| Reference | 1. PLoS One. 2018 Dec 20;13(12):e0209613. doi: 10.1371/journal.pone.0209613.
eCollection 2018.
<br>
Uptake in non-affected bone tissue does not differ between [18F]-DCFPyL and
[68Ga]-HBED-CC PSMA PET/CT.
<br>
Hammes J(1), Hohberg M(1), Täger P(1), Wild M(1), Zlatopolskiy B(2), Krapf P(3),
Neumaier B(2)(3), Schomäcker K(1), Kobe C(1), Schmidt M(1), Dietlein M(1),
Drzezga A(1).
<br>
Author information: <br>
(1)Department of Nuclear Medicine, University Hospital of Cologne, Cologne,
Germany.
(2)Institute of Radiochemistry and Experimental Molecular Imaging, University
Hospital of Cologne, Cologne, Germany.
(3)Institute of Neuroscience and Medicine-5 (Nuclear Chemistry), Research Center
Jülich, Jülich, Germany.
<br>
INTRODUCTION: [68Ga]PSMA-HBED-CC and [18F]DCFPyL show a high potential for the
detection of recurrent prostate cancer. While 18F-based tracers have several
advantages in availability and image resolution, their sensitivity in the
skeleton might be impaired by released [18F]fluoride due to its high bone
affinity. In turn, chemically unbound trivalent 68Ga might also accumulate in
osseous tissue, in cases of occupied binding sites of plasma proteins and thereby
influence bone signal.
METHODS: A comparison of average bone SUV was performed in 17 bone-negative and 4
bone-positive patients. All patients underwent PET/CT 125 minutes after
application of [18F]DCFPyL and 73 minutes after application of [68Ga]PSMA-HBED-CC
at another date.
RESULTS: Native SUVs in unaffected bone tissue and SUVs relative to liver uptake
were lower in [18F]DCFPyL (0.49) than in [68Ga]PSMA-HBED-CC scans (0.52). SUVs
relative to gluteal muscles did not differ between the two tracers. Average
lesional SUVs did not differ between tracers.
CONCLUSION: No difference of average bone signal intensity was observed for
[18F]DCFPyL-PET/CT in comparison to [68Ga]PSMA-HBED-CC scans indicating that
diagnostic assessment of the skeleton is not affected by non-specific
accumulation of free [18F]fluoride or 68Ga.
<br><br>
2. Indian J Nucl Med. 2018 Jul-Sep;33(3):202-208. doi: 10.4103/ijnm.IJNM_32_18.
<br>
Can Early Dynamic Positron Emission Tomography/Computed Tomography Obviate the
Need for Postdiuresis Image in 68Ga-PSMA-HBED-CC Scan for Evaluation of Prostate
Adenocarcinoma?
<br>
Perveen G(1), Arora G(1), Damle NA(1), Prabhu M(1), Arora S(1), Tripathi M(1),
Bal C(1), Kumar P(1), Kumar R(1), Singh P(2), Das CJ(3), Passah A(1).
<br>
Author information: <br>
(1)Department of Nuclear Medicine, AIIMS, New Delhi, India.
(2)Department of Urology, AIIMS, New Delhi, India.
(3)Department of Radiodiagnosis, AIIMS, New Delhi, India.
<br>
Introduction: Forced diuresis technique is often adopted to wash out the high
amount of urinary radioactivity that masks the foci of abnormal uptake in the
pelvic region on 68Ga-PSMA-HBED-CC positron emission tomography/computed
tomography (PET/CT) scan in prostate cancer (PC) patients. However, this method
is time-consuming, makes the patient non/less compliant, and is not feasible in
patients with renal dysfunction. We hypothesized that early dynamic imaging can
obviate the need for a postdiuresis view as the urinary activity is expected to
be low at the time.<br>
Materials and Methods: A total of 20 biopsy-proven PC patients who were referred
to our department for a 68Ga-PSMA PET/CT for staging/restaging were prospectively
studied. Dynamic PET/CT was done with on table intravenous (i.v.) injection of
2-3 mCi (74-111 MBq) of the radiotracer. Dynamic images were acquired over the
pelvis with a frame time of 1 min for 10 min. Static images of 2 min/bed position
were acquired between 45 and 60 min p.i. The patients were then administered i.v.
furosemide and encouraged water intake and frequent urination. A static view of
pelvic region was acquired at 5 min/bed at 120 min p.i. A three-dimensional
volume of interest (3D-VOI) was plotted on the primary lesion, bladder, involved
nodes if any, pelvic bones at involved and uninvolved sites, gluteal muscles, and
artery. The sentence seems fine. This was to generate the Time activity curve for
analysis.<br>
Results: Nine patients were referred for staging and 11 for restaging. Mean age
of 20 patients was 64.6 years, and median prostate-specific antigen level was
21.4 ng/ml (range: 0.05-2180). Prostatic lesion was present in 20 patients, nodal
involvement in 8, and bone involvement in 10 patients. Median maximum
standardized uptake value (SUVmax) of the prostatic lesion (P) showed an
ascending trend: 5.31 at 5 min, 10.65 at 60 min, and 10.52 at 120 min p.i. At the
same time, median SUVmax of the bladder (B) also progressed steeply and then
decreased postdiuresis: 1.01 at 5 min, 24.6 at 60 min, and 6.88 at 120 min.
Despite forced diuresis, the bladder activity remained higher than that during
early dynamic imaging. Median prostate-to-bladder (P/B) ratio was highest during
early dynamic imaging at 5 min p.i. was 5.17, while at 60 min, P/B ratio was 0.42
(P = 0.002) and, at 120 min, it was 1.27 (P = 0.009). Further, all the nodal and
bone lesions were clearly visualized on early dynamic images.
Conclusion: The study results suggest that early dynamic imaging performs better
than a postdiuresis view in terms of delineation of prostatic and regional
lesions on 68Ga-PSMA scan. Further, it saves time and the patients are more
compliant to this technique.
<br><br>
3. Radiat Oncol. 2018 May 2;13(1):81. doi: 10.1186/s13014-018-1036-8.
<br>
Focal dose escalation for prostate cancer using 68Ga-HBED-CC PSMA PET/CT and MRI:
a planning study based on histology reference.
<br>
Zamboglou C(1)(2)(3), Thomann B(4)(5), Koubar K(4)(5), Bronsert P(6)(5), Krauss
T(7)(5), Rischke HC(8)(5), Sachpazidis I(4)(5), Drendel V(6)(5), Salman N(8)(5),
Reichel K(9)(5), Jilg CA(9)(5), Werner M(6)(5), Meyer PT(10)(5), Bock M(11)(5),
Baltas D(4)(5), Grosu AL(8)(5).
<br>
Author information: <br>
(1)Department of Radiation Oncology, Medical Center – University of Freiburg,
Faculty of Medicine, Robert-Koch Straße 3, 79106, Freiburg, Germany.
[email protected].
(2)German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany.
[email protected].
(3)Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg,
Freiburg, Germany. [email protected].
(4)Division of Medical Physics, Department of Radiation Oncology, Medical Center
– University of Freiburg, Faculty of Medicine, Freiburg, Germany.
(5)German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany.
(6)Department of Pathology, Medical Center – University of Freiburg, Faculty of
Medicine, Freiburg, Germany.
(7)Department of Radiology, Medical Center – University of Freiburg, Faculty of
Medicine, Freiburg, Germany.
(8)Department of Radiation Oncology, Medical Center – University of Freiburg,
Faculty of Medicine, Robert-Koch Straße 3, 79106, Freiburg, Germany.
(9)Department of Urology, Medical Center – University of Freiburg, Faculty of
Medicine, Freiburg, Germany.
(10)Department of Nuclear Medicine, Medical Center – University of Freiburg,
Faculty of Medicine, Freiburg, Germany.
(11)Division of Medical Physics, Department of Radiology, Medical Center –
University of Freiburg, Faculty of Medicine, Freiburg, Germany.
<br>
BACKGROUND: Focal radiation therapy has gained of interest in treatment of
patients with primary prostate cancer (PCa). The question of how to define the
intraprostatic boost volume is still open. Previous studies showed that
multiparametric MRI (mpMRI) or PSMA PET alone could be used for boost volume
definition. However, other studies proposed that the combined usage of both has
the highest sensitivity in detection of intraprostatic lesions. The aim of this
study was to demonstrate the feasibility and to evaluate the tumour control
probability (TCP) and normal tissue complication probability (NTCP) of radiation
therapy dose painting using 68Ga-HBED-CC PSMA PET/CT, mpMRI or the combination of
both in primary PCa.<br>
METHODS: Ten patients underwent PSMA PET/CT and mpMRI followed by prostatectomy.
Three gross tumour volumes (GTVs) were created based on PET (GTV-PET), mpMRI
(GTV-MRI) and the union of both (GTV-union). Two plans were generated for each
GTV. Plan95 consisted of whole-prostate IMRT to 77 Gy in 35 fractions and a
simultaneous boost to 95 Gy (Plan95PET/Plan95MRI/Plan95union). Plan80 consisted
of whole-prostate IMRT to 76 Gy in 38 fractions and a simultaneous boost to 80 Gy
(Plan80PET/Plan80MRI/Plan80union). TCPs were calculated for GTV-histo
(TCP-histo), which was delineated based on PCa distribution in co-registered
histology slices. NTCPs were assessed for bladder and rectum.
RESULTS: Dose constraints of published protocols were reached in every treatment
plan. Mean TCP-histo were 99.7% (range: 97%-100%) and 75.5% (range: 33%-95%) for
Plan95union and Plan80union, respectively. Plan95union had significantly higher
TCP-histo values than Plan95MRI (p = 0.008) and Plan95PET (p = 0.008).
Plan80union had significantly higher TCP-histo values than Plan80MRI (p = 0.012),
but not than Plan80PET (p = 0.472). Plan95MRI had significantly lower NTCP-rectum
than Plan95union (p = 0.012). No significant differences in NTCP-rectum and
NTCP-bladder were observed for all other plans (p > 0.05).
CONCLUSIONS: IMRT dose escalation on GTVs based on mpMRI, PSMA PET/CT and the
combination of both was feasible. Boosting GTV-union resulted in significantly
higher TCP-histo with no or minimal increase of NTCPs compared to the other
plans.<br>
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