Unnecessary Dose Research Articles

Single grating method for low dose 1-D and 2-D phase contrast X-ray imaging

X-ray phase contrast imaging (XPCI) using a single absorption grating and a hybrid semiconductor pixel detector is a newly introduced approach with great potential for application in medicine, biology and material research. In comparison with a conventional grating interferometer technique, which requires a multiple-exposure (phase-stepping) procedure, our method is greatly simplified, because both phase gradient and absorption images are obtained from just one exposure. Consequently, the approach can significantly reduce the time-consuming scanning and also possibly the unnecessary dose. Examples of application of the single-grating approach as an imaging tool for investigations in biology are presented. Particularly, we present the extension of our 1-D single grating method to a two-direction sensitive technique. The novel 2-D sensitive XPCI method is based on precise sub-pixel position determination of the X-ray pattern projected by the two-dimensional transmission grating directly from the pattern image. In a single exposure, phase gradient images in two perpendicular directions together with the conventional attenuation image are produced. Results of the proof-of-concept experiment are presented.

Collective radiation dose from diagnostic x-ray examination in nine public hospitals in Addis Ababa, Ethiopia

Background: Medical x-ray exposures have the largest man made source of population exposure to ionizing radiation in different countries. Recent developments in medical imaging have led to rapid increases in a number of high dose xray examinations performed with significant consequences for individual patient doses and for collective dose to the population as a whole. It is therefore important in each country to make regular assessments of the magnitude of these large doses.Objectives: To calculate collective dose of the population as a result of radiation dose from diagnostic x-rays, thereby to estimate the annual incidence of cancer which would be reduced by the use of rare earth intensifying screen.Methods: Data on the number of diagnostic procedures using x-ray examination in year 2007 in nine governmental hospitals, excluding military hospitals, by body site were collected in Addis Ababa. The number of examinations of specific body site was multiplied by the average effective dose per examination to get the collective dose over the population. Based on International Commission on Radiological Protection (ICRP) the fatality risk of fatal cancers (5% per Sv) was estimated.Results: In this study, the annual collective dose over the population is 31.21manSv (0.0.42mSv per person). Based on ICRP fatality risk of 500 fatal cancers per 10,000 man-sieverts (5% per Sv), estimation of incidence of fatal cancers cases in year 2007 was 2 cases half of which can be reduced by adoption of rare earth screens.Conclusion: Although the use of ionizing radiation for diagnostic medical procedures is an acceptable part of modern medicine, there is also the potential for inappropriate use and unnecessary radiation dose to the patient, so the request of radiography must be justified. It is estimated that the adoption of rare earth screen technology might reduce the annual incidence of cancer which would be fatal after an average latency period of 18.4 years by half, hence this research recommended adopting rare earth screen technology in Ethiopia. [Ethiop. J. Health Dev. 2010;24(2):140-144]

212 Randomized Clinical Trial on Echocardiographically Guided (ECHOG) Versus Standard Ibuprofen Treatment (SIBT) for Patent Ductus Arteriosus (PDA): Pilot Study

Background: Pharmacological closure of PDA with SIbT protocol consists of three doses of ibuprofen (10-5-5 mg/k) given 24h apart. Associated side effects during treatment have been reported. Therefore, treatment strategies deserve further evaluation. Aims: To explore whether successful PDA closure with ibuprofen could be accomplished with a reduce number of doses. Methods: Preterm babies older than 12 h of postnatal life with PDA ≥ 1.5 mm were randomized to EchoG (additional ibuprofen doses only if PDA ≥1.5mm) or SIbT. Infants were serially scanned on days 1, 2, 3, 4, 7, 10 and 17 after being included in the study. The primary outcome was PDA reopening rate needing further treatment. Non-parametric tests were used for comparisons. Results: 17 (EchoG) and 28 (SIbT) infants were enrolled [gestational age 28 (2.2) vs 29.6 (2.7) wk, p< 0.05; birth weight 1032 (280) vs 1237 (382) g, p=0.08, respectively]. Patients received 2.8 (2.2) (EchoG) and 3.5 (1.3) (SIbT) (p=0.06) ibuprofen doses, at a mean age of 56.1 (17-168) h, without differences between groups. PDA was closed after the first ibuprofen dose in 44% of the study population. Rates for PDA reopening were 10.7% and 0% (p=0.28), and rates for surgical closure 28.6% and 5.9% (p=0.12), in EchoG and SIbT, respectively. Trends pointed towards lower incidence of necrotizing enterocolitis (7.1% and 17.6%, p=0.35), urine output change (+8% and -30% p=0.05), and serum creatinine rise (+5.9% and +34.2%, p=0.08) in EchoG vs SIbT. Conclusions: EchoG PDA treatment is a feasible strategy and avoids unnecessary ibuprofen doses.

Hard x-ray phase contrast imaging using single absorption grating and hybrid semiconductor pixel detector

A method for x-ray phase contrast imaging is introduced in which only one absorption grating and a microfocus x-ray source in a tabletop setup are used. The method is based on precise subpixel position determination of the x-ray pattern projected by the grating directly from the pattern image. For retrieval of the phase gradient and absorption image (both images obtained from one exposure), it is necessary to measure only one projection of the investigated object. Thus, our method is greatly simplified compared with the phase-stepping method and our method can significantly reduce the time-consuming scanning and possibly the unnecessary dose. Furthermore, the technique works with a fully polychromatic spectrum and gives ample variability in object magnification. Consequently, the approach can open the way to further widespread application of phase contrast imaging, e.g., into clinical practice. The experimental results on a simple testing object as well as on complex biological samples are presented.

Preparation of 177Lu-Labeled Oxine in Lipiodol as a Possible Agent for Therapy of Hepatocellular Carcinoma: A Preliminary Animal Study

Hepatocellular carcinoma (HCC) is one of the most prevalent forms of cancer with high morbidity. (131)I-lipiodol is used clinically and has been found to be effective for the treatment of HCC. However, this preparation has its limitations, including compromised yield and stability of exchange labeling and unnecessary dose burden from gamma emissions. In the present study, (177)Lu-oxine in lipiodol was considered as a possible alternative for radioiodinated lipiodol. Oxine or 8-hydroxyquinoline was labeled with (177)Lu obtained by neutron irradiation of natural lutetium. Under optimized conditions, the radiolabeled complex was obtained with yields >98% and adequate in vitro stability. (177)Lu-oxine dispersed in lipiodol showed appreciable uptake into rat liver cells (normal and HCC-induced) in vitro. (177)Lu-oxine-lipiodol showed initial localization in the liver, but subsequent leakage of radioactivity with deposition in the skeletal tissue was seen. The studies suggest that (177)Lu-oxine dispersed in lipiodol might not be suitable for treatment of HCC.

A Prospective Crossover Pilot Study to Evaluate the Use of a Topical Wound Gel in Patients with Cutaneous Toxicity Caused by Epidermal Growth Factor Receptor Inhibitors

One of the dose-limiting toxicities of epidermal growth factor receptor inhibitors (EGFRIs) is a papulopustular rash that is often pruritic and painful. Secondary skin infection can occur from scratching to relieve the pruritus. Studies suggest that this rash might be a surrogate marker for efficacy; therefore, effective rash management is needed to allow patients to use EGFRIs without unnecessary dose modifications. In this single-center, prospective, crossover study, we evaluated the use of a topical gel (Regenecare Wound Gel) for relieving the pruritus and pain of EGFRI-induced rash among oncology patients. The secondary end points were patient satisfaction, adverse effects, and EGFRI dose modifications. At the occurrence of grade 2 skin rash, patients started applying the study gel to the right side of their face; after 1 week, they began applying it to both sides of their face for up to an additional 5 weeks. Each week, providers performed a facial evaluation and patients rated their symptoms and satisfaction on questionnaires. Of the 20 patients enrolled, 13 were evaluable. Reduction in itch at the end of week 1 was greater on the right (treated) side in 69% of patients greater on the left (untreated) side in 8%, and the same in 23% (P = 0.01). The pattern was similar for pain, but the differences were not significant. On average, patients rated the gel as being moderately to extremely effective for alleviating symptoms, improving rash appearance, and promoting healing and found it easy to apply. No adverse effects were documented. Four patients (31%) required EGFRI dose modifications because of rash. Taken together, these findings suggest that the topical wound gel is effective in relieving rash-associated itching in patients receiving EGFRIs and is associated with high patient satisfaction.

Use of the anterior-posterior chest diameter in CT: reduction in radiation dose?

Use of the anterior-posterior chest diameter in CT: reduction in radiation dose?

SU-GG-T-104: Modulated Electron Radiotherapy for Bilateral Chest Wall Treatment

Purpose: To evaluate modulated electron radiotherapy (MERT) planning for delivery with the photon multicollimator (xMLC) for treatment of bilateral post-mastectomy chest wall treatment. Current techniques are complex, time consuming, and deficient in terms of target coverage and organ at risk (OAR) sparing. Conventional techniques require blocks and energy modifying bolus, while IMRT is volatile due to patient motion and provides unnecessary dose baths. Materials and Methods: An in-house Monte-Carlo-based MERT planning system has been developed for planning bilateral chest wall (MERT-biCW) treatment aided by previously developed in-house MERT optimization tools. The MERT-biCW planning was performed in three steps: 1) determine the number of portal fields needed to cover a PTV and partition the PTV into sub-PTVs for corresponding portals; 2) each sub-PTVs is then planned with MERT individually incorporating multiple energy assigned segments within each portal; 3) optimizing all portals to achieve the final plan. Several new features have been added to our MERT planning tools including; automatic selection of the best incident angle for each portal, whereby the distal surface of the tumor will be reached by selected energy and minimizing the air gap to <5 cm to maintain dose conformity. An algorithm has been developed to obtain optimal segments to facilitate target coverage and OAR sparing. Results: We typically covered the PTV with four portals for biCW. For a challenging case, we achieved acceptable PTV coverage with 80% isotope line covered by the prescription dose, and significantly reduced doses to OAR compared with conventional therapy. The V20 of left lung was reduced from 45.5 Gy to 36.9 Gy. V20 of heart was reduced from 18 to 5 Gy. Conclusions: MERT-biCW with its well-defined ranges and sharp fall-off is a promising alternative to conventional or IMRT post-mastectomy chest wall (CW) irradiation. Research is sponsored by Varian Grant.

Radiation dose optimisation in dynamic volume CT of the heart: tube current adaptation based on anterior–posterior chest diameter

To compare tube current adaptation based on 3 body mass index (BMI) categories versus anterior-posterior chest diameter (APD) for radiation dose optimisation in patients undergoing dynamic volume cardiac CT. Two cardiac imaging centres participated in the study. 20 patients underwent a prospectively triggered 320-slice single beat cardiac CT using the X-ray tube current [mA] manually adjusted to the patient's BMI (group I). In 20 subsequent patients, the tube current was adapted according to the patient's APD (group II). All other parameters were kept constant. Image noise was defined as the standard deviation of attenuation values and measured using a ROI in the descending aorta. Variation in image noise was statistically compared between both patient groups. Average and standard deviation of pixel noise were 29.1 HU and 14.8 HU in group I and 28.0 HU and 4.2 HU in group II. Inter-individual variation of pixel noise was significantly lower in group II compared to group I (p < 0.0001). Tube current adaptation based on APD is superior to stepwise adaptation based on BMI for optimising radiation dose in dynamic volume cardiac CT and therefore limits unnecessary radiation dose while ensuring diagnostic image quality in patients with diverse body habitus.

Specificity of a Circulating Antibody That Interferes With a Widely Used Tacrolimus Immunoassay

Accurate measurement of whole-blood tacrolimus concentration is essential for achieving therapeutic immunosuppression and minimizing toxicity in renal transplant recipients. Falsely elevated or decreased values may trigger unnecessary dose adjustments. We identified a falsely elevated whole-blood tacrolimus immunoassay result in a renal transplant patient. Twelve hours after the patient received his first dose, the blood concentration was 24.4 ng/mL using the Siemens Dimension RxL immunoassay. Immunoabsorption studies showed that the cause of the interference was an endogenous antibody present in the patient's plasma that recognized a unique epitope present on the antibody-enzyme (beta-galactosidase) conjugate used in the Siemens tacrolimus immunoassay but not on the antibody or beta-galactosidase alone. This report adds to the growing knowledge base of endogenous antibody interferences in diagnostic immunoassays. To our knowledge, this is the first such report of a falsely elevated tacrolimus concentration due to recognition of an epitope present only on the monoclonal antibody-enzyme conjugate.

Mammography radiation dose: initial results from Serbia based on mean glandular dose assessment for phantoms and patients

The primary objective of this study is to investigate the actual mammography dose levels in Serbia and establish a baseline dose database for the future screening programme. The mean glandular dose (MGD) was assessed for standard size breast substituted by 45 mm polymethyl methacrylate (PMMA) phantom and imaged under typical clinical conditions at 30 screen-film mammography facilities. Average MGD was (1.9 +/- 1.0) mGy, with a range of 0.12-5.2 mGy. These results were used for the calculation of the initial diagnostic reference levels in mammography in Serbia, which was set to 2.1 mGy for a standard breast. At some facilities, high doses were observed and the assessed MGD was supplemented by a patient dose survey. MGD was measured for 53 women having a diagnostic mammography in cranio-caudal (CC) and mediolateral oblique (MLO) projections at the largest mammography facilities in Serbia. The parameters recorded were: age, compressed breast thickness, tube potential (in kV), tube loading (in mAs) and the MLO projection angle. The average MGD per image was 2.8 mGy for the CC projection and 4.3 mGy for the MLO projection. Dose to breast was compared with dose for PMMA phantoms of various sizes, assessed at the same facilities. The results have indicated that phantom dose values can assist in setting optimisation activities in mammography. Both phantom and patient dose values indicated unnecessary high doses in facilities with an extremely high mammography workload. For these facilities, urgent dose-reduction measures and follow-up actions were recommended.

Filtered region of interest cone‐beam rotational angiography

Cone-beam rotational angiography (CBRA) is widely used in the modern clinical settings. In a number of procedures, the area of interest is often considerably smaller than the field of view (FOV) of the detector, subjecting the patient to potentially unnecessary x-ray dose. The authors therefore propose a filter-based method to reduce the dose in the regions of low interest, while supplying high image quality in the region of interest (ROI). For such procedures, the authors propose a method of filtered region of interest (FROI)-CBRA. In the authors' approach, a gadolinium filter with a circular central opening is placed into the x-ray beam during image acquisition. The central region is imaged with high contrast, while peripheral regions are subjected to a substantial lower intensity and dose through beam filtering. The resulting images contain a high contrast/intensity ROI, as well as a low contrast/intensity peripheral region, and a transition region in between. To equalize the two regions' intensities, the first projection of the acquisition is performed with and without the filter in place. The equalization relationship, based on Beer's law, is established through linear regression using corresponding filtered and nonfiltered data. The transition region is equalized based on radial profiles. Evaluations in 2D and 3D show no visible difference between conventional FROI-CBRA projection images and reconstructions in the ROI. CNR evaluations show similar image quality in the ROI, with a reduced CNR in the reconstructed peripheral region. In all filtered projection images, the scatter fraction inside the ROI was reduced. Theoretical and experimental dose evaluations show a considerable dose reduction; using a ROI half the original FOV reduces the dose by 60% for the filter thickness of 1.29 mm. These results indicate the potential of FROI-CBRA to reduce the dose to the patient while supplying the physician with the desired image detail inside the ROI.

An Assessment of Spinal Cord Dose Following Radiotherapy of Nasopharyngeal Cancer by TLD and Rando Phantom

Introduction: Nasopharyngeal carcinoma is one of the most common malignancies in the head and neck region and radiotherapy is its treatment of choice. In spite of the fact that it is widely used, due to the presence of many sensitive organs or tissues in this region, patients may suffer from a wide range of side effects. One such sensitive tissue is the spinal cord. If the absorbed dose to spinal cord is greater than its tolerance dose, then myelopathy and Lhermitte’s sign are not avoidable. Material and Methods: Thehead and neck of a Rando phantom (reference man) was employed as a hypothetical patient suffering from nasopharyngeal carcinoma. The full course of treatment consisted of three phases. At the beginning of every phase, an oncologist used a simulator to delineate the surface of the Rando Phantom for treatment. TLD chips (TLD-100) were employed for dose measurement. TLD chips were inserted in the previously made holes on the surface of selected slices adjacent to second cervical to fourth thoracic vertebra. Absorbed dose by TLDs were read by a Harshaw 3500 TLD reader. Results: Total measured dose (in Gy) of various parts of spinal cord adjacent to second cervical to fourth thoracic vertebra varied widely and were as follows respectively: 15.24±1.31, 50.31±1.06, 49.15±2.77, 47.48±1.42, 54.56±2.6, 48.92±0.6, 45.1±0.45. In other words, the range of doses received by different segments of the spinal cord could be as wide as 15.24 to 54.56 Gy. Conclusion: Although the spinal cord was excluded at the end of the first phase, a significant change in the absorbed dose at the end of the first and second phases was not observed. In phase three, the anterior neck field was replaced by a lateral field and the spinal cord absorbed dose was reduced considerably. According to our results, absorbed doses of the spinal cord segments corresponding to the region confined between the third cervical to third thoracic vertebra were more than the 47 Gy recommended tolerance dose value. Therefore, special attention must be paid to protect this sensitive tissue while the treatment is performed. Application of modern techniques such as IMRT, if available, will reduce the unnecessary dose the spinal cord and its consequent biological risks considerably.

Outpatient Management of Oral Anticoagulation Therapy in Patients with Nonvalvular Atrial Fibrillation

Due to heightened risk for thromboembolic complications, nonvalvular atrial fibrillation (NVAF) presents an absolute indication for long-term oral anticoagulation therapy. This was an observational, analytical, randomised, one-year clinical study, conducted in the Blood Transfusion Institute Sarajevo, Bosnia & Herzegovina. The aim of this study was to present the oral anticoagulation treatment in terms of International normalised ratio (INR) monitoring and warfarin/acenocoumarol dose titration in 117 patients with NVAF. INR values, the doses of warfarin and acenocoumarol, as well as the tendency and adequacy of their changes were monitored. Percentages of the therapeutic INR values were 51,77% and 53,62%, subtherapeutic 42,84% and 35,86%, and supratherapeutic 5,39% and 10,53% for the warfarin and acenocoumarol treatment, respectively. The average total weekly doses (TWD) which most frequently achieved the therapeutic INR values were 27,89+/-12,34 mg and 20,44+/-9,94 mg, for warfarin and acenocoumarol, respectively. The dose changes with the INR values 1,7 or lower/3,3 or higher were omitted in 13,46% and 15,63%, and with the INR values 1,8-3,2 were noted in 8,62% and 13,48% of all the check-up visits in the warfarin and acenocoumarol group, respectively. The annual dose changes were noted in 24,65% and 31,41%, and the daily dose changes in 74,43% and 73,36% of all the check-up visits of warfarin and acenocoumarol group, respectively. We can conclude that the management of the oral anticoagulation treatment in our country is in accordance with the relevant recommendations, but with the present tendency toward underdosing and unnecessary frequent dose changing.

Evolution of X‐ray machine quality control acceptance indices

The quality assurance (QA) of radiographic images based on the operating conditions of X‐ray equipment is essential for good image quality, accurate medical diagnostics and for the prevention of health professionals and patients to unnecessary doses of ionizing radiation. This paper presents a historical analysis of 1,635 Quality Assurance Technical Reports of Health Institutions in the state of São Paulo, Brazil, over a seven‐year period. Based on acceptable limits for variations between nominal and measured parameters as the variable to determine the quality of X‐ray equipment operating conditions, a significant improvement was found in the percentage of acceptance of the overall parameters described in the QA technical reports over this period. As expected, we found a strong concentration in the categories of conventional and portable X‐ray equipment, which represent 72% and 84%, respectively, of the total number of equipments. A mechanical parameter such as half‐value layer (HVL), which is important not only for image quality but also for radiation protection, showed significant improvements. Again, only 58% of portable X‐ray equipment showed HVL values recommended for 80 kVp (above 2.3 mm Al), a percentage that improved to 76% in 2006. With regard to mammographers, which are newer machines, all the analyzed systems presented acceptable HVL values. Conventional X‐ray machines showed an increase of this conformity index from 89% in 2000 to 94% in 2006. All this improvement was attributed to the continuous and extensive enforcement of Regulation Act 453 in the state of São Paulo. The improvement in equipment quality control standards is expected to result in the improvement of diagnostic quality, as well as in the reduction of exam repetitions, and thereby reducing the patient's exposure to radiation.PACS number: 87.57.C

Simple Carotid-Sparing Intensity-Modulated Radiotherapy Technique and Preliminary Experience for T1–2 Glottic Cancer

To investigate the dosimetry and feasibility of carotid-sparing intensity-modulated radiotherapy (IMRT) for early glottic cancer and to report preliminary clinical experience. Digital Imaging and Communications in Medicine radiotherapy (DICOM-RT) datasets from 6 T1-2 conventionally treated glottic cancer patients were used to create both conventional IMRT plans. We developed a simplified IMRT planning algorithm with three fields and limited segments. Conventional and IMRT plans were compared using generalized equivalent uniform dose and dose-volume parameters for in-field carotid arteries, target volumes, and organs at risk. We have treated 11 patients with this simplified IMRT technique. Intensity-modulated radiotherapy consistently reduced radiation dose to the carotid arteries (p < 0.05) while maintaining the clinical target volume coverage. With conventional planning, median carotid V35, V50, and V63 were 100%, 100%, and 69.0%, respectively. With IMRT planning these decreased to 2%, 0%, and 0%, respectively (p < 0.01). Radiation planning and treatment times were similar for conventional radiotherapy and IMRT. Treatment results have been excellent thus far. Intensity-modulated radiotherapy significantly reduced unnecessary radiation dose to the carotid arteries compared with conventional lateral fields while maintaining clinical target volume coverage. Further experience and longer follow-up will be required to demonstrate outcomes for cancer control and carotid artery effects.

Fast X-Ray Phase-Contrast Imaging Using High Resolution Detector

X-ray phase-contrast imaging is a potential nondestructive testing and diagnostic technology in medicine, biology and materials science. It provides high sensitivity and contrast of weakly absorbing low-Z objects by measuring phase shifts of the X-rays. In this paper, we propose a novel phase-contrast imaging method using only one absorption grating and a high-resolution detector. The intensity distribution downstream of the grating is recorded and analyzed by the high-resolution detector directly. We use a spatial phase demodulation method to retrieve the phase information. Only one image is needed. Numerical simulations are performed to validate that the setup of our method is greatly simplified compared with the phase-stepping method and our method can significantly reduce the time-consuming and the unnecessary dose.

SU‐FF‐I‐25: Quantitative Analysis of the Influence of KV Beam Characteristics and Image Acquisition Parameters On Image Quality in Cone‐Beam CT

Purpose: Image quality in cone‐beam CT (CBCT) imaging is influenced by a variety of factors associated with the selection of image acquisition parameters like kVp, tube current, field size, beam filter, number of projections, and reconstruction filter. An improper selection of scan protocols may lead to unoptimized image quality and unnecessary dose to the patient. Therefore, a rigorous study of CBCT image quality and its dependence on beam characteristics is vital. In this work, the relative influences of pertinent image acquisition parameters are evaluated for a clinical Elekta XVI CBCT system. Method and Materials: Image quality measurements were conducted using a conventional CatPhan phantom, wherein the line‐pair bar inserts and uniform slices were used to characterize spatial resolution and noise via modulation transfer function (MTF) and noise power spectrum (NPS) respectively for several combinations of kVp/current, field size, beam filters, and gantry rotation arcs. CTDI dose estimates were also acquired for each scan protocol. Overall image quality was evaluated in terms of the detective quantum efficiency (DQE), obtained from MTF and NPS spectra and normalized using the CTDI doses and a fluence — CTDI dose conversion factor obtained from Monte Carlo simulations. Results: The MTF, NPS and DQE measurements indicated that overall image quality was severely affected by the increased scatter from larger field sizes, and from the use of incomplete projection arcs. The use of beam filters led to some reduction in scatter and improved image quality, while also reducing patient dose. Conclusions: The image quality measurements indicated that the appropriate choice of scan parameters can lead to improved image quality and sparing of patient dose. However, more detailed investigations may be necessary to optimize CBCT image quality, including a better choice of beam compensators and possible use of anti‐scatter grids.

SU‐FF‐T‐104: Simultaneous Boost and Skin Dose Toxicity Reduction for Breast Cancer Treatments Using IMRT and RapidArc

Purpose: To reduce the overall treatment fractions by about a week and minimize the skin dose toxicity by treating stage I‐II breast cancer patients with IMRT and eventually RapidArc both, incorporating a simultaneous boost to the tumor bed. Background: Radiation therapy is prescribed to breast cancer patients after receiving a lumpectomy or mastectomy to remove cancerous tissue. In the past, treatments using two 6MV tangential fields with wedges followed by an electron boost to the tumor bed have often resulted in unnecessary dose to unaffected tissue. As a consequence, patients experienced edema, pain, desquamation, discoloration, and other negative side‐effects. IMRT and RapidArc are treatment techniques where the dose can be tailored to the shape of the target, reducing the exposure of adjacent tissues to unnecessary radiation and potential damage. Methods and Materials: Skin dose measurements using TLDs from 35 patients receiving conventional radiotherapy were collected over a period of 9 months. Seven 3×3×1 mm3 TLD chips were placed on the 4 quadrants of a patient's breast and 3 on the inframmary fold. Same TLD arrangement was used for patients receiving IMRT or RapidArc which, in addition, incorporated a simultaneous boost of an additional ∼10Gy delivered to the tumor bed, within the regular 28 treatment sessions. Results: Preliminary data indicates percent differences of 4–20% less skin dose on the IMRT/RapidArc cases, primarily in the inframammary fold region. Furthermore, our skin dose data on the IMRT/RapidArc treatments indicates a strong correlation to the size and shape of the breast under treatment suggesting that patients with large breast may experience little skin sparing — confirming observations reported elsewhere. Dose to heart, lungs and contralateral breast were kept to a minimum. Conclusion: This work continues with more breast patients receiving IMRT or RapidArc, and thus far the data continues to support our preliminary observations.

Toxicity associated with the long-term use of targeted therapies in patients with advanced renal cell carcinoma

VEGF and mTOR inhibitors have encouraging clinical activity for patients with advanced renal cell carcinoma (RCC), but may lead to significant short- and long-term toxicities. Although 40–70% of adverse events (AEs) are grade 1 and 2, 10–20% of patients develop grade 3 or 4 AEs requiring dose reductions, drug holidays or treatment discontinuation. The long-term impact of the most common grade 3 and 4 AEs observed in Phase III trials evaluating VEGF and mTOR inhibitors, including hypertension, decreased left ventricular ejection fraction, hand–foot-syndrome and myelosuppression, are a concern in RCC patients who are living longer and receiving chronic sequential or combination therapy. There is a clear need to develop a more rational way to individualize therapy for RCC. Long-term follow-up from existing Phase II/III trials should provide us with increased understanding of the potential implications of AEs in RCC patients. Prevention, early recognition and aggressive management of side effects are fundamental to avoid significant long-term complications and unnecessary dose reductions, which can ultimately reduce the efficacy of these novel agents.