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The purpose of this study was to investigate the magnitude and dosimetric relevance of translational and rotational shifts on IGRT prostate volumetric-modulated arc therapy (VMAT) using Protura six degrees of freedom (DOF) Robotic Patient Positioning System. Patients with cT3aN0M0 prostate cancer, treated with VMAT simultaneous integrated boost (VMAT-SIB), were enrolled. PTV2 was obtained adding 0.7 cm margin to seminal vesicles base (CTV2), while PTV1 adding to prostate (CTV1) 0.7 cm margin in all directions, except 1.2 cm, as caudal margin. A daily CBCT was acquired before dose delivery. The translational and rotational displacements were corrected through Protura Robotic Couch, collected and applied to the simulation CT to obtain a translated CT (tCT) and a rototranslated CT (rtCT) on which we recalculated the initial treatment plan (TP). We analyzed the correlation between dosimetric coverage, organs at risk (OAR) sparing, and translational or rotational displacements. The dosimetric impact of a rototranslational correction was calculated. From October 2012 to September 2013, a total of 263 CBCT scans from 12 patients were collected. Translational shifts were < 5 mm in 81% of patients and the rotational shifts were < 2° in 93% of patient scans. The dosimetric analysis was performed on 172 CBCT scans and calculating 344 VMAT-TP. Two significant linear correlations were observed between yaw and the V20 femoral heads and between pitch rotation and V50 rectum (p < 0.001); rototranslational correction seems to impact more on PTV2 than on PTV1, especially when margins are reduced. Rotational errors are of dosimetric significance in sparing OAR and in target coverage. This is relevant for femoral heads and rectum because of major distance from isocenter, and for seminal vesicles because of irregular shape. No correlation was observed between translational and rotational errors. A study considering the intrafractional error and the deformable registration is ongoing.

In-vivo dosimetry (IVD) in external beam radiotherapy is used to detect major clinically relevant differences between planned a.d delivered dose. Moreover, a.detailed a.alysis of its results, when routinely reported a.d discussed by the radiotherapy staff, can limit the likelihood of error transmission to many treatments. A first experience of routine EPID-based IVD in a.reference point has been performed in our department for 3D-CRT treatments over a.three-year period. More than 14 000 images were a.quired a.d 1287 treatment plans were verified. The IVD checks were obtained three times in the first week a.d then weekly. Tolerance levels of ±5% for pelvic-abdomen, head-neck a.d breast irradiations a.d ±6% for lung treatments were a.opted for the in-vivo measured dose per fraction. A statistical a.alysis of the IVD results was performed grouping the data by: a.atomical regions, treatment units, open a.d wedged fields a.d gantry a.gles. About 10% of the checked doses per fraction showed dosimetric discrepancies out of the tolerance levels. The causes of the discrepancies were 70% delivery or planning errors, 20% morphological changes a.d 10% procedural limitations. 41 cases (3.2%) have required special investigations because their in-vivo doses per fraction, a.eraged over the first three sessions, were out of the tolerance levels a.d in 19 cases (1.5%) the deviations gave rise to a. intervention. Statistically significant differences of a.erage variations between planned a.d delivered doses were observed for: (i) 30° wedged 10 MV fields with respect to those of other wedged or open 10 MV fields delivered by two linacs, due to the incorrect TPS implementation of that wedge transmission factor; (ii) a.terior-posterior a.d posterior-anterior beams with respect to the other gantry orientations for one linac, due to the beam a.tenuation introduced by the treatment couch; (iii) lateral fields with respect to medial fields of breast irradiations for a.l linacs, due to small

Purpose: The aim of the in vivo dosimetry, during the fractionated radiation therapy, is the verification of the correct dose delivery to patient. Nowadays, in vivo dosimetry procedures for photon beams are based on the use of the electronic portal imaging device and dedicated software to elaborate electronic portal imaging device images. Methods: In total, 8474 in vivo dosimetry tests were carried out for 386 patients treated with 3-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and volumetric modulated arc therapy techniques, using the SOFTDISO. SOFTDISO is a dedicated software that uses electronic portal imaging device images in order to (1) calculate the R index, that is, the ratio between daily reconstructed dose and the planned one at isocenter and (2) perform a gamma-like analysis between the signals, S, of a reference electronic portal imaging device image and that obtained in a daily fraction. It supplies 2 indexes, the percentage gamma% of points with gamma < 1 and the mean gamma value, gamma(mean). In gamma-like analysis, the pass criteria for the signals agreement Delta S% and distance to agreement Delta d have been selected based on the clinical experience and technology used. The adopted tolerance levels for the 3 indexes were fixed in 0.95 <= R <= 1.05, gamma% >= 90%, and gamma(mean) <= 0.5. Results: The results of R ratio, gamma-like, and a visual inspection of these data reported on a monitor screen permitted to individuate 2 classes of errors (1) class 1 that included errors due to inadequate standard quality controls and (2) class 2, due to patient morphological changes. Depending on the technique and anatomical site, a maximum of 18% of tests had at least 1 index out of tolerance; once removed the causes of class-1 errors, almost all patients (except patients with 4 lung and 2 breast cancer treated with 3-dimensional conformal radiotherapy) presented mean indexes values (<(R)over bar>, (gamma) over bar%

To present the interim results of a phase I trial on stereotactic radiosurgery (SRS) delivered using volumetric modulated arc therapy (VMAT) in patients with primary or metastatic tumours in different extracranial sites.

Objective. To report dosimetric and acute toxicity data in prospectively enrolled high-intermediate risk endometrial cancer (HIR-EC) patients postoperatively irradiated by simultaneous integrated boost volumetric modulated arc therapy (SIB-VMAT). Methods. Thirty prospectively enrolled HIR-EC patients were postoperatively treated by SIB-VMAT. Target coverage, dose homogeneity, and sparing of organs at risk (OARs) were compared with corresponding data retrieved from an historical control (30 consecutive selected matched patients) treated by concomitant boost three-dimensional conformal radiotherapy (3D CRT CB) from a previously published study (ADA-I trial). All patients received 45 Gy on pelvic lymph nodes plus 10 Gy boost on the vaginal vault. Results. The SIB-VMAT technique produced more inhomogeneous plans than 3D CRT CB, but showed significantly better conformity index (CIs) for both PTVs. SIB-VMAT was associated with significant reduction in the irradiated small bowel (SB) volume compared with 3D CRT CB for all dose range > 10 Gy (e.g. V15: 163.5 cm(3) vs. 341.3 cm(3), p = 0.001 and V40: 43.8 cm(3) vs. 85.2 cm(3), p = 0.008). With regard to bladder and rectum, SIB-VMAT showed a significant sparing advantage at all dose levels with respect to 3D CRT CB retrieved plans. Moreover, overall OARs Dmean were significantly reduced by the SIB-VMAT (p = 0.001). According to CTCAE v.4.0, acute (within three months) GI toxicities were more frequent in 3D CRT CB versus SIB-VMAT (90.0% vs. 66.7%; p-value 0.028). Conclusions. Compared to data from a historical database of patients administered 3D CRT CB, SIB-VMAT significantly improves the dose conformity and sparing of OARs in HIR-EC patients undergoing postoperative radiotherapy. The improvement in terms of acute toxicity justifies further prospective clinical evaluation.

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AIMS AND BACKGROUND: The aim of the study was to analyze the dose to be administered with two-dimensional involved-field palliative radiotherapy in advanced pancreatic carcinoma with respect to current dose-volume constraints (QUANTEC). METHODS AND STUDY DESIGN: The following standard regimens were evaluated: 30 Gy at 3 Gy/fraction (regimen A), 36 Gy at 2.4 Gy/fraction (regimen B), 45 Gy at 1.8 Gy/fraction (regimen C), and 50 Gy at 2 Gy /fraction (regimen D). The following constraints were considered: spinal cord Dmax <50 Gy, duodenum Dmax <55 Gy, liver Dmean <30 Gy, kidneys Dmean <15 Gy. For dose/fraction different from 1.8-2 Gy, the correction of constraints using a value of alpha/beta = 3 for late effects was considered. The calculation of dose/volume constraints was repeated for three different radiation beams: cobalt unit, 6 MV photons, and 15 MV photons. Standard field sizes were used and adapted according to the different beam types, using the parameters of our previous study. Respect of dose-volume constraints was assessed for each type of beam and treatment (dose per fractionation) in all patients. Treatments were considered acceptable in case of: 1) respect of the constraints for spinal cord and duodenum in all patients; 2) respect in >10/15 patients of constraints for kidneys and liver. Therefore, minor violations (<10%) of the constraints for these organs were accepted (in less than 5/15 patients), in consideration of the palliative aim of treatment. RESULTS: In regimen A (30 Gy, 3 Gy/fraction), evaluated constraints were respected in all patients, regardless of the type of energy. In regimen B (36 Gy, 2.4 Gy/fraction), constraints were met in all patients undergoing irradiation with 6 and 15 MV photons. However, using the cobalt unit, kidney constraint was respected only in 5 of 15 patients. In regimens C and D (45 Gy, 1.8 Gy/fraction and 50 Gy, 2 Gy/fraction, respectively), the constraint for the kidney was respected only in 2-5 patients, depending on

The aim of this study was to report early clinical experience in stereotactic body radiosurgery (SBRS) delivered using volumetric intensity modulated arc therapy (VMAT) in patients with primary or metastatic tumors in various extra-cranial body sites. Each enrolled subject was included in a different phase I study arm, depending on the tumor site and the disease stage (lung, liver, bone, metastatic), and sequentially assigned to a particular dose level. Technical feasibility and dosimetric results were investigated. The acute toxicity, tumor response and early local control were also studied. In total, 25 lesions in 20 consecutive patients (male/female, 11/9; median age, 67 years; age range, 47-86 years) were treated. Of these 25 lesions, 4 were primary or metastatic lung tumors, 6 were liver metastases, 8 were bone metastases and 7 were nodal metastases. The dose-volume constraints for organs at risk (OARs) were observed in 19 patients using a single-arc technique. Only in one patient were two arcs required. The treatment was performed without interruption or any other technical issues. The prescribed dose ranged from 12-26 Gy to the planning target volume (PTV). Delivery time ranged from 4 min to 9 min and 13 sec (median, 6 min and 6 sec). No incidence of grade 2-4 acute toxicity was recorded. The overall response rate was 48% (95% confidence interval (CI), 24.2-70.2) based on computed tomography (CT)/magnetic resonance imaging (MRI) and 89% (95% CI, 58.6-98.7) based on the positron emission tomography (PET) scan. SBRS delivered by means of VMAT allowed the required target coverage to be achieved while remaining within the normal tissue dose-volume constraints in the 20 consecutive patients. VMAT-SBRS resulted in adequate technical feasibility; the maximum tolerable dose has not yet been reached in any study arm.

The aim of this study was to report the feasibility of volumetric-modulated arc therapy (VMAT) in the postoperative irradiation of the vaginal vault. Moreover, the VMAT technique was compared with 3D conformal radiotherapy (3D-CRT) and fixed-field intensity-modulated radiotherapy (IMRT), in terms of target coverage and organs at risk sparing. The number of monitor units and the delivery time were analyzed to score the treatment efficiency. All plans were verified in a dedicated solid water phantom using a 2D array of ionization chambers. Twelve patients with endometrial carcinoma who underwent radical hystero-adenexectomy and fixed-field IMRT treatments were retrospectively included in this analysis; for each patient, plans were compared in terms of dose-volume histograms, homogeneity index, and conformity indexes. All techniques met the prescription goal for planning target volume coverage, with VMAT showing the highest level of conformity at all dose levels. VMAT resulted in significant reduction of rectal and bladder volumes irradiated at all dose levels compared with 3D-CRT. No significant differences were found with respect to IMRT. Moreover, a significant improvement of the dose conformity was reached by VMAT technique not only at the 95% dose level (0.74 vs. 0.67 and 0.62) but also at 50% and 75% levels of dose prescription. In addition, VMAT plans showed a significant reduction of monitor units by nearly 28% with respect to IMRT, and reduced treatment time from 11 to <3 minutes for a single 6-Gy fraction. In conclusion, VMAT plans can be planned and carried out with high quality and efficiency for the irradiation of vaginal vault alone, providing similar or better sparing of organs at risk to fixed-field IMRT and resulting in the most efficient treatment option. VMAT is currently our standard approach for radiotherapy of low-risk endometrial cancer.

OBJECTIVES: To evaluate the feasibility of intensity-modulated radiotherapy with simultaneous integrated boost to the dominant intraprostatic lesion for definitive treatment of prostate cancer. MATERIALS AND METHODS: Patients were deemed eligible for the study if they had histologically proven stage cT2-T3 N0M0 prostate adenocarcinoma. In addition <20% risk of lymph nodal involvement according to Roach formula, was required for enrollment. Patients were treated with intensity-modulated radiotherapy with simultaneous integrated boost technique to the dominant intraprostatic lesion defined by magnetic resonance imaging. The prescribed dose to the prostate and seminal vesicles was 72 Gy (1.8 Gy per fraction). The dose delivered to the intraprostatic lesion received was 80 Gy (2 Gy per fraction). Acute gastrointestinal (GI) and genitourinary (GU) toxicity was evaluated weekly during treatment, and at 1 and 3 months thereafter. Late GI and GU toxicity was evaluated by Kaplan Meier method. RESULTS: Forty patients were deemed evaluable. Acute and late GI and GU toxicity were evaluated in all patients. Two patients (5%) developed acute grade 3 GI toxicity and 1 patient (2.5%) developed acute grade 3 GU toxicity. No grade 4 acute GI or GU toxicity occurred. With a median follow-up of 19 months (interquartile range, 15 to 26 mo), the 2-year actuarial cumulative incidence of grade ≥2 rectal toxicity was 9.5%. The 2-year actuarial cumulative incidence of grade ≥2 urinary toxicity was 13.3%. CONCLUSIONS: Treatment related acute toxicity was low in our cohort. Prolonged observation with a larger series of patients is necessary to evaluate late toxicity and local control.

To report the feasibility of volumetric modulated arc therapy (VMAT) for neoadjuvant radiotherapy in locally advanced rectal cancer in a dose-escalation protocol and simultaneous integrated boost (SIB) approach. Moreover, the VMAT technique was compared with three-dimensional conformal radiotherapy (3D-CRT) and fixed-field intensity modulated radiotherapy (IMRT), in terms of target coverage and irradiation of organs at risk.

OBJECTIVES:: To determine the recommended phase II dose of postoperative accelerated intensity modulated radiotherapy (IMRT) for prostate cancer. MATERIAL AND METHODS:: Step and shoot IMRT with simultaneous integrated boost (SIB) was delivered in 25 fractions over 5 weeks to patients with high risk resected prostate adenocarcinoma (stage pT3-4 and/or positive surgical margins). Pelvic nodes received 45 Gy at 1.8 Gy/fraction; dose escalation was performed only to the prostate bed (planned dose escalation: 56.8 Gy at 2.27 Gy/fraction, 59.7 Gy at 2.39 Gy/fraction, 61.25 Gy at 2.45 Gy/fraction, 62.5 Gy at 2.5 Gy/fraction). Dose-limiting toxicity (DLT) was any grade ≥ 3 acute toxicity (RTOG score). RESULTS:: Twenty-five patients were treated: 7 patients at the 56.75 Gy dose level, 6 patients at each subsequent dose level. Pathologic stages were: pT2c: 2; pT3a: 11; pT3b: 12; pN0: 22; pN1: 3; R0: 7; R1: 18. Median follow-up time was 19 months (range: 6-36 months). No patient experienced DLT. Grade 1-2 acute rectal and urologic toxicity was common (17 and 22 patients, respectively). CONCLUSIONS:: The recommended dose was 62.5 Gy in 2.5 Gy/fraction. Postoperative hypofractionated IMRT SIB for prostate cancer seemed to be well tolerated and could be tested in phase II studies.

The purpose was to compare the dosimetric results observed in 201 breast cancer patients submitted to tangential forward intensity-modulated radiation therapy (IMRT) with those observed in 131 patients treated with a standard wedged 3D technique for postoperative treatment of whole breast, according to breast size and supraclavicular node irradiation. Following dosimetric parameters were used for the comparison: D(max), D(min), D(mean), V(95%) and V(107%) for the irradiated volume; D(max), D(mean), V(80%) and V(95%) for the ipsilateral lung; D(max), D(mean), V(80%) and V(95%) for the heart. Stratification was made according to breast size and supraclavicular (SCV) nodal irradiation. As respect to irradiated volume, a significant reduction of V(107%) (mean values: 7.0 ± 6.6 versus 2.4 ± 3.7, p < 0.001) and D(max) (mean % values: 111.2 ± 2.7 versus 107.7 ± 6.3, p < 0.001), and an increase of D(min) (mean % values: 65.0 ± 17.4 versus 74.9 ± 12.9, p < 0.001) were observed with forward IMRT. The homogeneity of dose distribution to target volume significantly improved with forward IMRT in all patient groups, irrespective of breast size or supraclavicular nodal irradiation. When patients treated with supraclavicular nodal irradiation were excluded from the analysis, forward IMRT slightly reduced V(80%) (mean values: 3.7 ± 2.6 versus 3.0 ± 2.4, p = 0.03) and V(95%) (mean values 1.9 ± 1.8 versus 1.2%± 1.5; p = 0.001) of the ipsilateral lung. The dose to the heart tended to be lower with IMRT but this difference was not statistically significant. Tangential forward IMRT in postoperative treatment of whole breast improved dosimetric parameters in terms of homogeneity of dose distribution to the target in a large sample of patients, independent of breast size or supraclavicular nodal irradiation. Lung irradiation was slightly reduced in patients not undergoing to supraclavicular irradiation.

PURPOSE: To evaluate the feasibility and efficacy of moderately accelerated intensity-modulated radiation therapy (IMRT) along with weekly cisplatin, after induction chemotherapy, in patients with locally advanced unresectable head and neck cancer (HNC). METHODS AND MATERIALS: Patients with Stage III or IV locally advanced HNC, without progressive disease after three courses of induction chemotherapy, received concurrent chemo-IMRT (weekly cisplatin 30 mg/m(2) plus simultaneous integrated boost IMRT). A total of 67.5 Gy in 30 fractions were delivered to primary tumor and involved nodes, 60 Gy in 30 fractions to high-risk nodal areas, and 55.5 Gy in 30 fractions to low-risk nodal areas. RESULTS: In all, 36 patients (median age, 56 years) with International Union Against Cancer (UICC) Stage III (n = 5) and IV (n = 31) were included. Of the 36 patients, 17 had received CF (cisplatin and 5-fluorouracil (CF) and 19 had received docetaxel cisplatin and 5-fluorouracil (DCF). During concurrent chemoradiation, 11 of 36 patients (30.5%) experienced Grade III mucositis (CF, 47%; DCF, 15%; p < 0.04). Grade III pharyngeal-esophageal toxicity was observed in 5 of 19 patients (26.3%; CF, 0.0%; DCF, 26.3%; p = 0.02). Two patients died of complications (5.5%). After chemoradiation, the complete response rate was 63.8%. Two-year local control was 88.7%. Two-year progression free survival and overall survival were 74.5% and 60.9%, respectively. CONCLUSIONS: In our experience, a moderately accelerated chemo-IMRT was feasible after induction chemotherapy. However, a noteworthy early death rate of 5.5% was observed. Intensive supportive care strategies should be defined to better manage radiation-induced toxic effects. Longer follow-up is required to determine the incidence of late radiation toxicities and tumor control rates.

Many researchers are studying new in vivo dosimetry methods based on the use of Elelctronic portal imaging devices (EPIDs) that are simple and efficient in their daily use. However the need of time consuming implementation measurements with solid water phantoms for the in vivo dosimetry implementation can discourage someone in their use. In this paper a procedure has been proposed to calibrate aSi EPIDs for in vivo transit dosimetry. The dosimetric equivalence of three aSi Varian EPIDs has been investigated in terms of signal reproducibility and long termstability, signal linearity withMUand dose per pulse and signaldependence on the field dimensions. The signal reproducibility was within +/-0.5% (2SD), while the long term signal stability has been maintained well within +/-2%. The signal linearity with the monitor units (MU) waswithin +/-2% and within +/-0.5% for the EPIDs controlled by the IAS 2, and IAS 3 respectively. In particular it was verified that the correction factor for the signal linearity with the monitor units, klin, is independent of the beam quality, and the dose per pulse absorbed by the EPID. For 6, 10 and 15 MV photon beams, a generalized set of correlation functions F(TPR,w,L) and empirical factors f(TPR,d,L) as a function of the Tissue Phantom Ratio (TPR), the phantom thickness, w, the square field side, L, and the distance, d, between the phantom mid-plane and the isocentre were determined to reconstruct the isocenter dose. The tolerance levels of the present in vivo dosimetry method ranged between +/-5% and +/-6% depending on the tumor body location. In conclusion, the procedure proposed, that use generalized correlation functions, reduces the effort for the in vivo dosimetry method implementation for those photon beams with TPR within +/-0.3% as respect those here used.

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An electronic portal imaging device (EPID) is an effective detector for in vivo transit dosimetry. In fact, it supplies two-dimensional information, does not require special efforts to be used during patient treatment, and can supply data in real time. In the present paper, a new procedure has been proposed to improve the EPID invivo dosimetry accuracy by taking into account the patient setup variations. The procedure was applied to the breast tangential irradiation for the reconstruction of the dose at the breast midpoint, Dm. In particular, the patient setup variations were accounted for by comparing EPID images versus digitally reconstructed radiographies. In this manner, EPID transit signals were obtained corresponding to the geometrical projections of the breast midpoint on the EPID for each therapy session. At the end, the ratios R between Dm and the doses computed by the treatment planning system (TPS) at breast midpoints, Dm,TPS, were determined for 800 therapy sessions of 20 patients. Taking into account the method uncertainty, tolerance levels equal to ±5% have been determined for the ratio R. The improvement of in vivo dosimetry results obtained (taking into account patient misalignment) has been pointed out comparing the R values obtained with and without considering patient setup variations. In particular, when patient misalignments were taken into account, the R values were within ± 5% for 93% of the checks; when patient setup variations were not taken into account, the R values were within ± 5% in 72% of the checks. This last result points out that the transit dosimetry method overestimates the dose discrepancies if patient setup variations are not taken into account for dose reconstruction. In this case, larger tolerance levels have to be adopted as a trade-off between workload and ability to detect errors, with the drawback being that some errors (such as the ones in TPS implementation or in beam calibration) cannot be detected, limiting the in vivo

To determine the maximum tolerated dose of short-course radiotherapy (intensity-modulated radiotherapy technique) to the upper two thirds of the vagina in endometrial cancers with low risk of local recurrence. PATIENTS AND METHODS: A Phase I clinical trial was performed. Eligible patients had low-risk resected primary endometrial adenocarcinomas. Radiotherapy was delivered in 5 fractions over 1 week. The planning target volume was the clinical target volume plus 5 mm. The clinical target volume was defined as the upper two thirds of the vagina as evidenced at CT simulation by a vaginal radio-opaque device. The planning target volume was irradiated by a seven-field intensity-modulated radiotherapy technique, planned by the Plato Sunrise inverse planning system. A first cohort of 6 patients received 25 Gy (5-Gy fractions), and a subsequent cohort received 30 Gy (6-Gy fractions). The Common Toxicity Criteria scale, version 3.0, was used to score toxicity. RESULTS: Twelve patients with endometrial cancer were enrolled. Median age was 58 years (range, 49-74 years). Pathologic stage was IB (83.3%) and IC (16.7%). Median tumor size was 30 mm (range, 15-50 mm). All patients completed the prescribed radiotherapy. No patient experienced a dose-limiting toxicity at the first level, and the radiotherapy dose was escalated from 25 to 30 Gy. No patients at the second dose level experienced dose-limiting toxicity. The most common Grade 2 toxicity was gastrointestinal, which was tolerable and manageable. CONCLUSIONS: The maximum tolerated dose of short-course radiotherapy was 30 Gy at 6 Gy per fraction. On the basis of this result, we are conducting a Phase II study with radiotherapy delivered at 30 Gy.

BACKGROUND AND PURPOSE: To evaluate the results in terms of dosimetric parameters and acute toxicity of two clinical studies (MARA-1 and MARA-2) on accelerated IMRT-based postoperative radiotherapy. These results are compared with historical control group (CG) of patients treated with "standard" 3D postoperative radiotherapy. MATERIALS AND METHODS: Prescribed dose to the breast was 50.4Gy in the CG, 40Gy in MARA-1 (low risk of local recurrence), and 50Gy in MARA-2 (medium-high risk of recurrence). The tumor bed total dose was 60.4Gy (sequential 10Gy electron boost), 44Gy (concomitant 4Gy boost), and 60Gy (concomitant 10Gy boost) in CG, MARA-1 and MARA-2 studies, respectively. Overall treatment time was of 32 fractions for CG (6.4weeks); 16 fractions for MARA-1 study (3.2weeks) and 25 fractions for MARA-2 study (5weeks). RESULTS: Three hundred and thirty two patients were included in the analysis. Dosimetric analysis showed D(max) and V(107%) reduction (p<0.001) and D(min) improvement (p<0.001) in the PTV in patients treated with IMRT. Grade 2 acute skin toxicity was 33.6%, 13.1%, and 45.1% in the CG, MARA-1, and MARA-2, respectively (p<0.001), and grade 3 acute skin toxicity was 3.1%, 1.0%, and 2.0%, respectively. Similarly, larger PTV and use of chemotherapy with anthracyclines and taxanes were associated with a greater acute toxicity. With a median follow-up of 31 months, no patients showed local or nodal relapse. CONCLUSIONS: A simplified step and shoot IMRT technique allowed better PTV coverage and reduced overall treatment time (CG, 6.6weeks; MARA-1, 3.2weeks; MARA-2, 5weeks) with acceptable short-term toxicity.

The article reports a feasibility study about the potentiality of an in vivo dosimetry method for the adaptive radiotherapy of the lung tumors treated by 3D conformal radiotherapy techniques 3D CRTs . At the moment image guided radiotherapy IGRT has been used for this aim, but it requires taking many periodic radiological images during the treatment that increase workload and patient dose. In vivo dosimetry reported here can reduce the above efforts, alerting the medical staff for the commissioning of new radiological images for an eventual adaptive plan. The in vivo dosimetry method applied on 20 patients makes use of the transit signal St on the beam central axis measured by a small ion chamber positioned on an electronic portal imaging device EPID or by the EPID itself. The reconstructed in vivo dosimetry at the isocenter point Diso requires a convolution between the transit signal St and a dose reconstruction factor C that essentially depends on i tissue inhomogeneities along the beam central axis and ii the in-patient isocenter depth. The C factors, one for every gantry angle, are obtained by processing the patient’s computed tomography scan. The method has been recently applied in some Italian centers to check the radiotherapy of pelvis, breast, head, and thorax treatments. In this work the dose reconstruction was carried out in five centers to check the Diso in the lung tumor during the 3D CRT, and the results have been used to detect the interfraction tumor anatomy variations that can require new CT imaging and an adaptive plan. In particular, in three centers a small ion chamber was positioned below the patient and used for the St measurement. In two centers, the St signal was obtained directly by 25 central pixels of an a-Si EPID, equipped with commercial software that enabled its use as a stable detector. A tolerance action level of 6% for every checked beam was assumed. This means that when a difference greater than 6% between the predicted dose by the t

Scarce data are available on the use of extracranial stereotactic radiotherapy in recurrent gynecological tumors. The aim of this report was to analyze the results of our preliminary experience with extracranial stereotactic radiotherapy in locally or distantly recurrent gynecological tumors. Extracranial stereotactic radiotherapy was planned by the Precise-Plan treatment planning system. Patients were immobilized using the Stereotactic Body-Frame. Five consecutive daily fractions were delivered; dose/fraction and total dose were defined based on an institutional dose-escalation protocol. A class solution with 4 non-coplanar fixed beams based on the tetrad configuration was used in all patients. Eleven patients (12 lesions), were included in the analysis. Stereotactic radiotherapy was delivered as first radiotherapy treatment (5 patients), or as retreatment (6 patients). Complete clinical response was achieved in 8/12 lesions (66.6%), while partial response was documented in 2/12 lesions (16.6%). With a median follow-up of 19 months (range, 2-37 months), 7 patients (63%) experienced local and/or distant progression of disease. The 2-year local progression-free survival was 81.8%, while the 2-year metastases-free survival was 54.4%. The 2-year overall survival was 63.6%. Acute and late toxicities were grade 2 or less. There was no difference in quality of life scores between the data collected before extracranial stereotactic radiotherapy and at first follow-up evaluation. Fractionated extracranial stereotactic radiotherapy administered up to a dose of 30 Gy in five fractions is well tolerated. Further studies of extracranial stereotactic radiotherapy and novel radiotherapy techniques are warranted in the challenging setting of recurrent gynecological tumors.

The breath-hold is one of the techniques to obtain the dose escalation for lung tumors. However, the change of the patient's breath pattern can influence the stability of the inhaled air volume, IAV, used in this work as a surrogate parameter to assure the tumor position reproducibility during dose delivery. MATERIALS AND METHOD: In this paper, an Elekta active breathing coordinator has been used for lung tumor irradiation. This device is not an absolute spirometer and the feasibility study here presented developed (i) the possibility to select a specific range epsilon of IAV values comfortable for the patient and (ii) the ability of a transit signal rate S(t), obtained by a small ion-chamber positioned on the portal image device, to supply in real time the in vivo isocenter dose reproducibility. Indeed, while the selection of the IAV range depends on the patient's ability to follow instructions for breath-hold, the S(t) monitoring can supply to the radiation therapist a surrogate of the tumor irradiation reproducibility. RESULTS: The detection of the S(t) in real time during breath-hold was used to determine the interfraction isocenter dose variations due to the reproducibility of the patient's breathing pattern. The agreement between the reconstructed and planned isocenter dose in breath-hold at the interfraction level was well within 1.5%, while in free breathing a disagreement up to 8% was observed. The standard deviation of the S(t) in breath-hold observed at the intrafraction level is a bit higher than the one obtained without the patient and this can be justified by the presence of a small residual tumor motion as heartbeat. CONCLUSION: The technique is simple and can be implemented for routine use in a busy clinic.

A method for the determination of the in vivo isocenter dose, Diso, has been applied to the dynamic conformal arc therapy DCAT for thoracic tumors. The method makes use of the transmitted signal, St, , measured at different gantry angles, , by a small ion chamber positioned on the electronic portal imaging device. The in vivo method is implemented by a set of correlation functions obtained by the ratios between the transmitted signal and the midplane dose in a solid phantom, irradiated by static fields. The in vivo dosimetry at the isocenter for the DCAT requires the convolution between the signals , St, , and the dose reconstruction factors, C , that depend on the patient’s anatomy and on its tissue inhomogeneities along the beam central axis in the direction. The C factors are obtained by processing the patient’s computed tomography scan. The method was tested by taking measurements in a cylindrical phantom and in a Rando Alderson phantom. The results show that the difference between the convolution calculations and the phantom measurements is within 2%. The in vivo dosimetry of the stereotactic DCAT for six lung tumors, irradiated with three or four arcs, is reported. The isocenter dose up to 17 Gy per therapy fraction was delivered on alternating days for three fractions. The agreement obtained in this pilot study between the total in vivo dose Diso and the planned dose Diso,TPS at the isocenter is 4%. The method has been applied on the DCAT obtaining a more extensive monitoring of possible systematic errors, the effect of which can invalidate the current therapy which uses a few high-dose fractions.