norkus, Darius; Miller, Albert; Kurtinaitis, Juozas; Valuckas, Konstantinas Povilas [Dept. of Radiotherapy, Inst. of Oncology, Vilnius Univ. (Lithuania); Haverkamp, Uwe [Dept. of Radiology, Clemenshospital, Muenster (Germany); Popov, Sergey [Dept. of Radiotherapy, Riga Eastern Hospital, Latvian Oncology Center, Riga (Latvia); Prott, Franz-Josef [Inst. of Radiology and Radiotherapy (RNS), St. Josefs Hospital, Wiesbaden (Germany)

2009-11-15

Purpose: to compare acute gastrointestinal (GI) and genitourinary (GU) toxicity between patient groups with localized prostate adenocarcinoma, treated with conventionally fractionated (CFRT) and hypofractionated (HFRT) three-dimensional conformal external-beam radiotherapy (3D-CRT). Patients and methods: 91 patients were enrolled into a randomized study with a minimum follow-up of 3 months. 44 men in the CFRT arm were irradiated with 74 Gy in 37 fractions at 2 Gy per fraction for 7.5 weeks. 47 men in the HFRT arm were treated with 57 Gy in 17 fractions for 3.5 weeks, given as 13 fractions of 3 Gy plus four fractions of 4.5 Gy. The clinical target volume (CTV) included the prostate and the base of seminal vesicles. The CTV-to-PTV (planning target volume) margin was 8-10 mm. Study patients had portal imaging and/or simulation performed on the first fractions and repeated at least weekly. Results: no acute grade 3 or 4 toxicities were observed. The grade 2 GU acute toxicity proportion was significantly lower in the HFRT arm: 19.1% versus 47.7% ({chi}{sup 2}-test, p = 0.003). The grade 2 GU acute toxicity-free survival was significantly better in the HFRT arm (log-rank test, p = 0.008). The median duration of overall GI acute toxicity was shorter with HFRT: 3 compared to 6 weeks with CFRT (median test, p = 0.017). Conclusion: in this first evaluation, the HFRT schedule is feasible and induces acceptable or even lower acute toxicity compared with the toxicities in the CFRT schedule. Extended follow-up is needed to justify this fractionation schedule's safety in the long term. (orig.)

Evaluation of signal intensity of various thyroid tissues on MR imaging

Energy Technology Data Exchange (ETDEWEB)

Baba, Koichiro; Imanishi, Yoshimasa [St. Marianna Univ., Kawasaki, Kanagawa (Japan). School of Medicine; Igarashi, Ryuukou; Shinagawa, Toshihito

2001-08-01

Although normal thyroid mainly consists of thyroid follicles and has large amount of water in them, it shows low signal intensity on T2 weighted MR image. In this paper, we analysed the signal intensity of the thyroid in clinical cases and investigated the relationship between signal intensity and iodine concentration. In forty-one patients who have clinically suspected thyroid diseases, fifty-three MRI examinations of the neck and forty-three thyroid CT examinations were performed. The MR imaging of the neck was performed with T1 weighted image, T2 weighted image, and STIR image. Iodine concentration of the thyroid was measured by the CT software which was originally made by one of the authors (Y.I.). The signal intensity on T2 weighted image negatively correlated with iodine concentration, although there was no relationship between iodine concentration and its signal intensity on T1 weighted image. On T2 weighted image, the intensity of thyroid with high iodine concentration showed a low signal and that of thyroid with low iodine concentration presented a high signal. The thyroid with chronic thyroiditis showed higher signal intensity than normal thyroid and adenmatous goiter on T2 weighted image and STIR image. On T2 weighted image and STIR image, the signal intensity of any thyroid nodules were higher than that of normal thyroid. In addition, follicular adenoma and partially malignant nodules showed a higher signal intensity than thyroid carcinomas. According to previous reports, decreased iodine concentration in thyroid follicles represents decreased concentration of iodine-binding proteins in follicles as well as decreased volume of follicular content in the thyroid. On MR imaging, very high concentration of protein in water solution does not only cause shortening of T1 relaxation time but also shortening of T2 relaxation time resulting in low signal intensity. In the present study, our data seem to suggest that very high concentration of iodine

Evaluation of signal intensity of various thyroid tissues on MR imaging

International Nuclear Information System (INIS)

Baba, Koichiro; Imanishi, Yoshimasa; Igarashi, Ryuukou; Shinagawa, Toshihito

2001-01-01

Although normal thyroid mainly consists of thyroid follicles and has large amount of water in them, it shows low signal intensity on T2 weighted MR image. In this paper, we analysed the signal intensity of the thyroid in clinical cases and investigated the relationship between signal intensity and iodine concentration. In forty-one patients who have clinically suspected thyroid diseases, fifty-three MRI examinations of the neck and forty-three thyroid CT examinations were performed. The MR imaging of the neck was performed with T1 weighted image, T2 weighted image, and STIR image. Iodine concentration of the thyroid was measured by the CT software which was originally made by one of the authors (Y.I.). The signal intensity on T2 weighted image negatively correlated with iodine concentration, although there was no relationship between iodine concentration and its signal intensity on T1 weighted image. On T2 weighted image, the intensity of thyroid with high iodine concentration showed a low signal and that of thyroid with low iodine concentration presented a high signal. The thyroid with chronic thyroiditis showed higher signal intensity than normal thyroid and adenmatous goiter on T2 weighted image and STIR image. On T2 weighted image and STIR image, the signal intensity of any thyroid nodules were higher than that of normal thyroid. In addition, follicular adenoma and partially malignant nodules showed a higher signal intensity than thyroid carcinomas. According to previous reports, decreased iodine concentration in thyroid follicles represents decreased concentration of iodine-binding proteins in follicles as well as decreased volume of follicular content in the thyroid. On MR imaging, very high concentration of protein in water solution does not only cause shortening of T1 relaxation time but also shortening of T2 relaxation time resulting in low signal intensity. In the present study, our data seem to suggest that very high concentration of iodine

A Variable Order Fractional Differential-Based Texture Enhancement Algorithm with Application in Medical Imaging.

Directory of Open Access Journals (Sweden)

Qiang Yu

Full Text Available Texture enhancement is one of the most important techniques in digital image processing and plays an essential role in medical imaging since textures discriminate information. Most image texture enhancement techniques use classical integral order differential mask operators or fractional differential mask operators using fixed fractional order. These masks can produce excessive enhancement of low spatial frequency content, insufficient enhancement of large spatial frequency content, and retention of high spatial frequency noise. To improve upon existing approaches of texture enhancement, we derive an improved Variable Order Fractional Centered Difference (VOFCD scheme which dynamically adjusts the fractional differential order instead of fixing it. The new VOFCD technique is based on the second order Riesz fractional differential operator using a Lagrange 3-point interpolation formula, for both grey scale and colour image enhancement. We then use this method to enhance photographs and a set of medical images related to patients with stroke and Parkinson's disease. The experiments show that our improved fractional differential mask has a higher signal to noise ratio value than the other fractional differential mask operators. Based on the corresponding quantitative analysis we conclude that the new method offers a superior texture enhancement over existing methods.

An integrated multimodality image-guided robot system for small-animal imaging research

International Nuclear Information System (INIS)

Hsu, Wen-Lin; Hsin Wu, Tung; Hsu, Shih-Ming; Chen, Chia-Lin; Lee, Jason J.S.; Huang, Yung-Hui

2011-01-01

We design and construct an image-guided robot system for use in small-animal imaging research. This device allows the use of co-registered small-animal PET-MRI images to guide the movements of robotic controllers, which will accurately place a needle probe at any predetermined location inside, for example, a mouse tumor, for biological readouts without sacrificing the animal. This system is composed of three major components: an automated robot device, a CCD monitoring mechanism, and a multimodality registration implementation. Specifically, the CCD monitoring mechanism was used for correction and validation of the robot device. To demonstrate the value of the proposed system, we performed a tumor hypoxia study that involved FMISO small-animal PET imaging and the delivering of a pO 2 probe into the mouse tumor using the image-guided robot system. During our evaluation, the needle positioning error was found to be within 0.153±0.042 mm of desired placement; the phantom simulation errors were within 0.693±0.128 mm. In small-animal studies, the pO 2 probe measurements in the corresponding hypoxia areas showed good correlation with significant, low tissue oxygen tensions (less than 6 mmHg). We have confirmed the feasibility of the system and successfully applied it to small-animal investigations. The system could be easily adapted to extend to other biomedical investigations in the future.

Impact of intensity-modulated and image-guided radiotherapy on elderly patients undergoing chemoradiation for locally advanced head and neck cancer

International Nuclear Information System (INIS)

Nguyen, N.P.; Chi, A.; Vock, J.

2012-01-01

Purpose: In this work, the treatment tolerance of elderly patients (≥ 70 years) undergoing intensity-modulated radiotherapy (IMRT) and image-guided radiotherapy (IGRT) and chemotherapy for locally advanced head and neck cancer was assessed. Patients and methods: A retrospective review of 112 patients undergoing concurrent chemoradiation for locally advanced head and neck cancer was performed. Treatment toxicity, protocol violations, long-term complications, and survival were compared between 85 younger patients (< 70 years) and 27 older patients (≥ 70 years). Results: Grade 3-4 treatment toxicity was observed in 88.2% and 88.8% for younger and older patients, respectively. Mean weight loss and treatment break were 5.9 and 3.9 kg (p = 0.03) and 7.3 and 7.8 days (p = 0.8) for younger and older patients, respectively. Seven patients (8.2%) did not complete treatment in the younger group compared to 1 patient (3.7%) in the older group (p = 0.6). No significant differences in protocol violations and survival were found between the two groups. Conclusion: Compared to younger patients, elderly patients with locally advanced head and neck cancer tolerated chemoradiation with IMRT and IGRT well, and should not be denied curative treatment based solely on age. (orig.)

Radiation-induced liver injury showing low intensity on T2-weighted images noted in Budd-Chiari syndrome

Energy Technology Data Exchange (ETDEWEB)

Mori, Harushi [Tokyo Univ. (Japan). Graduate School of Medicine; Yoshioka, Hiroshi; Saida, Yukihisa; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine; Mori, Kensaku [Tsukuba Univ., Ibaraki (Japan). Hospital; Ahmadi, T. [Shahid Beheshti Univ. of Medical Sciences, Teheran (Iran, Islamic Republic of); Okumura, Toshiyuki [Ibaraki Prefectural Central Hospital, Tomobe (Japan)

2002-04-01

Although it is documented that radiation can cause density or intensity changes on computed tomography or MR imaging in the irradiated hepatic parenchyma, few researchers have reported or understood the MR presentation of changes in hepatic parenchyma following radiotherapy in the patient with Budd-Chiari syndrome. The purpose of this study was to investigate the MR appearance of hepatic radiation injury in Budd-Chiari syndrome and to consider the underlying pathophysiology. The MR examinations of two patients with Budd-Chiari syndrome was compared with those of 11 patients without Budd-Chiari syndrome. The two groups, both of which suffered from hepatocellular carcinoma, underwent 50-72 Gy of proton-beam irradiation during a period of 14-43 days. Examinations including T1- and T2-weighted imaging, superparamagnetic iron oxide-enhanced imaging, and dynamic study were performed 3-10 weeks after the end of irradiation. Radiation-induced hepatic injury was observed as a low-intensity area on T2-weighted images and on delayed phase images of dynamic study in the Budd-Chiari patients, and as iso- or high-intensity areas on both images in the patients without Budd-Chiari syndrome. US-guided needle biopsy from the irradiated area in one patient with Budd-Chiari syndrome revealed mostly necrotic tissue and fibrous tissue. These MR features of hepatic radiation injury in Budd-Chiari syndrome were considered to be due to severe hepatic fibrosis. (author)

Intensity modulated radiotherapy with simultaneous integrated boost vs. conventional radiotherapy with sequential boost for breast cancer - A preliminary result.

Science.gov (United States)

Lee, Hsin-Hua; Hou, Ming-Feng; Chuang, Hung-Yi; Huang, Ming-Yii; Tsuei, Le-Ping; Chen, Fang-Ming; Ou-Yang, Fu; Huang, Chih-Jen

2015-10-01

This study was aimed to assess the acute dermatological adverse effect from two distinct RT techniques for breast cancer patients. We compared intensity-modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) and conventional radiotherapy followed by sequential boost (CRT-SB). The study population was composed of 126 consecutive female breast cancer patients treated with breast conserving surgery. Sixty-six patients received IMRT-SIB to 2 dose levels simultaneously. They received 50.4 Gy at 1.8 Gy per fraction to the whole breast and 60.2 Gy at 2.15 Gy per fraction to the tumor bed by integral boost. Sixty patients in the CRT-SB group received 50 Gy in 25 fractions to the whole breast followed by a boost irradiation to tumor bed in 5-7 fractions to a total dose of 60-64 Gy. Acute skin toxicities were documented in agreement with the Common Terminology Criteria for Adverse Events version 3 (CTCAE v.3.0). Ninety-eight patients had grade 1 radiation dermatitis while 14 patients had grade 2. Among those with grade 2, there were 3 patients in IMRT-SIB group (4.5%) while 11 in CRT-SB group (18.3%). (P = 0.048) There was no patient with higher than grade 2 toxicity. Three year local control was 99.2%, 3-year disease free survival was 97.5% and 3-year overall survival was 99.2%. A significant reduction in the severity of acute radiation dermatitis from IMRT-SIB comparing with CRT-SB is demonstrated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ankle ligamints : comparison of MR arthrography with conventional MR imaging in amputated feet

International Nuclear Information System (INIS)

Yoo, Jae Sung; Lee, Sang Yong; Lee, Jeong Min; Han, Young Min; Chung, Kyung Ho; Kim, CHong Soo

2001-01-01

To compare magnetic resonance (MR) arthrography with conventional MR imaging in the evaluation of ankle ligaments. Eight freshly amputated human feet underwent conventional MR imaging and MR arthrography. For the former, 1.5-T magnets in the axial, coronal and sagittal planes were used, and T1-weighted sequences were obtained. Following the injection of 6-10 ml of diluted contrast media (Gd-DTPA 1:250), T1-weighted images were obtained in the same positions as conventional MR images. Paired conventional MR imaging and MR arthrography of each ankle ligament were rated on a five-point scale, and to reflect inter-group differences a Wilcoxon singed-rank test was used to compare the different measurements (p<0.05). In two ankles, MR images of the ligaments were correlated with ankle dissection. Anterior and posterior talofibular ligaments were more clearly revealed by MR arthrography than by conventional MR imaging, while calcaneofibular ligaments showed no difference between these two modalities. With regard to deltoid ligaments, visualization of the anterior and posterior tibiotalar ligament was much improved when contrast material was used to outline the ligament's articular aspect. Visualization of the posterior inferior tibiofibular ligament and inferior transverse ligament were also improved when the use of contrast material provided delineation of the articular side of the ligaments and separated them from adjacent bone. In addition, MR arthography was very useful for indentification of the posterior intermalleolar ligament, though its use did not enhance visualization of the calcaneofibular, tibiocalcaneal, spring or tibiospring ligaments. MR arthrography accurately revealed the anatomic details of ankle ligaments, and may therefore be more useful than conventional Mr imaging for evaluation of these structures

RESEARCH OF REGISTRATION APPROACHES OF THERMAL INFRARED IMAGES AND INTENSITY IMAGES OF POINT CLOUD

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L. Liu

2017-09-01

Full Text Available In order to realize the analysis of thermal energy of the objects in 3D vision, the registration approach of thermal infrared images and TLS (Terrestrial Laser Scanner point cloud was studied. The original data was pre-processed. For the sake of making the scale and brightness contrast of the two kinds of data meet the needs of basic matching, the intensity image of point cloud was produced and projected to spherical coordinate system, histogram equalization processing was done for thermal infrared image.This paper focused on the research of registration approaches of thermal infrared images and intensity images of point cloud based on SIFT，EOH-SIFT and PIIFD operators. The latter of which is usually used for medical image matching with different spectral character. The comparison results of the experiments showed that PIIFD operator got much more accurate feature point correspondences compared to SIFT and EOH-SIFT operators. The thermal infrared image and intensity image also have ideal overlap results by quadratic polynomial transformation. Therefore, PIIFD can be used as the basic operator for the registration of thermal infrared images and intensity images, and the operator can also be further improved by incorporating the iteration method.

Haematuria: an imaging guide.

LENUS (Irish Health Repository)

Moloney, Fiachra

2014-01-01

This paper discusses the current status of imaging in the investigation of patients with haematuria. The physician must rationalize imaging so that serious causes such as malignancy are promptly diagnosed while at the same time not exposing patients to unnecessary investigations. There is currently no universal agreement about the optimal imaging work up of haematuria. The choice of modality to image the urinary tract will depend on individual patient factors such as age, the presence of risk factors for malignancy, renal function, a history of calculus disease and pregnancy, and other factors, such as local policy and practice, cost effectiveness and availability of resources. The role of all modalities, including conventional radiography, intravenous urography\\/excretory urography, ultrasonography, retrograde pyelography, multidetector computed tomography urography (MDCTU), and magnetic resonance urography, is discussed. This paper highlights the pivotal role of MDCTU in the imaging of the patient with haematuria and discusses issues specific to this modality including protocol design, imaging of the urothelium, and radiation dose. Examination protocols should be tailored to the patient while all the while optimizing radiation dose.

NON-CONVENTIONAL PET NUCLIDES: PRODUCTION AND IMAGING

OpenAIRE

Laforest, Richard

2015-01-01

Abstract Medical cyclotrons are now commonly used for the production of PET nuclides by the (pn) reaction. These devices are typically capable of delivering 10-15 MeV protons beams at sufficiently high intensity for timely production of β+ decaying nuclides. Non-conventional PET nuclides have emerged recently and offers new opportunities for diagnostic and therapy drug discovery. In this paper, we will review the production capabilities for such nuclides at Washington University Medical Schoo...

Clinical practice of image-guided spine radiosurgery - results from an international research consortium

Directory of Open Access Journals (Sweden)

Guckenberger Matthias

2011-12-01

Full Text Available Abstract Background Spinal radiosurgery is a quickly evolving technique in the radiotherapy and neurosurgical communities. However, the methods of spine radiosurgery have not been standardized. This article describes the results of a survey about the methods of spine radiosurgery at five international institutions. Methods All institutions are members of the Elekta Spine Radiosurgery Research Consortium and have a dedicated research and clinical focus on image-guided radiosurgery. The questionnaire consisted of 75 items covering all major steps of spine radiosurgery. Results Strong agreement in the methods of spine radiosurgery was observed. In particular, similarities were observed with safety and quality assurance playing an important role in the methods of all institutions, cooperation between neurosurgeons and radiation oncologists in case selection, dedicated imaging for target- and organ-at-risk delineation, application of proper safety margins for the target volume and organs-at-risk, conformal planning and precise image-guided treatment delivery, and close clinical and radiological follow-up. In contrast, three major areas of uncertainty and disagreement were identified: 1 Indications and contra-indications for spine radiosurgery; 2 treatment dose and fractionation and 3 tolerance dose of the spinal cord. Conclusions Results of this study reflect the current practice of spine radiosurgery in large academic centers. Despite close agreement was observed in many steps of spine radiosurgery, further research in form of retrospective and especially prospective studies is required to refine the details of spinal radiosurgery in terms of safety and efficacy.

Intra-fraction motion of larynx radiotherapy

Science.gov (United States)

Durmus, Ismail Faruk; Tas, Bora

2018-02-01

In early stage laryngeal radiotherapy, movement is an important factor. Thyroid cartilage can move from swallowing, breathing, sound and reflexes. The effects of this motion on the target volume (PTV) during treatment were examined. In our study, the target volume movement during the treatment for this purpose was examined. Thus, setup margins are re-evaluated and patient-based PTV margins are determined. Intrafraction CBCT was scanned in 246 fractions for 14 patients. During the treatment, the amount of deviation which could be lateral, vertical and longitudinal axis was determined. ≤ ± 0.1cm deviation; 237 fractions in the lateral direction, 202 fractions in the longitudinal direction, 185 fractions in the vertical direction. The maximum deviation values were found in the longitudinal direction. Intrafraction guide in laryngeal radiotherapy; we are sure of the correctness of the treatment, the target volume is to adjust the margin and dose more precisely, we control the maximum deviation of the target volume for each fraction. Although the image quality of intrafraction-CBCT scans was lower than the image quality of planning CT, they showed sufficient contrast for this work.

Alternative radiation-free registration technique for image-guided pedicle screw placement in deformed cervico-thoracic segments.

Science.gov (United States)

Kantelhardt, Sven R; Neulen, Axel; Keric, Naureen; Gutenberg, Angelika; Conrad, Jens; Giese, Alf

2017-10-01

Image-guided pedicle screw placement in the cervico-thoracic region is a commonly applied technique. In some patients with deformed cervico-thoracic segments, conventional or 3D fluoroscopy based registration of image-guidance might be difficult or impossible because of the anatomic/pathological conditions. Landmark based registration has been used as an alternative, mostly using separate registration of each vertebra. We here investigated a routine for landmark based registration of rigid spinal segments as single objects, using cranial image-guidance software. Landmark based registration of image-guidance was performed using cranial navigation software. After surgical exposure of the spinous processes, lamina and facet joints and fixation of a reference marker array, up to 26 predefined landmarks were acquired using a pointer. All pedicle screws were implanted using image guidance alone. Following image-guided screw placement all patients underwent postoperative CT scanning. Screw positions as well as intraoperative and clinical parameters were retrospectively analyzed. Thirteen patients received 73 pedicle screws at levels C6 to Th8. Registration of spinal segments, using the cranial image-guidance succeeded in all cases. Pedicle perforations were observed in 11.0%, severe perforations of >2 mm occurred in 5.4%. One patient developed a transient C8 syndrome and had to be revised for deviation of the C7 pedicle screw. No other pedicle screw-related complications were observed. In selected patients suffering from pathologies of the cervico-thoracic region, which impair intraoperative fluoroscopy or 3D C-arm imaging, landmark based registration of image-guidance using cranial software is a feasible, radiation-saving and a safe alternative.

Radiation therapy technology innovations applied to the treatment of head and neck patients: - Clinical results of Intensity Modulated Radiotherapy (IMRT), - Contribution of Image Guided Radiotherapy (IGRT) in the management of head and neck patients treated with IMRT

International Nuclear Information System (INIS)

Graff-Cailleaud, Pierre

2011-01-01

Numerous and exciting technological innovations were recently developed in radiotherapy. We aimed to assess benefits in two specific fields. 1) Clinical results of Intensity Modulated Radiotherapy (IMRT) applied to the treatment of Head and Neck (H and N) patients. The first study was a long-term mono-centric prospective registration of all H and N patients treated with IMRT in our institution. Locoregional control was excellent and toxicities limited. Recurrences were in-field. Dosimetric recommendations (parotids mean dose) were established. The second study assessed the impact of IMRT on health-related quality of life for H and N patients through a multicentric matched-pair comparison with conventional radiotherapy. Outstanding benefits were observed particularly in the fields of salivary dysfunction and oral discomfort. 2) Contribution of Image Guided Radiotherapy (IGRT) in the management of H and N patients treated with IMRT. The first study was a monitoring of delivered dose, using 3D dose recalculation from Megavoltage Cone-Beam CT (CBCT), as a quality assurance measure of a panel of H and N IMRT patients aligned with IGRT. Dosimetric consequences of anatomical changes were assessed. Contribution of color-coded MVCBCT dose-difference maps was studied. The aim of the second study was to quantify the inherent relative mobility between anatomic regions of the H and N area and to assess the dosimetric impact of several different matching procedures. Recommendations for the use of CBCT images in a daily practice were established. (author) [fr

MO-DE-202-01: Image-Guided Focused Ultrasound Surgery and Therapy

Energy Technology Data Exchange (ETDEWEB)

Farahani, K. [National Cancer Institute (United States)

2016-06-15

At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

MO-DE-202-01: Image-Guided Focused Ultrasound Surgery and Therapy

International Nuclear Information System (INIS)

Farahani, K.

2016-01-01

At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

LOR-interleaving image reconstruction for PET imaging with fractional-crystal collimation

International Nuclear Information System (INIS)

Li, Yusheng; Matej, Samuel; Karp, Joel S; Metzler, Scott D

2015-01-01

Positron emission tomography (PET) has become an important modality in medical and molecular imaging. However, in most PET applications, the resolution is still mainly limited by the physical crystal sizes or the detector’s intrinsic spatial resolution. To achieve images with better spatial resolution in a central region of interest (ROI), we have previously proposed using collimation in PET scanners. The collimator is designed to partially mask detector crystals to detect lines of response (LORs) within fractional crystals. A sequence of collimator-encoded LORs is measured with different collimation configurations. This novel collimated scanner geometry makes the reconstruction problem challenging, as both detector and collimator effects need to be modeled to reconstruct high-resolution images from collimated LORs. In this paper, we present a LOR-interleaving (LORI) algorithm, which incorporates these effects and has the advantage of reusing existing reconstruction software, to reconstruct high-resolution images for PET with fractional-crystal collimation. We also develop a 3D ray-tracing model incorporating both the collimator and crystal penetration for simulations and reconstructions of the collimated PET. By registering the collimator-encoded LORs with the collimator configurations, high-resolution LORs are restored based on the modeled transfer matrices using the non-negative least-squares method and EM algorithm. The resolution-enhanced images are then reconstructed from the high-resolution LORs using the MLEM or OSEM algorithm. For validation, we applied the LORI method to a small-animal PET scanner, A-PET, with a specially designed collimator. We demonstrate through simulated reconstructions with a hot-rod phantom and MOBY phantom that the LORI reconstructions can substantially improve spatial resolution and quantification compared to the uncollimated reconstructions. The LORI algorithm is crucial to improve overall image quality of collimated PET, which

Intensity correlation imaging with sunlight-like source

Science.gov (United States)

Wang, Wentao; Tang, Zhiguo; Zheng, Huaibin; Chen, Hui; Yuan, Yuan; Liu, Jinbin; Liu, Yanyan; Xu, Zhuo

2018-05-01

We show a method of intensity correlation imaging of targets illuminated by a sunlight-like source both theoretically and experimentally. With a Faraday anomalous dispersion optical filter (FADOF), we have modulated the coherence time of a thermal source up to 0.167 ns. And we carried out measurements of temporal and spatial correlations, respectively, with an intensity interferometer setup. By skillfully using the even Fourier fitting on the very sparse sampling data, the images of targets are successfully reconstructed from the low signal-noise-ratio(SNR) interference pattern by applying an iterative phase retrieval algorithm. The resulting imaging quality is as well as the one obtained by the theoretical fitting. The realization of such a case will bring this technique closer to geostationary satellite imaging illuminated by sunlight.

Smart travel guide: from internet image database to intelligent system

Science.gov (United States)

Chareyron, Ga"l.; Da Rugna, Jérome; Cousin, Saskia

2011-02-01

To help the tourist to discover a city, a region or a park, many options are provided by public tourism travel centers, by free online guides or by dedicated book guides. Nonetheless, these guides provide only mainstream information which are not conform to a particular tourist behavior. On the other hand, we may find several online image databases allowing users to upload their images and to localize each image on a map. These websites are representative of tourism practices and constitute a proxy to analyze tourism flows. Then, this work intends to answer this question: knowing what I have visited and what other people have visited, where should I go now? This process needs to profile users, sites and photos. our paper presents the acquired data and relationship between photographers, sites and photos and introduces the model designed to correctly estimate the site interest of each tourism point. The third part shows an application of our schema: a smart travel guide on geolocated mobile devices. This android application is a travel guide truly matching the user wishes.

Treatment outcome of high-dose image-guided intensity-modulated radiotherapy using intra-prostate fiducial markers for localized prostate cancer at a single institute in Japan

International Nuclear Information System (INIS)

Takeda, Ken; Shimizu, Eiji; Abe, Keiko; Shirata, Yuko; Ishikawa, Yohjiro

2012-01-01

Several studies have confirmed the advantages of delivering high doses of external beam radiotherapy to achieve optimal tumor-control outcomes in patients with localized prostate cancer. We evaluated the medium-term treatment outcome after high-dose, image-guided intensity-modulated radiotherapy (IMRT) using intra-prostate fiducial markers for clinically localized prostate cancer. In total, 141 patients with localized prostate cancer treated with image-guided IMRT (76 Gy in 13 patients and 80 Gy in 128 patients) between 2003 and 2008 were enrolled in this study. The patients were classified according to the National Comprehensive Cancer Network-defined risk groups. Thirty-six intermediate-risk patients and 105 high-risk patients were included. Androgen-deprivation therapy was performed in 124 patients (88%) for a median of 11 months (range: 2–88 months). Prostate-specific antigen (PSA) relapse was defined according to the Phoenix-definition (i.e., an absolute nadir plus 2 ng/ml dated at the call). The 5-year actuarial PSA relapse-free survival, the 5-year distant metastasis-free survival, the 5-year cause-specific survival (CSS), the 5-year overall survival (OS) outcomes and the acute and late toxicities were analyzed. The toxicity data were scored according to the Common Terminology Criteria for Adverse Events, version 4.0. The median follow-up was 60 months. The 5-year PSA relapse-free survival rates were 100% for the intermediate-risk patients and 82.2% for the high-risk patients; the 5-year actuarial distant metastasis-free survival rates were 100% and 95% for the intermediate- and high-risk patients, respectively; the 5-year CSS rates were 100% for both patient subsets; and the 5-year OS rates were 100% and 91.7% for the intermediate- and high-risk patients, respectively. The Gleason score (<8 vs. ≥8) was significant for the 5-year PSA relapse-free survival on multivariate analysis (p = 0.044). There was no grade 3 or 4 acute toxicity. The incidence of

Radiologists' leading position in image-guided therapy.

Science.gov (United States)

Helmberger, Thomas; Martí-Bonmatí, Luis; Pereira, Philippe; Gillams, Alice; Martínez, Jose; Lammer, Johannes; Malagari, Katarina; Gangi, Afshin; de Baere, Thierry; Adam, E Jane; Rasch, Coen; Budach, Volker; Reekers, Jim A

2013-02-01

Image-guided diagnostic and therapeutic procedures are related to, or performed under, some kind of imaging. Such imaging may be direct inspection (as in open surgery) or indirect inspection as in endoscopy or laparoscopy. Common to all these techniques is the transformation of optical and visible information to a monitor or the eye of the operator. Image-guided therapy (IGT) differs by using processed imaging data acquired before, during and after a wide range of different imaging techniques. This means that the planning, performing and monitoring, as well as the control of the therapeutic procedure, are based and dependent on the "virtual reality" provided by imaging investigations. Since most of such imaging involves radiology in the broadest sense, there is a need to characterise IGT in more detail. In this paper, the technical, medico-legal and medico-political issues will be discussed. The focus will be put on state-of-the-art imaging, technical developments, methodological and legal requisites concerning radiation protection and licensing, speciality-specific limitations and crossing specialty borders, definition of technical and quality standards, and finally to the issue of awareness of IGT within the medical and public community. The specialty-specific knowledge should confer radiologists with a significant role in the overall responsibility for the imaging-related processes in various non-radiological specialties. These processes may encompass purchase, servicing, quality management, radiation protection and documentation, also taking responsibility for the definition and compliance with the legal requirements regarding all radiological imaging performed by non-radiologists.

Feasibility of MRI-guided high intensity focused ultrasound treatment for adenomyosis

Energy Technology Data Exchange (ETDEWEB)

Fan, Tien-Ying [State Key Laboratory of Ultrasound Engineering in Medicine, Department of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Zhang, Lian; Chen, Wenzhi [Clinical Center of Tumor Therapy of 2nd Affiliated Hospital of Chongqing Medical University, Chongqing 400010 (China); Liu, Yinjiang; He, Min; Huang, Xiu [State Key Laboratory of Ultrasound Engineering in Medicine, Department of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Orsi, Franco [Interventional Radiology Unit, European Institute of Oncology, 435 Via Ripamonti, 20141 Milan (Italy); Wang, Zhibiao, E-mail: wangzhibiao@haifu.com.cn [State Key Laboratory of Ultrasound Engineering in Medicine, Department of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Clinical Center of Tumor Therapy of 2nd Affiliated Hospital of Chongqing Medical University, Chongqing 400010 (China)

2012-11-15

Highlights: Black-Right-Pointing-Pointer We tested the feasibility of MRIgHIFU ablation for adenomyosis. Black-Right-Pointing-Pointer Patients were treated with MRIgHIFU under conscious sedation. Black-Right-Pointing-Pointer Patient symptoms were assessed using SSS and UFS-QOL. Black-Right-Pointing-Pointer The mean SSS and UFS-QOL showed significant improvements at follow up. Black-Right-Pointing-Pointer No serious complications were observed 62.5 {+-} 21.6. -- Abstract: Purpose: To test the feasibility of MRI-guided high intensity focused ultrasound ablation for adenomyosis. Materials and methods: Patients with symptomatic adenomyosis were treated with MRI-guided high intensity focused ultrasound (MRIgHIFU). Under conscious sedation, MRIgHIFU was performed by a clinical MRI-compatible focused ultrasound tumour therapeutic system (JM15100, Haifu{sup Registered-Sign} Technology Co. Ltd., Chongqing, China) which is combined with a 1.5 T MRI system (Magnetom Symphony, Siemens Healthcare, Erlangen, Germany). MRI was used to calculate the volume of the uterus and lesion. Non-perfused volume of the targeted lesions was evaluated immediately after MRIgHIFU. Patient symptoms were assessed using symptom severity score (SSS) and uterine fibroids symptoms and quality of life questionnaire (UFS-QOL). Results: Ten patients with mean age of 40.3 {+-} 4 years with an average lesion size of 56.9 {+-} 12.7 mm in diameter were treated. Non-perfused volume and the percentage of non-perfused volume obtained from contrast-enhanced T1 Magnetic resonance images immediately post-treatment were 66.6 {+-} 49.4 cm{sup 3} and 62.5 {+-} 21.6%, respectively. The mean SSS and UFS-QOL showed significant improvements of 25%, 16% and 25% at 3, 6 and 12 months follow up, respectively, to pre-treatment scores. No serious complications were observed. Conclusion: Based on the results from this study, MRIgHIFU treatment appears to be a safe and feasible modality to ablate adenomyosis lesion and

Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy

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Bian, Junguo; Sharp, Gregory C.; Park, Yang-Kyun; Ouyang, Jinsong; Bortfeld, Thomas; El Fakhri, Georges

2016-05-01

It is well-known that projections acquired over an angular range slightly over 180° (so-called short scan) are sufficient for fan-beam reconstruction. However, due to practical imaging conditions (projection data and reconstruction image discretization, physical factors, and data noise), the short-scan reconstructions may have different appearances and properties from the full-scan (scans over 360°) reconstructions. Nevertheless, short-scan configurations have been used in applications such as cone-beam CT (CBCT) for head-neck-cancer image-guided radiation therapy (IGRT) that only requires a small field of view due to the potential reduced imaging time and dose. In this work, we studied the image quality trade-off for full, short, and full/short scan configurations with both conventional filtered-backprojection (FBP) reconstruction and iterative reconstruction algorithms based on total-variation (TV) minimization for head-neck-cancer IGRT. Anthropomorphic and Catphan phantoms were scanned at different exposure levels with a clinical scanner used in IGRT. Both visualization- and numerical-metric-based evaluation studies were performed. The results indicate that the optimal exposure level and number of views are in the middle range for both FBP and TV-based iterative algorithms and the optimization is object-dependent and task-dependent. The optimal view numbers decrease with the total exposure levels for both FBP and TV-based algorithms. The results also indicate there are slight differences between FBP and TV-based iterative algorithms for the image quality trade-off: FBP seems to be more in favor of larger number of views while the TV-based algorithm is more robust to different data conditions (number of views and exposure levels) than the FBP algorithm. The studies can provide a general guideline for image-quality optimization for CBCT used in IGRT and other applications.

Abdominal multi-organ segmentation from CT images using conditional shape-location and unsupervised intensity priors.

Science.gov (United States)

Okada, Toshiyuki; Linguraru, Marius George; Hori, Masatoshi; Summers, Ronald M; Tomiyama, Noriyuki; Sato, Yoshinobu

2015-12-01

This paper addresses the automated segmentation of multiple organs in upper abdominal computed tomography (CT) data. The aim of our study is to develop methods to effectively construct the conditional priors and use their prediction power for more accurate segmentation as well as easy adaptation to various imaging conditions in CT images, as observed in clinical practice. We propose a general framework of multi-organ segmentation which effectively incorporates interrelations among multiple organs and easily adapts to various imaging conditions without the need for supervised intensity information. The features of the framework are as follows: (1) A method for modeling conditional shape and location (shape-location) priors, which we call prediction-based priors, is developed to derive accurate priors specific to each subject, which enables the estimation of intensity priors without the need for supervised intensity information. (2) Organ correlation graph is introduced, which defines how the conditional priors are constructed and segmentation processes of multiple organs are executed. In our framework, predictor organs, whose segmentation is sufficiently accurate by using conventional single-organ segmentation methods, are pre-segmented, and the remaining organs are hierarchically segmented using conditional shape-location priors. The proposed framework was evaluated through the segmentation of eight abdominal organs (liver, spleen, left and right kidneys, pancreas, gallbladder, aorta, and inferior vena cava) from 134 CT data from 86 patients obtained under six imaging conditions at two hospitals. The experimental results show the effectiveness of the proposed prediction-based priors and the applicability to various imaging conditions without the need for supervised intensity information. Average Dice coefficients for the liver, spleen, and kidneys were more than 92%, and were around 73% and 67% for the pancreas and gallbladder, respectively. Copyright © 2015

Alveolar bone-loss area localization in periodontitis radiographs based on threshold segmentation with a hybrid feature fused of intensity and the H-value of fractional Brownian motion model.

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Lin, P L; Huang, P W; Huang, P Y; Hsu, H C

2015-10-01

Periodontitis involves progressive loss of alveolar bone around the teeth. Hence, automatic alveolar bone-loss (ABL) measurement in periapical radiographs can assist dentists in diagnosing such disease. In this paper, we propose an effective method for ABL area localization and denote it as ABLIfBm. ABLIfBm is a threshold segmentation method that uses a hybrid feature fused of both intensity and texture measured by the H-value of fractional Brownian motion (fBm) model, where the H-value is the Hurst coefficient in the expectation function of a fBm curve (intensity change) and is directly related to the value of fractal dimension. Adopting leave-one-out cross validation training and testing mechanism, ABLIfBm trains weights for both features using Bayesian classifier and transforms the radiograph image into a feature image obtained from a weighted average of both features. Finally, by Otsu's thresholding, it segments the feature image into normal and bone-loss regions. Experimental results on 31 periodontitis radiograph images in terms of mean true positive fraction and false positive fraction are about 92.5% and 14.0%, respectively, where the ground truth is provided by a dentist. The results also demonstrate that ABLIfBm outperforms (a) the threshold segmentation method using either feature alone or a weighted average of the same two features but with weights trained differently; (b) a level set segmentation method presented earlier in literature; and (c) segmentation methods based on Bayesian, K-NN, or SVM classifier using the same two features. Our results suggest that the proposed method can effectively localize alveolar bone-loss areas in periodontitis radiograph images and hence would be useful for dentists in evaluating degree of bone-loss for periodontitis patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The fractional Fourier transform and applications

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Bailey, David H.; Swarztrauber, Paul N.

1991-01-01

This paper describes the 'fractional Fourier transform', which admits computation by an algorithm that has complexity proportional to the fast Fourier transform algorithm. Whereas the discrete Fourier transform (DFT) is based on integral roots of unity e exp -2(pi)i/n, the fractional Fourier transform is based on fractional roots of unity e exp -2(pi)i(alpha), where alpha is arbitrary. The fractional Fourier transform and the corresponding fast algorithm are useful for such applications as computing DFTs of sequences with prime lengths, computing DFTs of sparse sequences, analyzing sequences with noninteger periodicities, performing high-resolution trigonometric interpolation, detecting lines in noisy images, and detecting signals with linearly drifting frequencies. In many cases, the resulting algorithms are faster by arbitrarily large factors than conventional techniques.

Multi-institutional MicroCT image comparison of image-guided small animal irradiators

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Johnstone, Chris D.; Lindsay, Patricia; E Graves, Edward; Wong, Eugene; Perez, Jessica R.; Poirier, Yannick; Ben-Bouchta, Youssef; Kanesalingam, Thilakshan; Chen, Haijian; E Rubinstein, Ashley; Sheng, Ke; Bazalova-Carter, Magdalena

2017-07-01

To recommend imaging protocols and establish tolerance levels for microCT image quality assurance (QA) performed on conformal image-guided small animal irradiators. A fully automated QA software SAPA (small animal phantom analyzer) for image analysis of the commercial Shelley micro-CT MCTP 610 phantom was developed, in which quantitative analyses of CT number linearity, signal-to-noise ratio (SNR), uniformity and noise, geometric accuracy, spatial resolution by means of modulation transfer function (MTF), and CT contrast were performed. Phantom microCT scans from eleven institutions acquired with four image-guided small animal irradiator units (including the commercial PXi X-RAD SmART and Xstrahl SARRP systems) with varying parameters used for routine small animal imaging were analyzed. Multi-institutional data sets were compared using SAPA, based on which tolerance levels for each QA test were established and imaging protocols for QA were recommended. By analyzing microCT data from 11 institutions, we established image QA tolerance levels for all image quality tests. CT number linearity set to R 2  >  0.990 was acceptable in microCT data acquired at all but three institutions. Acceptable SNR  >  36 and noise levels  1.5 lp mm-1 for MTF  =  0.2) was obtained at all but four institutions due to their large image voxel size used (>0.275 mm). Ten of the eleven institutions passed the set QA tolerance for geometric accuracy (2000 HU for 30 mgI ml-1). We recommend performing imaging QA with 70 kVp, 1.5 mA, 120 s imaging time, 0.20 mm voxel size, and a frame rate of 5 fps for the PXi X-RAD SmART. For the Xstrahl SARRP, we recommend using 60 kVp, 1.0 mA, 240 s imaging time, 0.20 mm voxel size, and 6 fps. These imaging protocols should result in high quality images that pass the set tolerance levels on all systems. Average SAPA computation time for complete QA analysis for a 0.20 mm voxel, 400 slice Shelley phantom microCT data set

Dynamic contrast-enhanced MR imaging of the water fraction of normal bone marrow and diffuse bone marrow disease

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Katsuya, Tomoo; Inoue, Tomio; Ishizaka, Hiroshi; Aoki, Jun; Endo, Keigo [Gunma Univ., Maebashi (Japan). School of Medicine

2000-10-01

To clarify the contrast-enhancement pattern of the normal hematopoietic element by isolating the signal of the water fraction in vertebral bone marrow and to investigate whether this approach can be used to characterize bone marrow pathology in several diffuse bone marrow diseases. Two groups were examined: 30 normal healthy volunteers and 19 patients with primary diffuse bone marrow disease (aplastic anemia [n=8], myelodysplastic syndrome (MDS) [n=5], chronic myelogenic leukemia (CML) [n=4], polycythemia vera [n=2]). Isolation of the signal of hematopoietic tissue was done by the chemical-shift misregistration effect. Twenty consecutive T1-weighted midsagittal lumber vertebral images were obtained immediately after the intravenous administration of Gd-DTPA of 0.1 mmol/kg body weight, and the pattern of the time-intensity curve, the peak contrast-enhancement (CE) ratio, and the washout rate (%/min) of bone marrow in normal volunteers were compared with those in patients suffering from primary diffuse bone marrow disease. The pattern of the time-intensity curve of patients with aplastic anemia showed a low peak value followed by a slow washout. However, the pattern of time-intensity curves in patients with MDS, CML, and polycythemia vera was similar to that of normal volunteers. The peak CE ratio of the water fraction in normal marrow ranged from 0.45 to 1.26 (mean {+-}S.D.: 0.87{+-}0.18). Patients with aplastic anemia showed an abnormally lower peak CE ratio of the water fraction (mean {+-}S.D.: 0.34{+-}0.19, p<0.0001). On the other hand, the peak CE ratio of the water fraction in patients with MDS was significantly higher than that of normal volunteers (mean {+-}S.D. 1.35{+-}0.39, p<0.05). In contrast, the peak CE ratio of patients with CML or polycythemia vera did not differ significantly from that of normal volunteers. The mean washout rate of patients with aplastic anemia was significantly lower than that of normal volunteers (mean {+-}S.D.: 3.50{+-}2.51 %/min

Dynamic contrast-enhanced MR imaging of the water fraction of normal bone marrow and diffuse bone marrow disease

International Nuclear Information System (INIS)

Katsuya, Tomoo; Inoue, Tomio; Ishizaka, Hiroshi; Aoki, Jun; Endo, Keigo

2000-01-01

To clarify the contrast-enhancement pattern of the normal hematopoietic element by isolating the signal of the water fraction in vertebral bone marrow and to investigate whether this approach can be used to characterize bone marrow pathology in several diffuse bone marrow diseases. Two groups were examined: 30 normal healthy volunteers and 19 patients with primary diffuse bone marrow disease (aplastic anemia [n=8], myelodysplastic syndrome (MDS) [n=5], chronic myelogenic leukemia (CML) [n=4], polycythemia vera [n=2]). Isolation of the signal of hematopoietic tissue was done by the chemical-shift misregistration effect. Twenty consecutive T1-weighted midsagittal lumber vertebral images were obtained immediately after the intravenous administration of Gd-DTPA of 0.1 mmol/kg body weight, and the pattern of the time-intensity curve, the peak contrast-enhancement (CE) ratio, and the washout rate (%/min) of bone marrow in normal volunteers were compared with those in patients suffering from primary diffuse bone marrow disease. The pattern of the time-intensity curve of patients with aplastic anemia showed a low peak value followed by a slow washout. However, the pattern of time-intensity curves in patients with MDS, CML, and polycythemia vera was similar to that of normal volunteers. The peak CE ratio of the water fraction in normal marrow ranged from 0.45 to 1.26 (mean ±S.D.: 0.87±0.18). Patients with aplastic anemia showed an abnormally lower peak CE ratio of the water fraction (mean ±S.D.: 0.34±0.19, p<0.0001). On the other hand, the peak CE ratio of the water fraction in patients with MDS was significantly higher than that of normal volunteers (mean ±S.D. 1.35±0.39, p<0.05). In contrast, the peak CE ratio of patients with CML or polycythemia vera did not differ significantly from that of normal volunteers. The mean washout rate of patients with aplastic anemia was significantly lower than that of normal volunteers (mean ±S.D.: 3.50±2.51 %/min vs. 7.13±1

A new fiducial marker for Image-guided radiotherapy of prostate cancer: Clinical experience

Energy Technology Data Exchange (ETDEWEB)

Carl, Jesper; Nielsen, Jane; Holmberg, Mats; Hoejkjaer Larsen, Erik; Fabrin, Knud; Fisker, Rune V. (Dept. of Medical Physics, Oncology, Aalborg Hospital (Denmark))

2008-08-15

Background. A new fiducial marker for image guided radiotherapy (IGRT) based on a removable prostate stent made of Ni Ti has been developed during two previous clinical feasibility studies. The marker is currently being evaluated for IGRT treatment in a third clinical study. Method. The new marker is used to co-register MR and planning CT scans with high accuracy in the region around the prostate. The co-registered MR-CT volumes are used for delineation of GTV before planning. In each treatment session the IGRT system is used to position the patient before treatment. The IGRT system use a stereo pair of kV images matched to corresponding Digital Reconstructed Radiograms (DRR) from the planning CT scan. The match is done using mutual gray scale information. The pair of DRR's for positioning is created in the IGRT system with a threshold in the Look Up Table (LUT). The resulting match provides the necessary shift in couch coordinates to position the stent with an accuracy of 1-2 mm within the planned position. Results. At the present time 39 patients have received the new marker. Of the 39 one has migrated to the bladder. Deviations of more than 5 mm between CTV outlined on CT and MR are seen in several cases and in anterior-posterior (AP), left-right (LR) and cranial-caudal (CC) directions. Intra-fraction translation movements up to +/- 3 mm are seen as well. As the stent is also clearly visible on images taken with high voltage x-rays using electronic portal images devices (EPID), the positioning has been verified independently of the IGRT system. Discussion. The preliminary result of an on going clinical study of a Ni Ti prostate stent, potentially a new fiducial marker for image guided radiotherapy, looks promising. The risk of migration appears to be much lower compared to previous designs

A new fiducial marker for Image-guided radiotherapy of prostate cancer: clinical experience.

Science.gov (United States)

Carl, Jesper; Nielsen, Jane; Holmberg, Mats; Højkjaer Larsen, Erik; Fabrin, Knud; Fisker, Rune V

2008-01-01

A new fiducial marker for image guided radiotherapy (IGRT) based on a removable prostate stent made of Ni Ti has been developed during two previous clinical feasibility studies. The marker is currently being evaluated for IGRT treatment in a third clinical study. The new marker is used to co-register MR and planning CT scans with high accuracy in the region around the prostate. The co-registered MR-CT volumes are used for delineation of GTV before planning. In each treatment session the IGRT system is used to position the patient before treatment. The IGRT system use a stereo pair of kV images matched to corresponding Digital Reconstructed Radiograms (DRR) from the planning CT scan. The match is done using mutual gray scale information. The pair of DRR's for positioning is created in the IGRT system with a threshold in the Look Up Table (LUT). The resulting match provides the necessary shift in couch coordinates to position the stent with an accuracy of 1-2 mm within the planned position. At the present time 39 patients have received the new marker. Of the 39 one has migrated to the bladder. Deviations of more than 5 mm between CTV outlined on CT and MR are seen in several cases and in anterior-posterior (AP), left-right (LR) and cranial-caudal (CC) directions. Intra-fraction translation movements up to +/- 3 mm are seen as well. As the stent is also clearly visible on images taken with high voltage x-rays using electronic portal images devices (EPID), the positioning has been verified independently of the IGRT system. The preliminary result of an on going clinical study of a Ni Ti prostate stent, potentially a new fiducial marker for image guided radiotherapy, looks promising. The risk of migration appears to be much lower compared to previous designs.

A new fiducial marker for Image-guided radiotherapy of prostate cancer: Clinical experience

International Nuclear Information System (INIS)

Carl, Jesper; Nielsen, Jane; Holmberg, Mats; Hoejkjaer Larsen, Erik; Fabrin, Knud; Fisker, Rune V.

2008-01-01

Background. A new fiducial marker for image guided radiotherapy (IGRT) based on a removable prostate stent made of Ni Ti has been developed during two previous clinical feasibility studies. The marker is currently being evaluated for IGRT treatment in a third clinical study. Method. The new marker is used to co-register MR and planning CT scans with high accuracy in the region around the prostate. The co-registered MR-CT volumes are used for delineation of GTV before planning. In each treatment session the IGRT system is used to position the patient before treatment. The IGRT system use a stereo pair of kV images matched to corresponding Digital Reconstructed Radiograms (DRR) from the planning CT scan. The match is done using mutual gray scale information. The pair of DRR's for positioning is created in the IGRT system with a threshold in the Look Up Table (LUT). The resulting match provides the necessary shift in couch coordinates to position the stent with an accuracy of 1-2 mm within the planned position. Results. At the present time 39 patients have received the new marker. Of the 39 one has migrated to the bladder. Deviations of more than 5 mm between CTV outlined on CT and MR are seen in several cases and in anterior-posterior (AP), left-right (LR) and cranial-caudal (CC) directions. Intra-fraction translation movements up to +/- 3 mm are seen as well. As the stent is also clearly visible on images taken with high voltage x-rays using electronic portal images devices (EPID), the positioning has been verified independently of the IGRT system. Discussion. The preliminary result of an on going clinical study of a Ni Ti prostate stent, potentially a new fiducial marker for image guided radiotherapy, looks promising. The risk of migration appears to be much lower compared to previous designs

Preoperative imaging as the basis for image-guided neurosurgery

International Nuclear Information System (INIS)

Winkler, D.; Strauss, G.; Hesse, S.; Sabri, O.; Goldammer, A.; Meixensberger, J.; Hund-Georgiadis, M.; Richter, A.; Kahn, T.

2004-01-01

With the progressive development of soft- and hardware, the acceptance of image-guided neurosurgery has increased dramatically. Additional image data are required to analyze the nature and the dimensions of pathological processes and the surrounding tissue. In this context, fMRI, SPECT, PET, as well as special modalities of CT and MR imaging, are routinely used. Secondary post-processing options are used to detect intracerebral lesions as well as adjacent functional eloquent regions in the parenchymatous organ pre- and intraoperatively. The integration of different image information guarantees the precise planning and realization of surgical maneuvers. The segmentation of interesting structures and risk structures, as well as their implementation in the neuronavigation systems, help to avoid additional intraoperative traumatization and offer a higher level of safety and precision. In this article the value and limitations of presurgical imaging will be discussed. (orig.) [de

Results of high intensity afterloading irradiation with 192 iridium in the therapy of genital tumors in women under different dose rates, fractionations and total doses in comparison with conventional radium contact irradiation. Ergebnisse der High-Intensity-Afterloadingbestrahlung mit 192 Iridium in der Therapie von Genitaltumoren der Frau unter verschiedenen Dosisleistungen, Fraktionierungen und Gesamtdosen im Vergleich mit konventioneller Radiumkontaktbestrahlung

Energy Technology Data Exchange (ETDEWEB)

Giers, G

1986-05-07

In comparison to conventional radium therapy are to be evaluated the results of the high intensity afterloading technique with the help of the parameters survial rate and complication rate. Thereby were included in the examination 4 documentations of results (collum, cervix stump, corpus and vaginal carcinoma) with altogether 742 patients with 2806 single irradiations and an evaluation of the therapy after several modifications of the therapy schemes. The 5-year survival rate was in the case of collum carcinoma: 68.4%, cervix stump: 50%, corpus carcinoma: 76%, and vaginal carcinoma: 66.6%. The corresponding 3-year survival rates were: 74.2%, 80%, 84% and 70% with primary irradiation. Only with cervix stump carcinoma were the values for post-operative irradiation. The description of the irradiation results showed, that with the changing of the fractionation mode and the dose level in collum and corpus carcinoma the irreversible complications as an expression of the success of a new therapy were reduced. The for now best suited therapy schema (fractionation and dosing) are described. (TRV).

Postcontrast T1-weighted brain magnetic resonance imaging in pediatric patients: comparison between postcontrast fat-suppression imaging and conventional T1-weighted or magnetization transfer imaging

International Nuclear Information System (INIS)

Lee, Choong Wook; Goo, Hyun Woo

2004-01-01

We wished to assess the merits and weaknesses of postcontrast fat-suppression (FS) brain MR imaging in children for the evaluation of various enhancing lesions as compared with postcontrast conventional T1-weighted or magnetization transfer (MT) imaging. We reviewed the records of those patients with enhancing lesions on brain MR imaging who had undergone both FS imaging and one of the conventional T1-weighted or MT imaging as a post-contrast T1-weighted brain MR imaging. Thirty-one patients (21 male, 10 female; mean age, 8.7 years) with 38 enhancing lesions (18 intra-axial, 16 extra-axial and 4 orbital locations) were included in this study. There were 27 pairs of FS and conventional imagings, and 13 pairs of FS and MT imagings available for evaluation. Two radiologists visually assessed by consensus the lesions' conspicuity, and they also looked for the presence of flow or susceptibility artifacts in a total of 40 pairs of MR imagings. For 19 measurable lesions (14 pairs of FS and conventional T1-weighted imagings, 5 pairs of FS and MT imagings), the contrast ratios between the lesion and the normal brain ([SIlesion-SIwater]/[SInormal brain-SIwater]) were calculated and compared. Compared with conventional imaging, the lesion conspicuity on FS imaging was better in 10 cases (7 extra-axial lesions, 2 orbital lesions and 1 fat-containing intra-axial lesion), equal in 16 cases, and worse in one case. Compared with MT imaging, the lesion conspicuity on FS imaging was better in 3 cases (2 extra-axial lesions and 1 intra-axial lesion), equal in 8 cases, and worse in 2 cases. Image quality of FS imaging was compromised by flow or susceptibility artifacts for 7 patients. The contrast ratios for FS imaging were not significantly different from those for conventional imaging (2.2±0.7 vs. 2.2±0.6, respectively, p=0.914) and they were significantly lower than those for MT imaging (2.4±0.8 vs. 4.5±1.5, respectively, p=0.018). Postcontrast FS brain MR imaging appears to be

Functional imaging to monitor vascular and metabolic response in canine head and neck tumors during fractionated radiotherapy.

Science.gov (United States)

Rødal, Jan; Rusten, Espen; Søvik, Åste; Skogmo, Hege Kippenes; Malinen, Eirik

2013-10-01

Radiotherapy causes alterations in tumor biology, and non-invasive early assessment of such alterations may become useful for identifying treatment resistant disease. The purpose of the current work is to assess changes in vascular and metabolic features derived from functional imaging of canine head and neck tumors during fractionated radiotherapy. Material and methods. Three dogs with spontaneous head and neck tumors received intensity-modulated radiotherapy (IMRT). Contrast-enhanced cone beam computed tomography (CE-CBCT) at the treatment unit was performed at five treatment fractions. Dynamic (18)FDG-PET (D-PET) was performed prior to the start of radiotherapy, at mid-treatment and at 3-12 weeks after the completion of treatment. Tumor contrast enhancement in the CE-CBCT images was used as a surrogate for tumor vasculature. Vascular and metabolic tumor parameters were further obtained from the D-PET images. Changes in these tumor parameters were assessed, with emphasis on intra-tumoral distributions. Results. For all three patients, metabolic imaging parameters obtained from D-PET decreased from the pre- to the inter-therapy session. Correspondingly, for two of three patients, vascular imaging parameters obtained from both CE-CBCT and D-PET increased. Only one of the tumors showed a clear metabolic response after therapy. No systematic changes in the intra-tumor heterogeneity in the imaging parameters were found. Conclusion. Changes in vascular and metabolic parameters could be detected by the current functional imaging methods. Vascular tumor features from CE-CBCT and D-PET corresponded well. CE-CBCT is a potential method for easy response assessment when the patient is at the treatment unit.

Super-Resolution Enhancement From Multiple Overlapping Images: A Fractional Area Technique

Science.gov (United States)

Michaels, Joshua A.

With the availability of large quantities of relatively low-resolution data from several decades of space borne imaging, methods of creating an accurate, higher-resolution image from the multiple lower-resolution images (i.e. super-resolution), have been developed almost since such imagery has been around. The fractional-area super-resolution technique developed in this thesis has never before been documented. Satellite orbits, like Landsat, have a quantifiable variation, which means each image is not centered on the exact same spot more than once and the overlapping information from these multiple images may be used for super-resolution enhancement. By splitting a single initial pixel into many smaller, desired pixels, a relationship can be created between them using the ratio of the area within the initial pixel. The ideal goal for this technique is to obtain smaller pixels with exact values and no error, yielding a better potential result than those methods that yield interpolated pixel values with consequential loss of spatial resolution. A Fortran 95 program was developed to perform all calculations associated with the fractional-area super-resolution technique. The fractional areas are calculated using traditional trigonometry and coordinate geometry and Linear Algebra Package (LAPACK; Anderson et al., 1999) is used to solve for the higher-resolution pixel values. In order to demonstrate proof-of-concept, a synthetic dataset was created using the intrinsic Fortran random number generator and Adobe Illustrator CS4 (for geometry). To test the real-life application, digital pictures from a Sony DSC-S600 digital point-and-shoot camera with a tripod were taken of a large US geological map under fluorescent lighting. While the fractional-area super-resolution technique works in perfect synthetic conditions, it did not successfully produce a reasonable or consistent solution in the digital photograph enhancement test. The prohibitive amount of processing time (up to

Effect of biological characteristics of different types of uterine fibroids, as assessed with T2-weighted magnetic resonance imaging, on ultrasound-guided high-intensity focused ultrasound ablation.

Science.gov (United States)

Zhao, Wen-Peng; Chen, Jin-Yun; Chen, Wen-Zhi

2015-02-01

The aims of this study were to assess the effects of the biological characteristics of different types of uterine fibroids, as assessed with T2-weighted magnetic resonance imaging (MRI), on ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation. Thirty-five patients with 39 symptomatic uterine fibroids who underwent myomectomy or hysterectomy were enrolled. Before surgery, the uterine fibroids were subdivided into hypo-intense, iso-intense, heterogeneous hyper-intense and homogeneous hyper-intense categories based on signal intensity on T2-weighted MRI. Tissue density and moisture content were determined in post-operative samples and normal uterine tissue, the isolated uterine fibroids were subjected to USgHIFU, and the extent of ablation was measured using triphenyltetrazolium chloride. Hematoxylin and eosin staining and sirius red staining were undertaken to investigate the organizational structure of the uterine fibroids. Estrogen and progesterone receptor expression was assayed via immunohistochemical staining. The mean diameter of uterine fibroids was 6.9 ± 2.8 cm. For all uterine fibroids, the average density and moisture content were 10.7 ± 0.7 mg/mL and 75.7 ± 2.4%, respectively; and for the homogeneous hyper-intense fibroids, 10.3 ± 0.5 mg/mL and 76.6 ± 2.3%. The latter subgroup had lower density and higher moisture content compared with the other subgroups. After USgHIFU treatment, the extent of ablation of the hyper-intense fibroids was 102.7 ± 42.1 mm(2), which was significantly less than those of the hypo-intense and heterogeneous hyper-intense fibroids. Hematoxylin and eosin staining and sirius red staining revealed that the homogeneous hyper-intense fibroids had sparse collagen fibers and abundant cells. Immunohistochemistry results revealed that estrogen and progesterone receptors were highly expressed in the homogeneous hyper-intense fibroids. This study revealed that lower density, higher moisture content, sparse collagen

Conventional 3T brain MRI and diffusion tensor imaging in the diagnostic workup of early stage parkinsonism

International Nuclear Information System (INIS)

Meijer, Frederick J.A.; Rumund, Anouke van; Tuladhar, Anil M.; Aerts, Marjolein B.; Titulaer, Imke; Esselink, Rianne A.J.; Bloem, Bastiaan R.; Verbeek, Marcel M.; Goraj, Bozena

2015-01-01

The aim of this study is to evaluate whether the diagnostic accuracy of 3 T brain MRI is improved by region of interest (ROI) measures of diffusion tensor imaging (DTI), to differentiate between neurodegenerative atypical parkinsonism (AP) and Parkinson's disease (PD) in early stage parkinsonism. We performed a prospective observational cohort study of 60 patients presenting with early stage parkinsonism and initial uncertain diagnosis. At baseline, patients underwent a 3 T brain MRI including DTI. After clinical follow-up (mean 28.3 months), diagnoses could be made in 49 patients (30 PD and 19 AP). Conventional brain MRI was evaluated for regions of atrophy and signal intensity changes. Tract-based spatial statistics and ROI analyses of DTI were performed to analyze group differences in mean diffusivity (MD) and fractional anisotropy (FA), and diagnostic thresholds were determined. Diagnostic accuracy of conventional brain MRI and DTI was assessed with the receiver operating characteristic (ROC). Significantly higher MD of the centrum semiovale, body corpus callosum, putamen, external capsule, midbrain, superior cerebellum, and superior cerebellar peduncles was found in AP. Significantly increased MD of the putamen was found in multiple system atrophy-parkinsonian form (MSA-P) and increased MD in the midbrain and superior cerebellar peduncles in progressive supranuclear palsy (PSP). The diagnostic accuracy of brain MRI to identify AP as a group was not improved by ROI measures of MD, though the diagnostic accuracy to identify MSA-P was slightly increased (AUC 0.82 to 0.85). The diagnostic accuracy of brain MRI to identify AP as a group was not improved by the current analysis approach to DTI, though DTI measures could be of added value to identify AP subgroups. (orig.)

Conventional 3T brain MRI and diffusion tensor imaging in the diagnostic workup of early stage parkinsonism

Energy Technology Data Exchange (ETDEWEB)

Meijer, Frederick J.A. [Radboud University Nijmegen Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Rumund, Anouke van; Tuladhar, Anil M.; Aerts, Marjolein B.; Titulaer, Imke; Esselink, Rianne A.J.; Bloem, Bastiaan R. [Radboud University Nijmegen Medical Center, Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen (Netherlands); Verbeek, Marcel M. [Radboud University Nijmegen Medical Center, Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen (Netherlands); Radboud University Nijmegen Medical Center, Department of Laboratory Medicine, Nijmegen (Netherlands); Goraj, Bozena [Radboud University Nijmegen Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Medical Center of Postgraduate Education, Department of Diagnostic Imaging, Warsaw (Poland)

2015-07-15

The aim of this study is to evaluate whether the diagnostic accuracy of 3 T brain MRI is improved by region of interest (ROI) measures of diffusion tensor imaging (DTI), to differentiate between neurodegenerative atypical parkinsonism (AP) and Parkinson's disease (PD) in early stage parkinsonism. We performed a prospective observational cohort study of 60 patients presenting with early stage parkinsonism and initial uncertain diagnosis. At baseline, patients underwent a 3 T brain MRI including DTI. After clinical follow-up (mean 28.3 months), diagnoses could be made in 49 patients (30 PD and 19 AP). Conventional brain MRI was evaluated for regions of atrophy and signal intensity changes. Tract-based spatial statistics and ROI analyses of DTI were performed to analyze group differences in mean diffusivity (MD) and fractional anisotropy (FA), and diagnostic thresholds were determined. Diagnostic accuracy of conventional brain MRI and DTI was assessed with the receiver operating characteristic (ROC). Significantly higher MD of the centrum semiovale, body corpus callosum, putamen, external capsule, midbrain, superior cerebellum, and superior cerebellar peduncles was found in AP. Significantly increased MD of the putamen was found in multiple system atrophy-parkinsonian form (MSA-P) and increased MD in the midbrain and superior cerebellar peduncles in progressive supranuclear palsy (PSP). The diagnostic accuracy of brain MRI to identify AP as a group was not improved by ROI measures of MD, though the diagnostic accuracy to identify MSA-P was slightly increased (AUC 0.82 to 0.85). The diagnostic accuracy of brain MRI to identify AP as a group was not improved by the current analysis approach to DTI, though DTI measures could be of added value to identify AP subgroups. (orig.)

Comparison of trans-perineal ultrasound-guided pressure augmented saline colostomy distension study and conventional contrast radiographic colostography in children with anorectal malformation.

Science.gov (United States)

Ekwunife, Okechukwu Hyginus; Umeh, Eric Okechukwu; Ugwu, Jideofor Okechukwu; Ebubedike, Uzoamaka Rufina; Okoli, Chinedu Christian; Modekwe, Victor Ifeanyichukwu; Elendu, Kelechi Collins

2016-01-01

In children with high and intermediate anorectal malformation, distal colostography is an important investigation done to determine the relationship between the position of the rectal pouch and the probable site of the neo-anus as well as the presence or absence of a fistula. Conventionally, this is done using contrast with fluoroscopy or still X-ray imaging. This, however, has the challenges of irradiation, availability and affordability, especially in developing countries. This study compared the accuracy of trans-perineal ultrasound-guided pressure augmented saline colostomy distension study (SCDS) with conventional contrast distal colostography (CCDC) in the determination of the precise location of the distal rectal pouch and in detecting the presence and site of fistulous communication between the rectum and the urogenital tract was studied. Trans-perineal ultrasound-guided pressure augmented SCDS, CCDC and intra-operative measurements were done sequentially for qualified infants with anorectal malformation and colostomy. Pouch skin distance and presence or absence of recto urinary or genital fistula was measured prospectively in each case. Statistical significance was inferred at P-value of 0.01. On its ability to detect presence or absence of a fistula: SCDS had a sensitivity of 50.0%, specificity of 100.0%, accuracy of 69.2%, negative predictive value of fistulas of 55.6% and a positive predictive value of fistulas of 100.0%. Ultrasound-guided pressure augmented SCDS can safely and reliably be used to assess the distal colonic anatomy and the presence of fistula in infants with Anorectal malformation who are on colostomy.

Usefulness of automated biopsy guns in image-guided biopsy

International Nuclear Information System (INIS)

Lee, Jung Hyung; Rhee, Chang Soo; Lee, Sung Moon; Kim, Hong; Woo, Sung Ku; Suh, Soo Jhi

1994-01-01

To evaluate the usefulness of automated biopsy guns in image-guided biopsy of lung, liver, pancreas and other organs. Using automated biopsy devices, 160 biopsies of variable anatomic sites were performed: Biopsies were performed under ultrasonographic(US) guidance in 95 and computed tomographic (CT) guidance in 65. We retrospectively analyzed histologic results and complications. Specimens were adequate for histopathologic diagnosis in 143 of the 160 patients(89.4%)-Diagnostic tissue was obtained in 130 (81.3%), suggestive tissue obtained in 13(8.1%), and non-diagnostic tissue was obtained in 14(8.7%). Inadequate tissue was obtained in only 3(1.9%). There was no statistically significant difference between US-guided and CT-guided percutaneous biopsy. There was no occurrence of significant complication. We have experienced mild complications in only 5 patients-2 hematuria and 2 hematochezia in transrectal prostatic biopsy, and 1 minimal pneumothorax in CT-guided percutaneous lung biopsy. All of them were resolved spontaneously. The image-guided biopsy using the automated biopsy gun was a simple, safe and accurate method of obtaining adequate specimen for the histopathologic diagnosis

Usefulness of automated biopsy guns in image-guided biopsy

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung Hyung; Rhee, Chang Soo; Lee, Sung Moon; Kim, Hong; Woo, Sung Ku; Suh, Soo Jhi [School of Medicine, Keimyung University, Daegu (Korea, Republic of)

1994-12-15

To evaluate the usefulness of automated biopsy guns in image-guided biopsy of lung, liver, pancreas and other organs. Using automated biopsy devices, 160 biopsies of variable anatomic sites were performed: Biopsies were performed under ultrasonographic(US) guidance in 95 and computed tomographic (CT) guidance in 65. We retrospectively analyzed histologic results and complications. Specimens were adequate for histopathologic diagnosis in 143 of the 160 patients(89.4%)-Diagnostic tissue was obtained in 130 (81.3%), suggestive tissue obtained in 13(8.1%), and non-diagnostic tissue was obtained in 14(8.7%). Inadequate tissue was obtained in only 3(1.9%). There was no statistically significant difference between US-guided and CT-guided percutaneous biopsy. There was no occurrence of significant complication. We have experienced mild complications in only 5 patients-2 hematuria and 2 hematochezia in transrectal prostatic biopsy, and 1 minimal pneumothorax in CT-guided percutaneous lung biopsy. All of them were resolved spontaneously. The image-guided biopsy using the automated biopsy gun was a simple, safe and accurate method of obtaining adequate specimen for the histopathologic diagnosis.

Targeting intensive versus conventional glycaemic control for type 1 diabetes mellitus

DEFF Research Database (Denmark)

Kähler, Pernille; Grevstad, Berit; Almdal, Thomas

2014-01-01

OBJECTIVE: To assess the benefits and harms of targeting intensive versus conventional glycaemic control in patients with type 1 diabetes mellitus. DESIGN: A systematic review with meta-analyses and trial sequential analyses of randomised clinical trials. DATA SOURCES: The Cochrane Library, MEDLINE......, EMBASE, Science Citation Index Expanded and LILACS to January 2013. STUDY SELECTION: Randomised clinical trials that prespecified different targets of glycaemic control in participants at any age with type 1 diabetes mellitus were included. DATA EXTRACTION: Two authors independently assessed studies...... for inclusion and extracted data. RESULTS: 18 randomised clinical trials included 2254 participants with type 1 diabetes mellitus. All trials had high risk of bias. There was no statistically significant effect of targeting intensive glycaemic control on all-cause mortality (risk ratio 1.16, 95% CI 0.65 to 2...

The first clinical implementation of real-time image-guided adaptive radiotherapy using a standard linear accelerator.

Science.gov (United States)

Keall, Paul J; Nguyen, Doan Trang; O'Brien, Ricky; Caillet, Vincent; Hewson, Emily; Poulsen, Per Rugaard; Bromley, Regina; Bell, Linda; Eade, Thomas; Kneebone, Andrew; Martin, Jarad; Booth, Jeremy T

2018-04-01

Until now, real-time image guided adaptive radiation therapy (IGART) has been the domain of dedicated cancer radiotherapy systems. The purpose of this study was to clinically implement and investigate real-time IGART using a standard linear accelerator. We developed and implemented two real-time technologies for standard linear accelerators: (1) Kilovoltage Intrafraction Monitoring (KIM) that finds the target and (2) multileaf collimator (MLC) tracking that aligns the radiation beam to the target. Eight prostate SABR patients were treated with this real-time IGART technology. The feasibility, geometric accuracy and the dosimetric fidelity were measured. Thirty-nine out of forty fractions with real-time IGART were successful (95% confidence interval 87-100%). The geometric accuracy of the KIM system was -0.1 ± 0.4, 0.2 ± 0.2 and -0.1 ± 0.6 mm in the LR, SI and AP directions, respectively. The dose reconstruction showed that real-time IGART more closely reproduced the planned dose than that without IGART. For the largest motion fraction, with real-time IGART 100% of the CTV received the prescribed dose; without real-time IGART only 95% of the CTV would have received the prescribed dose. The clinical implementation of real-time image-guided adaptive radiotherapy on a standard linear accelerator using KIM and MLC tracking is feasible. This achievement paves the way for real-time IGART to be a mainstream treatment option. Copyright © 2018 Elsevier B.V. All rights reserved.