Carbon-11 acetate PET/CT based dose escalated IMRT in prostate cancer (original) (raw)
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International Journal of Radiation Oncology*Biology*Physics, 2012
After the embargo period via non-commercial hosting platforms such as their institutional repository via commercial sites with which Elsevier has an agreement In all cases accepted manuscripts should: link to the formal publication via its DOI bear a CC-BY-NC-ND licensethis is easy to do, click here to find out how if aggregated with other manuscripts, for example in a repository or other site, be shared in alignment with our hosting policy not be added to or enhanced in any way to appear more like, or to substitute for, the published journal article SUMMARY 11 C-choline PET scans can be used to identify foci of cancer within the prostate. A planning study on eight patients with localized prostate cancer compared the use of 11 C-choline PET-guided IMRT dose painting to 90 Gy with standard radiotherapy to 78 Gy in terms of technical feasibility and biological modeling. IMRT dose painting using 11 C-choline PET is technically feasible, results in higher tumor control probability, and does not raise the rectal normal tissue complication probability. Chang 5 ABSTRACT Purpose: To demonstrate the technical feasibility of IMRT dose painting using 11 Ccholine PET scans in patients with localized prostate cancer. Methods and materials: This was a radiotherapy planning study of eight patients with prostate cancer who had 11 C-choline PET scans prior to radical prostatectomy. Two contours were semi-automatically generated on the basis of the PET scans for each patient: 60% and 70% of the maximum standardized uptake values (SUV60% and SUV70%). Three IMRT plans were generated for each patient: PLAN78 which consisted of whole prostate radiotherapy to 78 Gy; PLAN78-90 which consisted of whole prostate radiotherapy to 78 Gy, a boost to the SUV60% to 84 Gy and a further boost to the SUV70% to 90 Gy; and PLAN72-90 which consisted of whole prostate radiotherapy to 72 Gy, a boost to the SUV60% to 84 Gy and a further boost to the SUV70% to 90 Gy. The feasibility of these plans was judged by their ability to reach prescription doses while adhering to published dose constraints. Tumor control probabilities based on PET scan-defined volumes (TCPPET) and on prostatectomydefined volumes (TCPpath), and rectal normal tissue complication probabilities (NTCP) were compared between the plans. Results: All plans for all patients reached prescription doses while adhering to dose constraints. The TCPPET values for PLAN78, PLAN78-90 and PLAN72-90 were 65%, 97% and 96%, respectively. The TCPpath values were 71%, 97% and 89%, respectively. Both PLAN78-90 and PLAN72-90 had significantly higher TCPPET (p = 0.002 and 0.001) and TCPpath (p < 0.001 and 0.014) than PLAN78. PLAN78-90 and Chang 6
Radiation Oncology, 2012
Background: In comparison to the conventional whole-prostate dose escalation, an integrated boost to the macroscopic malignant lesion might potentially improve tumor control rates without increasing toxicity. Quality of life after radiotherapy (RT) with vs. without 18 F-choline PET-CT detected simultaneous integrated boost (SIB) was prospectively evaluated in this study. Methods: Whole body image acquisition in supine patient position followed 1 h after injection of 178-355MBq 18 F-choline. SIB was defined by a tumor-to-background uptake value ratio > 2 (GTV PET ). A dose of 76Gy was prescribed to the prostate (PTV prostate ) in 2Gy fractions, with or without SIB up to 80Gy. Patients treated with (n = 46) vs. without (n = 21) SIB were surveyed prospectively before (A), at the last day of RT (B) and a median time of two (C) and 19 month (D) after RT to compare QoL changes applying a validated questionnaire (EPICexpanded prostate cancer index composite). Results: With a median cut-off standard uptake value (SUV) of 3, a median GTV PET of 4.0 cm 3 and PTV boost (GTV PET with margins) of 17.3 cm 3 was defined. No significant differences were found for patients treated with vs. without SIB regarding urinary and bowel QoL changes at times B, C and D (mean differences ≤3 points for all comparisons). Significantly decreasing acute urinary and bowel score changes (mean changes > 5 points in comparison to baseline level at time A) were found for patients with and without SIB. However, long-term urinary and bowel QoL (time D) did not differ relative to baseline levels -with mean urinary and bowel function score changes < 3 points in both groups (median changes = 0 points). Only sexual function scores decreased significantly (> 5 points) at time D. Conclusions: Treatment planning with 18 F-choline PET-CT allows a dose escalation to a macroscopic intraprostatic lesion without significantly increasing toxicity.
Clinical Nuclear Medicine, 2015
Introduction: Aim of the study is to evaluate the impact of Cho-PET/CT in decision-making strategy of patients with localized prostate cancer (PC) eligible to definitive radiotherapy (RT). Materials and Methods: Sixty patients Cho-PET/CT before RT were prospectively enrolled. All patients were treated with volumetric modulated arc therapy with simultaneous integrated boost in 28 fractions. Androgen deprivation therapy was prescribed according to National Comprehensive Cancer Network (NCCN) risk classification. Therapeutic strategy based on the Cho-PET/CT evaluation was compared with the strategy that would have been proposed in case of PET not available and/or not strictly indicated, according to international and national PC guidelines. Results: Cho-PET/CT was positive in 57 cases (95%): T in 45 (79%); T in combination with N in 8 (14%); and M (bone) in combination with T or N, or both, in 4 (7%). After Cho-PET/CT, patients were stratified as follows: 26 (43%) low risk, 10 (16%) intermediate risk, and 24 (41%) high risk. Cho-PET/CT shifted treatment indication in 13 cases (21%). The changes regarding radiation treatment volumes were as follows: 6 intermediate risk (10%) shifted to high risk and consequently were irradiated on prostate, seminal vesicles, and pelvic nodes PTVs; in 7 high risk (11%), the Cho-PET/CT showed bone and/or N uptake, and consequently, a simultaneous integrated boost on PET positive sites was prescribed. Conclusions: Cho-PET/CT seems to be a promising diagnostic tool in patients who are candidates for radical RT and supporting the decision making in treatment planning, in particular in intermediate-high risk.
Abstract Introduction Intensity-Modulated Radiotherapy (IMRT) is becoming an increasingly routine treatment method. IMRT can be delivered by use of conventional Multileaf Collimators (MLCs) and/or physical compensators. One of the most important factors in selecting an appropriate IMRT technique is integral dose. Integral dose is equal to the mean energy deposited in the total irradiated volume of the patient. The aim of the present study was to calculate and compare the integral dose in normal and target organs in two different procedures of IMRT: Step-and-Shoot (SAS) and compensator-based IMRT. Materials and Methods In this comparative study, five patients with prostate cancer were selected. Module Integrated Radiotherapy System was applied, using three energy ranges. In both treatment planning methods, the integral dose dramatically decreased by increasing energy. Results Comparison of two treatment methods showed that on average, the integral dose of body in SAS radiation therapy was about 1.62% lower than that reported in compensator-based IMRT. In planning target volume, rectum, bladder, and left and right femoral heads, the integral doses for SAS method were 1.01%, 1.02%, 1.11%, 1.47%, and 1.40% lower than compensator-based IMRT, respectively. Conclusion Considering the treatment conditions, the definition of dose volume constraints for healthy tissues, and the equal volume of organs in both treatment methods, SAS radiation therapy by providing a lower integral dose seems to be more advantageous and efficient for prostate cancer treatment, compared to compensator-based IMRT.
The aim of radiation therapy treatment planning is to achieve an optimal balance between delivering a high dose to target volume and a low dose to healthy tissues. The integral dose, conformity and homogeneity indexes, hence, are the important guidance for predicting the radiation effects and choosing the optimal treatment plan. The goal of this study is to compare and investigate the aforementioned parameters in 3DCRT vs. IMRT plan. In order to evaluate dosimetric parameters, data from five patients with prostate cancer, planned by IMRT and 3DCRT were obtained. Prescribed doses for IMRT procedure and 3DCRT were 80Gy and 70 Gy, respectively. Also, the target coverage was achieved with 95% of the prescribed dose to 95% of the PTV in 3DCRT and 95% of the prescribed dose to 98% of the PTV in IMRT method. A total of thirty IMRT and 3DCRT plans were performed for evaluation of dosimetric parameters (for each patient both treatment plans, step and shoot IMRT and 3DCRT with 6, 10 and 18MV energies) were done. The integral dose was calculated as the mean- dose times the volume of the structure. The mean integral dose (ID) received by rectum for 3DCRT was almost 1.01% greater than IMRT while in bladder mean value of ID for IMRT was approximately 1.68% higher than 3DCRT. For PTV in IMRT the ID of target volume had the biggest value (1.14%) compared to that of 3DCRT. Dose conformity in PTV volume in S.A.S and 3DCRT was almost equal. The same outcome was achieved in homogeneity index. The results of this study shows that IMRT method leads to adequate target dose coverage while the prescribed dose for this modality is higher than 3DCRT. IMRT has the ability of increasing the maximum dose to tumor region and improves conformity and homogeneity indexes in target volume and also reduces dose to OAR.
Planning of External Beam Radiotherapy for Prostate Cancer Guided by PET/CT
Current radiopharmaceuticals, 2015
In this paper, we give an overview of articles on non-choline tracers for PET/CT for patients with prostate cancer and planning of radiotherapy guided by PET/CT. Nineteen articles described <sup>11</sup>C-Acetate PET/CT. Of 629 patients 483 (77%, 95% CI 74% - 80%) had positive <sup>11</sup>C-Acetate PET/CT scans. Five articles described <sup>18</sup>F-FACBC PET/CT. Of 174 patients 127 (73%, 95% CI 68% - 78%) had positive scans. Both tracers detected local lesions, lesions in regional lymph nodes, and distant organs. Ten articles described <sup>18</sup>F-NaF PET/CT and found that 1289 of 3918 patients (33%) had positive reactive lesions in bones. PET/CT scan can guide external beam radiotherapy (EBRT) planning for patients with loco-regional prostate cancer. In six studies with 178 patients with localized prostate cancer, PET/CT pointed out dominant intraprostatic lesions (DIL). Oncologists gave the patients EBRT to the whole prostate a...
Current Radiopharmaceuticals, 2015
Molecular imaging is the only way of defining biological target volume (BTV) for externalbeam radiation therapy (EBRT) and may be used for advanced targeting in dose planning and dose painting. There are, however, no reports about the EBRT response when dose planning is based on BTV target definition in advanced prostate cancer. Clinical and biochemical results of two clinically equal group of patients with advanced prostate cancer patients were compared. Both groups were treated with volumetric modulated arc therapy (VMAT) based on target definition by PET/CT (1 st group) or conventional imaging (2 nd group). Biochemical relapse occurred in 16.6% (in 1 out of 6) of the patients in the first group and 50% (3 out of 6) patients in the second group during the follow up period. Clinical manifestation of disease occurred in 33% (2 out of 6) patients of the first group and in 5 out of 6 (83,3%) patients in the second one. 4 patients in the first group had no biochemical relapse and no clinical manifestation during the follow up period. The difference in the duration of progression free period was statistically significant between the groups (p<0.010) being in the first group 16.5±5.4 (10-24) months and 4.6±2.9 (2-10) months in the second one. Because patients with PET/CT based VMAT had lower incidence of biochemical relapse, less clinical manifestations and longer, statistically significant duration of progression free period as compared to patients treated with VMAT based on conventional imaging, our preliminary results suggest introducing BTV definition based on PET imaging for VMAT in the EBRT of prostate cancer.