The inverse square law: A basic principle in brachytherapy.

The purpose of this article is to remind the importance of the inverse square law in radiotherapy and especially in brachytherapy. Indeed, beyond the impact in radiation therapy with high energy beam, there is the use of radionuclides and low energy photons with short FSD where it is still more important. Comparisons between Iridium Brachytherapy and low energy X-rays brachytherapy show equivalent dose distributions in the first few centimeters.

Organ or sphincter preservation for rectal cancer. The role of contact X-ray brachytherapy in a monocentric series of 112 patients.

Background: Contact X-ray brachytherapy (CXB) has been used at Centre Antoine Lacassagne since 2002 to increase the chance of conservative treatment (organ or sphincter preservation) in rectal cancer. A consecutive series of 112 patients (pts) is reported.

Methods: Three protocols were used in selected rectal adenocarcinomas.

Combination of phosphotidylinositol-3-kinase targeting with cetuximab and irradiation: A preclinical study on an orthotopic xenograft model of head and neck cancer.

Background: The purpose of this study was to investigate the effects of combining the phosphotidylinositol-3-kinase (PI3K) inhibitor buparlisib (BKM)120 with the anti-epidermal growth factor receptor (EGFR) agent cetuximab and radiotherapy (RT) on an orthotopic model of head and neck squamous cell carcinoma (HNSCC).

Methods: We evaluated the antitumor efficacy of BKM120, cetuximab, and RT, administered alone or in combination, using the human PIK3CA-mutated HNSCC cell line, CAL33, injected into the floor of the mouth of nude mice.

Results: Compared with control, the BKM120-cetuximab and the BKM120-cetuximab-RT combinations led to the highest tumor inhibition (p < .

Assessment and quantification of patient set-up errors in nasopharyngeal cancer patients and their biological and dosimetric impact in terms of generalized equivalent uniform dose (gEUD), tumour control probability (TCP) and normal tissue complication probability (NTCP).

Objective: The aim of this study is to assess and quantify patients' set-up errors using an electronic portal imaging device and to evaluate their dosimetric and biological impact in terms of generalized equivalent uniform dose (gEUD) on predictive models, such as the tumour control probability (TCP) and the normal tissue complication probability (NTCP).

Methods: 20 patients treated for nasopharyngeal cancer were enrolled in the radiotherapy-oncology department of HCA. Systematic and random errors were quantified.

Effects and consequences of Digisonic SP cochlear implant on radiotherapy planning.

The aim of this study was to assess dose attenuation by a Digisonic SP cochlear implant (CI) and evaluate its impact on treatment planning. The Digisonic CI was irradiated with 6 MV photons. Overall dose attenuation was assessed with MOSFET dosimeters and Gafchromic films.

[Safety in brachytherapy].

No technique can now be used without previously considering the safety of patients, staff and public and risk management. This is the case for brachytherapy. The various aspects of brachytherapy are discussed for both the patient and the staff.

Knock-down of hypoxia-induced carbonic anhydrases IX and XII radiosensitizes tumor cells by increasing intracellular acidosis.

The relationship between acidosis within the tumor microenvironment and radioresistance of hypoxic tumor cells remains unclear. Previously we reported that hypoxia-induced carbonic anhydrases (CA) IX and CAXII constitute a robust intracellular pH (pH(i))-regulating system that confers a survival advantage on hypoxic human colon carcinoma LS174Tr cells in acidic microenvironments. Here we investigate the role of acidosis, CAIX and CAXII knock-down in combination with ionizing radiation.

Renaissance of contact x-ray therapy for treating rectal cancer.

Contact x-ray therapy (CXRT) with 50 kV has proven to be an efficient radiation therapy technique to achieve local control and rectal preservation for early rectal adenocarcinoma. Despite these results, CXRT has not been used due to the shortage of the no longer manufactured Philips RT 50™ unit. Recently, a new CXRT machine (Papillon 50™) became available on the market.

Dentalmaps: automatic dental delineation for radiotherapy planning in head-and-neck cancer.

Purpose: To propose an automatic atlas-based segmentation framework of the dental structures, called Dentalmaps, and to assess its accuracy and relevance to guide dental care in the context of intensity-modulated radiotherapy.

Methods And Materials: A multi-atlas-based segmentation, less sensitive to artifacts than previously published head-and-neck segmentation methods, was used. The manual segmentations of a 21-patient database were first deformed onto the query using nonlinear registrations with the training images and then fused to estimate the consensus segmentation of the query.

[Pacemaker, implanted cardiac defibrillator and irradiation: Management proposal in 2010 depending on the type of cardiac stimulator and prognosis and location of cancer].

Ionizing radiation may interfere with electric components of pacemakers or implantable cardioverter-defibrillators. The type, severity and extent of radiation damage to pacemakers, have previously been shown to depend on the total dose and dose rate. Over 300,000 new cancer cases are treated yearly in France, among which 60% are irradiated in the course of their disease.

[Cyberknife robotic stereotactic radiotherapy: technical aspects and recent developments].

Cyberknife (Accuray Inc. Sunnyvale, USA) stereotactic body radiation therapy (SBRT) involves the delivery of a small number of large doses of radiation to a target volume using continuously evolving advanced technology. It has emerged as a novel treatment modality for cancer and modified some concepts of cancer treatment.

[Current indications and ongoing clinical trials with CyberKnife stereotactic radiotherapy in France in 2009].

Image-guided frameless fractionated stereotactic radiotherapy can be performed with millimetric accuracy using the CyberKnife (Accuray Inc. Sunnyvale, USA) equipped with an integrated tracking system for intra- and extracranial lesions. Highly conformal hypofractionated irradiation has been used to treat lesions with curative or palliative intent.

CyberKnife stereotactic radiotherapy for spinal tumors: value of computed tomographic myelography in spinal cord delineation.

Objective: For para- and intraspinal tumors, precise spinal cord delineation is critical for CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiotherapy. We evaluated whether computed tomographic (CT) myelography is superior to magnetic resonance imaging (MRI) for accurate spinal cord delineation.

[State of the art and advances in radiotherapy for bladder cancer].

Radical cystectomy is the treatment of choice for nonmetastatic, muscle-infiltrating bladder cancer. However, bladder-sparing approaches can be discussed in carefully selected patients. Bladder-preservation protocols aim to guaranty local control and survival with a functional bladder and a good quality of life.

[Accelerated partial breast irradiation using interstitial high dose rate brachytherapy: preliminary clinical and dosimetric results after 61 patients].

Purpose: Among all the accelerated and partial breast irradiation (APBI) techniques, low then high dose rate, interstitial brachytherapy (HDIB) was the first to be used in this field. This study presents the preliminary clinical and dosimetric results of the APBI using HDIB, performed in Antoine Lacassagne Cancer Center of Nice.

Patients And Methods: From June 2004 to March 2008, 61 patients (37 primary tumors and 24 second conservative treatments after local recurrence) presenting with T1-2 pN0 non-lobular invasive breast carcinoma, underwent lumpectomy with sentinel lymph node dissection and intraoperative tube placement for HDIB.

[CyberKnife robotic stereotactic radiotherapy: technical aspects and medical indications].

In 2006, 3 sites have been selected by the Institut national of cancer (Lille, Nancy et Nice) to evaluate a radiotherapy robot, the CyberKnife. This machine, able to track mobile tumours in real time, gives new possibilities in the field of extra cranial stereotactic radiotherapy. Functionalities and medico economical issues of the machine will be evaluated during 2 years on the 3 sites.

[Robotic radiotherapy for prostate cancer with CyberKnife].

After 3D conformal radiation therapy without and with modulated intensity, image-guided radiation therapy represents a new technological step. Should prostate cancer treatment using radiotherapy with the CyberKnife robotic system be considered as a new treatment and then investigated through classical clinical research procedure rather than a technical improvement of an already validated treatment? After a general presentation of the CyberKnife , the authors focused on prostate cancer treatment assuming that, according to dosimetric and biological considerations, the treatment by robotic system appears comparable to high dose rate brachytherapy. For prostate cancer treatment are discussed: biological rational for hypofractionated treatment, high dose rate brachytherapy boost and interest of dose escalation.

[The cost of intensity modulated radiation therapy in head and neck cancers: results of the 2002 STIC study].

An economic evaluation of intensity modulated radiotherapy (IMRT) in head and neck cancer was carried out to assess the cost of treatment and compare it to reimbursement paid to hospitals in the French Prospective Payment System. Planning required in average 20 hours of work for the physician and 6 hours for the radiation oncologist. Radiation consisted of 33 fractions in average and required 29 hours of work for the radiotherapy technician, 8 hours for the physician and 3 hours for the radiation oncologist.

Laparoscopic seminal vesicle and pelvic lymph node resection before high-dose three-dimensional conformal radiation therapy for localized prostate cancer. Results of a dosimetric study.

Purpose: To analyze the dosimetric implications of seminal vesicle (SV) resection at the time of laparoscopic pelvic lymph node (PLN) dissection in patients presenting with high-risk prostate cancer regarding PLN and SV involvement.

Patients And Methods: Between June and September 2005, twelve patients underwent laparoscopic SV resection and PLN dissection before delivering a total dose of 80 Gy through a three-dimensional conformal radiation therapy (3D-CRT). Dose-volume histograms (DVHs; rectum, bladder, femoral heads) were obtained from G1 (group 1 with SV) and G2 (group 2 without SV) according to either three- dimensional or intensity-modulated treatment planning.

Monte Carlo simulation of a medical linear accelerator for radiotherapy use.

A Monte Carlo code MCNPX (Monte Carlo N-particle) was used to model a 25 MV photon beam from a PRIMUS (KD2-Siemens) medical linear electron accelerator at the Centre Antoine Lacassagne in Nice. The entire geometry including the accelerator head and the water phantom was simulated to calculate the dose profile and the relative depth-dose distribution. The measurements were done using an ionisation chamber in water for different square field ranges.

In vivo measurements with MOSFET detectors in oropharynx and nasopharynx intensity-modulated radiation therapy.

Purpose: To evaluate the feasibility of in vivo measurements with metal oxide semiconductor field effect transistor (MOSFET) dosimeters for oropharynx and nasopharynx intensity-modulated radiation therapy (IMRT).

Methods And Materials: During a 1-year period, in vivo measurements of the dose delivered to one or two points of the oral cavity by IMRT were obtained with MOSFET dosimeters. Measurements were obtained during each session of 48 treatment plans for 21 patients, all of whom were fitted with a custom-made mouth plate.

[Preliminary results of the assessment of intensity modulated radiotherapy (IMRT) for prostatic and head and neck tumors (STIC 2001)].

Introduction: Between May 2002 and May 2004, eight French comprehensive cancer centres did a prospective nonrandomized study including 200 patients, 100 with cancer of the prostate and 100 with head and neck cancers. Half of each patient group was treated by IMRT and the others by RTC 3D. This clinical study was associated with an economic study and a physics study.

[Recommendations for a head and neck IMRT quality assurance protocol].

Head and neck tumors represent very interesting targets for IMRT techniques because of the complex shape of the structures and the organs at risk close by. The use of this kind of techniques requires a quality assurance protocol. The physicists of the GORTEC group shared their experience to define some recommendations in order to draw up a QA protocol.

Distinct MDM2 and P14ARF expression and centrosome amplification in well-differentiated liposarcomas.

Well-differentiated liposarcomas (WDLs) are common soft-tissue tumors in adults. They are characterized by large marker chromosomes and/or ring chromosomes containing 12q-derived sequences in which MDM2 is consistently amplified. WDLs are subdivided into two subtypes according to their karyotype.