Development and evaluation of an automated EPTN-consensus based organ at risk atlas in the brain on MRI.

Background And Purpose: During radiotherapy treatment planning, avoidance of organs at risk (OARs) is important. An international consensus-based delineation guideline was recently published with 34 OARs in the brain. We developed an MR-based OAR autosegmentation atlas and evaluated its performance compared to manual delineation.

Accelerated Partial Breast Irradiation Using External Beam or Intraoperative Electron Radiation Therapy: 5-Year Oncological Outcomes of a Prospective Cohort Study.

Purpose: To evaluate the ipsilateral breast tumor recurrence (IBTR) after 2 accelerated partial breast irradiation (APBI) techniques (intraoperative electron radiation therapy [IOERT] and external beam APBI [EB-APBI]) in patients with early-stage breast cancer.

Methods And Materials: Between 2011 and 2016, women ≥60 years of age with breast carcinoma or Ductal Carcinoma In Situ (DCIS) of ≤30 mm and cN0 undergoing breast-conserving therapy were included in a 2-armed prospective multicenter cohort study. IOERT (1 × 23.

Health-related quality of life of early-stage breast cancer patients after different radiotherapy regimens.

Purpose: To evaluate and compare health-related quality of life (HRQL) of women with early-stage breast cancer (BC) treated with different radiotherapy (RT) regimens.

Methods: Data were collected from five prospective cohorts of BC patients treated with breast-conserving surgery and different RT regimens: intraoperative RT (IORT, 1 × 23.3 Gy; n = 267), external beam accelerated partial breast irradiation (EB-APBI, 10 × 3.

Lower doses to hippocampi and other brain structures for skull-base meningiomas with intensity modulated proton therapy compared to photon therapy.

Background And Purpose: Radiotherapy of skull-base meningiomas is challenging due to the close proximity of multiple sensitive organs at risk (OARs). This study systematically compared intensity modulated proton therapy (IMPT), non-coplanar volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) based on automated treatment planning. Differences in OARs sparing, with specific focus on the hippocampi, and low-dose delivery were quantified.

Left-sided breast cancer radiotherapy with and without breath-hold: does IMRT reduce the cardiac dose even further?

Purpose: In radiotherapy for left-sided breast cancer, Active Breathing Control enables a decrease of cardiac and Left Anterior Descending (LAD) coronary artery dose. We compared 3D-Conformal (3D-CRT) to Intensity Modulated Radiotherapy (IMRT) treatment plans based on free-breathing (FB) and breath-hold (BH). We investigated whether IMRT enables an additional decrease of cardiac dose in radiotherapy plans with and without BH.

Preradiotherapy calcium scores of the coronary arteries in a cohort of women with early-stage breast cancer: a comparison with a cohort of healthy women.

Purpose: Breast cancer radiotherapy has been associated with an increased risk of cardiac toxicity. However, no data are available on the probability of developing coronary artery disease (CAD) in breast cancer patients when compared with healthy women. Therefore, baseline coronary artery calcium (CAC) scores, as an accepted tool to predict CAD, were determined and compared with the CAC scores of a healthy, asymptomatic cohort, the Multi-Ethnic Study of Atherosclerosis (MESA) cohort.

MRI- versus CT-based volume delineation of lumpectomy cavity in supine position in breast-conserving therapy: an exploratory study.

Purpose: To examine magnetic resonance imaging (MRI) and computed tomography (CT) for lumpectomy cavity (LC) volume delineation in supine radiotherapy treatment position and to assess the interobserver variability.

Methods And Materials: A total of 15 breast cancer patients underwent a planning CT and directly afterward MRI in supine radiotherapy treatment position. Then, 4 observers (2 radiation oncologists and 2 radiologists) delineated the LC on the CT and MRI scans and assessed the cavity visualization score (CVS).

Magnetic resonance imaging- versus computed tomography-based target volume delineation of the glandular breast tissue (clinical target volume breast) in breast-conserving therapy: an exploratory study.

Purpose: To examine MRI and CT for glandular breast tissue (GBT) volume delineation and to assess interobserver variability.

Methods And Materials: Fifteen breast cancer patients underwent a planning CT and MRI, consecutively, in the treatment position. Four observers (two radiation oncologists and two radiologists) delineated the GBT according to the CT and separately to the MR images.

Stereotactic radiotherapy of intracranial tumors: a comparison of intensity-modulated radiotherapy and dynamic conformal arc.

Purpose: Intensity-modulated radiotherapy (IMRT) and dynamic conformal arc (DCA) are two state-of-the-art techniques for linac-based stereotactic radiotherapy (SRT) using the micromultileaf collimator. The purpose of this planning study is to examine the relative merits of these techniques in the treatment of intracranial tumors.

Materials And Methods: SRT treatment plans were made for 25 patients with a glioma or meningioma.

Does 4 MV perform better compared to 6 MV in the presence of air cavities in the head and neck region?

Background And Purpose: The underdose near air cavities in the head and neck region at photon energies of 4 MV and 6 MV was studied in search for clinical advantages of the 4 MV over 6 MV treatments.

Materials And Methods: The on-axis and off-axis dose distributions were measured with a parallel-plate ionization chamber and films in polystyrene phantoms containing an air cavity of appropriate size based on the results of computed tomography scans.

Results: Although most results are similar for both energies, the 4 MV photon beams give a somewhat smaller underdose effect and a faster re-build up than the 6 MV.

How to assess post-occlusive reactive hyperaemia by means of laser Doppler perfusion monitoring: application of a standardised protocol to patients with peripheral arterial obstructive disease.

The standardisation of manoeuvres to perform clinically discriminative microvascular flow reserve tests is still poorly developed, as well as the response analysis. The aim of this study was to establish a reproducible analysis method for the post-occlusive reactive hyperaemia (PORH) test measured using laser Doppler perfusion monitoring (LDPM). LDPM data were measured from the PORH response of 24 Fontaine class II-III peripheral atherosclerotic/arterial obstructive disease (PAOD) patients and 30 healthy subjects.

Suppression of dynamic laser speckle signals in multimode fibers of various lengths.

The effects of fiber coupling and fiber length on photocurrent fluctuations are studied when the light of a laser diode transmitted to and from a dynamic turbid medium by a step-index multimode fiber is studied. When the laser light is coupled asymmetrically, filling only the higher-order modes, the photocurrent fluctuations are suppressed significantly when fiber lengths of as much as 16 m are added between the laser and the medium. Addition of as much as 16 m of detection fiber, or any fiber in the case of symmetric light coupling, leads to much less or no suppression of the photocurrent fluctuations.

Glass-fiber self-mixing intra-arterial laser Doppler velocimetry: signal stability and feedback analysis.

We have developed a blood velocimeter based on the principle of self-mixing in a semiconductor laser diode through an optical fiber. The intensity of the light is modulated by feedback from moving scattering particles that contain the Doppler-shift frequency. Upon feedback the characteristics of the laser diode change.