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Aim: To investigate the potential role of an additional magnetic resonance imaging (MRI) examination performed during neoadjuvant chemoradiation therapy (CRT) in the prediction of pathological response in locally advanced rectal cancer (LARC). Material and methods: Forty-eight consecutive patients with LARC underwent neoadjuvant CRT. MRI studies at 1.5 T, including high-resolution T2-weighted sequences that were acquired parallel and perpendicular to the main axis of the tumour were performed before (preMRI), during (midMRI), and 6-8 weeks after the end of CRT (postMRI). Cancer volumes (Vpre, Vmid, Vpost) were drawn manually and the reduction rate calculated (ΔVmid, ΔVpost). According to Rödel's pathological tumour regression grade (TRG), patients were considered non-responders (NR; TRG0-2), partial responders (PR; TRG3), and complete responders (CR; TRG4). Multivariate regression analysis was performed to identify the best MRI predictors of NR, PR, and CR. Results: Twenty-five patients were considered PR (52%), 13 CR (27%), and 10 NR (22%). Tumour shrinkage mainly occurred shortly after CRT (ΔVmid: CR: 80±10% versus PR: 56±19% versus NR: 28±22%, p=2.2×10-16). Vmid, Vpost, ΔVmid, and ΔVpostcorrelated with TRG (p

We present a simple and new scheme for producing multi colour Thomson/Compton radiation with the possibility of controlling separately their polarization, based on the interaction of one single electron beam with two and more laser pulses that can come from the same laser setup or from two different lasers system and that collide with the electrons at different angle inside one optical cavity. One of the most interesting cases for medical applications is to provide two X-ray pulses across the iodine K-edge at 33.2 keV. The iodine is used as contrast medium in various imaging techniques and the availability of two spectral lines accross the K-edge allows one to produce subtraction images with a great increase in accuracy., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Purpose: To report on planning and toxicity findings of hypofractionated adjuvant radiotherapy with helical Tomotherapy (HTT) after radical prostatectomy (RP) for prostate carcinoma (pCa). Methods and materials: Fifty consecutive patients submitted to RP for pT2R1/pT3a/pT3b-pN0 pCa were enrolled in a Phase I-II trial to receive 58 Gy/20 fractions (5/week) on tumoral bed. Endpoint was to verify a risk of toxicity and biochemical failure not exceeding that observed in our Institutional 3DCRT, conventionally fractionated series (15 3 patients). Toxicities were graded according the RTOG scoring system. Results: Excellent coverage of PTV and high homogeneity of dose distribution were always achieved. Median follow-up was 25 months. Acute G2-3 RTOG genitourinary (GU) and acute G2 intestinal toxicities were similar (12% vs 15.6% and 4% vs 7%, respectively), while acute G2 proctitis was 0% vs 9% in HTT and 3DCRT group, respectively. Similarly, late Grade >= 2 gastrointestinal sequelae were 0% vs 8.5%. The incidence of late urethral stricture, 8% and 9% in HTT and 3DCRT group, respectively, is comparable to that of RP-only series. Conclusions: Acute toxicity and early late toxicity outcomes of a moderately hypofractionated regimen with HTT post-RP are excellent. A longer follow-up is needed to fully assess the validity of this approach. (c) 2008 Elsevier Ireland Ltd. All rights reserved. Purpose: To report on planning and toxicity findings of hypofractionated adjuvant radiotherapy with helical Tomotherapy (HTT) after radical prostatectomy (RP) for prostate carcinoma (pCa). Methods and materials: Fifty consecutive patients submitted to RP for pT2R1/pT3a/pT3b-pN0 pCa were enrolled in a Phase I-II trial to receive 58 Gy/20 fractions (5/week) on tumoral bed. Endpoint was to verify a risk of toxicity and biochemical failure not exceeding that observed in our Institutional 3DCRT, conventionally fractionated series (15 3 patients). Toxicities were graded according the RTOG scoring system. Results: Excellent coverage of PTV and high homogeneity of dose distribution were always achieved. Median follow-up was 25 months. Acute G2-3 RTOG genitourinary (GU) and acute G2 intestinal toxicities were similar (12% vs 15.6% and 4% vs 7%, respectively), while acute G2 proctitis was 0% vs 9% in HTT and 3DCRT group, respectively. Similarly, late Grade >= 2 gastrointestinal sequelae were 0% vs 8.5%. The incidence of late urethral stricture, 8% and 9% in HTT and 3DCRT group, respectively, is comparable to that of RP-only series. Conclusions: Acute toxicity and early late toxicity outcomes of a moderately hypofractionated regimen with HTT post-RP are excellent. A longer follow-up is needed to fully assess the validity of this approach. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

OBJECTIVE To compare prospective electrocardiogram (ECG)-triggered high-voltage coronary computed tomography (CT) angiography (CTA; 140-kVp P-cCTA) with retrospective ECG-gated standard-voltage cCTA (120-kVp R-cCTA), in patients with coronary stents. METHODS Fifty-two patients with coronary stents were studied with 64-slice multidetector scanner. Ninety-three stents were analyzed: 55 with 140-kVp P-cCTA and 38 with 120-kVp R-cCTA. Image quality (IQ), diagnostic confidence (DC), in-stent assessable lumen, artificial narrowing, and effective radiation dose were compared between techniques. RESULTS Image quality and DC were significantly better for the 140-kVp P-cCTA in comparison with the 120-kVp R-cCTA (IQ, 1.1 ± 0.36 vs 1.7 ± 0.60, respectively; P < 0.00001. Diagnostic confidence: 1.1 ± 0.29 vs 1.5 ± 0.65 respectively; P < 0.0001). In-stent assessable lumen and artificial narrowing were comparable between the techniques. Effective dose was lower for the 140-kVp P-cCTA (6.7 ± 2.07 mSv vs 15.8 ± 6.89 mSv; P < 0.0001). CONCLUSIONS High voltage combined with axial prospective ECG-triggered scan improved IQ and DC in stent cCTA imaging but failed to improve the diameter of in-stent assessable lumen and to reduce the artificial narrowing compared with the 120-kVp R-cCTA. Effective dose was 60% lower for the 140-kVp P-cCTA.

The aim of this investigation was to explore the potential of biological optimization in the case of simultaneous integrated boost on intra-prostatic dominant lesions (DIL) and evaluating the impact of TCP parameters uncertainty. Different combination of TCP parameters (TD50 and γ50 in the Poisson-like model), were considered for DILs and the prostate outside DILs (CTV) for 7 intermediate/high-risk prostate patients. The aim was to maximize TCP while constraining NTCPs below 5% for all organs at risk. TCP values were highly depending on the parameters used and ranged between 38.4% and 99.9%; the optimized median physical doses were in the range 94–116 Gy and 69–77 Gy for DIL and CTV respectively. TCP values were correlated with the overlap PTV-rectum and the minimum distance between rectum and DIL. In conclusion, biological optimization for selective dose escalation is feasible and suggests prescribed dose around 90–120 Gy to the DILs. The obtained result is critically depending on the assumptions concerning the higher radioresistence in the DILs. In case of very resistant clonogens into the DIL, it may be difficult to maximize TCP to acceptable levels without violating NTCP constraints.

PURPOSE: to verify the possibility of using Helical Tomotherapy to safely escalate dose to single or multiple highly radioresistant dominant intra-prostatic lesions (DILs) as assessed by functional magnetic resonance imaging (MRI). MATERIAL: in seven intermediate/high risk patients, T2WI, T1WI and DWI MRI imaging showed evidence of one DIL in four patients and two DILs in three patients in the peripheral zone of the prostate. The planning strategy was to deliver median doses of 80, 90, 100 and 120 Gy to PTVDIL while delivering 71.4 Gy/28 fractions (EQD(2)=75 Gy) to the remaining portion of PTV. A higher priority was assigned to rectal constraints relative to DIL coverage. Rectal NTCP calculations were performed using the most recently available model data. RESULTS: the median dose to DIL could safely be escalated to at least 100 Gy (EQD(2,α/β=10)=113 Gy) without violating safe constraints for the organs at risk. Typical rectal NTCP values were around or below 1-3% for G3 toxicity and 5-7% for G2-G3 toxicity. For the 100 Gy DIL dose boost strategy, mean D95% of DIL and PTVDIL were 98.8 Gy and 86.7 Gy, respectively. The constraints for bladder, urethra and femoral heads were always respected. CONCLUSIONS: IGRT by Helical Tomotherapy may permit the safe escalation of EQD(2,α/β=10) to at least 113 Gy to DILs without significantly increasing rectal NTCP compared to plans without dose escalation. A Phase I-II clinical study is warranted

Current imaging methods permit an accurate target definition in radiotherapy considered as a fundamental requirement for precise treatment execution. The combination of PET/CT and tomotherapy has as its objective the early, accurate recognition of tumor extension (staging), optimal definition of treatment volume and complete response of the treated lesion, providing a valid alternative to surgery not only in advanced disease but also in potential surgical cases. This new technical approach has resulted in a previously unreachable level of selectivity in radiation therapy, together with more reliable target definition, better control of target position, improved patient set up reproducibility and dramatically dose fall-off between tumor and surrounding normal tissues. The clinical result consists not only in the possibility to deliver significantly higher dose but also the realization of hypofractionated treatments. Metabolically guided radiotherapy and hypofractionation can result in a series of advantages: improvement in treatment quality (set-up error reduction, effective dose fall-off and control of target movement); elevated disease control for the possibility of higher dose radiation and reduced side effects; greater frequency of complete clinical response with possibility of avoiding surgery; improved patient management (in terms of logistic and economic problems); more patients treated per machine with significant reduction of waiting list (the time factor from radiobiological perspective is an important variable to disease control); cost containment (by means of hypofractionation it is possible to reduce the number of treatment and consequently the total cost of therapy). To this end both methodological and clinical protocols have been drown up at our Institution (Hospital San Raffaele: HSR) and approved by the Ethics Committee. The clinical protocols are relative to treatment of pulmonary neoplasm, prostate cancer, head and neck cancer, pancreatic cancer, lung and liver lesions. In this paper the following issues will be considered: prostate cancer (radical and adjuvant treatment), liver and lung lesions and locally advanced pancreatic cancer. Copyright © 2007 by new Magazine edizioni s.r.l.

In this review there will be presented an overview of the literature about the recent developments on radiotracers imaging using optical methods and their applications. We will begin with a short summary regarding the discovery of Cerenkov radiation (CR) and then focus on the early developments and experimental validation of planar Cerenkov luminescence imaging. A significant improvement in Cerenkov luminescence imaging was given by the development of tomographic methods in order to obtain in vivo whole body 3D images of Cerenkov sources. An interesting and original application discussed in this review is the use of CR as the excitation source of quantum dots and fluorophores. We will also present some recent experimental results on in vivo radio luminescence imaging of alpha and gamma emitters. All these results make optical radioisotopes imaging an interesting cost-effective tool for the screening of new probes for both imaging and therapeutic applications. Other interesting aspects are the uses of Cerenkov radiation for radiotherapy and for radiopharmaceuticals synthesis applications. We will conclude by summarising the most important results and the future challenges.

BACKGROUND: The study of lung parenchyma anatomical modification is useful to estimate dose discrepancies during the radiation treatment of Non-Small-Cell Lung Cancer (NSCLC) patients. We propose and validate a method, based on free-form deformation and mutual information, to elastically register planning kVCT with daily MVCT images, to estimate lung parenchyma modification during Tomotherapy. METHODS: We analyzed 15 registrations between the planning kVCT and 3 MVCT images for each of the 5 NSCLC patients. Image registration accuracy was evaluated by visual inspection and, quantitatively, by Correlation Coefficients (CC) and Target Registration Errors (TRE). Finally, a lung volume correspondence analysis was performed to specifically evaluate registration accuracy in lungs. RESULTS: Results showed that elastic registration was always satisfactory, both qualitatively and quantitatively: TRE after elastic registration (average value of 3.6 mm) remained comparable and often smaller than voxel resolution. Lung volume variations were well estimated by elastic registration (average volume and centroid errors of 1.78% and 0.87 mm, respectively). CONCLUSIONS: Our results demonstrate that this method is able to estimate lung deformations in thorax MVCT, with an accuracy within 3.6 mm comparable or smaller than the voxel dimension of the kVCT and MVCT images. It could be used to estimate lung parenchyma dose variations in thoracic Tomotherapy.

We developed an efficient technique to auto-propagate parotid gland contours from planning kVCT to daily MVCT images of head-and-neck cancer patients treated with helical tomotherapy. The method deformed a 3D surface mesh constructed from manual kVCT contours by B-spline free-form deformation to generate optimal and smooth contours. Deformation was calculated by elastic image registration between kVCT and MVCT images. Data from ten head-and-neck cancer patients were considered and manual contours by three observers were included in both kVCT and MVCT images. A preliminary inter-observer variability analysis demonstrated the importance of contour propagation in tomotherapy application: a high variability was reported in MVCT parotid volume estimation (p = 0.0176, ANOVA test) and a larger uncertainty of MVCT contouring compared with kVCT was demonstrated by DICE and volume variability indices (Wilcoxon signed rank test, p < 10-4 for both indices). The performance analysis of our method showed no significant differences between automatic and manual contours in terms of volumes (p > 0.05, in a multiple comparison Tukey test), center-of-mass distances (p = 0.3043, ANOVA test), DICE values (p = 0.1672, Wilcoxon signed rank test) and average and maximum symmetric distances (p = 0.2043, p = 0.8228 Wilcoxon signed rank tests). Results suggested that our contour propagation method could successfully substitute human contouring on MVCT images.

The Jacobian of the deformation field of elastic registration between images taken during radiotherapy is a measure of inter-fraction local deformation. The histogram of the Jacobian values (Jac) within an organ was introduced (JVH-Jacobian-volume-histogram) and first applied in quantifying parotid shrinkage. MVCTs of 32 patients previously treated with helical tomotherapy for head-neck cancers were collected. Parotid deformation was evaluated through elastic registration between MVCTs taken at the first and last fractions. Jac was calculated for each voxel of all parotids, and integral JVHs were calculated for each parotid; the correlation between the JVH and the planning dose-volume histogram (DVH) was investigated. On average, 82% (±17%) of the voxels shrinks (Jac < 1) and 14% (±17%) shows a local compression >50% (Jac < 0.5). The best correlation between the DVH and the JVH was found between V10 and V15, and Jac < 0.4-0.6 (p < 0.01). The best constraint predicting a higher number of largely compressing voxels (Jac0.5

PURPOSE/OBJECTIVE: Whole pelvis irradiation with IMRT (WPRT-IMRT) after prostatectomy is efficient in reducing acute toxicity: however, a number of patients still experience moderate acute bowel toxicity. MATERIALS AND METHODS: Ninety-six patients treated with WPRT-IMRT after prostatectomy with adjuvant or salvage intent were analysed. A number of parameters were individually recovered, including the DVHs of the intestinal cavity outside PTV and of the loops referred to both the WPRT phase and the whole treatment. Correlation between clinical-dosimetric parameters and acute bowel toxicity was investigated by logistic analyses. Best predictive cut-off values for continuous variables were assessed by ROC curves. RESULTS: 15/96 (15.6%) Patients experienced grade 2 toxicity (no grade 3). Best dose-volume predictors were the fraction of loops receiving more than 45, 50 and 55Gy (respectively, V45TL50cc, V50TL13cc, V55TL3cc; p-values ranging from 0.005 to 0.027). Age, GU acute toxicity, rectal acute toxicity and time between prostatectomy and IMRT were also predictors of acute bowel toxicity. Multivariate analysis showed that the most predictive independent parameters were age (OR: 1.13; 95%CI: 1.02-1.25; p=0.021) and V50TL (13cc, OR: 8.2; 95%CI: 1.7-40; p=0.009). CONCLUSIONS: The risk of moderate acute uGI toxicity during WPRT-IMRT for post-operatively treated patients increases with age; the risk is substantially reduced in patients with small overlap between PTV and loops.

Purpose. To find correlation between dose-volume histograms (DVHs) of the intestinal cavity (IC) and moderate-severe acute bowel toxicity in men with prostate cancer treated with pelvic nodal irradiation. Methods and Materials. The study group consisted of 191 patients with localized prostate cancer who underwent whole-pelvis radiotherapy with radical or adjuvant/salvage intent during January 2004 to November 2007. Complete planning/clinical data were available in 175 of these men, 91 of whom were treated with a conventional four-field technique (50.4 Gy, 1.8 Gy/fraction) and 84 of whom were treated with IMRT using conventional Linac (n = 26, 50.4 Gy, 1.8 Gy/fraction) or Helical TomoTherapy (n = 58, 50–54 Gy, 1.8–2 Gy/fraction). The IC outside the planning target volume (PTV) was contoured and the DVH for the first 6 weeks of treatment was recovered in all patients. The correlation between a number of clinical and DVH (V10–V55) variables and toxicity was investigated in univariate and multivariate analyses. The correlation between DVHs for the IC outside the PTV and DVHs for the whole IC was also assessed. Results. Twenty-two patients experienced toxicity (3/22 in the IMRT/tomotherapy group). Univariate analyses showed a significant correlation between V20–V50 and toxicity (p = 0.0002–0.001), with a higher predictive value observed for V40–V50. Previous prostatectomy (p = 0.066) and abdominal/pelvic surgery (p = 0.12) also correlated with toxicity. Multivariate analysis that included V45, abdominal/pelvic surgery, and prostatectomy showed that the most predictive parameters were V45 (p = 0.002) and abdominal/pelvic surgery (p = 0.05, HR = 2.4) Conclusions. Our avoidance IMRT approach drastically reduces the incidence of acute bowel toxicity. V40–V50 of IC and, secondarily, previous abdominal/pelvic surgery were the main predictors of acute bowel toxicity.

PURPOSE: To report planning and acute toxicity data of the first 60 patients treated within a Phase I-II study with moderate hypofractionation by image-guided helical tomotherapy. METHODS AND MATERIALS: Various clinical target volumes (CTVs) were defined: CTV1-pelvic nodes; CTV2-upper portion of seminal vesicles; CTV3-lower portion of SV; CTV4-prostate; overlap between planning target volume (PTV) 4 and rectum. Different doses to each PTV were simultaneously delivered in 28 fractions. For 31 low-risk patients: 56.0, 61.6, and 71.4 Gy for PTV2-4, respectively; for 20 intermediate-risk patients: 51.8, 61.6, 65.5, and 74.2 Gy for PTV1-4, respectively; for 9 high-risk patients: 51.8 and 65.5 Gy for PTV1-2 and 74.2 Gy for PTV3-4. For all patients, the dose to overlap was 65.5 Gy. RESULTS: The mean fraction of rectum receiving more than 65 Gy (V65) and rectal Dmax were 10% and 70.8 Gy respectively. In cases of pelvic node irradiation, the intestinal cavity (outside PTV) receiving > 45 and 50 Gy was 86 and 12 cc, respectively. A homogeneous dose distribution within each PTV was guaranteed. Acute genitourinary toxicity according to RTOG scoring system was as follows: 21/60 (35%) Grade 1, 12/60 (20%) Grade 2, 2/60 (3%) Grade 3. Acute rectal toxicities were: 18/60 (30%) Grade 1. Twelve (20%) patients showed Grade 1 upper intestinal toxicity (uGI). No patients experienced >/= Grade 2 acute rectal or uGI side effects. CONCLUSIONS: This study shows excellent results with regard to acute toxicity. Further research is necessary to assess definitive late toxicity and tumor control outcome.

Primary cutaneous mucinous carcinomas originating from sweat glands are rare tumors with patterns of spread that are difficult to predict. We present a case of a five times recurring eccrine mucinous adenocarcinoma of the scalp, previously treated with surgery and adjuvant radiation therapy. After magnetic resonance imaging (MRI) and 18F-fluoro-2-deoxyglucose positron-emission tomography/computed tomography (18FDG-PET/CT), which documented local recurrence, the patient was considered eligible for salvage irradiation of the scalp. We decided to use helical tomotherapy, which combines conformity of dose delivery with the possibility of daily control of the setup accuracy. Forty gray (2Gy/fraction) to the planning target volume and 50 Gy (2.5Gy/fraction) to the biological target volume defined on the basis of 18FDG-PET/CT was prescribed with a simultaneous integrated boost technique. After 12 fractions the patient was submitted to intermediate evaluation by 18FDG-PET/CT, which showed a partial response to the treatment. After 2, 4, 8, and 12 months, 18FDG-PET/CT showed a complete metabolic local response. This experience suggests a possible role of 18FDG-PET/CT-guided helical tomotherapy as an alternative to repeated and frequently demolitive surgery approaches.

PURPOSE: To compare intensity-modulated proton therapy (IMPT) and helical tomotherapy (HT) treatment plans for nasopharynx cancer using a simultaneous integrated boost approach. METHODS AND MATERIALS: The data from 6 patients who had previously been treated with HT were used. A three-beam IMPT technique was optimized in the Hyperion treatment planning system, simulating a "beam scanning" technique. HT was planned using the tomotherapy treatment planning system. Both techniques were optimized to simultaneously deliver 66 Gy in 30 fractions to planning target volume (PTV1; GTV and enlarged nodes) and 54 Gy to PTV2 subclinical, electively treated nodes. Normal tissue complication probability calculation was performed for the parotids and larynx. RESULTS: Very similar PTVs coverage and homogeneity of the target dose distribution for IMPT and HT were found. The conformity index was significantly lower for protons than for photons (1.19 vs. 1.42, respectively). The mean dose to the ipsilateral and contralateral parotid glands decreased by 6.4 Gy and 5.6 Gy, respectively, with IMPT. The volume of mucosa and esophagus receiving >/=20 Gy and >/=30 Gy with IMPT was significantly lower than with HT. The average volume of larynx receiving >/=50 Gy was significantly lower with HT, while for thyroid, it was comparable. The volume receiving >/=30, >/=20, and >/=10 Gy in total body volume decreased with IMPT by 14.5%, 19.4%, and 23.1%, respectively. The normal tissue complication probability for the parotid glands was significantly lower with IMPT for all sets of parameters; however, we also estimated an almost full recovery of the contralateral parotid with HT. The normal tissue complication probability for the larynx was not significantly different between the two irradiation techniques. CONCLUSION: Excellent target coverage, homogeneity within the PTVs, and sparing of the organs at risk were reached with both modalities. IMPT allows for better sparing of most organs at risk at medium-to-low doses.

BACKGROUND AND PURPOSE: Image-guided helical tomotherapy (HT) is a new modality for delivering intensity modulated radiation therapy (IMRT) with helical irradiation: the slip ring continuously rotates while the couch moves into the bore. The radiation source (Linac, 6MV) is collimated into a fan beam and modulated by means of a binary multileaf collimator (MLC). A xenon detector array, opposite the radiation source, allows a megavoltage-CT (MVCT) acquisition of patient images for set-up verification. The aim of this paper is to report the results of a two-year quality control (QC) program for the physical and dosimetric characterization of an HT unit installed at our Institute and clinically activated in November 2004, in order to monitor and verify the stability and the reliability of this promising radiation treatment unit. MATERIALS AND METHODS: Conventional Linac acceptance protocols (ATP) and QC protocols were adapted to HT with the addition of specific items reflecting important differences between the two irradiation modalities. QC tests can be summarized as: (a) mechanical and geometrical characterization of the system's components: evaluation of alignment among radiation source-gantry rotation plan-jaws-MLC-MVCT; (b) treatment beam configuration in static condition: depth dose curves (PDD) and profiles, output factors, output reproducibility and linearity; (c) dynamic component characterization: accuracy and reproducibility of MLC positioning; rotational output reproducibility and linearity, leaf latency, couch movement constancy; (d) gantry-couch and MLC-gantry synchronization; and (e) MVCT image quality. Peculiar periodicity specific tolerance and action levels were defined. Ionization chambers (Exradin A1SL 0.056cc), films (XOmat-V/EDR2), water and solid water phantoms were used to perform quality assurance measurements. RESULTS: Over a two-year period the final average output variation after possible beam output adjustment was -0.2+/-1% for the static condition and equal to 0+/-1% for the rotational condition: around 98% of the collected output data was within the action level compared to 94% if no beam output adjustment was considered. An average energy variation of -0.4+/-0.4% was found. The daily absolute dose verification of IMRT plans showed a dose reproducibility of -0.5+/-1.2% and -0.4+/-2.2%, for low and high dose gradient regions, respectively. Source-jaws-MLC and MVCT alignment results and jaw and leaf positioning accuracy were +/-1mm. Couch-gantry-MLC synchrony tests showed good stability level (+/-2mm). CONCLUSIONS: QC results indicated good reproducibility of all HT mechanical-dosimetric performance.

PURPOSE: To report on planning and toxicity findings of hypofractionated adjuvant radiotherapy with helical Tomotherapy (HTT) after radical prostatectomy (RP) for prostate carcinoma (pCa). METHODS AND MATERIALS: Fifty consecutive patients submitted to RP for pT2R1/pT3a/pT3b-pN0 pCa were enrolled in a Phase I-II trial to receive 58Gy/20 fractions (5/week) on tumoral bed. Endpoint was to verify a risk of toxicity and biochemical failure not exceeding that observed in our Institutional 3DCRT, conventionally fractionated series (153 patients). Toxicities were graded according the RTOG scoring system. RESULTS: Excellent coverage of PTV and high homogeneity of dose distribution were always achieved. Median follow-up was 25 months. Acute G2-3 RTOG genitourinary (GU) and acute G2 intestinal toxicities were similar (12% vs 15.6% and 4% vs 7%, respectively), while acute G2 proctitis was 0% vs 9% in HTT and 3DCRT group, respectively. Similarly, late Grade 2 gastrointestinal sequelae were 0% vs 8.5%. The incidence of late urethral stricture, 8% and 9% in HTT and 3DCRT group, respectively, is comparable to that of RP-only series. CONCLUSIONS: Acute toxicity and early late toxicity outcomes of a moderately hypofractionated regimen with HTT post-RP are excellent. A longer follow-up is needed to fully assess the validity of this approach.

PURPOSE: To assess setup and organ motion error by means of analysis of daily megavoltage computed tomography (MVCT) of patients treated with hypofractionated helical tomotherapy (71.4-74.2 Gy in 28 fractions). METHODS AND MATERIALS: Data from 21 patients were analyzed. Patients were instructed to empty the rectum carefully before planning CT and every morning before therapy by means of a self-applied rectal enema. The position of the prostate was assessed by means of automatic bone matching (BM) with the planning kilovoltage CT (BM, setup error) followed by a direct visualization (DV) match on the prostate. Deviations between planning and therapy positions referred to BM and BM + DV were registered for the three main axes. In case of a full rectum at MVCT with evident shift of the prostate, treatment was postponed until after additional rectal emptying procedures; in this case, additional MVCT was performed before delivering the treatment. Data for 522 fractions were available; the impact of post-MVCT procedure was investigated for 17 of 21 patients (410 fractions). RESULTS: Prostate motion relative to bony anatomy was limited. Concerning posterior-anterior shifts, only 4.9% and 2.7% of fractions showed deviation of 3 mm or greater of the prostate relative to BM without and with consideration of post-MVCT procedures, respectively. Interobserver variability for BM + DV match was within 0.8 mm (1 SD). CONCLUSIONS: Daily MVCT-based correction is feasible. The BM + DV matching was found to be consistent between operators. Rectal emptying using a daily enema is an efficient tool to minimize prostate motion, even for centers that have not yet implemented image-guided radiotherapy.